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- Gylling, Anne Theil, et al.
(författare)
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The influence of prolonged strength training upon muscle and fat in healthy and chronically diseased older adults
- 2020
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Ingår i: Experimental Gerontology. - : Elsevier. - 0531-5565 .- 1873-6815. ; 136
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Tidskriftsartikel (refereegranskat)abstract
- Background: Physical muscle function and brain hippocampus size declines with age, accelerating after the age of 60. Strength training over a few months improves physical function, but less is known about how long-term strength training affects physical function and hippocampus volume. Therefore, we aimed to investigate the effect of 1-year strength training of two different intensities upon muscle mass, function, and hippocampus volume in retirement-age individuals.Methods: In this multidisciplinary randomized controlled trial (clinicaltrials.gov: NCT02123641), participants were allocated to either a) supervised, heavy resistance training (HRT, n = 149, 3/wk), b) moderate intensity resistance training (MIT, n = 154, 3/wk) or c) non-exercise activities (CON, n = 148). 451 participants were randomized (62-70 yrs., women 61%, approximate to 80% with a chronic medical disease) and 419 were included in the intention-to-treat analysis (n = 143, 144 and 132; HRT, MIT and CON). Changes in muscle power (primary outcome), strength and size, physical function, body composition, hippocampus volume and physical/mental well-being were analyzed.Findings: Of the participants (HRT + MIT), 83% completed training at least 2/week. Leg extensor power was unchanged in all groups, but strength training had a positive effect on isometric knee extensor strength in both groups, whereas an increased muscle mass, cross-sectional area of vastus lateralis muscle, a decreased whole-body fat percentage, visceral fat content and an improved mental health (SF-36) occurred in HRT only. Further, chair-stand performance improved in all groups, whereas hippocampus volume decreased in all groups over time with no influence of strength training.Interpretation: Together, the results indicate that leg extensor power did not respond to long-term supervised strength training, but this type of training in a mixed group of healthy and chronically diseased elderly individuals can be implemented with good compliance and induces consistent changes in physiological parameters of muscle strength, muscle mass and abdominal fat.
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- Herchenhan, Andreas, et al.
(författare)
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Early Growth Response Genes Increases Rapidly After Mechanical Overloading and Unloading in Tendon Constructs
- 2020
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Ingår i: Journal of Orthopaedic Research. - : WILEY. - 0736-0266 .- 1554-527X. ; 38:1, s. 173-181
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Tidskriftsartikel (refereegranskat)abstract
- Tendon cells exist in a dense extracellular matrix and mechanical loading is important for the strength development of this matrix. We therefore use a three-dimensional (3D) culture system for tendon formation in vitro. The objectives of this study were to elucidate the temporal expression of tendon-related genes during the formation of artificial tendons in vitro and to investigate if early growth response-1 (EGR1), EGR2, FOS, and cyclooxygenase-1 and -2 (PTGS1 and PTGS2) are sensitive to mechanical loading. First, we studied messenger RNA (mRNA) levels of several tendon-related genes during formation of tendon constructs. Second, we studied the mRNA levels of, for example, EGR1 and EGR2 after different degrees of loading; dynamic physiologic-range loading (2.5% strain), dynamic overloading (approximately 10% strain), or tension release. The gene expression for tendon-related genes (i.e., EGR2, MKX, TNMD, COL3A1) increased with time after seeding into this 3D model. EGR1, EGR2, FOS, PTGS1, and PTGS2 did not respond to physiologic-range loading. But overloading (and tension release) lead to elevated levels of EGR1 and EGR2 (p amp;lt;= 0.006). FOS and PTGS2 were increased after overloading (both p amp;lt; 0.007) but not after tension release (p = 0.06 and 0.08). In conclusion, the expression of tendon-related genes increases during the formation of artificial tendons in vitro, including EGR2. Furthermore, the gene expression of EGR1 and EGR2 in human tendon cells appear to be sensitive to overloading and unloading but did not respond to the single episode of physiologic-range loading. These findings could be helpful for the understanding of tendon tensional homeostasis. (c) 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
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- Kjeldsen-Kragh, Jens, et al.
(författare)
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Fetal/neonatal alloimmune thrombocytopenia : A systematic review of impact of HLA-DRB3∗01:01 on fetal/neonatal outcome
- 2020
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Ingår i: Blood Advances. - : American Society of Hematology. - 2473-9529 .- 2473-9537. ; 4:14, s. 3368-3377
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Forskningsöversikt (refereegranskat)abstract
- The most common, severe cases of fetal and neonatal alloimmune thrombocytopenia among whites are caused by antibodies against human platelet antigen 1a (HPA-1a). The aims of this systematic review and meta-analysis are to determine the association between maternal HLA-DRB3∗01:01 and: (1) HPA-1a-alloimmunization and (2) neonatal outcome in children born of HPA-1a-immunized women. A systematic literature search identified 4 prospective and 8 retrospective studies. Data were combined across studies to estimate pooled odds ratios (ORs) and the associated 95% confidence intervals (CIs). The population represented by the prospective studies was more than 150 000. In the prospective studies, there were 64 severely thrombocytopenic newborns (platelet count < 50 × 109/L) of whom 3 had intracranial hemorrhage. The mothers of all 64 children were HLA-DRB3∗01:01+. The number of severely thrombocytopenic children born of HPA-1a-alloimmunized women in the retrospective studies was 214; 205 of whom were born of HLA-DRB3∗01:01+ women. For HLA-DRB3∗01:01- women, the OR (95% CI) for alloimmunization was 0.05 (0.00-0.60), and for severe neonatal thrombocytopenia 0.08 (0.02-0.37). This meta-analysis demonstrates that the risk of alloimmunization and of having a child with severe thrombocytopenia are both very low for HPA-1a- women who are HLA-DRB3∗01:01-.
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- Shalgunov, Vladimir, et al.
(författare)
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Blocking of efflux transporters in rats improves translational validation of brain radioligands
- 2020
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Ingår i: EJNMMI Research. - : SPRINGER. - 2191-219X. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Positron emission tomography (PET) is a molecular imaging technique that can be used to investigate the in vivo pharmacology of drugs. Initial preclinical evaluation of PET tracers is often conducted in rodents due to the accessibility of disease models as well as economic considerations. Compared to larger species, rodents display a higher expression and/or activity of efflux transporters such as the P-glycoprotein (P-gp). Low brain uptake could, therefore, be species-specific and uptake in rodents not be predictive for that in humans. We hypothesized that a better prediction from rodent data could be achieved when a tracer is evaluated under P-gp inhibition. Consequently, we compared the performance of eight neuroreceptor tracers in rats with and without P-gp inhibition including a specific binding blockade. This data set was then used to predict the binding of these eight tracers in pigs. Methods PET tracers targeting serotonin 5-HT(2A)receptors ([F-18]MH.MZ, [F-18]Altanserin, [C-11]Cimbi-36, [C-11]Pimavanserin), serotonin 5-HT(7)receptors ([C-11]Cimbi-701, [C-11]Cimbi-717 and [C-11]BA-10) and dopamine D(2/3)receptors ([F-18]Fallypride) were used in the study. The brain uptake and target-specific binding of these PET radiotracers were evaluated in rats with and without inhibition of P-gp. Rat data were subsequently compared to the results obtained in pigs. Results Without P-gp inhibition, the amount of target-specific binding in the rat brain was sufficient to justify further translation for three out of eight evaluated tracers. With P-gp inhibition, results for five out of eight tracers justified further translation. The performance in pigs could correctly be predicted for six out of eight tracers when rat data obtained under P-gp inhibition were used, compared to four out of eight tracers without P-gp inhibition. Conclusions P-gp strongly affects the uptake of PET tracers in rodents, but false prediction outcomes can be reduced by evaluating a tracer under P-gp inhibition.
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- Thiel Gylling, Anne, et al.
(författare)
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Maintenance of muscle strenght following a one-year resistance training program in older adults
- 2020
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Ingår i: Experimental Gerontology. - : Elsevier. - 0531-5565 .- 1873-6815. ; 139
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Tidskriftsartikel (refereegranskat)abstract
- Background: Muscle mass, strength and function declines with advancing age. Strength training (ST) improves these parameters in older adults, but the gains often disappear after completion of a short-term intervention. The purpose of the present study was to investigate muscle mass, -strength and -function one year after the com-pletion of a successful long-term (12 months) supervised ST program in older adults.Method: Men and women (n = 419, age: 62–70 years) completed one year of supervised heavy resistance training (HRT, n = 143) or moderate intensity resistance training (MIT, n = 144) and were compared to a non- exercising control group (CON, n = 132). At 1-year follow-up, 398 participants returned for measurements of muscle power, -strength and -mass, physical function, body composition, hippocampus volume and physical/ mental well-being. The results were compared to pre-training (baseline) and post-training (1-year) values. Further, the participants from the two previous training groups (HRT + MIT, n = 265) were divided into 1) those who on their own continued the ST program (> 9 months) the year after completion of the supervised ST program (CONTIN, n = 65) and 2) those who stopped during the follow-up year (< 9 months) (STOP, n = 200).Results: Out of all the improvements obtained after the 1-year training intervention, only knee extensor muscle strength in HRT was preserved at 1-year follow-up (p < 0.0001), where muscle strength was 7% higher than baseline. Additionally, the decrease in muscle strength over the second year was lower in CONTIN than in STOP with decreases of 1% and 6%, respectively (p < 0.05). Only in CONTIN was the muscle strength still higher at 1- year follow-up compared with baseline with a 14% increase (p < 0.0001). The heavy strength training induced increase in whole-body lean mass was erased at 1-year follow-up. However, there was a tendency for main-tenance of the cross-sectional area of m. vastus lateralis from baseline to 1-year follow-up in HRT compared with CON (p = 0.06). Waist circumference decreased further over the second year in CONTIN, whereas it increased in STOP (p < 0.05).Conclusion: Even though long-term strength training effectively improved muscle function and other health parameters in older adults, only knee extensor muscle strength was preserved one year after completion of heavy (but not moderate intensity) resistance training. Continuation of strength training resulted in better maintenance of muscle strength and health, which indicates that it is required to continue with physical activity to benefit from the long-term effects of strength training upon muscle function and health in older men and women.
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