| 1. |
- Benetou, V, et al.
(författare)
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Mediterranean diet and incidence of hip fractures in a European cohort
- 2013
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Ingår i: Osteoporosis International. - : Springer London. - 0937-941X .- 1433-2965. ; 24:5, s. 1587-1598
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Tidskriftsartikel (refereegranskat)abstract
- Prevention of hip fractures is of critical public health importance. In a cohort of adults from eight European countries, evidence was found that increased adherence to Mediterranean diet, measured by a 10-unit dietary score, is associated with reduced hip fracture incidence, particularly among men. INTRODUCTION: Evidence on the role of dietary patterns on hip fracture incidence is scarce. We explored the association of adherence to Mediterranean diet (MD) with hip fracture incidence in a cohort from eight European countries. METHODS: A total of 188,795 eligible participants (48,814 men and 139,981 women) in the European Prospective Investigation into Cancer and nutrition study with mean age 48.6 years (±10.8) were followed for a median of 9 years, and 802 incident hip fractures were recorded. Diet was assessed at baseline through validated dietary instruments. Adherence to MD was evaluated by a MD score (MDs), on a 10-point scale, in which monounsaturated were substituted with unsaturated lipids. Association with hip fracture incidence was assessed through Cox regression with adjustment for potential confounders. RESULTS: Increased adherence to MD was associated with a 7 % decrease in hip fracture incidence [hazard ratio (HR) per 1-unit increase in the MDs 0.93; 95 % confidence interval (95 % CI) = 0.89-0.98]. This association was more evident among men and somewhat stronger among older individuals. Using increments close to one standard deviation of daily intake, in the overall sample, high vegetable (HR = 0.86; 95 % CI = 0.79-0.94) and high fruit (HR = 0.89; 95 % CI = 0.82-0.97) intake was associated with decreased hip fracture incidence, whereas high meat intake (HR = 1.18; 95 % CI = 1.06-1.31) with increased incidence. Excessive ethanol consumption (HR high versus moderate = 1.74; 95 % CI = 1.32-2.31) was also a risk factor. CONCLUSIONS: In a prospective study of adults, increased adherence to MD appears to protect against hip fracture occurrence, particularly among men.
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| 2. |
- Bergström, Ulrica, 1970-, et al.
(författare)
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Fracture mechanisms and fracture pattern in men and women aged 50 years and older : a study of a 12-year population-based injury register, Umeå, Sweden
- 2008
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Ingår i: Osteoporosis International. - London : Springer International. - 0937-941X .- 1433-2965. ; 19:9, s. 1267-1273
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Tidskriftsartikel (refereegranskat)abstract
- Summary: In a study of a 12-year population-based injury register, Umeå, Sweden, we analyzed the fracture mechanisms and fracture pattern in men and women 50 years and older. Low-energy trauma was responsible for the major and costliest part of the fracture panorama, but the pattern differs between age groups. Introduction: Osteoporosis-related fracture is a major health problem: the number of hip fractures is expected to double to 2030. While osteoporosis is one of many risk factors, trauma is almost always involved. Therefore, we analyzed injury mechanisms in patients aged over 50. Methods: We registered injury mechanism, cause, diagnosis in all trauma patients at Umeå University hospital, Sweden. This population-based register (1993–2004) comprises a total of 113,668 injuries (29,189 fractures). Patients ≥50 years contributed to 13,279 fractures. Results: Low-energy trauma (fall <1 m) caused 53% of all fractures ≥50 years and older. In those over 75 low-energy trauma caused >80%. The seasonal variation of fractures was maximally 25%. With increasing age, proximal fractures became more common, in both upper and lower extremities. Proximal locations predominate in older age groups. Conclusions: Low-energy trauma was responsible for the largest and costliest part of the fracture panorama. In fact, almost all fractures in middle-aged and old people were caused by low-energy mechanisms; thus, most fractures in these patients have a fragility component, and the contribution of osteoporosis-related fractures is more important than previously thought. A better understanding of injury mechanisms also in low-energy trauma is a prerequisite for preventive interventions.
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| 3. |
- Bergström, Ulrica, et al.
(författare)
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Fracture panorama in Umeå
- 2006
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Ingår i: Läkartidningen. - 0023-7205. ; 103:40, s. 2967-8
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Bergström, Ulrica, 1970-, et al.
(författare)
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The hip fracture incidence curve is shifting to the right : a forecast of the age-quake
- 2009
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 80:5, s. 520-524
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Tidskriftsartikel (refereegranskat)abstract
- Background The number of hip fractures has doubled in the last 30–40 years in many countries. Age-adjusted incidence has been reported to be decreasing in Europe and North America, but is there a decreasing trend in all age groups? Patients and methods This population-based study included all hip-fracture patients over 50 years of age (a total of 2,919 individuals, 31% of whom were men) admitted to Umeå University Hospital, Sweden, from 1993 through 2005. Results The incidence of hip fracture declined between the periods 1993–1996 and 2001–2005: from 706 to 625 hip fractures per 105 women and from 390 to 317 hip fractures per 105 men. However, there was a 114% increase in the number of fractures in women aged 90 or older (12 and 25 hip fractures/year, respectively, in the two time periods). For the period 2001–05, women ≥ 90 years of age accounted for almost the same numbers of hip fractures as women aged 75–79 (27 fractures/year). The rate increased during this period, from 2,700 per 105 women to 3,900 per 105 women > 90 years. In men there were declining trends for both relative and absolute numbers. Interpretation Although age-adjusted incidence declined in the population > 50 years of age, absolute fracture rate and incidence increased in the very old. Women over 90 now have the same absolute number of hip fractures every year as women aged 75–79 years. There was a right-shift in hip fracture distribution towards the oldest old, probably due to an increased number of octo/nonagenarians, a new population of particularly frail old people that hardly existed earlier. Better health among septuagenarians may also have delayed the age at which fractures occurred. This changing pattern will strain orthopedic and geriatric resources even more.
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| 5. |
- Björklund Svensson, Jonas, et al.
(författare)
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Low-divergence femtosecond X-ray pulses from a passive plasma lens
- 2021
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Ingår i: Nature Physics. - : Springer Science and Business Media LLC. - 1745-2481 .- 1745-2473. ; 17:5, s. 639-645
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Tidskriftsartikel (refereegranskat)abstract
- Electron and X-ray beams originating from compact laser-wakefield accelerators have very small source sizes that are typically on the micrometre scale. Therefore, the beam divergences are relatively high, which makes it difficult to preserve their high quality during transport to applications. To improve on this, tremendous efforts have been invested in controlling the divergence of the electron beams, but no mechanism for generating collimated X-ray beams has yet been demonstrated experimentally. Here we propose and realize a scheme where electron bunches undergoing focusing in a dense, passive plasma lens can emit X-ray pulses with divergences approaching the incoherent limit. Compared with conventional betatron emission, the divergence of this so-called plasma lens radiation is reduced by more than an order of magnitude in solid angle, while maintaining a similar number of emitted photons per electron. This X-ray source offers the possibility of producing brilliant and collimated few-femtosecond X-ray pulses for ultra-fast science, in particular for studies based on X-ray diffraction and absorption spectroscopy. X-ray pulses with low divergences are produced in a laser-wakefield accelerator by focusing electron bunches in a dense passive plasma lens.
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| 6. |
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| 7. |
- Brax-Olofsson, Lisbeth, et al.
(författare)
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Periosteal transplantation to the rabbit patella.
- 2007
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Ingår i: Knee Surgery, Sports Traumatology, Arthroscopy. - Berlin : Springer Internat.. - 0942-2056 .- 1433-7347. ; 15:5, s. 560-563
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Tidskriftsartikel (refereegranskat)abstract
- Autologous periosteal transplantation (without chondrocyte cell transplantation) for treating traumatic articular cartilage defects of the patella gives pain relief in uncontrolled clinical studies. To study the whole transplanted area macroscopically and microscopically, animal studies are motivated. In this pilot study, we reproduce the surgical technique for periosteum transplantation on human patella to a rabbit model. A full-thickness cartilage defect of the whole patella was created in eight adult female rabbits. The defect was treated with autologous periosteal transplantation. After surgery, the rabbits were allowed free activity. This is the difference compared to the treatment in humans, where our group uses CPM for 5 days and non-weight-bearing for 12 weeks. After 21 weeks, there was a diffuse synovitis in all transplanted knees, and in five of eight knees there were signs of osteoarthritis in the patello-femoral joint. Histologically, in three animals, small islands of hyaline cartilage surrounded by fibrocartilage were seen in the transplanted area. In the other five animals, fibrocartilage was the predominant tissue. In contrast to previous experimental studies using a rabbit model, we did not achieve hyaline cartilage resurfacing.
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| 8. |
- Burza, Matthias, et al.
(författare)
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Laser wakefield acceleration using wire produced double density ramps
- 2013
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Ingår i: Physical Review Special Topics. Accelerators and Beams. - 1098-4402. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- A novel approach to implement and control electron injection into the accelerating phase of a laser wakefield accelerator is presented. It utilizes a wire, which is introduced into the flow of a supersonic gas jet creating shock waves and three regions of differing plasma electron density. If tailored appropriately, the laser plasma interaction takes place in three stages: Laser self-compression, electron injection, and acceleration in the second plasma wave period. Compared to self-injection by wave breaking of a nonlinear plasma wave in a constant density plasma, this scheme increases beam charge by up to 1 order of magnitude in the quasimonoenergetic regime. Electron acceleration in the second plasma wave period reduces electron beam divergence by approximate to 25%, and the localized injection at the density downramps results in spectra with less than a few percent relative spread. DOI: 10.1103/PhysRevSTAB.16.011301
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| 9. |
- Conaway, H Herschel, et al.
(författare)
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Retinoids inhibit differentiation of hematopoietic osteoclast progenitors.
- 2009
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Ingår i: The FASEB journal. - Bethesda, Md. : Wiley. - 1530-6860 .- 0892-6638. ; 23:10, s. 3526-38
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Tidskriftsartikel (refereegranskat)abstract
- Whether vitamin A promotes skeletal fragility, has no effect on fracture rate, or protects against bone loss is unclear. In the present study, effects of retinoids on osteoclast differentiation in cultured mouse bone marrow cells (BMCs), bone marrow macrophages (BMMs), spleen cells, and RAW264.7 cells were evaluated by analyzing osteoclast formation and expression of genes important in signal transduction and osteoclast function. All-trans-retinoic acid (ATRA) did not stimulate osteoclastogenesis in BMCs, but inhibited hormone and RANKL-induced gene expression and formation of osteoclasts. In BMMs, spleen cells, and RAW264.7 cells, osteoclast differentiation and formation stimulated by M-CSF/RANKL were inhibited (IC(50) = 0.3 nM) by ATRA. The effect was exerted at an early step of RANKL-induced differentiation. ATRA also abolished increases of the transcription factors c-Fos and NFAT2 stimulated by RANKL and suppressed down-regulation of the antiosteoclastogenic transcription factor MafB. By comparing effects of several compounds structurally related to ATRA, as well as by using receptor antagonists, evaluation pointed to inhibition being mediated by RARalpha, with no involvement of PPARbeta/delta. The results suggest that activation of RARalpha by retinoids in myeloid hematopoietic precursor cells decreases osteoclast formation by altering expression of the transcription factors c-Fos, NFAT2, and MafB.
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| 10. |
- Conaway, H Herschel, et al.
(författare)
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Retinoids stimulate periosteal bone resorption by enhancing the protein RANKL, a response inhibited by monomeric glucocorticoid receptor.
- 2011
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Ingår i: The Journal of biological chemistry. - 1083-351X .- 0021-9258. ; 286:36, s. 31425-36
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Tidskriftsartikel (refereegranskat)abstract
- Increased vitamin A (retinol) intake has been suggested to increase bone fragility. In the present study, we investigated effects of retinoids on bone resorption in cultured neonatal mouse calvarial bones and their interaction with glucocorticoids (GC). All-trans-retinoic acid (ATRA), retinol, retinalaldehyde, and 9-cis-retinoic acid stimulated release of (45)Ca from calvarial bones. The resorptive effect of ATRA was characterized by mRNA expression of genes associated with osteoclast differentiation, enhanced osteoclast number, and bone matrix degradation. In addition, the RANKL/OPG ratio was increased by ATRA, release of (45)Ca stimulated by ATRA was blocked by exogenous OPG, and mRNA expression of genes associated with bone formation was decreased by ATRA. All retinoid acid receptors (RARα/β/γ) were expressed in calvarial bones. Agonists with affinity to all receptor subtypes or specifically to RARα enhanced the release of (45)Ca and mRNA expression of Rankl, whereas agonists with affinity to RARβ/γ or RARγ had no effects. Stimulation of Rankl mRNA by ATRA was competitively inhibited by the RARα antagonist GR110. Exposure of calvarial bones to GC inhibited the stimulatory effects of ATRA on (45)Ca release and Rankl mRNA and protein expression. This inhibitory effect was reversed by the glucocorticoid receptor (GR) antagonist RU 486. Increased Rankl mRNA stimulated by ATRA was also blocked by GC in calvarial bones from mice with a GR mutation that blocks dimerization (GR(dim) mice). The data suggest that ATRA enhances periosteal bone resorption by increasing the RANKL/OPG ratio via RARα receptors, a response that can be inhibited by monomeric GR.
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