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- Aspenberg, Per, et al.
(författare)
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Teriparatide for Acceleration of Fracture Repair in Humans: A Prospective, Randomized, Double-Blind Study of 102 Postmenopausal Women With Distal Radial Fractures
- 2010
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Ingår i: JOURNAL OF BONE AND MINERAL RESEARCH. - : Wiley. - 0884-0431 .- 1523-4681. ; 25:2, s. 404-414
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Tidskriftsartikel (refereegranskat)abstract
- Animal experiments show a dramatic improvement in skeletal repair by teriparatide. We tested the hypothesis that recombinant teriparatide, at the 20 mu g dose normally used for osteoporosis treatment or higher, would accelerate fracture repair in humans. Postmenopausal women (45 to 85 years of age) who had sustained a dorsally angulated distal radial fracture in need of closed reduction but no surgery were randomly assigned to 8 weeks of once-daily injections of placebo (n = 34) or teriparatide 20 mu g (n = 34) or teriparatide 40 mu g (n = 34) within 10 days of fracture. Hypotheses were tested sequentially, beginning with the teriparaticle 40 mu g versus placebo comparison, using a gatekeeping strategy. The estimated median time from fracture to first radiographic evidence of complete cortical bridging in three of four cortices was 9.1, 7.4, and 8.8 weeks for placebo and teriparaticle 20 1 and 40 mu g, respectively (overall p = .015). There was no significant difference between the teriparaticle 40 mu g versus placebo groups (p = .523). In post hoc analyses, there was no significant difference between teriparaticle 40 1 versus 20 mu g (p = .053); however, the time to healing was shorter in teriparaticle 20 mu g than placebo (p = .006). The primary hypothesis that teriparatide 40 jug would shorten the time to cortical bridging was not supported. The shortened time to healing for teriparaticle 20 mu g compared with placebo still may suggest that fracture repair can be accelerated by teriparaticle, but this result should be interpreted with caution and warrants further study.
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| 4. |
- Aspenberg, Magnus, et al.
(författare)
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Hygiene may attenuate selection for antibiotic resistance by changing microbial community structure
- 2023
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Ingår i: Evolution, Medicine and Public Health. - : Oxford University Press (OUP). - 2050-6201. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Good hygiene, in both health care and the community, is central to containing the rise of antibiotic resistance, as well as to infection control more generally. But despite the well-known importance, the ecological mechanisms by which hygiene (or other transmission control measures) affect the evolution of resistance remain to be elucidated. Using metacommunity ecology theory, we here propose that hygiene attenuates the effect of antibiotic selection pressure. Specifically, we predict that hygiene limits the scope for antibiotics to induce competitive release of resistant bacteria within treated hosts, and that this is due to an effect of hygiene on the distribution of resistant and sensitive strains in the host population. We show this in a mathematical model of bacterial metacommunity dynamics, and test the results against data on antibiotic resistance, antibiotic treatment, and the use of alcohol-based hand rub in long-term care facilities. The data are consistent with hand rub use attenuating the resistance promoting effect of antibiotic treatment. Our results underscore the importance of hygiene, and point to a concrete way to weaken the link between antibiotic use and increasing resistance.
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| 5. |
- Aspenberg, P., et al.
(författare)
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Drug test chamber : a titanium implant for administration of biochemical agents to a standardized bone callus in situ
- 1988
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Ingår i: Journal of Biomedical Engineering. - : Elsevier BV. - 0141-5425. ; 10:1, s. 70-73
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Tidskriftsartikel (refereegranskat)abstract
- A titanium implant in which a conduit is gradually filled with ingrowing bone (the Bone Harvest Chamber) has been modified to allow continuous local treatment of the conduit tissue with biochemical agents. Implants were inserted bilaterally in rabbit tibiae. The tissue content of the bone ingrowth conduits was studied with histology, 99mTc-MDP scintimetry and measurements of total calcium content. Bone was formed in the conduit by endochondral formation starting at both ends and continuing until fusion in the middle. After 2 weeks the bone had not yet met in the middle where fibrous tissue was seen. In eight animals 3H-proline was applied via one of the chambers, with the contralateral chamber as a saline-treated control. The collagen of the harvested tissue from the 3H-proline treated side had a 3H-hydroxyproline content 1000 times greater than had the control side. The 'drug test chamber' makes possible the study of local effects of drugs on healing of mature bone in vivo.
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| 6. |
- Aspenberg, P., et al.
(författare)
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Failure of bone induction by bone matrix in adult monkeys
- 1988
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Ingår i: Journal of Bone and Joint Surgery: British Volume. - 0301-620X. ; 70:4, s. 625-627
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Tidskriftsartikel (refereegranskat)abstract
- Extraskeletal bone formation can be induced in rodents by implantation of demineralised bone matrix and such implantation has been used to treat bone defects in man, but it is uncertain if induction or merely conduction occurs. We studied bone induction in primates by excising segments of the fibulae of adult squirrel monkeys, defatting and demineralising them before reimplanting them into the quadriceps of the same animal. As a control experiment, rat matrix was prepared in exactly the same way and implanted in rats. After six weeks the implants were harvested and either ashed and analysed for calcium content or prepared for histology. In the rats, the calcium content indicated that about 20% of the original matrix had been replaced by new bone. In the monkeys the calcium content was about the same as that in normal body fluid and no bone was seen in histological sections. This result casts doubt on the use of demineralised human bone matrix as a bone inductor, although it may function by other mechanisms.
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| 8. |
- Aspenberg, P., et al.
(författare)
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Monkey bone matrix induces bone formation in the athymic rat, but not in adult monkeys
- 1991
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Ingår i: Journal of Orthopaedic Research. - : Wiley. - 0736-0266 .- 1554-527X. ; 9:1, s. 20-25
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Tidskriftsartikel (refereegranskat)abstract
- Demineralized bone matrix from young and adult monkeys was implanted intramuscularly for 6 weeks in athymic rats and adult monkeys. Cartilage and bone induction was evaluated by histology and calcium content. In the athymic rat, most implants induced cartilage or bone. In the monkeys, cartilage was formed only on rare occasions and there was no sign of bone formation. We conclude that (a) adult monkey bone matrix contains bone inductive properties; (b) these properties are not sufficient to induce bone formation in adult monkey muscle sites.
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| 9. |
- Bogl, H. P., et al.
(författare)
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Undisturbed local bone formation capacity in patients with atypical femoral fractures: a case series
- 2017
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Ingår i: Osteoporosis International. - : SPRINGER LONDON LTD. - 0937-941X .- 1433-2965. ; 28:8, s. 2439-2444
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Tidskriftsartikel (refereegranskat)abstract
- We excised the fracture site in 8 patients with incomplete atypical femoral fractures by drilling an 11-mmdiameter hole. New bone formation could be seen in the hole within a normal time frame. Delayed healing of these fractures might be unrelated to an impaired capacity to form bone. Introduction Incomplete atypical femoral fractures (undisplaced cracks) heal slowly or not at all, and often progress to a complete fracture with minimal trauma. The impaired healing has been attributed to an impaired biologic healing capacity related to bisphosphonate use, or, alternatively, to the mechanical environment within the fracture crack. This study aimed to investigate the capacity for bone formation after resection of the fracture site. Methods Between 2008 and 2014, we recruited eight patients with incomplete atypical femoral fractures. All used oral bisphosphonates before the fracture for on average 8 years (range 4 to 15) and complained of thigh pain. The fractures were stabilized with reamed cephalomedullary nails. During surgery, the fracture site in the lateral cortex was resected with a cylindrical drill (diameter 11.5 mm). The cylindrical cortical defect allowed radiographic evaluation of new bone formation, and the patients were followed clinically and radiologically for 24 months (range 15 to 92). Results After 3 months, newly formed bone could be seen in the cortical defects in all patients. After 13-26 months, the previous defects showed continuous cortical bone. At final follow-up, all patients reported full recovery of pre-surgical complaints. No complications occurred and no reoperations were performed. Conclusions New bone formation occurred within a time frame that appears normal for healing of cortical bone defects. This suggests that the capacity to form new bone is intact.
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| 10. |
- de Rooij, Philippe P., et al.
(författare)
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The fate of mechanically induced cartilage in an unloaded environment
- 2001
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Ingår i: Journal of Biomechanics. - 1873-2380. ; 34:7, s. 961-966
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Tidskriftsartikel (refereegranskat)abstract
- According to mechanobiologic theories, persistent intermittent mechanical stimulation is required to maintain differentiated cartilage. In a rat model for bone repair, we studied the fate of mechanically induced cartilage after unloading. In three groups of rats, regenerating mesenchymal tissue was submitted to different loading conditions in bone chambers. Two groups were immediately killed after loading periods of 3 or 6 weeks (the 3-group and the 6-group). The third group was loaded for 3 weeks and then kept unloaded for another 3 weeks (the (3 + 3)-group). Cartilage was found in all loaded groups. Without loading, cartilage does not appear in this model. In the 3-group there was no clear ongoing endochondral ossification, the 6-group showed ossification in 2 out of 5 cartilage containing specimens, and in the (3 + 3)-group all cartilage was undergoing ossification. These results suggest a tendency of the cartilage to be maintained also under unloaded conditions until it is reached by bone that can replace it through endochondral ossification.Additional measurements showed less amount of new bone in the loaded specimens. In most of the loaded specimens in the 3-group, necrotic bone fragments were seen embedded in the fibrous tissue layer close to the loading piston, indicating that bone tissue had been resorbed due to the hydrostatic compressive load. In some specimens, a continuous cartilage layer covered the end of the specimen and seemed to protect the underlying bone from pressure-induced resorption. We suggest that one of the functions of the cartilage forming in the compressive loaded parts of a bone callus is to protect the surrounding bone callus from pressure-induced fluid flow leading to resorption.
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