29 results on '"Loeffler M"'
Search Results
2. Clinical practice of fluid resuscitation in severe sepsis and septic shock on German ICUs
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Ragaller M, Christoph Engel, Gotschlich B, Bloos F, Loeffler M, and Reinhart K
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Poster Presentation - Published
- 2006
3. Epidemiology of severe sepsis and septic shock in Germany: results from the German 'Prevalence' study
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Brunkhorst, FM, Engel, C, Reinhart, K, Bone, H-G, Brunkhorst, R, Burchardi, H, Eckhardt, K-U, Forst, H, Gerlach, H, Grond, S, Gründling, M, Huhle, G, Oppert, M, Olthoff, D, Quintel, M, Ragaller, M, Rossaint, R, Seeger, W, Stüber, F, Weiler, N, Welte, T, and Loeffler, M
- Subjects
Poster Presentation - Published
- 2005
4. Associations between person-environment fit and mental health - results from the population-based LIFE-Adult-Study.
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Jung FU, Löbner M, Rodriguez FS, Engel C, Kirsten T, Reyes N, Glaesmer H, Hinz A, Witte AV, Zacher H, Loeffler M, Villringer A, Luppa M, and Riedel-Heller SG
- Subjects
- Humans, Male, Female, Adult, Cross-Sectional Studies, Middle Aged, Workplace psychology, Cohort Studies, Mental Health statistics & numerical data, Depression epidemiology, Depression psychology, Anxiety epidemiology
- Abstract
Within occupational settings, mental health of employees can be affected by complex interactions between individuals and their work environment. The aim of this cross-sectional analysis was to investigate the association between person-environment fit and mental health in employees. Data of n = 568 participants from the LIFE adult cohort study was analysed, including socio-demographic characteristics, three dimensions of person-environment fit (P-E fit), symptoms of depression and anxiety. Assessment took place between 2017 and 2021. Statistical analysis included descriptive analyses as well as generalized linear regression models adjusted for age, gender, socioeconomic status, marital status, and job status. Correlational analysis revealed significant associations between age, marital status, SES, employment status, symptoms of depression and anxiety and P-E fit. According to regression models, greater perceived fit between person and organization was associated with lower depression scores and lower symptoms of anxiety. Higher perceived fit between demands and abilities was significantly related to lower severity of depression and anxiety. Similarly, participants reporting a higher fit between needs and supplies, exhibited less symptom severity regarding depression and anxiety. These results underline the importance of person-environment fit regarding mental health. Finding ways to obtain an optimal balance should not only be recognized as an important factor for health and well-being, but might also be beneficial for organizations and employers in the long-term., (© 2024. The Author(s).)
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- 2024
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5. Sex and statin-related genetic associations at the PCSK9 gene locus: results of genome-wide association meta-analysis.
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Pott J, Kheirkhah A, Gadin JR, Kleber ME, Delgado GE, Kirsten H, Forer L, Hauck SM, Burkhardt R, Scharnagl H, Loeffler M, März W, Thiery J, Gieger C, Peters A, Silveira A, Hooft FV, Kronenberg F, and Scholz M
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- Male, Humans, Female, Proprotein Convertase 9 genetics, Proprotein Convertase 9 metabolism, Genome-Wide Association Study, Cholesterol, LDL genetics, Oxidoreductases, N-Demethylating, Jumonji Domain-Containing Histone Demethylases, Hydroxymethylglutaryl-CoA Reductase Inhibitors
- Abstract
Background: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key player of lipid metabolism with higher plasma levels in women throughout their life. Statin treatment affects PCSK9 levels also showing evidence of sex-differential effects. It remains unclear whether these differences can be explained by genetics., Methods: We performed genome-wide association meta-analyses (GWAS) of PCSK9 levels stratified for sex and statin treatment in six independent studies of Europeans (8936 women/11,080 men respectively 14,825 statin-free/5191 statin-treated individuals). Loci associated in one of the strata were tested for statin- and sex-interactions considering all independent signals per locus. Independent variants at the PCSK9 gene locus were then used in a stratified Mendelian Randomization analysis (cis-MR) of PCSK9 effects on low-density lipoprotein cholesterol (LDL-C) levels to detect differences of causal effects between the subgroups., Results: We identified 11 loci associated with PCSK9 in at least one stratified subgroup (p < 1.0 × 10
-6 ), including the PCSK9 gene locus and five other lipid loci: APOB, TM6SF2, FADS1/FADS2, JMJD1C, and HP/HPR. The interaction analysis revealed eight loci with sex- and/or statin-interactions. At the PCSK9 gene locus, there were four independent signals, one with a significant sex-interaction showing stronger effects in men (rs693668). Regarding statin treatment, there were two significant interactions in PCSK9 missense mutations: rs11591147 had stronger effects in statin-free individuals, and rs11583680 had stronger effects in statin-treated individuals. Besides replicating known loci, we detected two novel genome-wide significant associations: one for statin-treated individuals at 6q11.1 (within KHDRBS2) and one for males at 12q24.22 (near KSR2/NOS1), both with significant interactions. In the MR of PCSK9 on LDL-C, we observed significant causal estimates within all subgroups, but significantly stronger causal effects in statin-free subjects compared to statin-treated individuals., Conclusions: We performed the first double-stratified GWAS of PCSK9 levels and identified multiple biologically plausible loci with genetic interaction effects. Our results indicate that the observed sexual dimorphism of PCSK9 and its statin-related interactions have a genetic basis. Significant differences in the causal relationship between PCSK9 and LDL-C suggest sex-specific dosages of PCSK9 inhibitors., (© 2024. The Author(s).)- Published
- 2024
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6. Clinical and radiologic outcomes in patients with meniscal root tears.
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Manatrakul R, Loeffler M, Bharadwaj UU, Joseph GB, Lansdown D, Feeley B, Baal JD, Guimaraes JB, and Link TM
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- Humans, Radiography, Magnetic Resonance Imaging methods, Arthroscopy methods, Rupture, Pain, Retrospective Studies, Menisci, Tibial diagnostic imaging, Menisci, Tibial surgery, Knee Injuries diagnostic imaging, Knee Injuries surgery
- Abstract
Background: Meniscal root tears can lead to early knee osteoarthritis and pain. This study aimed (1) to compare clinical and radiological outcomes between patients who underwent arthroscopic meniscal root repair after meniscal root tears and those who received non-surgical treatment, and (2) to identify whether baseline MRI findings could be potential predictors for future treatment strategies., Methods: Patients with meniscal root tears were identified from our picture archiving and communication system from 2016 to 2020. Two radiologists reviewed radiographs and MRI studies using Kellgren-Lawrence (KL) grading and a modified Whole Organ MRI Scoring (WORMS) at baseline and follow-up. The median (interquartile range [IQR]) of follow-up radiographs and MRI studies were 134 (44-443) days and 502 (260-1176) days, respectively. MR images were assessed for root tear-related findings. Pain scores using visual analogue scale (VAS) and management strategies (non-surgical vs. arthroscopic root repair) were also collected. Chi-squared tests and independent t-tests were used to assess differences regarding clinical and imaging variables between treatment groups. Logistic regression analyses were performed to evaluate the associations between baseline MRI findings and each future treatment., Results: Ninety patients were included. VAS pain scores were significantly (p < 0.01) lower after arthroscopic repair compared to conservative treatment (1.27±0.38vs.4±0.52) at the last follow-up visit with median (IQR) of 325 (180-1391) days. Increased meniscal extrusion (mm) was associated with higher odds of receiving non-surgical treatment (OR = 1.65, 95%CI 1.02-2.69, p = 0.04). The odds of having arthroscopic repair increased by 19% for every 1 mm increase in the distance of the tear from the root attachment (OR = 1.19, 95% CI: 1.05-1.36, p < 0.01). The odds of undergoing arthroscopic repair were reduced by 49% for every 1 mm increase in the extent of meniscal extrusion (OR = 0.51, 95% CI: 0.29-0.91, p = 0.02) as observed in the baseline MRI., Conclusions: Patients who underwent arthroscopic repair had lower pain scores than patients with conservative treatment in the follow-up. Distance of the torn meniscus to the root attachment and the extent of meniscal extrusion were significant predictors for arthroscopic repair in the next three weeks (time from the baseline MRI to the surgery date)., (© 2024. The Author(s).)
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- 2024
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7. Perceived stress of mental demands at work, objective stress and resilience - an analysis of the LIFE-Adult-study.
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Jung FU, Pabst A, Rodriguez FS, Luppa M, Engel C, Kirsten T, Witte V, Reyes N, Loeffler M, Villringer A, and Riedel-Heller SG
- Abstract
Background: So far, previous research suggests positive effects of mental demands at the workplace. However, it may depend on how stressfull these demands are perceived on an individual level., Objective: The aim was to build on previous research by investigating how mental demands are related to stress, overload, and work discontent and whether this relationship is mediated by individuals resources, such as resilience., Method: A sub-sample of the LIFE Adult Cohort (n = 480) was asked to answer questions on sociodemographic characteristics, objective stress (using the Trier Inventory of Chronic Stress (TICS)), and perceptions of stress with regard to verbal and executive mental demands at work., Results: According to generalized linear regression models, higher verbal as well as executive mental demands were associated with higher levels of chronic stress, work overload and discontent. Higher levels of resilience were associated with lower levels of these outcomes. Analyses regarding interaction effects revealed that the interaction between resilience and perceived stress of verbal mental demands was significant only in terms of work overload., Conclusion: Higher perceived stressfulness of mental demands was associated with higher chronic stress, work overload and work discontent. Therefore, mental demands should be targeted by occupational interventions that aim to improve job conditions and employees' overall well-being. Besides resilience, other potential influencers or personal resources should be focused on in future studies to develop interventions., (© 2023. BioMed Central Ltd., part of Springer Nature.)
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- 2023
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8. Phase I/II study testing the combination of AGuIX nanoparticles with radiochemotherapy and concomitant temozolomide in patients with newly diagnosed glioblastoma (NANO-GBM trial protocol).
- Author
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Thivat E, Casile M, Moreau J, Molnar I, Dufort S, Seddik K, Le Duc G, De Beaumont O, Loeffler M, Durando X, and Biau J
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- Female, Humans, Temozolomide therapeutic use, Antineoplastic Agents, Alkylating therapeutic use, Chemoradiotherapy methods, Randomized Controlled Trials as Topic, Multicenter Studies as Topic, Clinical Trials, Phase II as Topic, Clinical Trials, Phase I as Topic, Glioblastoma drug therapy, Glioblastoma pathology, Brain Neoplasms pathology, Nanoparticles
- Abstract
Background: Despite standard treatments including chemoradiotherapy with temozolomide (TMZ) (STUPP protocol), the prognosis of glioblastoma patients remains poor. AGuIX nanoparticles have a high radiosensitizing potential, a selective and long-lasting accumulation in tumors and a rapid renal elimination. Their therapeutic effect has been proven in vivo on several tumor models, including glioblastoma with a potential synergetic effect when combined with TMZ based chemoradiotherapy, and they are currently evaluated in 4 ongoing Phase Ib and II clinical trials in 4 indications (brain metastases, lung, pancreatic and cervix cancers) (> 100 patients received AGuIX). Thus, they could offer new perspectives for patients with newly diagnosed glioblastoma. The aim of this study is to determine the recommended dose of AGuIX as a radiosensitizer in combination with radiotherapy and TMZ during the concurrent radio-chemotherapy period for phase II (RP2D) and to estimate the efficacy of the combination., Methods: NANO-GBM is a multicenter, phase I/II, randomized, open-label, non-comparative, therapeutic trial. According to a dose escalation scheme driven by a TITE-CRM design, 3 dose levels of AGuIX (50, 75 and 100 mg/kg) will be tested in phase I added to standard concomitant radio-chemotherapy. Patients with grade IV glioblastoma, not operated or partially operated, with a KPS ≥ 70% will be eligible for the study. The primary endpoints are i) for phase I, the RP2D of AGuIX, with DLT defined as any grade 3-4 NCI-CTCAE toxicity and ii) for phase II, the 6-month progression-free survival rate. The pharmacokinetics, distribution of nanoparticles, tolerance of the combination, neurological status, overall survival (median, 6-month and 12-month rates), response to treatment, and progression-free survival (median and 12-month rates) will be assessed as secondary objectives. Maximum sixty-six patients are expected to be recruited in the study from 6 sites., Discussion: The use of AGuIX nanoparticles could allow to overpass the radioresistance to the reference treatment of newly diagnosed glioblastomas that have the poorest prognosis (incomplete resection or biopsy only)., Trial Registration: Clinicaltrials.gov: NCT04881032 , registered on April 30, 2021. Identifier with the French National Agency for the Safety of Medicines and Health Products (ANSM): N°Eudra CT 2020-004552-15., Protocol: version 3, 23 May 2022., (© 2023. The Author(s).)
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- 2023
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9. Colorectal cancer incidences in Lynch syndrome: a comparison of results from the prospective lynch syndrome database and the international mismatch repair consortium.
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Møller P, Seppälä T, Dowty JG, Haupt S, Dominguez-Valentin M, Sunde L, Bernstein I, Engel C, Aretz S, Nielsen M, Capella G, Evans DG, Burn J, Holinski-Feder E, Bertario L, Bonanni B, Lindblom A, Levi Z, Macrae F, Winship I, Plazzer JP, Sijmons R, Laghi L, Valle AD, Heinimann K, Half E, Lopez-Koestner F, Alvarez-Valenzuela K, Scott RJ, Katz L, Laish I, Vainer E, Vaccaro CA, Carraro DM, Gluck N, Abu-Freha N, Stakelum A, Kennelly R, Winter D, Rossi BM, Greenblatt M, Bohorquez M, Sheth H, Tibiletti MG, Lino-Silva LS, Horisberger K, Portenkirchner C, Nascimento I, Rossi NT, da Silva LA, Thomas H, Zaránd A, Mecklin JP, Pylvänäinen K, Renkonen-Sinisalo L, Lepisto A, Peltomäki P, Therkildsen C, Lindberg LJ, Thorlacius-Ussing O, von Knebel Doeberitz M, Loeffler M, Rahner N, Steinke-Lange V, Schmiegel W, Vangala D, Perne C, Hüneburg R, de Vargas AF, Latchford A, Gerdes AM, Backman AS, Guillén-Ponce C, Snyder C, Lautrup CK, Amor D, Palmero E, Stoffel E, Duijkers F, Hall MJ, Hampel H, Williams H, Okkels H, Lubiński J, Reece J, Ngeow J, Guillem JG, Arnold J, Wadt K, Monahan K, Senter L, Rasmussen LJ, van Hest LP, Ricciardiello L, Kohonen-Corish MRJ, Ligtenberg MJL, Southey M, Aronson M, Zahary MN, Samadder NJ, Poplawski N, Hoogerbrugge N, Morrison PJ, James P, Lee G, Chen-Shtoyerman R, Ankathil R, Pai R, Ward R, Parry S, Dębniak T, John T, van Overeem Hansen T, Caldés T, Yamaguchi T, Barca-Tierno V, Garre P, Cavestro GM, Weitz J, Redler S, Büttner R, Heuveline V, Hopper JL, Win AK, Lindor N, Gallinger S, Le Marchand L, Newcomb PA, Figueiredo J, Buchanan DD, Thibodeau SN, Ten Broeke SW, Hovig E, Nakken S, Pineda M, Dueñas N, Brunet J, Green K, Lalloo F, Newton K, Crosbie EJ, Mints M, Tjandra D, Neffa F, Esperon P, Kariv R, Rosner G, Pavicic WH, Kalfayan P, Torrezan GT, Bassaneze T, Martin C, Moslein G, Ahadova A, Kloor M, Sampson JR, and Jenkins MA
- Abstract
Objective: To compare colorectal cancer (CRC) incidences in carriers of pathogenic variants of the MMR genes in the PLSD and IMRC cohorts, of which only the former included mandatory colonoscopy surveillance for all participants., Methods: CRC incidences were calculated in an intervention group comprising a cohort of confirmed carriers of pathogenic or likely pathogenic variants in mismatch repair genes (path_MMR) followed prospectively by the Prospective Lynch Syndrome Database (PLSD). All had colonoscopy surveillance, with polypectomy when polyps were identified. Comparison was made with a retrospective cohort reported by the International Mismatch Repair Consortium (IMRC). This comprised confirmed and inferred path_MMR carriers who were first- or second-degree relatives of Lynch syndrome probands., Results: In the PLSD, 8,153 subjects had follow-up colonoscopy surveillance for a total of 67,604 years and 578 carriers had CRC diagnosed. Average cumulative incidences of CRC in path_MLH1 carriers at 70 years of age were 52% in males and 41% in females; for path_MSH2 50% and 39%; for path_MSH6 13% and 17% and for path_PMS2 11% and 8%. In contrast, in the IMRC cohort, corresponding cumulative incidences were 40% and 27%; 34% and 23%; 16% and 8% and 7% and 6%. Comparing just the European carriers in the two series gave similar findings. Numbers in the PLSD series did not allow comparisons of carriers from other continents separately. Cumulative incidences at 25 years were < 1% in all retrospective groups., Conclusions: Prospectively observed CRC incidences (PLSD) in path_MLH1 and path_MSH2 carriers undergoing colonoscopy surveillance and polypectomy were higher than in the retrospective (IMRC) series, and were not reduced in path_MSH6 carriers. These findings were the opposite to those expected. CRC point incidence before 50 years of age was reduced in path_PMS2 carriers subjected to colonoscopy, but not significantly so., (© 2022. The Author(s).)
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- 2022
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10. Renal function and lipid metabolism are major predictors of circumpapillary retinal nerve fiber layer thickness-the LIFE-Adult Study.
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Rauscher FG, Wang M, Francke M, Wirkner K, Tönjes A, Engel C, Thiery J, Stenvinkel P, Stumvoll M, Loeffler M, Elze T, and Ebert T
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- Adult, Female, Humans, Kidney physiology, Male, Nerve Fibers, Retinal Ganglion Cells, Lipid Metabolism, Optic Disk
- Abstract
Background: Circumpapillary retinal nerve fiber layer thickness (cpRNFLT) as assessed by spectral domain optical coherence tomography (SD-OCT) is a new technique used for the detection and evaluation of glaucoma and other optic neuropathies. Before translating cpRNFLT into clinics, it is crucially important to investigate anthropometric, biochemical, and clinical parameters potentially affecting cpRNFLT in a large population-based dataset., Methods: The population-based LIFE-Adult Study randomly selected 10,000 participants from the population registry of Leipzig, Germany. All participants underwent standardized systemic assessment of various cardiometabolic risk markers and ocular imaging, including cpRNFLT measurement using SD-OCT (Spectralis, Heidelberg Engineering). After employing strict SD-OCT quality criteria, 8952 individuals were analyzed. Multivariable linear regression analyses were used to evaluate the independent associations of various cardiometabolic risk markers with sector-specific cpRNFLT. For significant markers, the relative strength of the observed associations was compared to each other to identify the most relevant factors influencing cpRNFLT. In all analyses, the false discovery rate method for multiple comparisons was applied., Results: In the entire cohort, female subjects had significantly thicker global and also sectoral cpRNFLT compared to male subjects (p < 0.05). Multivariable linear regression analyses revealed a significant and independent association between global and sectoral cpRNFLT with biomarkers of renal function and lipid profile. Thus, thinner cpRNFLT was associated with worse renal function as assessed by cystatin C and estimated glomerular filtration rate. Furthermore, an adverse lipid profile (i.e., low high-density lipoprotein (HDL) cholesterol, as well as high total, high non-HDL, high low-density lipoprotein cholesterol, and high apolipoprotein B) was independently and statistically significantly related to thicker cpRNFLT. In contrast, we do not observe a significant association between cpRNFLT and markers of inflammation, glucose homeostasis, liver function, blood pressure, or obesity in our sector-specific analysis and globally., Conclusions: Markers of renal function and lipid metabolism are predictors of sectoral cpRNFLT in a large and deeply phenotyped population-based study independently of previously established covariates. Future studies on cpRNFLT should include these biomarkers and need to investigate whether incorporation will improve the diagnosis of early eye diseases based on cpRNFLT., (© 2021. The Author(s).)
- Published
- 2021
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11. Cancer risks in Lynch syndrome, Lynch-like syndrome, and familial colorectal cancer type X: a prospective cohort study.
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Bucksch K, Zachariae S, Aretz S, Büttner R, Holinski-Feder E, Holzapfel S, Hüneburg R, Kloor M, von Knebel Doeberitz M, Morak M, Möslein G, Nattermann J, Perne C, Rahner N, Schmiegel W, Schulmann K, Steinke-Lange V, Strassburg CP, Vangala DB, Weitz J, Loeffler M, and Engel C
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- Adult, Aged, Aged, 80 and over, Brain Neoplasms genetics, Colorectal Neoplasms genetics, DNA Mismatch Repair, Female, Follow-Up Studies, Humans, Male, Microsatellite Instability, Middle Aged, Neoplastic Syndromes, Hereditary genetics, Prognosis, Prospective Studies, Survival Rate, Biomarkers, Tumor genetics, Brain Neoplasms epidemiology, Colorectal Neoplasms classification, Colorectal Neoplasms epidemiology, DNA Repair Enzymes genetics, Genetic Predisposition to Disease, Genetics, Population, Neoplastic Syndromes, Hereditary epidemiology
- Abstract
Background: Individuals with pathogenic germline variants in DNA mismatch repair (MMR) genes are at increased risk of developing colorectal, endometrial and other cancers (Lynch syndrome, LS). While previous studies have extensively described cancer risks in LS, cancer risks in individuals from families without detectable MMR gene defects despite MMR deficiency (Lynch-like syndrome, LLS), and in individuals from families fulfilling the Amsterdam-II criteria without any signs of MMR deficiency (familial colorectal cancer type X, FCCX) are less well studied. The aim of this prospective study was to characterise the risk for different cancer types in LS, LLS, and FCCX, and to compare these with the cancer risks in the general population., Methods: Data was taken from the registry of the German Consortium for Familial Intestinal Cancer, where individuals were followed up prospectively within the framework of an intensified surveillance programme at recommended annual examination intervals. A total of 1120 LS, 594 LLS, and 116 FCCX individuals were analysed. From this total sample, eight different cohorts were defined, in which age-dependent cumulative risks and standardised incidence ratios were calculated regarding the first incident occurrence of any, colorectal, stomach, small bowel, urothelial, female breast, ovarian, and endometrial cancer, separately for LS, LLS, and FCCX., Results: The number of individuals at risk for first incident cancer ranged from 322 to 1102 in LS, 120 to 586 in LLS, and 40 to 116 in FCCX, depending on the cancer type of interest. For most cancer types, higher risks were observed in LS compared to LLS, FCCX, and the general population. Risks for any, colorectal, stomach, urothelial, and endometrial cancer were significantly higher in LLS compared to the general population. No significantly increased risks could be detected in FCCX compared to LLS patients, and the general population. Colorectal and endometrial cancer risks tended to be higher in LLS than in FCCX., Conclusions: The characterisation of cancer risks in patients with LLS and FCCX is important to develop appropriate surveillance programmes for these specific intermediate risk groups. Larger prospective studies are needed to obtain more precise risk estimates.
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- 2020
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12. Are social conflicts at work associated with depressive symptomatology? Results from the population-based LIFE-Adult-Study.
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Zuelke AE, Roehr S, Schroeter ML, Witte AV, Hinz A, Engel C, Enzenbach C, Thiery J, Loeffler M, Villringer A, and Riedel-Heller SG
- Abstract
Background: Psychosocial stressors in the workplace can be detrimental to mental health. Conflicts at work, e.g. aggression, hostility or threats from coworkers, supervisors or customers, can be considered a psychosocial stressor, possibly increasing risk for depressive symptoms. Existing studies, however, differ in the assessment of social conflicts, i.e. as individual- or job-level characteristics. Here, we investigated the association between conflicts at work assessed as objective job characteristics, and depressive symptomatology, using data from a large population-based sample. Additionally, we investigated gender differences and the impact of personality traits and social resources., Methods: We used data from the population-based LIFE-Adult-Study from Leipzig, Germany. Information on conflicts at work, assessed as job characteristics, were drawn from the Occupational Information Network, depressive symptoms were assessed via the Center for Epidemiological Studies Depression Scale. Multilevel linear regression models with individuals and occupations as levels of analysis were applied to investigate the association between conflicts at work and depressive symptoms., Results: Our sample included 2164 employed adults (age: 18-65 years, mean: 49.3, SD: 7.9) in 65 occupations. No association between conflicts s at work and depressive symptomatology was found (men: b = - 0.14; p = 0.74, women: b = 0.17, p = 0.72). Risk for depression was mostly explained by individual-level factors like e.g. neuroticism or level of social resources. The model showed slightly higher explanatory power in the female subsample., Conclusion: Conflicts at work, assessed as objective job characteristics, were not associated with depressive symptoms. Possible links between interpersonal conflict and impaired mental health might rather be explained by subjective perceptions of social stressors and individual coping styles., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s). 2020.)
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- 2020
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13. Venous thromboembolism rates after hip and knee arthroplasty and hip fractures.
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Mula V, Parikh S, Suresh S, Bottle A, Loeffler M, and Alam M
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- Aged, Aged, 80 and over, Anticoagulants administration & dosage, Enoxaparin administration & dosage, Female, Follow-Up Studies, Humans, Male, Postoperative Complications mortality, Risk, Venous Thromboembolism mortality, Venous Thromboembolism prevention & control, Arthroplasty, Replacement, Hip adverse effects, Arthroplasty, Replacement, Knee adverse effects, Hip Fractures surgery, Postoperative Complications etiology, Venous Thromboembolism diagnosis, Venous Thromboembolism etiology
- Abstract
Background: The ideal thromboprophylaxis regime following lower limb arthroplasty and proximal femur fractures remains controversial. Guidelines disagree on the type of chemical prophylaxis, its dose or duration. This article describes a method of monitoring venous thromboembolism (VTE) rates following Total Hip (THA), Total Knee Arthroplasty (TKA) and surgery for hip fractures (NOF#)., Methods: Over 3 years, all patients investigated for VTE were analysed using Picture Archiving Communications System (PACS). All positive scans were then cross-referenced using PACS and local registry data to see if they had undergone THA, TKA or NOF# in the preceding 90 days. Mortality data were obtained from the national administrative database, Hospital Episode Statistics., Results: Five thousand seven hundred eighty-eight patients underwent investigation for VTE and there were 29 diagnoses of PE and 24 of DVT. There was a 0.77% rate of symptomatic DVT after THA, 0.05% after TKA and 0.55% after NOF #. The rate of confirmed symptomatic PE for THA was 0.46, 0.27% for TKA and 0.96% for NOF #. Mortality at one-year post-THA was 0.6, 0.6% for TKA and 25.9% after NOF#. All patients contacted either remained within the catchment area for the minimum 90 postoperative days or died within the catchment area., Conclusions: The 90 day post-operative prevalence of symptomatic VTE of 1.2, 0.3 and 1.5% in THA, TKA and NOF # respectively are similar to other studies using symptomatic and imaging positive VTE as their endpoint. The study uses a method of collecting data which can be utilised in centres where PACS is available.
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- 2020
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14. Integration of mathematical model predictions into routine workflows to support clinical decision making in haematology.
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Hoffmann K, Cazemier K, Baldow C, Schuster S, Kheifetz Y, Schirm S, Horn M, Ernst T, Volgmann C, Thiede C, Hochhaus A, Bornhäuser M, Suttorp M, Scholz M, Glauche I, Loeffler M, and Roeder I
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- Humans, Proof of Concept Study, Clinical Decision-Making methods, Computer Simulation, Decision Support Systems, Clinical, Hematologic Diseases, Models, Theoretical, Software, Workflow
- Abstract
Background: Individualization and patient-specific optimization of treatment is a major goal of modern health care. One way to achieve this goal is the application of high-resolution diagnostics together with the application of targeted therapies. However, the rising number of different treatment modalities also induces new challenges: Whereas randomized clinical trials focus on proving average treatment effects in specific groups of patients, direct conclusions at the individual patient level are problematic. Thus, the identification of the best patient-specific treatment options remains an open question. Systems medicine, specifically mechanistic mathematical models, can substantially support individual treatment optimization. In addition to providing a better general understanding of disease mechanisms and treatment effects, these models allow for an identification of patient-specific parameterizations and, therefore, provide individualized predictions for the effect of different treatment modalities., Results: In the following we describe a software framework that facilitates the integration of mathematical models and computer simulations into routine clinical processes to support decision-making. This is achieved by combining standard data management and data exploration tools, with the generation and visualization of mathematical model predictions for treatment options at an individual patient level., Conclusions: By integrating model results in an audit trail compatible manner into established clinical workflows, our framework has the potential to foster the use of systems-medical approaches in clinical practice. We illustrate the framework application by two use cases from the field of haematological oncology.
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- 2020
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15. Evaluating selection bias in a population-based cohort study with low baseline participation: the LIFE-Adult-Study.
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Enzenbach C, Wicklein B, Wirkner K, and Loeffler M
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- Adult, Aged, Cohort Studies, Educational Status, Employment, Female, Germany, Health Status, Humans, Logistic Models, Male, Marital Status statistics & numerical data, Middle Aged, Selection Bias, Smokers statistics & numerical data, Patient Participation statistics & numerical data, Population Surveillance methods, Research Design, Surveys and Questionnaires
- Abstract
Background: Participation in epidemiologic studies is steadily declining, which may result in selection bias. It is therefore an ongoing challenge to clarify the determinants of participation to judge possible selection effects and to derive measures to minimise that bias. We evaluated the potential for selection bias in a recent population-based cohort study with low baseline participation and investigated reasons for nonparticipation., Methods: LIFE-Adult is a cohort study in the general population of the city of Leipzig (Germany) designed to gain insights into the distribution and development of civilisation diseases. Nine thousand one hundred forty-five participants aged 40-79 years were randomly sampled in 2011-2014. We compared LIFE-Adult participants with both the Leipzig population and nonparticipants using official statistics and short questionnaire data. We applied descriptive statistics and logistic regression analysis to evaluate the determinants of study participation., Results: Thirty-one percent of the invited persons participated in the LIFE-Adult baseline examination. Study participants were less often elderly women and more often married, highly educated, employed, and current nonsmokers compared to both the Leipzig population and nonparticipants. They further reported better health than nonparticipants. The observed differences were considerable in education and health variables. They were generally stronger in men than in women. For example, in male study participants aged 50-69, the frequency of high education was 1.5 times that of the general population, and the frequency of myocardial infarction was half that of nonparticipants. Lack of time and interest, as well as health problems were the main reasons for nonparticipation., Conclusions: Our investigation suggests that the low baseline participation in LIFE-Adult is associated with the typical selection of study participants with higher social status and healthier lifestyle, and additionally less disease. Notably, education and health status seem to be crucial selection factors. Consequently, frequencies of major health conditions in the general population will likely be underestimated. A differential selection related to sex might also distort effect estimates. The extent of the assessment, the interest in the research topic, and health problems of potential participants should in future be considered in LIFE-Adult and in similar studies to raise participation and to minimise selection bias.
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- 2019
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16. Low frequency of mismatch repair deficiency in gallbladder cancer.
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Goeppert B, Roessler S, Renner M, Loeffler M, Singer S, Rausch M, Albrecht T, Mehrabi A, Vogel MN, Pathil A, Czink E, Köhler B, Springfeld C, Rupp C, Weiss KH, Schirmacher P, von Knebel Doeberitz M, and Kloor M
- Subjects
- Adenocarcinoma diagnosis, Adenocarcinoma pathology, Aged, Brain Neoplasms diagnosis, Brain Neoplasms pathology, Cohort Studies, Colorectal Neoplasms diagnosis, Colorectal Neoplasms pathology, DNA Mismatch Repair, Female, Gallbladder Neoplasms diagnosis, Gallbladder Neoplasms pathology, Humans, Immunohistochemistry, Male, Neoplastic Syndromes, Hereditary diagnosis, Neoplastic Syndromes, Hereditary pathology, Phenotype, Adenocarcinoma genetics, Brain Neoplasms genetics, Colorectal Neoplasms genetics, Gallbladder Neoplasms genetics, Microsatellite Instability, MutL Protein Homolog 1 genetics, Neoplastic Syndromes, Hereditary genetics
- Abstract
Background: DNA mismatch repair (MMR) deficiency is a major pathway of genomic instability in cancer. It leads to the accumulation of numerous mutations predominantly at microsatellite sequences, a phenotype known as microsatellite instability (MSI). MSI tumors have a distinct clinical behavior and commonly respond well to immune checkpoint blockade, irrespective of their origin. Data about the prevalence of MSI among gallbladder cancer (GBC) have been conflicting. We here analyzed a well-characterized cohort of 69 Western-world GBCs., Methods: We analyzed the mononucleotide MSI marker panel consisting of BAT25, BAT26, and CAT25 to determine the prevalence of MMR deficiency-induced MSI., Results: MSI was detected in 1/69 (1.4%) of analyzed GBCs. The detected MSI GBC had a classical histomorphology, i.e. of acinar/tubular/glandular pancreatobiliary phenotype, and showed nuclear expression of all four MMR proteins MLH1, MSH2, MSH6, and PMS2. The MSI GBC patient showed a prolonged overall survival, despite having a high tumor stage at diagnosis. The patient had no known background or family history indicative of Lynch syndrome., Conclusions: Even though the overall number of MSI tumors is low in GBC, the potentially therapeutic benefit of checkpoint blockade in the respective patients may justify MSI analysis of GBC.
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- 2019
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17. A modular transcriptome map of mature B cell lymphomas.
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Loeffler-Wirth H, Kreuz M, Hopp L, Arakelyan A, Haake A, Cogliatti SB, Feller AC, Hansmann ML, Lenze D, Möller P, Müller-Hermelink HK, Fortenbacher E, Willscher E, Ott G, Rosenwald A, Pott C, Schwaenen C, Trautmann H, Wessendorf S, Stein H, Szczepanowski M, Trümper L, Hummel M, Klapper W, Siebert R, Loeffler M, and Binder H
- Subjects
- Humans, Lymphoma, B-Cell metabolism, Lymphoma, B-Cell pathology, Machine Learning, Gene Expression Regulation, Neoplastic, Lymphoma, B-Cell genetics, Transcriptome
- Abstract
Background: Germinal center-derived B cell lymphomas are tumors of the lymphoid tissues representing one of the most heterogeneous malignancies. Here we characterize the variety of transcriptomic phenotypes of this disease based on 873 biopsy specimens collected in the German Cancer Aid MMML (Molecular Mechanisms in Malignant Lymphoma) consortium. They include diffuse large B cell lymphoma (DLBCL), follicular lymphoma (FL), Burkitt's lymphoma, mixed FL/DLBCL lymphomas, primary mediastinal large B cell lymphoma, multiple myeloma, IRF4-rearranged large cell lymphoma, MYC-negative Burkitt-like lymphoma with chr. 11q aberration and mantle cell lymphoma., Methods: We apply self-organizing map (SOM) machine learning to microarray-derived expression data to generate a holistic view on the transcriptome landscape of lymphomas, to describe the multidimensional nature of gene regulation and to pursue a modular view on co-expression. Expression data were complemented by pathological, genetic and clinical characteristics., Results: We present a transcriptome map of B cell lymphomas that allows visual comparison between the SOM portraits of different lymphoma strata and individual cases. It decomposes into one dozen modules of co-expressed genes related to different functional categories, to genetic defects and to the pathogenesis of lymphomas. On a molecular level, this disease rather forms a continuum of expression states than clearly separated phenotypes. We introduced the concept of combinatorial pattern types (PATs) that stratifies the lymphomas into nine PAT groups and, on a coarser level, into five prominent cancer hallmark types with proliferation, inflammation and stroma signatures. Inflammation signatures in combination with healthy B cell and tonsil characteristics associate with better overall survival rates, while proliferation in combination with inflammation and plasma cell characteristics worsens it. A phenotypic similarity tree is presented that reveals possible progression paths along the transcriptional dimensions. Our analysis provided a novel look on the transition range between FL and DLBCL, on DLBCL with poor prognosis showing expression patterns resembling that of Burkitt's lymphoma and particularly on 'double-hit' MYC and BCL2 transformed lymphomas., Conclusions: The transcriptome map provides a tool that aggregates, refines and visualizes the data collected in the MMML study and interprets them in the light of previous knowledge to provide orientation and support in current and future studies on lymphomas and on other cancer entities.
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- 2019
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18. Programmed cell death ligand 1 (PD-L1, CD274) in cholangiocarcinoma - correlation with clinicopathological data and comparison of antibodies.
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Kriegsmann M, Roessler S, Kriegsmann K, Renner M, Longuespée R, Albrecht T, Loeffler M, Singer S, Mehrabi A, Vogel MN, Pathil A, Köhler B, Springfeld C, Rupp C, Weiss KH, and Goeppert B
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- Adult, Aged, Aged, 80 and over, B7-H1 Antigen antagonists & inhibitors, B7-H1 Antigen immunology, Bile Duct Neoplasms drug therapy, Bile Duct Neoplasms immunology, Bile Duct Neoplasms mortality, Bile Ducts, Intrahepatic immunology, Bile Ducts, Intrahepatic pathology, Cohort Studies, Female, Humans, Immunohistochemistry methods, Klatskin Tumor drug therapy, Klatskin Tumor immunology, Klatskin Tumor mortality, Male, Middle Aged, Neoplasm Staging, Staining and Labeling methods, Survival Analysis, Tissue Array Analysis, Antibodies immunology, B7-H1 Antigen metabolism, Bile Duct Neoplasms pathology, Klatskin Tumor pathology
- Abstract
Background: Cholangiocarcinoma (CCA) may arise in the intra- or extrahepatic biliary tract and is associated with a poor prognosis. Despite recent advances, to date there is still no established targeted therapeutic approach available. Non-surgical therapeutic agents are urgently needed, as most patients are non-eligible to surgical resection. Anti-PD-L1 therapy prevents cancer cells from evading the immune system and has emerged as a new treatment option in several cancer entities. Recently, PD-L1 expression has been analyzed in comparably small CCA patient cohorts. However, a systematic validation of different PD-L1 antibodies has not been performed in CCA so far., Methods: We stained a tissue microarray consisting of 170 patients, including 72 intrahepatic cholangiocarcinomas (iCCAs), 57 perihilar cholangiocarcinomas (pCCAs) and 41 distal cholangiocarcinomas (dCCAs) by immunohistochemistry and evaluated PD-L1 positivity in tumor and stromal cells. We analyzed three different PD-L1 antibodies (clones 28-8, SP142, and SP263) that are frequently used and recommended for predictive diagnostic testing in other cancer types., Results: For PD-L1 antibody clone SP263, 5% of iCCAs, 4% of pCCAs and 3% of dCCAs exhibited PD-L1 expression on tumor cells, thereby showing the highest frequencies of PD-L1 positivity. Accordingly, highest PD-L1 positivity rates of stromal cells with 31% in iCCA, 40% in pCCA and 61% in dCCA were detected for clone SP263. Agreement of PD-L1 positivity in tumor cells was moderate for clone 28-8 and SP263 (κ = 0.44) and poor between 28-8 and SP142 (κ = 0.13), as well as SP142 and SP263 (κ = 0.11), respectively. Statistical analyses of PD-L1 expression (clone SP263) on tumor cells with clinicopathological data revealed a positive correlation with shortened overall survival in CCA patients., Conclusions: Selection of appropriate PD-L1 antibodies and careful evaluation of immunohistochemical staining patterns have a significant impact on PD-L1 testing in CCA. Clinical trials are necessary to investigate the putative beneficial effects of PD-L1 targeted immunotherapy in CCA patients.
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- 2019
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19. Memory-related subjective cognitive symptoms in the adult population: prevalence and associated factors - results of the LIFE-Adult-Study.
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Luck T, Roehr S, Rodriguez FS, Schroeter ML, Witte AV, Hinz A, Mehnert A, Engel C, Loeffler M, Thiery J, Villringer A, and Riedel-Heller SG
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- Adult, Aged, Cohort Studies, Female, Germany epidemiology, Humans, Male, Middle Aged, Prevalence, Cognitive Dysfunction epidemiology, Diagnostic Self Evaluation, Memory Disorders epidemiology
- Abstract
Background: Subjectively perceived memory problems (memory-related Subjective Cognitive Symptoms/SCS) can be an indicator of a pre-prodromal or prodromal stage of a neurodegenerative disease such as Alzheimer's disease. We therefore sought to provide detailed empirical information on memory-related SCS in the dementia-free adult population including information on prevalence rates, associated factors and others., Methods: We studied 8834 participants (40-79 years) of the population-based LIFE-Adult-Study. Weighted prevalence rates with confidence intervals (95%-CI) were calculated. Associations of memory-related SCS with participants' socio-demographic characteristics, physical and mental comorbidity, and cognitive performance (Verbal Fluency Test Animals, Trail-Making-Test, CERAD Wordlist tests) were analyzed., Results: Prevalence of total memory-related SCS was 53.0% (95%-CI = 51.9-54.0): 26.0% (95%-CI = 25.1-27.0) of the population had a subtype without related concerns, 23.6% (95%-CI = 22.7-24.5) a subtype with some related concerns, and 3.3% (95%-CI = 2.9-3.7) a subtype with strong related concerns. Report of memory-related SCS was unrelated to participants' socio-demographic characteristics, physical comorbidity (except history of stroke), depressive symptomatology, and anxiety. Adults with and without memory-related SCS showed no significant difference in cognitive performance. About one fifth (18.1%) of the participants with memory-related SCS stated that they did consult/want to consult a physician because of their experienced memory problems., Conclusions: Memory-related SCS are very common and unspecific in the non-demented adult population aged 40-79 years. Nonetheless, a substantial proportion of this population has concerns related to experienced memory problems and/or seeks help. Already available information on additional features associated with a higher likelihood of developing dementia in people with SCS may help clinicians to decide who should be monitored more closely.
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- 2018
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20. PROGRESS - prospective observational study on hospitalized community acquired pneumonia.
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Ahnert P, Creutz P, Scholz M, Schütte H, Engel C, Hossain H, Chakraborty T, Bauer M, Kiehntopf M, Völker U, Hammerschmidt S, Loeffler M, and Suttorp N
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- Databases, Factual, Disease Progression, Germany epidemiology, Humans, Longitudinal Studies, Prospective Studies, Sepsis etiology, Severity of Illness Index, Community-Acquired Infections epidemiology, Hospitalization, Pneumonia, Bacterial epidemiology
- Abstract
Background: Community acquired pneumonia (CAP) is a high incidence disease resulting in about 260,000 hospital admissions per year in Germany, more than myocardial infarction or stroke. Worldwide, CAP is the most frequent infectious disease with high lethality ranging from 1.2 % in those 20-29 years old to over 10 % in patients older than 70 years, even in industrial nations. CAP poses numerous medical challenges, which the PROGRESS (Pneumonia Research Network on Genetic Resistance and Susceptibility for the Evolution of Severe Sepsis) network aims to tackle: Operationalization of disease severity throughout the course of disease, outcome prediction for hospitalized patients and prediction of transitions from uncomplicated CAP to severe CAP, and finally, to CAP with sepsis and organ failure as a life-threatening condition. It is a major aim of PROGRESS to understand and predict patient heterogeneity regarding outcome in the hospital and to develop novel treatment concepts., Methods: PROGRESS was designed as a clinical, observational, multi-center study of patients with CAP requiring hospitalization. More than 1600 patients selected for low burden of co-morbidities have been enrolled, aiming at a total of 3000. Course of disease, along with therapy, was closely monitored by daily assessments and long-term follow-up. Daily blood samples allow in depth molecular-genetic characterization of patients. We established a well-organized workflow for sample logistics and a comprehensive data management system to collect and manage data from more than 50 study centers in Germany and Austria. Samples are stored in a central biobank and clinical data are stored in a central data base which also integrates all data from molecular assessments., Discussion: With the PROGRESS study, we established a comprehensive data base of high quality clinical and molecular data allowing investigation of pressing research questions regarding CAP. In-depth molecular characterization will contribute to the discovery of disease mechanisms and establishment of diagnostic and predictive biomarkers. A strength of PROGRESS is the focus on younger patients with low burden of co-morbidities, allowing a more direct look at host biology with less confounding. As a resulting limitation, insights from PROGRESS will require validation in representative patient cohorts to assess clinical utility., Trial Registration: The PROGRESS study was retrospectively registered on May 24(th), 2016 with ClinicalTrials.gov: NCT02782013.
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- 2016
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21. The LIFE-Adult-Study: objectives and design of a population-based cohort study with 10,000 deeply phenotyped adults in Germany.
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Loeffler M, Engel C, Ahnert P, Alfermann D, Arelin K, Baber R, Beutner F, Binder H, Brähler E, Burkhardt R, Ceglarek U, Enzenbach C, Fuchs M, Glaesmer H, Girlich F, Hagendorff A, Häntzsch M, Hegerl U, Henger S, Hensch T, Hinz A, Holzendorf V, Husser D, Kersting A, Kiel A, Kirsten T, Kratzsch J, Krohn K, Luck T, Melzer S, Netto J, Nüchter M, Raschpichler M, Rauscher FG, Riedel-Heller SG, Sander C, Scholz M, Schönknecht P, Schroeter ML, Simon JC, Speer R, Stäker J, Stein R, Stöbel-Richter Y, Stumvoll M, Tarnok A, Teren A, Teupser D, Then FS, Tönjes A, Treudler R, Villringer A, Weissgerber A, Wiedemann P, Zachariae S, Wirkner K, and Thiery J
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- Adult, Aged, Cohort Studies, Female, Germany epidemiology, Health Surveys, Humans, Male, Middle Aged, Physical Examination, Research Design, Health Status, Health Status Indicators, Population Surveillance methods, Urban Population statistics & numerical data
- Abstract
Background: The LIFE-Adult-Study is a population-based cohort study, which has recently completed the baseline examination of 10,000 randomly selected participants from Leipzig, a major city with 550,000 inhabitants in the east of Germany. It is the first study of this kind and size in an urban population in the eastern part of Germany. The study is conducted by the Leipzig Research Centre for Civilization Diseases (LIFE). Our objective is to investigate prevalences, early onset markers, genetic predispositions, and the role of lifestyle factors of major civilization diseases, with primary focus on metabolic and vascular diseases, heart function, cognitive impairment, brain function, depression, sleep disorders and vigilance dysregulation, retinal and optic nerve degeneration, and allergies., Methods/design: The study covers a main age range from 40-79 years with particular deep phenotyping in elderly participants above the age of 60. The baseline examination was conducted from August 2011 to November 2014. All participants underwent an extensive core assessment programme (5-6 h) including structured interviews, questionnaires, physical examinations, and biospecimen collection. Participants over 60 underwent two additional assessment programmes (3-4 h each) on two separate visits including deeper cognitive testing, brain magnetic resonance imaging, diagnostic interviews for depression, and electroencephalography., Discussion: The participation rate was 33 %. The assessment programme was accepted well and completely passed by almost all participants. Biomarker analyses have already been performed in all participants. Genotype, transcriptome and metabolome analyses have been conducted in subgroups. The first follow-up examination will commence in 2016.
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- 2015
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22. Modelling chemotherapy effects on granulopoiesis.
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Schirm S, Engel C, Loeffler M, and Scholz M
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- Granulocyte Colony-Stimulating Factor metabolism, Granulocyte Colony-Stimulating Factor pharmacokinetics, Granulocytes physiology, Hematopoiesis physiology, Humans, Cytotoxins adverse effects, Drug-Related Side Effects and Adverse Reactions metabolism, Granulocyte Colony-Stimulating Factor pharmacology, Granulocytes drug effects, Hematopoiesis drug effects, Models, Biological
- Abstract
Background: Although the growth-factor G-CSF is widely used to prevent granulotoxic side effects of cytotoxic chemotherapies, its optimal use is still unknown since treatment outcome depends on many parameters such as dosing and timing of chemotherapies, pharmaceutical derivative of G-CSF used and individual risk factors. We showed in the past that a pharmacokinetic and -dynamic model of G-CSF and human granulopoiesis can be used to predict the performance of yet untested G-CSF schedules. However, only a single chemotherapy was considered so far., Results: Model assumptions proved to be feasible in explaining granulotoxicity of 10 different chemotherapeutic drugs or drug-combinations applied in 33 different schedules with and without G-CSF. Risk groups of granulotoxicity were traced back to differences in toxicity parameters., Conclusion: We established a comprehensive model of combined G-CSF and chemotherapy action in humans which allows us to predict and compare the outcome of alternative G-CSF schedules. We aim to apply the model in different clinical contexts to optimize and individualize G-CSF treatment.
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- 2014
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23. A combined model of human erythropoiesis and granulopoiesis under growth factor and chemotherapy treatment.
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Schirm S, Engel C, Loeffler M, and Scholz M
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- Cell Differentiation, Cell Division drug effects, Granulocytes cytology, Humans, Stem Cells cytology, Stem Cells drug effects, Antineoplastic Agents pharmacology, Erythropoiesis drug effects, Erythropoietin pharmacology, Granulocyte Colony-Stimulating Factor pharmacology, Granulocytes drug effects, Models, Biological
- Abstract
Background: Haematotoxicity of conventional chemotherapies often results in delays of treatment or reduction of chemotherapy dose. To ameliorate these side-effects, patients are routinely treated with blood transfusions or haematopoietic growth factors such as erythropoietin (EPO) or granulocyte colony-stimulating factor (G-CSF). For the latter ones, pharmaceutical derivatives are available, which differ in absorption kinetics, pharmacokinetic and -dynamic properties. Due to the complex interaction of cytotoxic effects of chemotherapy and the stimulating effects of different growth factor derivatives, optimal treatment is a non-trivial task. In the past, we developed mathematical models of thrombopoiesis, granulopoiesis and erythropoiesis under chemotherapy and growth-factor applications which can be used to perform clinically relevant predictions regarding the feasibility of chemotherapy schedules and cytopenia prophylaxis with haematopoietic growth factors. However, interactions of lineages and growth-factors were ignored so far., Results: To close this gap, we constructed a hybrid model of human granulopoiesis and erythropoiesis under conventional chemotherapy, G-CSF and EPO applications. This was achieved by combining our single lineage models of human erythropoiesis and granulopoiesis with a common stem cell model. G-CSF effects on erythropoiesis were also implemented. Pharmacodynamic models are based on ordinary differential equations describing proliferation and maturation of haematopoietic cells. The system is regulated by feedback loops partly mediated by endogenous and exogenous EPO and G-CSF. Chemotherapy is modelled by depletion of cells. Unknown model parameters were determined by fitting the model predictions to time series data of blood counts and cytokine profiles. Data were extracted from literature or received from cooperating clinical study groups. Our model explains dynamics of mature blood cells and cytokines after growth-factor applications in healthy volunteers. Moreover, we modelled 15 different chemotherapeutic drugs by estimating their bone marrow toxicity. Taking into account different growth-factor schedules, this adds up to 33 different chemotherapy regimens explained by the model., Conclusions: We conclude that we established a comprehensive biomathematical model to explain the dynamics of granulopoiesis and erythropoiesis under combined chemotherapy, G-CSF, and EPO applications. We demonstrate how it can be used to make predictions regarding haematotoxicity of yet untested chemotherapy and growth-factor schedules.
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- 2014
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24. Retrospective analysis of 104 histologically proven adult brainstem gliomas: clinical symptoms, therapeutic approaches and prognostic factors.
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Reithmeier T, Kuzeawu A, Hentschel B, Loeffler M, Trippel M, and Nikkhah G
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- Adolescent, Adult, Age Factors, Aged, Aged, 80 and over, Biopsy, Brain Stem Neoplasms diagnosis, Brain Stem Neoplasms mortality, Brain Stem Neoplasms therapy, Combined Modality Therapy, Female, Glioma diagnosis, Glioma mortality, Glioma therapy, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Neoplasm Grading, Neuroimaging, Prognosis, Retrospective Studies, Treatment Outcome, Young Adult, Brain Stem Neoplasms pathology, Glioma pathology
- Abstract
Background: Adult brainstem gliomas are rare primary brain tumors (<2% of gliomas). The goal of this study was to analyze clinical, prognostic and therapeutic factors in a large series of histologically proven brainstem gliomas., Methods: Between 1997 and 2007, 104 patients with a histologically proven brainstem glioma were retrospectively analyzed. Data about clinical course of disease, neuropathological findings and therapeutic approaches were analyzed., Results: The median age at diagnosis was 41 years (range 18-89 years), median KPS before any operative procedure was 80 (range 20-100) and median survival for the whole cohort was 18.8 months. Histopathological examinations revealed 16 grade I, 31 grade II, 42 grade III and 14 grade IV gliomas. Grading was not possible in 1 patient. Therapeutic concepts differed according to the histopathology of the disease. Median overall survival for grade II tumors was 26.4 months, for grade III tumors 12.9 months and for grade IV tumors 9.8 months. On multivariate analysis the relative risk to die increased with a KPS ≤ 70 by factor 6.7, with grade III/IV gliomas by the factor 1.8 and for age ≥ 40 by the factor 1.7. External beam radiation reduced the risk to die by factor 0.4., Conclusion: Adult brainstem gliomas present with a wide variety of neurological symptoms and postoperative radiation remains the cornerstone of therapy with no proven benefit of adding chemotherapy. Low KPS, age ≥ 40 and higher tumor grade have a negative impact on overall survival.
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- 2014
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25. Merging concepts - coupling an agent-based model of hematopoietic stem cells with an ODE model of granulopoiesis.
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Krinner A, Roeder I, Loeffler M, and Scholz M
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- Bone Marrow Transplantation, Granulocytes drug effects, Hematopoietic Stem Cells drug effects, Humans, Granulocytes cytology, Hematopoiesis drug effects, Hematopoietic Stem Cells cytology, Models, Biological
- Abstract
Background: Hematopoiesis is a complex process involving different cell types and feedback mechanisms mediated by cytokines. This complexity stimulated various models with different scopes and applications. A combination of complementary models promises to provide their mutual confirmation and to explain a broader range of scenarios. Here we propose a combination of an ordinary differential equation (ODE) model of human granulopoiesis and an agent-based model (ABM) of hematopoietic stem cell (HSC) organization. The first describes the dynamics of bone marrow cell stages and circulating cells under various perturbations such as G-CSF treatment or chemotherapy. In contrast to the ODE model describing cell numbers, our ABM focuses on the organization of individual cells in the stem population., Results: We combined the two models by replacing the HSC compartment of the ODE model by a difference equation formulation of the ABM. In this hybrid model, regulatory mechanisms and parameters of the original models were kept unchanged except for a few specific improvements: (i) Effect of chemotherapy was restricted to proliferating HSC and (ii) HSC regulation in the ODE model was replaced by the intrinsic regulation of the ABM. Model simulations of bleeding, chronic irradiation and stem cell transplantation revealed that the dynamics of hybrid and ODE model differ markedly in scenarios with stem cell damage. Despite these differences in response to stem cell damage, both models explain clinical data of leukocyte dynamics under four chemotherapy regimens., Conclusions: ABM and ODE model proved to be compatible and were combined without altering the structure of both models. The new hybrid model introduces model improvements by considering the proliferative state of stem cells and enabling a cell cycle-dependent effect of chemotherapy. We demonstrated that it is able to explain and predict granulopoietic dynamics for a large variety of scenarios such as irradiation, bone marrow transplantation, chemotherapy and growth factor applications. Therefore, it promises to serve as a valuable tool for studies in a broader range of clinical applications, in particular where stem cell activation and proliferation are involved.
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- 2013
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26. Validity, intra- and inter-observer reliability of automated devices for the assessment of ankle brachial index using photo-plethysmography.
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Teren A, Beutner F, Wirkner K, Loeffler M, and Scholz M
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- Aged, Ankle Brachial Index methods, Automation, Female, Humans, Male, Observer Variation, Pilot Projects, Ankle Brachial Index standards, Photoplethysmography standards, Ultrasonography, Doppler standards
- Abstract
Background: Ankle-brachial-Index (ABI) measured by manual Dopplersonography is an easily assessable marker of global cardiovascular risk. The aim of this study was to establish novel photo-plethysmography (PPG)-based ABI assessments in an epidemiologic context and to compare its results with those of Doppler., Methods: Two devices for PPG-based ABI assessments (Vicorder, Vascular Explorer) were tested and compared against Doppler in 56 putatively healthy subjects. We determined acceptance, time requirements, agreement of repeat measurements, agreement with Doppler and intra- and inter-observer concordances for both devices and compared the results. Differences between cuff inflation- and deflation-based methods were also studied for Vascular Explorer., Results: Acceptance was similar for both devices but Vascular Explorer was more time consuming. Agreement of multiple measurements was moderate for both methods highlighting the importance of measurement replicates. Both automated devices showed significantly higher ABI compared to Doppler which can be traced back to higher brachial pressures (Vicorder) or higher ankle pressures (Vascular Explorer). This effect is more pronounced for Vascular Explorer but can be ameliorated using the deflation method of measurement. Intra-observer concordances were similar. Inter-observer concordance was non-significantly better for Vicorder., Conclusions: Both devices proved to be feasible in epidemiologic studies, but compared to Doppler, do not constitute an advantage regarding time requirement and accuracy of ABI assessment. Since PPG-based ABI values are inflated compared to Doppler, it will be necessary to adjust Doppler-based cut-offs for risk stratification.
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- 2013
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27. Pharmacokinetic and -dynamic modelling of G-CSF derivatives in humans.
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Scholz M, Schirm S, Wetzler M, Engel C, and Loeffler M
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- Bone Marrow drug effects, Filgrastim, Granulocyte Colony-Stimulating Factor pharmacology, Granulocytes drug effects, Hematopoiesis drug effects, Humans, Polyethylene Glycols, Recombinant Proteins pharmacokinetics, Recombinant Proteins pharmacology, Granulocyte Colony-Stimulating Factor pharmacokinetics, Models, Biological
- Abstract
Background: The human granulocyte colony-stimulating factor (G-CSF) is routinely applied to support recovery of granulopoiesis during the course of cytotoxic chemotherapies. However, optimal use of the drug is largely unknown. We showed in the past that a biomathematical compartment model of human granulopoiesis can be used to make clinically relevant predictions regarding new, yet untested chemotherapy regimen. In the present paper, we aim to extend this model by a detailed pharmacokinetic and -dynamic modelling of two commonly used G-CSF derivatives Filgrastim and Pegfilgrastim., Results: Model equations are based on our physiological understanding of the drugs which are delayed absorption of G-CSF when applied to the subcutaneous tissue, dose-dependent bioavailability, unspecific first order elimination, specific elimination in dependence on granulocyte counts and reversible protein binding. Pharmacokinetic differences between Filgrastim and Pegfilgrastim were modelled as different parameter sets. Our former cell-kinetic model of granulopoiesis was essentially preserved, except for a few additional assumptions and simplifications. We assumed a delayed action of G-CSF on the bone marrow, a delayed action of chemotherapy and differences between Filgrastim and Pegfilgrastim with respect to stimulation potency of the bone marrow. Additionally, we incorporated a model of combined action of Pegfilgrastim and Filgrastim or endogenous G-CSF which interact via concurrent receptor binding. Unknown pharmacokinetic or cell-kinetic parameters were determined by fitting the predictions of the model to available datasets of G-CSF applications, chemotherapy applications or combinations of it. Data were either extracted from the literature or were received from cooperating clinical study groups. Model predictions fitted well to both, datasets used for parameter estimation and validation scenarios as well. A unique set of parameters was identified which is valid for all scenarios considered. Differences in pharmacokinetic parameter estimates between Filgrastim and Pegfilgrastim were biologically plausible throughout., Conclusion: We conclude that we established a comprehensive biomathematical model to explain the dynamics of granulopoiesis under chemotherapy and applications of two different G-CSF derivatives. We aim to apply the model to a large variety of chemotherapy regimen in the future in order to optimize corresponding G-CSF schedules or to individualize G-CSF treatment according to the granulotoxic risk of a patient.
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- 2012
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28. Population-genetic comparison of the Sorbian isolate population in Germany with the German KORA population using genome-wide SNP arrays.
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Gross A, Tönjes A, Kovacs P, Veeramah KR, Ahnert P, Roshyara NR, Gieger C, Rueckert IM, Loeffler M, Stoneking M, Wichmann HE, Novembre J, Stumvoll M, and Scholz M
- Subjects
- Adult, Aged, Czech Republic ethnology, Ethnicity genetics, Germany, Humans, Middle Aged, Phenotype, Poland ethnology, Population Groups genetics, Principal Component Analysis, Genetics, Population, Polymorphism, Single Nucleotide
- Abstract
Background: The Sorbs are an ethnic minority in Germany with putative genetic isolation, making the population interesting for disease mapping. A sample of N = 977 Sorbs is currently analysed in several genome-wide meta-analyses. Since genetic differences between populations are a major confounding factor in genetic meta-analyses, we compare the Sorbs with the German outbred population of the KORA F3 study (N = 1644) and other publically available European HapMap populations by population genetic means. We also aim to separate effects of over-sampling of families in the Sorbs sample from effects of genetic isolation and compare the power of genetic association studies between the samples., Results: The degree of relatedness was significantly higher in the Sorbs. Principal components analysis revealed a west to east clustering of KORA individuals born in Germany, KORA individuals born in Poland or Czech Republic, Half-Sorbs (less than four Sorbian grandparents) and Full-Sorbs. The Sorbs cluster is nearest to the cluster of KORA individuals born in Poland. The number of rare SNPs is significantly higher in the Sorbs sample. FST between KORA and Sorbs is an order of magnitude higher than between different regions in Germany. Compared to the other populations, Sorbs show a higher proportion of individuals with runs of homozygosity between 2.5 Mb and 5 Mb. Linkage disequilibrium (LD) at longer range is also slightly increased but this has no effect on the power of association studies. Oversampling of families in the Sorbs sample causes detectable bias regarding higher FST values and higher LD but the effect is an order of magnitude smaller than the observed differences between KORA and Sorbs. Relatedness in the Sorbs also influenced the power of uncorrected association analyses., Conclusions: Sorbs show signs of genetic isolation which cannot be explained by over-sampling of relatives, but the effects are moderate in size. The Slavonic origin of the Sorbs is still genetically detectable. Regarding LD structure, a clear advantage for genome-wide association studies cannot be deduced. The significant amount of cryptic relatedness in the Sorbs sample results in inflated variances of Beta-estimators which should be considered in genetic association analyses.
- Published
- 2011
- Full Text
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29. Individual fates of mesenchymal stem cells in vitro.
- Author
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Krinner A, Hoffmann M, Loeffler M, Drasdo D, and Galle J
- Subjects
- Computer Simulation, In Vitro Techniques, Cell Differentiation physiology, Mesenchymal Stem Cells cytology, Models, Biological
- Abstract
Background: In vitro cultivated stem cell populations are in general heterogeneous with respect to their expression of differentiation markers. In hematopoietic progenitor populations, this heterogeneity has been shown to regenerate within days from isolated subpopulations defined by high or low marker expression. This kind of plasticity has been suggested to be a fundamental feature of mesenchymal stem cells (MSCs) as well. Here, we study MSC plasticity on the level of individual cells applying a multi-scale computer model that is based on the concept of noise-driven stem cell differentiation., Results: By simulation studies, we provide detailed insight into the kinetics of MSC organisation. Monitoring the fates of individual cells in high and low oxygen culture, we calculated the average transition times of individual cells into stem cell and differentiated states. We predict that at low oxygen the heterogeneity of a MSC population with respect to differentiation regenerates from any selected subpopulation in about two days. At high oxygen, regeneration becomes substantially slowed down. Simulation results on the composition of the functional stem cell pool of MSC populations suggest that most of the cells that constitute this pool originate from more differentiated cells., Conclusions: Individual cell-based models are well-suited to provide quantitative predictions on essential features of the spatio-temporal organisation of MSC in vitro. Our predictions on MSC plasticity and its dependence on the environment motivate a number of in vitro experiments for validation. They may contribute to a better understanding of MSC organisation in vitro, including features of clonal expansion, environmental adaptation and stem cell ageing.
- Published
- 2010
- Full Text
- View/download PDF
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