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Petrovic A, Aigner CS, Rund A, Stollberger R. A time domain signal equation for multi-echo spin-echo sequences with arbitrary excitation and refocusing angle and phase. J Magn Reson 2019; 309:106515. [PMID: 31648131 DOI: 10.1016/j.jmr.2019.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 05/13/2023]
Abstract
Accurate T2 mapping using multi-echo spin-echo is usually impaired by non-ideal refocusing due to B1+ inhomogeneities and slice profile effects. Incomplete refocusing gives rise to stimulated echo and so called "T1-mixing" and consequently a non-exponential signal decay. Here we present a time domain formula that incorporates all relaxation and pulse parameters and enables accurate and realistic modelling of the magnetization decay curve. By pulse parameters here we specifically mean the actual refocusing angle and axis, and phase angle of both the excitation and refocusing pulse. The method used for derivation comprises the so called Generating functions approach with subsequent back-transformation to the time domain. The proposed approach was validated by simulations using realistic RF pulse shapes as well as by comparison to phantom measurements. Excellent agreement between simulations and measurements underpin the validity of the presented approach. Conclusively, we here present a complete time domain formula ready to use for accurate T2 mapping with multi-echo spin-echo sequences.
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Affiliation(s)
- Andreas Petrovic
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria.
| | - Christoph Stefan Aigner
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria
| | - Armin Rund
- Institute for Mathematics and Scientific Computing, University of Graz, Heinrichstrasse 36, 8010 Graz, Austria
| | - Rudolf Stollberger
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria; BioTechMed-Graz, Austria
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Kruk D, Masiewicz E, Umut E, Petrovic A, Kargl R, Scharfetter H. Estimation of the magnitude of quadrupole relaxation enhancement in the context of magnetic resonance imaging contrast. J Chem Phys 2019; 150:184306. [DOI: 10.1063/1.5082177] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Danuta Kruk
- Faculty of Mathematics and Computer Science, University of Warmia and Mazury in Olsztyn, Słoneczna 54, 10-710 Olsztyn, Poland
| | - Elzbieta Masiewicz
- Faculty of Mathematics and Computer Science, University of Warmia and Mazury in Olsztyn, Słoneczna 54, 10-710 Olsztyn, Poland
| | - Evrim Umut
- Faculty of Mathematics and Computer Science, University of Warmia and Mazury in Olsztyn, Słoneczna 54, 10-710 Olsztyn, Poland
| | - Andreas Petrovic
- Institute for Chemistry and Technology of Materials, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
| | - Rupert Kargl
- Institute for Chemistry and Technology of Materials, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
- Laboratory for Characterization and Processing of Polymers (LCPP), Faculty of Mechanical Engineering, University of Maribor, Smetanova Ulica 17, 2000 Maribor, Slovenia
| | - Hermann Scharfetter
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16 / III, A-8010 Graz, Austria
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Widek T, Genet P, Merkens H, Boldt J, Petrovic A, Vallis J, Scheurer E. Dental age estimation: The chronology of mineralization and eruption of male third molars with 3T MRI. Forensic Sci Int 2019; 297:228-235. [PMID: 30831415 DOI: 10.1016/j.forsciint.2019.02.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/16/2018] [Accepted: 02/14/2019] [Indexed: 11/17/2022]
Abstract
Forensic age estimation has recently become an important topic due to a steady increase of cross border migration. Dental age assessment is one pillar of the forensic age estimation in living persons. Currently it is done by evaluating an orthopantomogram, which is generated using ionizing radiation. Nevertheless, the use of X-ray without medical indication is ethically questionable. Therefore, the aim of the study was to provide reference values for dental MRI to have an alternative radiation-free method for the assessment of dental age. In this cross-sectional study, 316 adolescent, male individuals were investigated. Two dentists evaluated the stage of mineralization and eruption of the third molars of the upper and lower jaws, according to the staging systems established by Demirjian and Olze. Following data analysis and the creation of reference tables, the likelihood ratios to be over specific age limits were calculated. In the mineralization evaluation mainly stages D-H were seen (range A-H); regarding eruption, all four stages (A-D) appeared. A significant difference between the teeth was only found for eruption stage A. However, the evaluation of participants who had all four third molars, showed partly different stages for the individual teeth as well for mineralization as for the eruption. Therefore, it seems to be important to include all available teeth in the age estimation. The likelihood ratios showed about 99% probability to be 18 years or older for stage H (mineralization), but only about 93% for stage D (eruption). In summary, it can be concluded that dental MRI holds promise as an alternative to conventional orthopantomogram based age assessment.
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Affiliation(s)
- Thomas Widek
- Ludwig Boltzmann Institute for Clinical Forensic Imaging, Universitätsplatz 4/II, 8010 Graz, Austria; Medical University of Graz, 8010 Graz, Austria; BioTechMed-Graz, Austria.
| | - Pia Genet
- University Centre of Legal Medicine Lausanne, Lausanne University Hospital, Chemin de la Vulliette 4, 1000 Lausanne 25, Switzerland; University Centre of Legal Medicine Geneva, Geneva University Hospital, Rue Michel-Servet 1, 1211 Geneva 4, Switzerland
| | - Heiko Merkens
- Ludwig Boltzmann Institute for Clinical Forensic Imaging, Universitätsplatz 4/II, 8010 Graz, Austria
| | - Julian Boldt
- Department of Prosthodontics, University of Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Andreas Petrovic
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria; BioTechMed-Graz, Austria
| | - Jacquie Vallis
- School of Health and Social Care, Teesside University, Middlesbrough, Tees Valley TS1 3BX, United Kingdom
| | - Eva Scheurer
- Ludwig Boltzmann Institute for Clinical Forensic Imaging, Universitätsplatz 4/II, 8010 Graz, Austria; Institute of Forensic Medicine, University Basel, Pestalozzistrasse 22, 4056 Basel, Switzerland
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Bödenler M, Basini M, Casula MF, Umut E, Gösweiner C, Petrovic A, Kruk D, Scharfetter H. R 1 dispersion contrast at high field with fast field-cycling MRI. J Magn Reson 2018; 290:68-75. [PMID: 29574318 DOI: 10.1016/j.jmr.2018.03.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 03/16/2018] [Accepted: 03/17/2018] [Indexed: 06/08/2023]
Abstract
Contrast agents with a strong R1 dispersion have been shown to be effective in generating target-specific contrast in MRI. The utilization of this R1 field dependence requires the adaptation of an MRI scanner for fast field-cycling (FFC). Here, we present the first implementation and validation of FFC-MRI at a clinical field strength of 3 T. A field-cycling range of ±100 mT around the nominal B0 field was realized by inserting an additional insert coil into an otherwise conventional MRI system. System validation was successfully performed with selected iron oxide magnetic nanoparticles and comparison to FFC-NMR relaxometry measurements. Furthermore, we show proof-of-principle R1 dispersion imaging and demonstrate the capability of generating R1 dispersion contrast at high field with suppressed background signal. With the presented ready-to-use hardware setup it is possible to investigate MRI contrast agents with a strong R1 dispersion at a field strength of 3 T.
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Affiliation(s)
- Markus Bödenler
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, A-8010 Graz, Austria.
| | - Martina Basini
- Physic Deppartment and INSTM, Università degli Studi di Milano, Via Celoria 16, I-20133 Milan, Italy
| | - Maria Francesca Casula
- Department of Chemical and Soil Sciences and INSTM, University of Cagliari, I-09042 Monserrato, CA, Italy
| | - Evrim Umut
- Faculty of Mathematics and Computer Science, University of Warmia and Mazury, Słoneczna 54, 10-710 Olsztyn, Poland
| | - Christian Gösweiner
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, A-8010 Graz, Austria
| | - Andreas Petrovic
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, A-8010 Graz, Austria
| | - Danuta Kruk
- Faculty of Mathematics and Computer Science, University of Warmia and Mazury, Słoneczna 54, 10-710 Olsztyn, Poland
| | - Hermann Scharfetter
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, A-8010 Graz, Austria
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Petrovic A, Konnert C. HOW DO FAMILY MEMBERS DEAL WITH CONFLICT IN LONG-TERM CARE? APPLICATION OF CONFLICT THEORY. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.3071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. Petrovic
- Psychology, University of Calgary, Calgary, Alberta, Canada
| | - C.A. Konnert
- Psychology, University of Calgary, Calgary, Alberta, Canada
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Petrovic A, Krauskopf A, Hassler E, Stollberger R, Scheurer E. Time related changes of T1, T2, and T2* of human blood in vitro. Forensic Sci Int 2016; 262:11-7. [DOI: 10.1016/j.forsciint.2016.02.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 02/10/2016] [Accepted: 02/18/2016] [Indexed: 11/15/2022]
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Ladas EJ, Bhatia M, Chen L, Sandler E, Petrovic A, Berman DM, Hamblin F, Gates M, Hawks R, Sung L, Nieder M. The safety and feasibility of probiotics in children and adolescents undergoing hematopoietic cell transplantation. Bone Marrow Transplant 2015; 51:262-6. [PMID: 26569091 DOI: 10.1038/bmt.2015.275] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 09/18/2015] [Accepted: 10/07/2015] [Indexed: 12/19/2022]
Abstract
Hematopoietic cell transplantation (HCT) has become a standard treatment for many adult and pediatric conditions. Emerging evidence suggests that perturbations in the microbiota diversity increase recipients' susceptibilities to gut-mediated conditions such as diarrhea, infection and acute GvHD. Probiotics preserve the microbiota and may minimize the risk of developing a gut-mediated condition; however, their safety has not been evaluated in the setting of HCT. We evaluated the safety and feasibility of the probiotic, Lactobacillus plantarum (LBP), in children and adolescents undergoing allogeneic HCT. Participants received once-daily supplementation with LBP beginning on day -8 or -7 and continued until day +14. Outcomes were compliance with daily administration and incidence of LBP bacteremia. Administration of LBP was feasible with 97% (30/31, 95% confidence interval (CI) 83-100%) of children receiving at least 50% of the probiotic dose (median 97%; range 50-100%). We did not observe any case of LBP bacteremia (0% (0/30) with 95% CI 0-12%). There were not any unexpected adverse events related to LBP. Our study provides preliminary evidence that administration of LBP is safe and feasible in children and adolescents undergoing HCT. Future steps include the conduct of an approved randomized, controlled trial through Children's Oncology Group.
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Affiliation(s)
- E J Ladas
- Division of Pediatric Hematology/Oncology/Stem Cell Transplant, Columbia University Medical Center, New York, NY, USA.,Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University Medical Center, New York, NY, USA
| | - M Bhatia
- Division of Pediatric Hematology/Oncology/Stem Cell Transplant, Columbia University Medical Center, New York, NY, USA
| | - L Chen
- Children's Oncology Group, Acadia, CA, USA.,Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA
| | - E Sandler
- Division of Hematology/Oncology, Nemours Children's Health System, Jacksonville, FL, USA
| | - A Petrovic
- Blood and Bone Marrow Transplantation, All Children's Hospital John Hopkins Medicine, St Petersburg, FL, USA
| | - D M Berman
- Division of Pediatric Infectious Diseases, All Children's Hospital, John Hopkins Medicine, St Petersburg, FL, USA
| | - F Hamblin
- All Children's Hospital, John Hopkins Medicine, St Petersburg, FL, USA
| | - M Gates
- All Children's Hospital, John Hopkins Medicine, St Petersburg, FL, USA
| | - R Hawks
- Division of Pediatric Hematology/Oncology/Stem Cell Transplant, Columbia University Medical Center, New York, NY, USA
| | - L Sung
- Division of Haematology/Oncology, The Hospital for Sick Kids, Toronto, Ontario, Canada
| | - M Nieder
- Department of Blood and Marrow Transplantation, Moffitt Cancer Center, Tampa, FL, USA
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Richter A, Petrovic A, Diekhof E, Trost S, Wolter S, Gruber O. Hyperresponsivity and impaired prefrontal control of the mesolimbic reward system in schizophrenia. Pharmacopsychiatry 2015. [DOI: 10.1055/s-0035-1557987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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Richter A, Petrovic A, Diekhof E, Trost S, Wolter S, Gruber O. Hyperresponsivity and impaired prefrontal control of the mesolimbic reward system in schizophrenia. Pharmacopsychiatry 2015. [DOI: 10.1055/s-0035-1558043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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10
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Baumann P, Widek T, Merkens H, Boldt J, Petrovic A, Urschler M, Kirnbauer B, Jakse N, Scheurer E. Dental age estimation of living persons: Comparison of MRI with OPG. Forensic Sci Int 2015; 253:76-80. [PMID: 26093127 DOI: 10.1016/j.forsciint.2015.06.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 05/30/2015] [Accepted: 06/01/2015] [Indexed: 10/23/2022]
Abstract
The need for forensic age estimations in living adolescents is high mainly due to migration, particularly from countries where birth dates are not reliably documented. To date, the gold standard of dental age estimation is the evaluation of the mineralization and eruption stages of the third molars using an orthopantomogram (OPG). However, the use of ionizing radiation without medical indication is ethically controversial and not permitted in many countries. Thus, the aim of this study was to investigate if dental MRI can be used for the assessment of dental age with equally good results as when using an OPG. 27 healthy volunteers (19 ♀, 8 ♂, age range 13.6-23.1 years, median 18.9 years) underwent an MRI scan of the jaw after a clinically indicated OPG. Mineralization and eruption stages of the molars were independently analyzed on OPGs and MRI by two blinded dentists according to the staging system established by Demirjian and Olze, respectively. The results of OPG and MRI were compared and inter-rater agreement was determined. The developmental stages of the 262 evaluated molars could be clearly differentiated in MRI. For both, mineralization and eruption, there was a good correlation between MRI and OPG. Overall MRI tended to yield slightly lower stages than the OPG. Inter-rater agreement was moderate for mineralization and good regarding eruption. Although a validation of these results using modality-specific reference values is needed, dental MRI seems to be suitable for a use in dental age estimation.
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Affiliation(s)
- Pia Baumann
- Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Universitätsplatz 4/II, 8010 Graz, Austria; Institute of Forensic Medicine, Medical University Graz, Universitätsplatz 4/II, 8010 Graz, Austria
| | - Thomas Widek
- Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Universitätsplatz 4/II, 8010 Graz, Austria
| | - Heiko Merkens
- Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Universitätsplatz 4/II, 8010 Graz, Austria
| | - Julian Boldt
- Department of Prosthodontics, Julius Maximilians University Würzburg, Pleicherwall 2, 97070 Würzburg, Germany
| | - Andreas Petrovic
- Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Universitätsplatz 4/II, 8010 Graz, Austria; Institute of Medical Engineering, BioTechMed, Graz University of Technology, Kronesgasse 5/II, 8010 Graz, Austria
| | - Martin Urschler
- Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Universitätsplatz 4/II, 8010 Graz, Austria
| | - Barbara Kirnbauer
- Department of Oral Surgery and Radiology, Medical University Graz, Auenbruggerplatz 12, 8036 Graz, Austria
| | - Norbert Jakse
- Department of Oral Surgery and Radiology, Medical University Graz, Auenbruggerplatz 12, 8036 Graz, Austria
| | - Eva Scheurer
- Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Universitätsplatz 4/II, 8010 Graz, Austria; Institute of Forensic Medicine, Medical University Graz, Universitätsplatz 4/II, 8010 Graz, Austria.
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Pournaras JAC, Petrovic A, Bergin C, Bovey EH, Wolfensberger TJ. Pseudophakic Retinal Detachment Surgery by 23 G Vitrectomy using Slit-Lamp and Non-Contact 90 D Lens. Klin Monbl Augenheilkd 2015; 232:548-51. [PMID: 25902118 DOI: 10.1055/s-0035-1545745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND The purpose of this study is to report the anatomic and functional results of primary 23 G vitrectomy using slit-lamp and non-contact 90 D lens for the treatment of pseudophakic rhegmatogenous retinal detachment. PATIENTS AND METHODS Pseudophakic eyes were operated by 23 G vitrectomy using slit-lamp and non-contact 90 D lens, internal subretinal fluid drainage, cryopexy and internal gas tamponade. The preoperative and postoperative characteristics were analysed. Main outcome measures were anatomic success rates after initial surgical intervention and after reoperation for primary failures, visual outcome at the last follow-up visit, and complications. RESULTS 46 pseudophakic eyes were included in this retrospective study (October 2013- January 2014). In 40 cases, sulfur hexafluoride 23% gastamponade was used, silicone oil in 6 cases (13%). The retina was reattached successfully after a single surgery in 44 eyes (96%). Recurrence of retinal detachment occurred in 2 eyes. Final anatomic reattachment was obtained in 100% after a second operation. Silicone oil was removed in all eyes. Visual acuity improved significantly from logMAR 0 (IQR 0-0.9) to logMAR 0 (IQR 0-0.2) (p<0.005). CONCLUSIONS Primary 23 G vitrectomy using slit-lamp and non contact 90 D lens for the treatment of pseudophakic rhegmatogenous retinal detachment provides a high anatomic and functional success rate and is associated with few complications.
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Affiliation(s)
- J-A C Pournaras
- Department of Ophthalmology, Jules Gonin Eye Hospital, Fondation Asile des Aveugles, Vitreoretinal Surgery Unit, University of Lausanne, Switzerland (Chairman: Pr. Francine Behar-Cohen)
| | - A Petrovic
- Department of Ophthalmology, Jules Gonin Eye Hospital, Fondation Asile des Aveugles, Vitreoretinal Surgery Unit, University of Lausanne, Switzerland (Chairman: Pr. Francine Behar-Cohen)
| | - C Bergin
- Department of Ophthalmology, Jules Gonin Eye Hospital, Fondation Asile des Aveugles, Vitreoretinal Surgery Unit, University of Lausanne, Switzerland (Chairman: Pr. Francine Behar-Cohen)
| | - E H Bovey
- Department of Ophthalmology, Jules Gonin Eye Hospital, Fondation Asile des Aveugles, Vitreoretinal Surgery Unit, University of Lausanne, Switzerland (Chairman: Pr. Francine Behar-Cohen)
| | - T J Wolfensberger
- Department of Ophthalmology, Jules Gonin Eye Hospital, Fondation Asile des Aveugles, Vitreoretinal Surgery Unit, University of Lausanne, Switzerland (Chairman: Pr. Francine Behar-Cohen)
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Petrovic A, Pournaras JA. Unusual Post-Traumatic Subretinal Hemorrhages Reveal Angioid Streaks. Klin Monbl Augenheilkd 2015; 232:581-2. [DOI: 10.1055/s-0035-1545790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- A. Petrovic
- Department of Ophthalmology, Jules Gonin Eye Hospital, University of Lausanne, Fondation Asile des Aveugles, Lausanne, Switzerland
| | - J.-A. Pournaras
- Department of Ophthalmology, Jules Gonin Eye Hospital, University of Lausanne, Fondation Asile des Aveugles, Lausanne, Switzerland
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Webb BA, Petrovic A, Urschler M, Scheurer E. Assessment of fiducial markers to enable the co-registration of photographs and MRI data. Forensic Sci Int 2015; 248:148-53. [PMID: 25637718 DOI: 10.1016/j.forsciint.2014.12.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 12/29/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE To investigate the visualisation of novel external fiducial skin markers in photography and MRI. To co-register photographs and MR images, and additionally assess the spatial accuracy of these co-registrations with the view of future application in the investigation of forensically relevant soft tissue lesions. METHODS AND MATERIALS Strand-shaped fiducial markers were secured externally over hematomas on the thigh of 10 volunteers. The region of interest was photographed and examined using MRI at 3T in oblique and transversal orientations and the visibility of the markers assessed. Markers provided 'control points' in both sets of images, enabling the computation of an affine transform to register oblique MR images to photographs. The fiducial registration error was evaluated by calculating the root-mean-square error of nine corresponding evaluation points visible in both modalities. RESULTS Fiducial markers were clearly visualised in both photography and MRI. The co-registration of photographs and oblique MR images was achieved for all participants. The overall root-mean-square error for registrations was 1.18mm (TIRM) and 1.46mm (TSE2D with SPAIR fat-suppression). CONCLUSIONS The proposed approach led to the successful visualisation of non-invasive fiducial markers using photography and MRI (TIRM and TSE2D (SPAIR) sequences). This visualisation, combined with an affine transformation process provided a simple, cost-effective way to accurately co-register photographs and MR images of subcutaneous hematomas located on the thigh. Further investigation of the novel markers and the proposed co-visualisation approach holds potential to improve not only the forensic documentation of soft tissue lesions, but to also improve certain clinical applications, including the area of dermatology.
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Affiliation(s)
- Bridgette A Webb
- Ludwig Boltzmann Institute for Clinical Forensic Imaging, Graz, Austria.
| | - Andreas Petrovic
- Ludwig Boltzmann Institute for Clinical Forensic Imaging, Graz, Austria; Institute of Medical Engineering, BioTechMed, Graz University of Technology, Austria
| | - Martin Urschler
- Ludwig Boltzmann Institute for Clinical Forensic Imaging, Graz, Austria; Institute for Computer Graphics and Vision, BioTechMed, Graz University of Technology, Austria
| | - Eva Scheurer
- Ludwig Boltzmann Institute for Clinical Forensic Imaging, Graz, Austria; Institute of Forensic Medicine, Medical University Graz, Austria
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Sumpf TJ, Petrovic A, Uecker M, Knoll F, Frahm J. Fast T2 mapping with improved accuracy using undersampled spin-echo MRI and model-based reconstructions with a generating function. IEEE Trans Med Imaging 2014; 33:2213-22. [PMID: 24988592 PMCID: PMC4469336 DOI: 10.1109/tmi.2014.2333370] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
A model-based reconstruction technique for accelerated T2 mapping with improved accuracy is proposed using undersampled Cartesian spin-echo magnetic resonance imaging (MRI) data. The technique employs an advanced signal model for T2 relaxation that accounts for contributions from indirect echoes in a train of multiple spin echoes. An iterative solution of the nonlinear inverse reconstruction problem directly estimates spin-density and T2 maps from undersampled raw data. The algorithm is validated for simulated data as well as phantom and human brain MRI at 3T. The performance of the advanced model is compared to conventional pixel-based fitting of echo-time images from fully sampled data. The proposed method yields more accurate T2 values than the mono-exponential model and allows for retrospective undersampling factors of at least 6.Although limitations are observed for very long T2 relaxation times, respective reconstruction problems may be overcome by a gradient dampening approach. The analytical gradient of the utilized cost function is included as appendix. The source code is made available to the community.
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Affiliation(s)
- Tilman J. Sumpf
- Biomedizinische NMR Forschungs GmbH, Max-Planck-Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Andreas Petrovic
- Institute for Medical Engineering, Graz University of Technology, 8010 Graz, Austria and also with the Ludwig Boltzmann Institute for Clinical Forensic Imaging, 8010 Graz, Austria
| | - Martin Uecker
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, 94720 CA USA
| | - Florian Knoll
- Institute for Medical Engineering, Graz University of Technology, 8010 Graz, Austria, and also with the Center for Biomedical Imaging, New York University School of Medicine, New York, NY 10016 USA
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH, Max-Planck-Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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Hassler EM, Ogris K, Petrovic A, Neumayer B, Widek T, Yen K, Scheurer E. Contrast of artificial subcutaneous hematomas in MRI over time. Int J Legal Med 2014; 129:317-24. [DOI: 10.1007/s00414-014-1124-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 11/11/2014] [Indexed: 11/27/2022]
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Neumayer B, Hassler E, Petrovic A, Widek T, Ogris K, Scheurer E. Age determination of soft tissue hematomas. NMR Biomed 2014; 27:1397-1402. [PMID: 25208978 DOI: 10.1002/nbm.3202] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 07/29/2014] [Accepted: 08/13/2014] [Indexed: 06/03/2023]
Abstract
In clinical forensic medicine, the estimation of the age of injuries such as externally visible subcutaneous hematomas is important for the reconstruction of violent events, particularly to include or exclude potential suspects. Since the estimation of the time of origin based on external inspection is unreliable, the aim of this study was to use contrast in MRI to develop an easy-to-use model for hematoma age estimation. In a longitudinal study, artificially created subcutaneous hematomas were repetitively imaged using MRI over a period of two weeks. The hemorrhages were created by injecting autologous blood into the subcutaneous tissue of the thigh in 20 healthy volunteers. For MRI, standard commercially available sequences, namely proton-density-weighted, T2 -weighted and inversion recovery sequences, were used. The hematomas' MRI data were analyzed regarding their contrast behavior using the most suitable sequences to derive a model allowing an objective estimation of the age of soft tissue hematomas. The Michelson contrast between hematoma and muscle in the proton-density-weighted sequence showed an exponentially decreasing behavior with a dynamic range of 0.6 and a maximum standard deviation of 0.1. The contrast of the inversion recovery sequences showed increasing characteristics and was hypointense for TI = 200ms and hyperintense for TI =1000ms. These sequences were used to create a contrast model. The cross-validation of the model finally yielded limits of agreement for hematoma age determination (corresponding to ±1.96 SD) of ±38.7h during the first three days and ±54 h for the entire investigation period. The developed model provides lookup tables which allow for the estimation of a hematoma's age given a single contrast measurement applicable by a radiologist or a forensic physician. This is a first step towards an accurate and objective dating method for subcutaneous hematomas, which will be particularly useful in child abuse.
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Affiliation(s)
- Bernhard Neumayer
- Ludwig Boltzmann Institute for Clinical Forensic Imaging, Universitätsplatz 4, A-8010, Graz, Austria
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Petrovic A, Simic V, Paunovic M, Stojanovic B. A New Records ofEpeorus Yougoslavicus(Šamal, 1935) [Ephemeroptera] in Serbia and Montenegro. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.1080/13102818.2006.10817344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Petrovic A, Scheurer E, Stollberger R. Closed-form solution for T2 mapping with nonideal refocusing of slice selective CPMG sequences. Magn Reson Med 2014; 73:818-27. [PMID: 24634257 DOI: 10.1002/mrm.25170] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 01/14/2014] [Accepted: 01/15/2014] [Indexed: 12/23/2022]
Abstract
PURPOSE T2 quantification with multiecho sequences is typically impaired by the contribution of stimulated echoes to the echo decay due to B1 + inhomogeneity and slice profile effects. In this work, a compact signal model based on the generating functions approach, which accounts for both sources of error, is presented. METHODS The generating functions (GF) approach is used to obtain a closed solution to the evolution of the transverse magnetization in an echo train, however, not in the time domain, but in the transformed z-domain. The approach is generalized by the incorporation of flip angle distribution across the refocusing slice profiles. The approach is tested by fitting the model to simulated data as well as to phantom and in vivo measurements, followed by a comparison with the common monoexponential fitting approach. RESULTS The fitting simulations indicate that T2 errors of up to 30% can be commonplace in a clinical setting using the monoexponential method. Conversely, the GF approach produced accurate results. Phantom and in vivo experiments showed a good agreement of the GF values with spectroscopic measurements and single-echo spin-echo sequences. CONCLUSION A correction for stimulated echoes is necessary to compute comparable T2 values. The presented approach provides a solution to this issue.
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Affiliation(s)
- Andreas Petrovic
- Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Graz, Austria; Graz University of Technology, Institute for Medical Engineering, Graz, Austria
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Cakic S, Mojsilovic M, Mihaljica D, Milutinovic M, Petrovic A, Tomanovic S. Molecular characterization of COI gene of Ixodes ricinus (Linnaeus, 1758) from Serbia. ARCH BIOL SCI 2014. [DOI: 10.2298/abs1402683c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The Ixodes ricinus tick is common in the central part of the Balkan
Peninsula. It is a vector of pathogenic agents causing diseases in humans and
animals. Little is known about the genetic structure of I. ricinus in this
region. We have investigated intraspecific variability of the COI gene among
I. ricinus ticks collected from different regions of Serbia, and the
correlation between the various types of habitat and genetic variability of
ticks. The obtained COI gene sequences are the first barcoding sequences of
I. ricinus ticks collected at localities in Serbia. Intraspecific variability
of these COI gene sequences was very low, and there was no correlation
between the various types of habitat and genetic variability of ticks.
Samples from isolated localities (canyon/gorge) showed no genetic
differentiations from the majority of samples from open areas.
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Affiliation(s)
- Sanja Cakic
- Institute for Medical Research, Center of Excellence for Toxoplasmosis and Medical Entomology, Laboratory for Medical Entomology, Department of Parasitology, Belgrade
| | | | - D. Mihaljica
- Institute for Medical Research, Center of Excellence for Toxoplasmosis and Medical Entomology, Laboratory for Medical Entomology, Department of Parasitology, Belgrade
| | - Marija Milutinovic
- Institute for Medical Research, Center of Excellence for Toxoplasmosis and Medical Entomology, Laboratory for Medical Entomology, Department of Parasitology, Belgrade
| | - A. Petrovic
- Institute of Zoology, Faculty of Biology, Belgrade
| | - Snezana Tomanovic
- Institute for Medical Research, Center of Excellence for Toxoplasmosis and Medical Entomology, Laboratory for Medical Entomology, Department of Parasitology, Belgrade
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Scharfetter H, Petrovic A, Stollberger R. Wideband Probe for Magnetic Quadrupole Resonance Spectroscopy. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-L/bmt-2013-4298/bmt-2013-4298.xml. [DOI: 10.1515/bmt-2013-4298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Wojtłowska-Wiechetek D, Tworus R, Dziuk M, Petrovic A, Szymańska S, Zbyszewski M, Ilnicki S, Krzesiński P. Estimation of usefulness of positron emission tomography (PET) in the diagnosis of post-traumatic stress disorders--preliminary report. Stud Health Technol Inform 2013; 191:178-180. [PMID: 23792869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The aim of this study was to evaluate the possibility of using PET both in assessing the susceptibility to stress and in the diagnosis of post-traumatic stress disorders. Mentally and somatically healthy soldiers were subjected to PET-CT head scan examinations before and after virtual reality stimulation with warfare scenarios. Despite stimulation of peripheral nervous system after 10 minutes, VR exposure in any of the examined soldiers simulation did not cause changes in any brain structure that was visualized in PET. PET-CT head scan was also performed in patients with typical symptoms of acute PTSD according to the criteria of DSM IV TR. In those patients no changes in any brain structure was found. Initially it was found that VR exposure techniques like clinically typical acute symptoms of PTSD do not leave changes in CNS, which could be visualized in PET. The preliminary hypothesis was put forward that exposure to stimuli like symptoms of PTSD must remain long enough to induce permanent damage of brain structure.
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Nieder M, Hamblin F, Gates M, Bhatia M, Petrovic A, Ladas E. Safety of Probiotic Usage in Children Undergoing Hematopoietic Cell Transplantation (HCT): A Preliminary Report. Biol Blood Marrow Transplant 2012. [DOI: 10.1016/j.bbmt.2011.12.298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Gruber O, Diekhof EK, Zvonik K, Trost S, Weber K, Petrovic A, Henseler I, Zilles D, Melcher T, Keil M, Dechent P, Falkai P. Multi-functional MRI studies of disordered brain circuits in schizophrenic and affective psychoses. Pharmacopsychiatry 2011. [DOI: 10.1055/s-0031-1292483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Petrovic A, Abramovic M, Mihailovic D, Gligorijevic J, Zivkovic V, Mojsilovic M, Ilic I. Multicolor counterstaining for immunohistochemistry – a modified Movat's pentachrome. Biotech Histochem 2010; 86:429-35. [DOI: 10.3109/10520295.2010.528026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- A Petrovic
- Institute of Histology and Embryology, Faculty of Medicine
| | | | - D Mihailovic
- Institute of Pathology, Faculty of Medicine,
Blv Zorana Djindjica 81, 18000 Nis, University of Nis, Serbia
| | - J Gligorijevic
- Institute of Pathology, Faculty of Medicine,
Blv Zorana Djindjica 81, 18000 Nis, University of Nis, Serbia
| | - V Zivkovic
- Institute of Pathology, Faculty of Medicine,
Blv Zorana Djindjica 81, 18000 Nis, University of Nis, Serbia
| | - M Mojsilovic
- Institute of Histology and Embryology, Faculty of Medicine
| | - I Ilic
- Institute of Pathology, Faculty of Medicine,
Blv Zorana Djindjica 81, 18000 Nis, University of Nis, Serbia
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Uher R, Muthén B, Souery D, Mors O, Jaracz J, Placentino A, Petrovic A, Zobel A, Henigsberg N, Rietschel M, Aitchison KJ, Farmer A, McGuffin P. Trajectories of change in depression severity during treatment with antidepressants. Psychol Med 2010; 40:1367-1377. [PMID: 19863842 DOI: 10.1017/s0033291709991528] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Response and remission defined by cut-off values on the last observed depression severity score are commonly used as outcome criteria in clinical trials, but ignore the time course of symptomatic change and may lead to inefficient analyses. We explore alternative categorization of outcome by naturally occurring trajectories of symptom change. METHOD Growth mixture models were applied to repeated measurements of depression severity in 807 participants with major depression treated for 12 weeks with escitalopram or nortriptyline in the part-randomized Genome-based Therapeutic Drugs for Depression study. Latent trajectory classes were validated as outcomes in drug efficacy comparison and pharmacogenetic analyses. RESULTS The final two-piece growth mixture model categorized participants into a majority (75%) following a gradual improvement trajectory and the remainder following a trajectory with rapid initial improvement. The rapid improvement trajectory was over-represented among nortriptyline-treated participants and showed an antidepressant-specific pattern of pharmacogenetic associations. In contrast, conventional response and remission favoured escitalopram and produced chance results in pharmacogenetic analyses. Controlling for drop-out reduced drug differences on response and remission but did not affect latent trajectory results. CONCLUSIONS Latent trajectory mixture models capture heterogeneity in the development of clinical response after the initiation of antidepressants and provide an outcome that is distinct from traditional endpoint measures. It differentiates between antidepressants with different modes of action and is robust against bias due to differential discontinuation.
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Affiliation(s)
- R Uher
- Medical Research Council Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, King's College London, UK.
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Popovic J, Gasic J, Zivkovic S, Petrovic A, Radicevic G. Evaluation of biological debris on endodontic instruments after cleaning and sterilization procedures. Int Endod J 2010; 43:336-41. [DOI: 10.1111/j.1365-2591.2010.01686.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Stutzmann J, Petrovic A. La vitesse de renouvellement de l'os alvéolaire chez l'adulte avant et pendant le traitement orthodontique. ACTA ACUST UNITED AC 2010. [DOI: 10.1051/odf/1980024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Eng W, Dorsey M, Sleasman J, Petrovic A, Westbrock W. A Novel Mutation CHS1 (LYST) Mutation: Osteomyelitis in a Child with Chediak-Higashi Syndrome. J Allergy Clin Immunol 2010. [DOI: 10.1016/j.jaci.2009.12.289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Petrovic A, Dorsey M, Miotke J, Shepherd C, Day N. Hematopoietic stem cell transplantation for pediatric patients with primary immunodeficiency diseases at All Children’s Hospital/University of South Florida. Immunol Res 2009; 44:169-78. [DOI: 10.1007/s12026-009-8111-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Stutzmann J, Petrovic A, Malan A. Seasonal variations of the human alveolar bone turn‐over. A quantitative evaluation in organ culture. ACTA ACUST UNITED AC 2008. [DOI: 10.1080/09291018109359738] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Affiliation(s)
| | | | - M. Zorko
- Institute of Public Health of the Republic of Slovenia, Slovenia
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Tonchev A, Rancic G, Fiore M, Tuncel N, Kostov D, Valchanov K, Ghenev P, Pancheva R, Panayotov P, Georgieva Z, Nikolova V, Peneva V, Petrovic A, Stoev S, Yamori Y, Aloe L, Chaldakov G. PERIADVENTITIAL ADIPOSE TISSUE (TUNICA ADIPOSA): A FRIEND-AND-FOE CONCEPT OF ATHEROGENESIS. ATHEROSCLEROSIS SUPP 2008. [DOI: 10.1016/s1567-5688(08)70907-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bagg A, Gonzalez-Peralta R, Petrovic A, Sleasman J. Novel CYBA Gene Mutation in a Patient with Chronic Granulomatous Disease Associated with Autoimmune Hepatitis. J Allergy Clin Immunol 2007. [DOI: 10.1016/j.jaci.2006.11.080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Zivkovic V, Basic M, Gligorijevic J, Pavlovic V, Lazarevic V, Petrovic A. Follicular dendritic cell sarcoma in the lymph nodes of the neck. BRATISL MED J 2007; 108:368-370. [PMID: 18203543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Follicular dendritic cell sarcoma (FDCS) is a rare tumor, derived from antigen-presenting cells that normally form meshworks in lymphoid follicles. FDCS in general recapitulate the immunophenotypic profile of follicular dendritic cells (FDCs). This tumor affects mainly the lymph nodes, but may arise at a variety of extranodal sites in about one third of cases. We present a case of FDCS in a 52-year-old woman with left neck mass. Histologically, the tumor was composed of oval-to-spindle cells arranged in a fascicular and storiform pattern. Immunohistochemically, the tumor cells were positive for CD21, CD35, and to a lesser extent for EMA and vimentin (Fig. 3, Ref. 14). Full Text (Free, PDF) www.bmj.sk.
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Affiliation(s)
- V Zivkovic
- Institute of Pathology, Faculty of Medicine, University of Nis, Serbia.
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Petrovic A, Cvetkoviæ N, Trajkovic S, Ibric S, Popadic D, Djuric Z. Mixture design evaluation of drug release from matrix tablets containing carbomer and HPMC. J Control Release 2006; 116:e104-6. [DOI: 10.1016/j.jconrel.2006.09.073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Venkatesan S, Petrovic A, Locati M, Kim YO, Weissman D, Murphy PM. A membrane-proximal basic domain and cysteine cluster in the C-terminal tail of CCR5 constitute a bipartite motif critical for cell surface expression. J Biol Chem 2001; 276:40133-45. [PMID: 11514564 DOI: 10.1074/jbc.m105722200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We examined the structural requirements for cell surface expression, signaling, and human immunodeficiency virus co-receptor activity for the chemokine receptor, CCR5. Serial C-terminal truncation of CCR5 resulted in progressive loss of cell surface expression; mutants truncated at the 317th position and shorter were not detected at the cell surface. Alanine substitution of basic residues in the membrane-proximal domain (residues 314-322) in the context of a full-length C-tail resulted in severe reduction in surface expression. C-terminal truncation that excised the three cysteines in this domain reduced surface expression, but further truncation of upstream basic residue(s) abolished surface expression. Substituting the carboxyl-terminal domain of CXCR4 for that of CCR5 failed to rectify the trafficking defect of the tailless CCR5. In contrast, tailless CXCR4 or a CXCR4 chimera that exchanged the native cytoplasmic domain for that of wild type CCR5 was expressed at the cell surface. Deletion mutants that expressed at the cell surface responded to chemokine stimulation and mediated human immunodeficiency virus entry. Substitution of all serine and threonine residues in the C-terminal tail of CCR5 abolished chemokine-mediated receptor phosphorylation but preserved downstream signaling (Ca(2+) flux), while substitutions of tyrosine residues in the C-tail affected neither phenotype. CCR5 mutants that failed to traffic to the plasma membrane did not exhibit obvious changes in metabolic turnover and were retained in the Golgi or pre-Golgi compartments(s). Thus, the basic domain (-KHIAKRF-) and the cysteine cluster (-CKCC-) in the C-terminal tail of CCR5 function cooperatively for optimal surface expression.
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Affiliation(s)
- S Venkatesan
- Laboratory of Molecular Microbiology and Laboratory of Host Defenses, NIAID, National Institutes of Health, Bldg. 10, Rm. 6A05, Bethesda, MD 20892, USA.
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Nam YS, Petrovic A, Jeong KS, Venkatesan S. Exchange of the basic domain of human immunodeficiency virus type 1 Rev for a polyarginine stretch expands the RNA binding specificity, and a minimal arginine cluster is required for optimal RRE RNA binding affinity, nuclear accumulation, and trans-activation. J Virol 2001; 75:2957-71. [PMID: 11222721 PMCID: PMC115922 DOI: 10.1128/jvi.75.6.2957-2971.2001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Rev regulatory protein of human immunodeficiency virus (HIV) facilitates the nuclear export of unspliced and partially spliced HIV RNAs. Using a Rev:MS2 phage coat protein fusion that could be targeted to bind and activate the Rev-responsive element (RRE) RNA or heterologous MS2 phage operator RNA, we analyzed the role(s) of the arginine-rich RNA binding domain in RNA binding and transactivation. The arginine-rich domain could be functionally replaced by a stretch of nine arginines. However, polyarginine substitutions expanded the RNA binding specificity of the resultant mutant Rev protein. Polyarginine insertions in place of residues 24 to 60 that excised the RNA binding and oligomerization domains of Rev preserved the activation for MS2 RNA, but not for the RRE. A nine-arginine insertion outside of the natural context of the Rev nuclear localization signal domain was incompatible with activation of either RNA target. Insertions of fewer than eight arginines impaired RRE activation. Interrupted lysine clusters and disruption of the arginine stretch with lysine or neutral residues resulted in a similar phenotype. Some of these mutants with a null phenotype for RRE activated the heterologous MS2 RNA target. Under steady-state conditions, mutants that preserved the Rev response for RRE RNA localized to the nuclei; those with poor or no Rev response accumulated mostly in the cytoplasm. Many of the cytoplasmically resident derivatives became nuclear when leptomycin B (LMB) treatment inhibited nuclear export of nuclear export signal-containing proteins. Mutants that had a null activation potential for either RNA target were particularly resistant to LMB treatment. Abbreviated nuclear residence times and differences in RRE binding affinity may have compromised their activation potential for RRE. High-affinity binding to MS2 RNA through the intact coat protein was sufficient to overcome the short nuclear residence times and to facilitate MS2 activation by some derivatives.
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Affiliation(s)
- Y S Nam
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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Shaye R, Stutzmann J, Petrovic A. A matter of priority. Am J Orthod Dentofacial Orthop 1999; 116:17A. [PMID: 10474094 DOI: 10.1016/s0889-5406(99)70067-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kroegel C, Reissig A, Hengst U, Petrovic A, Häfner D, Grahmann RP. Ulcerative colitis following introduction of zafirlukast and corticosteroid withdrawal in severe atopic asthma. Eur Respir J 1999; 14:243. [PMID: 10489861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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Patel B, Berhane Y, Petrovic A, Mowbray J. The mitochondrial phosphoglyceroyl-ATP-containing polymer, purinogen, is unchanged by cardiac ischaemia and reperfusion but may function in the regulation of free intracellular inorganic phosphate concentrations. Eur J Biochem 1998; 254:75-80. [PMID: 9652397 DOI: 10.1046/j.1432-1327.1998.2540075.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previous work in our laboratory demonstrating large unexplained systematic variations in the heart contents of free adenine nucleotides led us to propose the existence of some unrecognised sequestered form and thence to the purification of very labile acid-insoluble oligomers which we characterised as oligo[3-phospho-glyceroyl-gamma-triphospho(5')adenosine(3')] , abbreviated to (PG-ATP)n. More recently, we provided evidence that these oligomers appear to be the end chains of a complex polymer located in the mitochondrial intermembrane space of a number of rat tissues. We called this polymer purinogen and devised a means of assaying it quantitively [Patel, B., Sarcina, M. & Mowbray, J. (1994) Eur. J. Biochem. 220, 663-669]. Here we report measurements of purinogen in perfused hearts subjected to moderate and severe global ischaemia and reperfusion. Measurements of tissue and perfusate nucleotides, nucleosides and purine degradation products demonstrate that ischaemia led to the augmentation of the free nucleotide content by up to 30% and its re-sequestration on reperfusion in reversible but not in irreversible ischaemia. The purinogen content was unchanged by ischaemia or reperfusion implying the existence of some other unidentified storage pool. By contrast, glucose addition to glycolytically deprived hearts or removal of Pi from perfusion medium, conditions which might be expected to alter demand for intracellular Pi, led to the quantitative transfer of nucleotides between phosphate-rich purinogen and free nucleotides. The possibility that purinogen may act as a rapidly accessible reservoir of intracellular inorganic phosphate is discussed.
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Affiliation(s)
- B Patel
- Regulatory Mechanisms and Signalling Group, Department of Biochemistry and Molecular Biology, University College London, UK
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Petrovic A. Reply to letter by Dr. Remmelink. Am J Orthod Dentofacial Orthop 1997; 111:16A. [PMID: 9199585 DOI: 10.1016/s0889-5406(97)70162-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Abstract
Previous work using homogenate binding has shown that the development of (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten-5,10imin e maleate (MK-801) binding in cat visual cortex increases from 21 days to 42 days, the height of the plastic period, and decreases in adulthood. We have studied the generality of this finding by examining the development of NMDA binding sites in several brain regions and by examining the development of other binding sites in the visual cortex. After confirming the original finding, we extended it by showing that the sensitivity of MK-801 binding sites to glutamate and glycine decreases when the cat becomes an adult. We then examined the regional specificity of MK-801 binding. Retinal binding did not change significantly with age. Binding in both visual cortex and hippocampus increased significantly from 7 days to 42 days regardless of whether binding was measured per milligram wet weight or per milligram protein. The decline from 42 days to adulthood was less dramatic in the hippocampus than in the visual cortex and was statistically significant only when binding was measured per milligram protein. Saturation analyses also showed a difference in the two structures. Bmax in the visual cortex, but not in the hippocampus, decreased from 42 days to adulthood. To determine whether these developmental changes were specific to MK-801 binding sites, we compared the age-dependent binding of MK-801, kainate, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and muscimol. Like MK-801, kainate binding increased from 7 days to 42 days and decreased from 42 days to adulthood. AMPA and muscimol binding showed a similar increase in binding from 7 days to 42 days but did not decrease significantly from 42 days to adulthood. Displacement experiments suggest that AMPA and kainate bind to separate sites. The 42-day peak in NMDA and kainate binding suggests that their associated receptors may have a role in determining the plastic period of visual cortex.
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Affiliation(s)
- B Gordon
- Institute of Neuroscience, University of Oregon, Eugene 97403, USA
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Petrovic A. Auxologic categorization and chronobiologic specification for the choice of appropriate orthodontic treatment. Am J Orthod Dentofacial Orthop 1994; 105:192-205. [PMID: 8311041 DOI: 10.1016/s0889-5406(94)70114-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Yeadon M, Dougan FL, Petrovic A, Beesley JE, Payne AN. Effect of BW B70C, a novel inhibitor of arachidonic acid 5-lipoxygenase, on allergen-induced bronchoconstriction and late-phase lung eosinophil accumulation in sensitised guinea-pigs. Agents Actions 1993; 38:8-18. [PMID: 8480540 DOI: 10.1007/bf02027207] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The actions of BW B70C, an orally available, biologically persistent and selective inhibitor of arachidonic acid 5-lipoxygenase, have been examined in two systems of anaphylaxis in actively sensitised guinea-pigs in vivo. In anaesthetised, artificially ventilated animals pretreated with mepyramine and indomethacin to leave only the "peptidoleukotriene-dependent" component (leukotrienes C4, D4 and E4) of the anaphylactic response, direct inhalation of nebulised allergen resulted in a slowly developing bronchoconstriction which was prevented in a dose-dependent manner by BW B70C (2-50 mg/kg p.o.) administered 1 or 6 h before challenge. In conscious animals fasted overnight and then pretreated with mepyramine to prevent death due to acute bronchial anaphylaxis, exposure to nebulised allergen produced slight respiratory symptoms. When blood and lung samples were analysed 4-48 h after allergen provocation a sustained leukocytosis and pulmonary eosinophil accumulation were observed. In contrast, in food-replete conscious animals, the early respiratory symptoms were still observed upon allergen inhalation, but no significant blood leukocytosis or accumulation of eosinophils in the lungs occurred subsequently. The eosinophil influx induced by allergen in fasted animals was assessed both by histological examination and determination of tissue peroxidase content, two measures which demonstrated reasonable agreement. Administration of a single dose of BW B70C (10 mg/kg p.o.) 1 h prior to allergen challenge did not affect the subsequent eosinophil infiltration 24 h later, but 20 mg/kg given in divided doses (-1 and +12 h) produced 67% inhibition of cell accumulation. A single dose of 50 mg/kg (-1 h) had a similar effect (78% inhibition). The potent glucocorticosteroid betamethasone was used as a reference compound, and 4 mg/kg given as a divided dose (-1 and +7) fully inhibited lung inflammation assessed 24 h after provocation with allergen. BW B70C inhibited both acute and allergic bronchoconstriction and late-phase eosinophil accumulation subsequent to allergen inhalation in guinea-pigs. In view of the apparent requirement for sustained plasma levels of BW B70C in order to prevent late-phase eosinophil recruitment to the lung after a single challenge with allergen, it is unclear whether inhibition of 5-lipoxygenase underlies the observed anti-eosinophil accumulation effects of the compound, but the anti-bronchoconstrictor effects are consistent with the known inhibitory activity of BW B70C against 5-lipoxygenase.
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Affiliation(s)
- M Yeadon
- Department of Pharmacology, Wellcome Research Laboratories, Beckenham, Kent, UK
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Simoes WA, Petrovic A, Stutzmann J. Modus operandi of Planas' appliance. J Clin Pediatr Dent 1992; 16:79-85. [PMID: 1498051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Planas' approach to the management of a distocclusion, as applied by Simoes, is analyzed physiologically by taking into account the Petrovic-Stutzmann's cybernetic vision of facial growth. This scientifically based theorization further strengthens the clinical validity of this orthodontic ideology and procedure. The clinician, the orthodontist, the functional orthopedist or the functional orthodontist are fundamentally dependent on their knowledge about biophysics, biochemistry and mainly physiology. It is important then that they be acquainted with fundamental concepts of basic sciences as applicable to the specialty. In planning the treatment of a malocclusion, it is necessary to select the appliance or the series of them for sequential use in the correction of a intermaxillary malrelation. It is also useful to be able to predict the response to each appliance. In this case it must be considered the input (appliance in the mouth) designed to produce either displacements of the teeth or other modifications within the dentofacial complex and the output (appliance effect). According to Petrovic and Stutzmann there are 6 tissue level growth categories. Previous investigations using Frankel appliance, LSU Activator, Bionator, Chin Cup and Begg techniques, have shown that when going from the growing category number 1 to number 6 it becomes easier to stimulate the growth rate and amount of the condylar cartilage and of the posterior border of the ramus and it becomes more difficult to restrain their growth rate and amount. In other words we have also to test clinically the effectiveness of the Planas Appliance by taking into account the inter-individual variation in the tissue level responsiveness to it. (Fig. 1-4).(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
The myosin light chains of platysma samples originating from 2 to 86 year old patients of the maxillo-facial surgery clinic were investigated. The platysma contained both fast and slow myosin. No change in the proportion of myosin type in relation to age was found. Female patients often displayed less fast myosin than male patients. Each time when the platysma muscle activity has been reduced a decrease in the amount of slow myosin light chains was observed. In the reported study, variations of the fast and slow myosin light chains resulted mainly from the platysma activity level, i.e. from the pathology requiring the surgery, rather than from the patients' age.
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Affiliation(s)
- C Oudet
- Dept. of Maxillo-Facial Surgery, Faculté de Médecine, CHU, Strasbourg, France
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Petrovic A, Oudet C, Stutzmann J. Ultradian mitotic rhythms in culture of human sarcomatous bone cells originating from the patient before and after chemotherapy. Chronobiol Int 1989; 6:173-83. [PMID: 2743470 DOI: 10.3109/07420528909064628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Bone sarcomatous cells derived from human malignant tumors were cultured. The mitotic index was recorded for 39 hr. When the cultured cells originated from patients with cancer disease before any chemotherapy, ultradian mitotic rhythms of a 6-9-hr period were detected, but in many cases only after a sensitive statistical analysis was performed. When the cultured cells originated from cancer patients undergoing chemotherapy, the mitotic index was decreased, and the amplitudes of the 6-9-hr component oscillations of the mitotic index were highly significantly increased. Damping and fading out of an ultradian mitotic rhythmicity was a bad prognostic portent in bone cancer. With reference to chemotherapy, the restored and amplified ultradian rhythmicity disclosed an appreciable antitumor effect and better survival prospects for the patient.
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Affiliation(s)
- A Petrovic
- Unité de Recherches sur la Croissance des Cartilages, INSERM--U. 213, Faculté de Médecine, Strasbourg, France
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Petrovic A. [Treatment of mandibular dysfunction with the Bioblock]. Fortschr Kieferorthop 1988; 49:315-6. [PMID: 3165366 DOI: 10.1007/bf02164455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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