| 1. |
- Brook, Matthew S, et al.
(författare)
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Neither myonuclear accretion nor a myonuclear domain size ceiling is a feature of the attenuated hypertrophic potential of aged human skeletal muscle
- 2023
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Ingår i: GeroScience. - : Springer. - 2509-2715 .- 2509-2723. ; 45, s. 451-462
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Tidskriftsartikel (refereegranskat)abstract
- Ageing limits growth capacity of skeletal muscle (e.g. in response to resistance exercise), but the role of satellite cell (SC) function in driving this phenomenon is poorly defined. Younger (Y) (~ 23 years) and older (O) men (~ 69 years) (normal-weight BMI) underwent 6 weeks of unilateral resistance exercise training (RET). Muscle biopsies were taken at baseline and after 3-/6-week training. We determined muscle size by fibre CSA (and type), SC number, myonuclei counts and DNA synthesis (via D2O ingestion). At baseline, there were no significant differences in fibre areas between Y and O. RET increased type I fibre area in Y from baseline at both 3 weeks and 6 weeks (baseline: 4509 ± 534 µm2, 3 weeks; 5497 ± 510 µm2 P < 0.05, 6 weeks; 5402 ± 352 µm2 P < 0.05), whilst O increased from baseline at 6 weeks only (baseline 5120 ± 403 µm2, 3 weeks; 5606 ± 620 µm2, 6 weeks; 6017 ± 482 µm2 P < 0.05). However, type II fibre area increased from baseline in Y at both 3 weeks and 6 weeks (baseline: 4949 ± 459 µm2, 3 weeks; 6145 ± 484 µm2 (P < 0.01), 6 weeks; 5992 ± 491 µm2 (P < 0.01), whilst O showed no change (baseline 5210 ± 410 µm2, 3 weeks; 5356 ± 535 µm2 (P = 0.9), 6 weeks; 5857 ± 478 µm2 (P = 0.1). At baseline, there were no differences in fibre myonuclei number between Y and O. RET increased type I fibre myonuclei number from baseline in both Y and O at 3 weeks and 6 weeks with RET (younger: baseline 2.47 ± 0.16, 3 weeks; 3.19 ± 0.16 (P < 0.001), 6 weeks; 3.70 ± 0.29 (P < 0.0001); older: baseline 2.29 ± 0.09, 3 weeks; 3.01 ± 0.09 (P < 0.001), 6 weeks; 3.65 ± 0.18 (P < 0.0001)). Similarly, type II fibre myonuclei number increased from baseline in both Y and O at 3 weeks and 6 weeks (younger: baseline 2.49 ± 0.14, 3 weeks; 3.31 ± 0.21 (P < 0.001), 6 weeks; 3.86 ± 0.29 (P < 0.0001); older: baseline 2.43 ± 0.12, 3 weeks; 3.37 ± 0.12 (P < 0.001), 6 weeks; 3.81 ± 0.15 (P < 0.0001)). DNA synthesis rates %.d-1 exhibited a main effect of training but no age discrimination. Declines in myonuclei addition do not underlie impaired muscle growth capacity in older humans, supporting ribosomal and proteostasis impairments as we have previously reported.
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| 2. |
- Deane, Colleen S., et al.
(författare)
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The acute transcriptional response to resistance exercise : impact of age and contraction mode
- 2019
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Ingår i: Aging. - : Impact Journals LLC. - 1945-4589 .- 1945-4589. ; 11:7, s. 2111-2126
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Tidskriftsartikel (refereegranskat)abstract
- Optimization of resistance exercise (RE) remains a hotbed of research for muscle building and maintenance. However, the interactions between the contractile components of RE (i.e. concentric (CON) and eccentric (ECC)) and age, are poorly defined. We used transcriptomics to compare age-related molecular responses to acute CON and ECC exercise. Eight young (21 +/- 1 y) and eight older (70 +/- 1 y) exercise-naive male volunteers had vastus lateralis biopsies collected at baseline and 5 h post unilateral CON and contralateral ECC exercise. RNA was subjected to next-generation sequencing and differentially expressed (DE) genes tested for pathway enrichment using Gene Ontology (GO). The young transcriptional response to CON and ECC was highly similar and older adults displayed moderate contraction-specific profiles, with no GO enrichment. Age-specific responses to ECC revealed 104 DE genes unique to young, and 170 DE genes in older muscle, with no GO enrichment. Following CON, 15 DE genes were young muscle-specific, whereas older muscle uniquely expressed 147 up-regulated genes enriched for cell adhesion and blood vessel development, and 28 down-regulated genes involved in mitochondria! respiration, amino acid and lipid metabolism. Thus, older age is associated with contraction-specific regulation often without clear functional relevance, perhaps reflecting a degree of stochastic age-related dysregulation.
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| 3. |
- Kimberling, William J., et al.
(författare)
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Usher syndrome : clinical findings and gene localization studies
- 1989
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Ingår i: The Laryngoscope. - : Wiley. - 0023-852X .- 1531-4995. ; 99:1, s. 66-72
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Tidskriftsartikel (refereegranskat)abstract
- The issue of genetic heterogeneity is a critical problem in the localization of the gene(s) for Usher syndrome. Based on the data obtained on families studied to date, the differences between type I and type II Usher syndrome appear quite distinct with regard to auditory and vestibular function. Although the majority of families can be confidently diagnosed as typical type I or type II, clinical investigations revealed four families with findings that did not fit into either of the two more common subtypes. These findings emphasize the critical importance of an indepth clinical analysis concomitant with the linkage investigation to assure accurate subtyping of Usher syndrome. Based on an analysis of only those families with definite type I or type II Usher syndrome, approximately 17% of the genome can be excluded as a potential site of the gene for type I, and 14% can be excluded as the site for the type II gene. This study will continue until the Usher gene(s) is successfully localized.
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| 4. |
- Lund, Lars, et al.
(författare)
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Use of venous-thrombotic-embolic prophylaxis in patients undergoing surgery for renal tumors : a questionnaire survey in the Nordic countries (The NORENCA-2 study)
- 2018
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Ingår i: Research and Reports in Urology. - : DOVE Medical Press Ltd.. - 2253-2447. ; 10, s. 181-187
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To examine the variation in venous thromboembolism prophylactic treatment (VTEP) among renal cancer patients undergoing surgery.Materials and methods: An Internet-based questionnaire on renal tumor management before and after surgery was mailed to all Nordic departments of urology. The questions focused on the use of VTEP and were subdivided into different surgical modalities.Results: Questionnaires were mailed to 91 institutions (response rate 53%). None of the centers used VTEP before surgery, unless the patient had a vena caval tumor thrombus. Overall, the VTEP utilized during hospitalization for patients undergoing renal surgery included early mobilization (45%), compression stockings (52%) and low-molecular-weight heparin (89%). In patients undergoing open radical Nx, 80% of institutions used VTEP during their hospitalization (23% compression stockings and 94% low-molecular-weight heparin). After leaving the hospital, the proportion and type of VTEP received varied considerably across institutions. The most common interval, used in 60% of the institutions, was for a period of 4 weeks. The restriction to the Nordic countries was a limitation and, therefore, may not reflect the practice patterns elsewhere. It is a survey study and, therefore, cannot measure the behaviors of those institutions that did not participate.Conclusion: We found variation in the type and duration of VTEP use for each type of local intervention for renal cancer. These widely disparate variations in care strongly argue for the establishment of national and international guidelines regarding VTEP in renal surgery.
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| 5. |
- Willis, Craig R.G., et al.
(författare)
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Network analysis of human muscle adaptation to aging and contraction
- 2020
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Ingår i: Aging. - : Impact Journals LLC. - 1945-4589 .- 1945-4589. ; 12:1, s. 740-755
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Tidskriftsartikel (refereegranskat)abstract
- Resistance exercise (RE) remains a primary approach for minimising aging muscle decline. Understanding muscle adaptation to individual contractile components of RE (eccentric, concentric) might optimise RE-based intervention strategies. Herein, we employed a network-driven pipeline to identify putative molecular drivers of muscle aging and contraction mode responses. RNA-sequencing data was generated from young (21±1 y) and older (70±1 y) human skeletal muscle before and following acute unilateral concentric and contralateral eccentric contractions. Application of weighted gene co-expression network analysis identified 33 distinct gene clusters ('modules') with an expression profile regulated by aging, contraction and/or linked to muscle strength. These included two contraction 'responsive' modules (related to 'cell adhesion' and 'transcription factor' processes) that also correlated with the magnitude of post-exercise muscle strength decline. Module searches for 'hub' genes and enriched transcription factor binding sites established a refined set of candidate module-regulatory molecules (536 hub genes and 60 transcription factors) as possible contributors to muscle aging and/or contraction responses. Thus, network-driven analysis can identify new molecular candidates of functional relevance to muscle aging and contraction mode adaptations.
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