| 1. |
- Bogdanova, Svetlana, et al.
(författare)
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Volgo-Uralia: The First U-Pb, Lu-Hf and Sm-Nd Isotopic Evidence of Preserved Paleoarchean Crust
- 2010
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Ingår i: American Journal of Science. - : American Journal of Science (AJS). - 0002-9599. ; 310:10, s. 1345-1383
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Tidskriftsartikel (refereegranskat)abstract
- The crustal segment Volgo-Uralia is the least known part of the East European Craton. Its crystalline crust is hidden beneath a thick Neoproterozoic to Phanerozoic cover but disclosed by thousands of drill holes. In conjunction with the recent "Tatseis" reflection seismic profile, we conducted the first isotopic study of the Bakaly granitoid block in eastern Volgo-Uralia, which represents a subsurface section of the layered upper-middle crust. The study included whole-rock Sm-Nd and ion-probe zircon U-Th-Pb (SIMS) and Lu-Hf (LA-ICPMS) analyses of granitoids from seven drill cores. The Bakaly block was also targeted because its rocks have never been subjected to granulite facies metamorphism, making it possible to date pristine, pre-metamorphic zircon. Our study showed that the four principal suites of granitoids in the Bakaly block are different in age, each corresponding to a particular stage of Archean crustal evolution between 3.3 and 2.6 Ga. The Tashliar monzonitic suite, belonging to an alkaline series yielded zircon ages of 3.3 and 3.2 Ga, which are the oldest ages yet found in Volgo-Urafia. The epsilon(Hf)(T) values of the dated zircon and the epsilon(Nd)(T) values of their host rocks indicate that a Paleo- to Eoarchean protolith with model T-DM ages up to 3.8 Ga had been involved in the formation of the Tashliar melts. Three Neoarchean rock suites, one comprising quartz dioritic and tonalitic gneisses (the Bak 1), another K-rich granodiorites, granites and migmatites (the Bak 2), and the third monzonitic granitoids (the Aktanysh suite) were formed sequentially between 2.72 and 2.60 Ga. The 2.72 Ga Bak 1 suite is chemically diverse. It includes granitoids of the TTG type related to slab/subduction melts as well as rocks formed by the re-melting of older crust with whole-rock Nd T-DM and Hf T-DM model ages of 3.4 to 3.2 Ga. The 2.69 to 2.65 Ga Bak 2 suite was probably associated with a major collisional event, which defined the stacked structure of the Archean crust in Volgo-Uralia and its seismic layering. Our data suggest that the Bak 2 melts originated partly from juvenile sources with epsilon(Hf)(T) zircon values up to +4.8, as well as mixed crustal and juvenile mantle materials. Some crustal contamination of the melts appears to have occurred as evidenced by incorporated xenocrystic zircon. The chemical compositions of Bak 2 granitoids from the different plutons, their zircon epsilon(Hf) values, and the Hf- and Nd T-DM ages all mirror a heterogeneous, collisional, crustal structure. During post-collisional extension at 2.6 Ga, the intrusion of Aktanysh monzonitic granitoids took place. These rocks also bear evidence of a long crustal pre-history with Nd and Hf T-DM model ages of 3.3 to 3.5 Ga. The Aktanysh rocks are coeval with the Tuymazy gabbro-norite-anorthosite intrusions, which are widely distributed along post-collisional shear zones in the Bakaly block. They could have provided the heat necessary to melt the crust at this stage. Altogether, the isotopic evidence suggests several episodes of crustal growth and recycling possibly reaching back to 3.6 and 3.8 Ga. Metamorphic zircon rims show that the Archean crust in the Bakaly block were subjected to several tectonothermal overprints in the Paleoproterozoic between 2.4 and 1.9 Ga ago.
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| 2. |
- Bogdanova, Svetlana V., et al.
(författare)
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Palaeoproterozoic reworking of early Archaean lithospheric blocks : Rocks and zircon records from charnockitoids in Volgo-Uralia
- 2021
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Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268. ; 360
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Tidskriftsartikel (refereegranskat)abstract
- The Volgo-Uralia segment, which constitutes one fourth of the East European Craton, is covered by sedimentary deposits. From geophysical studies and examination of thousands of drillcores, Volgo-Uralia has been recognised as a vast high-grade terrain with a complex crustal history extending from the Palaeoarchaean to the Palaeoproterozoic. Our recent studies are focused on the search for the oldest crust formation event by extracting whole rock Sm-Nd and zircon U-Th-Pb and Lu-Hf isotope information from samples recovered by drilling in southern Volgo-Uralia. Particular attention is devoted to the Kolyvan charnockitoid rock suite, which makes up several large areas of gneisses and granitoids of enderbite, charnockite and tonalite composition. The zircon from the granitoids show complex internal structures and consists of large magmatic cores with oscillatory zoning, surrounded by CL black-and-bright bands of metamorphic rims. The crystallisation age of the cores is defined as 3140 ± 7 Ma (SHRIMP) and 3127 ± 46 Ma (LA-ICPMS), while the CL-bright rims are dated at 1950 ± 25 Ma (LA-ICPMS). The ingressive recrystallisation of primary magmatic zircon correlates with depletion in REE, which is observed in each studied core-rim pair. No differences in O-isotopic compositions have been detected between the cores and the rims. δO18 values with an average of 5.8 ± 0.3‰ (1SD) implying that no supracrustal rocks were involved in the source of the Kolyvan melts. The Hf-isotope compositions of magmatic cores (−3 to −9 εHfT) and metamorphic rims (−14 to −28 εHfT), and their similar crustal model ages from 3.42 to 3.86 Ga indicate Eo- to Palaeoarchaean crustal sources for the charnockitic magmas. Sm-Nd model ages of ca 3.46 Ga for the Kolyvan rocks are consistent with the zircon Hf-isotope data and indicate a long crustal prehistory of a source of the Mesoarchaean magmas. We conclude that the Mesoarchaean Kolyvan suite rocks was formed by reworking of Eo- to Palaeoarchaean lithosphere, which probably had been widespread throughout Volgo-Uralia. The obtained geochemical and isotope data can be reconciled in a model of deep mantle-plume activity at 3.1 Ga causing mantle underplating, extension of the Palaeoarchaean crust and high-T magmatism.
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| 3. |
- Burisch, Johan, et al.
(författare)
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Construction and validation of a web-based epidemiological database for inflammatory bowel diseases in Europe An EpiCom study
- 2011
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Ingår i: JOURNAL OF CROHNS and COLITIS. - : Elsevier Science B.v; Amsterdam. - 1873-9946 .- 1876-4479. ; 5:4, s. 342-349
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Tidskriftsartikel (refereegranskat)abstract
- Background: The EpiCom-study investigates a possible East-West-gradient in Europe in the incidence of IBD and the association with environmental factors. A secured web-based database is used to facilitate and centralize data registration. Aim: To construct and validate a web-based inception cohort database available in both English and Russian language. Method: The EpiCom database has been constructed in collaboration with all 34 participating centers. The database was translated into Russian using forward translation, patient questionnaires were translated by simplified forward-backward translation. Data insertion implies fulfillment of international diagnostic criteria, disease activity, medical therapy, quality of life, work productivity and activity impairment, outcome of pregnancy, surgery, cancer and death. Data is secured by the WinLog3 System, developed in cooperation with the Danish Data Protection Agency. Validation of the database has been performed in two consecutive rounds, each followed by corrections in accordance with comments. Results: The EpiCom database fulfills the requirements of the participating countries local data security agencies by being stored at a single location. The database was found overall to be "good" or "very good" by 81% of the participants after the second validation round and the general applicability of the database was evaluated as "good" or "very good" by 77%. In the inclusion period January 1st -December 31st 2010 1336 IBD patients have been included in the database. Conclusion: A user-friendly, tailor-made and secure web-based inception cohort database has been successfully constructed, facilitating remote data input. The incidence of IBD in 23 European countries can be found at www.epicom-ecco.eu. (C) 2011 European Crohns and Colitis Organisation. Published by Elsevier B.V. All rights reserved.
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| 4. |
- Burisch, Johan, et al.
(författare)
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Costs and resource utilization for diagnosis and treatment during the initial year in a European inflammatory bowel disease inception cohort : an ECCO-EpiCom Study
- 2015
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Ingår i: Inflammatory Bowel Diseases. - 1078-0998 .- 1536-4844. ; 21:1, s. 121-131
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: No direct comparison of health care cost in patients with inflammatory bowel disease across the European continent exists. The aim of this study was to assess the costs of investigations and treatment for diagnostics and during the first year after diagnosis in Europe.METHODS: The EpiCom cohort is a prospective population-based inception cohort of unselected inflammatory bowel disease patients from 31 Western and Eastern European centers. Patients were followed every third month from diagnosis, and clinical data regarding treatment and investigations were collected. Costs were calculated in euros (&OV0556;) using the Danish Health Costs Register.RESULTS: One thousand three hundred sixty-seven patients were followed, 710 with ulcerative colitis, 509 with Crohn's disease, and 148 with inflammatory bowel disease unclassified. Total expenditure for the cohort was &OV0556;5,408,174 (investigations: &OV0556;2,042,990 [38%], surgery: &OV0556;1,427,648 [26%], biologicals: &OV0556;781,089 [14%], and standard treatment: &OV0556;1,156,520 [22%)]). Mean crude expenditure per patient in Western Europe (Eastern Europe) with Crohn's disease: investigations &OV0556;1803 (&OV0556;2160) (P = 0.44), surgery &OV0556;11,489 (&OV0556;13,973) (P = 0.14), standard treatment &OV0556;1027 (&OV0556;824) (P = 0.51), and biologicals &OV0556;7376 (&OV0556;8307) (P = 0.31). Mean crude expenditure per patient in Western Europe (Eastern Europe) with ulcerative colitis: investigations &OV0556;1189 (&OV0556;1518) (P < 0.01), surgery &OV0556;18,414 (&OV0556;12,395) (P = 0.18), standard treatment &OV0556;896 (&OV0556;798) (P < 0.05), and biologicals &OV0556;5681 (&OV0556;72) (P = 0.51).CONCLUSIONS: In this population-based unselected cohort, costs during the first year of disease were mainly incurred by investigative procedures and surgeries. However, biologicals accounted for >15% of costs. Long-term follow-up of the cohort is needed to assess the cost-effectiveness of biological agents.
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| 5. |
- Burisch, Johan, et al.
(författare)
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Disease course of inflammatory bowel disease unclassified in a European population-based inception cohort : an Epi-IBD study
- 2019
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Ingår i: Journal of Gastroenterology and Hepatology. - : John Wiley & Sons. - 0815-9319 .- 1440-1746. ; 34:6, s. 996-1003
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A definitive diagnosis of Crohn's disease (CD) or ulcerative colitis (UC) is not always possible and a proportion of patients will be diagnosed as inflammatory bowel disease unclassified (IBDU). The aim of the study was to investigate the prognosis of patients initially diagnosed with IBDU and the disease course during the following five years.METHODS: The Epi-IBD study is a prospective population-based cohort of 1,289 IBD patients diagnosed in centres across Europe. Clinical data were captured prospectively throughout the follow-up period.RESULTS: Overall, 476 (37%) patients were initially diagnosed with CD, 701 (54%) with UC, and 112 (9%) with IBDU. During follow-up, 28 (25%) IBDU patients were changed diagnoses to either UC (n=20, 71%) or CD (n=8, 29%) after a median of six months (IQR: 4-12), while 84 (7% of the total cohort) remained IBDU. A total of 17 (15%) IBDU patients were hospitalized for their IBD during follow-up, while 8 (7%) patients underwent surgery. Most surgeries (n=6, 75%) were performed on patients whose diagnosis was later changed to UC; three of these colectomies led to a definitive diagnosis of UC. Most patients (n=107, 96%) received 5-aminosalicylic acid, while 11 (10%) patients received biologicals, of whom five remained classified as IBDU.CONCLUSIONS: In a population-based inception cohort, 7% of IBD patients were not given a definitive diagnosis of IBD after five years of follow-up. One in four patients with IBDU eventually were classified as CD or UC. Overall, the disease course and medication burden in IBDU patients were mild.
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| 6. |
- Burisch, Johan, et al.
(författare)
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Initial Disease Course and Treatment in an Inflammatory Bowel Disease Inception Cohort in Europe : The ECCO-EpiCom Cohort
- 2014
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Ingår i: Inflammatory Bowel Diseases. - : Lippincott Williams & Wilkins. - 1078-0998 .- 1536-4844. ; 20:1, s. 36-46
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Tidskriftsartikel (refereegranskat)abstract
- Background:The EpiCom cohort is a prospective, population-based, inception cohort of inflammatory bowel disease (IBD) patients from 31 European centers covering a background population of 10.1 million. The aim of this study was to assess the 1-year outcome in the EpiCom cohort.Methods:Patients were followed-up every third month during the first 12 (3) months, and clinical data, demographics, disease activity, medical therapy, surgery, cancers, and deaths were collected and entered in a Web-based database (www.epicom-ecco.eu).Results:In total, 1367 patients were included in the 1-year follow-up. In western Europe, 65 Crohn's disease (CD) (16%), 20 ulcerative colitis (UC) (4%), and 4 IBD unclassified (4%) patients underwent surgery, and in eastern Europe, 12 CD (12%) and 2 UC (1%) patients underwent surgery. Eighty-one CD (20%), 80 UC (14%), and 13 (9%) IBD unclassified patients were hospitalized in western Europe compared with 17 CD (16%) and 12 UC (8%) patients in eastern Europe. The cumulative probability of receiving immunomodulators was 57% for CD in western (median time to treatment 2 months) and 44% (1 month) in eastern Europe, and 21% (5 months) and 5% (6 months) for biological therapy, respectively. For UC patients, the cumulative probability was 22% (4 months) and 15% (3 months) for immunomodulators and 6% (3 months) and 1% (12 months) for biological therapy, respectively in the western and eastern Europe.Discussion:In this cohort, immunological therapy was initiated within the first months of disease. Surgery and hospitalization rates did not differ between patients from eastern and western Europe, although more western European patients received biological agents and were comparable to previous population-based inception cohorts.
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| 7. |
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| 8. |
- Burisch, Johan, et al.
(författare)
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Natural Disease Course of Ulcerative Colitis During the First Five Years of Follow-up in a European Population-based Inception Cohort-An Epi-IBD Study
- 2019
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Ingår i: Journal of Crohn's & Colitis. - : Oxford University Press. - 1873-9946 .- 1876-4479. ; 13:2, s. 198-208
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims: Few population-based cohort studies have assessed the disease course of ulcerative colitis [UC] in the era of biological therapy and widespread use of immunomodulators. The aim of this study was to assess the 5-year outcome and disease course of patients with UC in the Epi-IBD cohort.Methods: In a prospective, population-based inception cohort of unselected patients with UC, patients were followed up from the time of their diagnosis, which included the collection of their clinical data, demographics, disease activity, medical therapy, and rates of surgery, cancers, and deaths. Associations between outcomes and multiple covariates were analysed by Cox regression analysis.Results: A total of 717 patients were included in the study. During follow-up, 43 [6%] patients underwent a colectomy and 163 [23%] patients were hospitalised. Of patients with limited colitis [distal to the left flexure], 90 [21%] progressed to extensive colitis. In addition, 92 [27%] patients with extensive colitis experienced a regression in disease extent, which was associated with a reduced risk of hospitalisation (hazard ratio [HR]: 0.5 95% CI: 0.3-0.8]. Overall, patients were treated similarly in both geographical regions; 80 [11%] patients needed biological therapy and 210 [29%] patients received immunomodulators. Treatment with immunomodulators was found to reduce the risk of hospitalisation [HR: 0.5 95% CI: 0.3-0.8].Conclusions: Although patients in this population-based cohort were treated more aggressively with immunomodulators and biological therapy than in cohorts from the previous two decades, their disease outcomes, including colectomy rates, were no different. However, treatment with immunomodulators was found to reduce the risk of hospitalisation.
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| 9. |
- Burisch, Johan, et al.
(författare)
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Occurrence of anaemia in the first year of inflammatory bowel disease in a European population-based inception cohort : An ECCO-EpiCom study
- 2017
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Ingår i: Journal of Crohn's & Colitis. - : Oxford University Press. - 1873-9946 .- 1876-4479. ; 11:10, s. 1213-1222
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Anaemia is an important complication of inflammatory bowel disease (IBD). The aim of this study was to determine the prevalence of anaemia and the practice of anaemia screening during the first year following diagnosis in a European prospective population-based inception cohort.Methods: Newly diagnosed IBD patients were included and followed prospectively for one year in 29 European and 1 Australian centre. Clinical data including demographics, medical therapy, surgery and blood samples were collected. Anaemia was defined according to the World Health Organization.Results: A total of 1,871 patients (CD: 686, 88%; UC: 1,021, 87%; IBDU 164. 81%) were included in the study. The prevalence of anaemia was higher in CD than in UC patients and overall, 49% of CD and 39% of UC patients had at least one instance of anaemia during the first 12 months after diagnosis. UC patients with more extensive disease and those from Eastern European countries, and CD patients with penetrating disease or colonic disease location, had higher risks of anaemia. CD and UC patients in need of none or only mild anti-inflammatory treatment had a lower risk of anaemia. In a significant proportion of patients, anaemia was not assessed until several months after diagnosis, and in almost half of all cases of anaemia a thorough work-up was not performed.Conclusions: Overall, 42% of patients had at least one instance of anaemia during the first year following diagnosis. Most patients were assessed for anaemia regularly; however, a full anaemia work-up was frequently neglected in this community setting.
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| 10. |
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