| 1. |
- Keyak, J. H., et al.
(författare)
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Effect of finite element model loading condition on fracture risk assessment in men and women: The AGES-Reykjavik study
- 2013
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Ingår i: Bone. - : Elsevier BV. - 1873-2763 .- 8756-3282. ; 57:1, s. 18-29
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Tidskriftsartikel (refereegranskat)abstract
- Proximal femoral (hip) strength computed by subject-specific CT scan-based finite element (FE) models has been explored as an improved measure for identifying subjects at risk of hip fracture. However, to our knowledge, no published study has reported the effect of loading condition on the association between incident hip fracture and hip strength. In the present study, we performed a nested age- and sex-matched case-control study in the Age Gene/Environment Susceptibility (AGES) Reykjavik cohort Baseline (pre-fracture) quantitative CT (QCT) scans of 5500 older male and female subjects were obtained. During 4-7 years follow-up, 51 men and 77 women sustained hip fractures. Ninety-seven men and 152 women were randomly selected as controls from a pool of age- and sex-matched subjects. From the QCT data, FE models employing nonlinear material properties computed FE-strength of the left hip of each subject in loading from a fall onto the posterolateral (F-PL), posterior (F-P) and lateral (F-L) aspects of the greater trochanter (patent pending). For comparison, FE strength in stance loading (F-Stance) and total femur areal bone mineral density (aBMD) were also computed. For all loading conditions, the reductions in strength associated with fracture in men were more than twice those in women (p <= 0.01). For fall loading specifically, posterolateral loading in men and posterior loading in women were most strongly associated with incident hip fracture. After adjusting for aBMD, the association between F-P and fracture in women fell short of statistical significance (p = 0.08), indicating that FE strength provides little advantage over aBMD for identifying female hip fracture subjects. However, in men, after controlling for aBMD, F-PL was 424 N (11%) less in subjects with fractures than in controls (p = 0.003). Thus, in men, FE models of posterolateral loading include information about incident hip fracture beyond that in aBMD. (c) 2013 Elsevier Inc. All rights reserved.
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| 2. |
- Keyak, J. H., et al.
(författare)
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Male-female differences in the association between incident hip fracture and proximal femoral strength: A finite element analysis study
- 2011
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Ingår i: Bone. - : Elsevier BV. - 1873-2763 .- 8756-3282. ; 48:6, s. 1239-1245
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Tidskriftsartikel (refereegranskat)abstract
- Hip fracture risk is usually evaluated using dual energy X-ray absorptiometry (DXA) or quantitative computed tomography (QCT) which provide surrogate measures for proximal femoral strength. However, proximal femoral strength can best be estimated explicitly by combining QCT with finite element (FE) analysis. To evaluate this technique for predicting hip fracture in older men and women, we performed a nested age- and sex-matched case-control study in the Age Gene/Environment Susceptibility (AGES) Reykjavik cohort. Baseline (pre-fracture) QCT scans of 5500 subjects were obtained. During 4-7 years follow-up, 51 men and 77 women sustained hip fractures. Ninety-seven men and 152 women were randomly selected as age- and sex-matched controls. FE-strength of the left hip of each subject for stance (F-Stance) and posterolateral fall (F-Fall) loading, and total femur areal bone mineral density (aBMD) were computed from the QCT data. F-Stance and F-Fall in incident hip fracture subjects were 13%-25% less than in control subjects (p <= 0.006) after controlling for demographic parameters. The difference between FE strengths of fracture and control subjects was disproportionately greater ill men (stance, 22%; fall, 25%) than in women (stance, 13%; fall, 18%) (p <= 0.033), considering that Fstar,ce and FFall in fracture subjects were greater in men than in women ( p < 0.001). For men, F-Stance was associated with hip fracture after accounting for aBMD (p = 0.013). These data indicate that F-Stance provides information about fracture risk that is beyond that provided by aBMD (p = 0.013). These findings support further exploration of possible sex differences in the predictors of hip fracture and of sex-specific strategies for using FE analysis to manage osteoporosis. (C) 2011 Elsevier Inc. All rights reserved.
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| 3. |
- Lang, T. F., et al.
(författare)
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Age-related loss of proximal femoral strength in elderly men and women: The Age Gene/Environment Susceptibility Study - Reykjavik
- 2012
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Ingår i: Bone. - : Elsevier BV. - 1873-2763 .- 8756-3282. ; 50:3, s. 743-748
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Tidskriftsartikel (refereegranskat)abstract
- The risk of hip fracture rises rapidly with age, and is particularly high in women. This increase in fracture risk reflects both the age-related change in the risk of falling and decrements in the strength of the proximal femur. To better understand the extent to which proximal femoral density, structure and strength change with age as a function of gender, we have carried out a longitudinal analysis of proximal femoral volumetric quantitative computed tomographic (vQCT) images in men and women, analyzing changes in trabecular and cortical bone properties, and using subject-specific finite element modeling (FEM) to estimate changes in bone strength. In the AGES-Reykjavik Study vQCT scans of the hip were performed at a baseline visit in 2002-2006 and at a second visit 5.05 +/- 0.25 years later. From these, 223 subjects (111 men, 112 women, aged 68-87 years) were randomly selected. The subjects were evaluated for longitudinal changes in three bone variables assessed in a region similar to the total femur region quantified by DXA: areal bone mineral density (aBMD), trabecular volumetric bone mineral density (tBMD) and the ratio of cortical to total tissue volume (cvol/ivol). They were also evaluated for changes in bone strength using FEM models of the left proximal femur. Models were analyzed under single-limb stance loading (F-Stance), which approximates normal physiologic loading of the hip, as well as a load approximating a fall onto the posterolateral aspect of the greater trochanter (F-Fall). We computed five-year absolute and percentage changes in aBmD, tBMD, cvol/ivol, F-Fall and F-Stance. The Mann-Whitney Test was employed to compare changes in bone variables between genders and the Wilcoxon Signed Rank Test was used to compare changes in bone strength between loading conditions. Multiple (linear) regression was employed to determine the association of changes in F-Fall and F-Stance with baseline age and five-year weight loss. Both men and women showed declines in indices of proximal femoral density and structure (aBMD: men -3.9 +/- 6.0%, women -6.1 +/- 6.2%; tBMD: men -14.8 +/- 20.3%, women -23.9 +/- 26.8%; cvol/ivol: men -2.6 +/- 4.6%, women -4.7 +/- 4.8%, gender difference: p<0.001). Both men and women lost bone strength in each loading condition (F-Stance: men -4.2 +/- 9.9%, women -8.3 +/- 8.5%; F-Fall: men -7.0 +/- 15.7%, women -12.8 +/- 13.2%; all changes from baseline p<0.0001). The gender difference in bone strength loss was statistically significant in both loading conditions (p<0.001 for F-Stance and P<0.01 for F-Fall) and F-Fall, was lost at a higher rate than F-Stance in men (p<0.01) and women (p<0.0001). The gender difference in strength loss was statistically significant after adjustment for baseline age and weight loss in both loading conditions (p<0.01). In these multi-linear models, men showed increasing rates of bone loss with increasing age (F-Fall: p=0.002; F-Stance; p=0.03), and women showed increasing bone strength loss with higher degrees of weight loss (F-Stance: p=0.003). The higher loss of F-Fall compared to F-Stance supports previous findings in animal and human studies that the sub-volumes of bone stressed under normal physiologic loading are relatively better protected in aging. The gender difference in hip bone strength loss is consistent with the higher incidence of hip fractureamong elderly women. (C) 2011 Elsevier Inc. All rights reserved.
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| 6. |
- Gerdtsson, Axel, et al.
(författare)
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Validation of a prediction model for post-chemotherapy fibrosis in nonseminoma patients
- 2023
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Ingår i: Bju International. - 1464-4096 .- 1464-410X. ; 132:3, s. 329-336
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Tidskriftsartikel (refereegranskat)abstract
- Objective To validate Vergouwe's prediction model using the Swedish and Norwegian Testicular Cancer Group (SWENOTECA) RETROP database and to define its clinical utility. Materials and methods Vergouwe's prediction model for benign histopathology in post-chemotherapy retroperitoneal lymph node dissection (PCRPLND) uses the following variables: presence of teratoma in orchiectomy specimen; pre-chemotherapy level of alphafetoprotein; b-Human chorionic gonadotropin and lactate dehydrogenase; and lymph node size pre- and postchemotherapy. Our validation cohort consisted of patients included in RETROP, a prospective population-based database of patients in Sweden and Norway with metastatic nonseminoma, who underwent PC-RPLND in the period 2007-2014. Discrimination and calibration analyses were used to validate Vergouwe's prediction model results. Calibration plots were created and a Hosmer-Lemeshow test was calculated. Clinical utility, expressed as opt-out net benefit (NBopt-out), was analysed using decision curve analysis. Results Overall, 284 patients were included in the analysis, of whom 130 (46%) had benign histology after PC-RPLND. Discrimination analysis showed good reproducibility, with an area under the receiver-operating characteristic curve (AUC) of 0.82 (95% confidence interval 0.77-0.87) compared to Vergouwe's prediction model (AUC between 0.77 and 0.84). Calibration was acceptable with no recalibration. Using a prediction threshold of 70% for benign histopathology, NBopt-out was 0.098. Using the model and this threshold, 61 patients would have been spared surgery. However, only 51 of 61 were correctly classified as benign. Conclusions The model was externally validated with good reproducibility. In a clinical setting, the model may identify patients with a high chance of benign histopathology, thereby sparing patients of surgery. However, meticulous follow-up is required.
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| 9. |
- Sone, Izumi, et al.
(författare)
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Investigating commercially relevant packaging solutions to improve storage stability of mechanically filleted Atlantic mackerel (Scomber scombrus) produced under industrial conditions
- 2020
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Ingår i: European Food Research and Technology. - : Springer Science and Business Media LLC. - 1438-2385 .- 1438-2377. ; 246:4, s. 693-701
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the efficacy of three commercially relevant packaging methods (vacuum with water glazing VAC-G; vacuum with seawater VAC-S; shatter-layer packaging SL) to improve frozen storage stability of mechanically filleted Atlantic mackerel at − 25 °C, in comparison to water glazing alone (GL) and storage as whole unglazed, block frozen fish. Besides proximate composition and pH of raw material, quality changes were analysed by free fatty acid content (FFA), water holding capacity (WHC), cooking yield, lipid oxidation (lipid hydroperoxides, PV; non-protein bound thiobarbituric acid reactive substances, TBARS) and sensory profiles of cooked samples after 3.5, 8, 10 and 12 months of frozen storage. Vacuum-packaging was effective in mitigating the PV and TBARS as well as rancid odour and flavour. The inclusion of seawater in VAC-S altered the sensory textural attributes of the mackerel fillet to be more juicy, tender and soft and increased the attribute of salty flavour in the sample. SL delayed rancid odour and flavour by 2 months compared to GL. Processing of mackerel under industrial conditions, including filleting, handling, double-freezing and glazing accelerated the formation of FFA as well as losses of WHC and cooking yield in the fillet regardless the packaging methods.
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| 10. |
- Sveinsdóttir, Hildur I., et al.
(författare)
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Effect of antioxidants on the sensory quality and physicochemical stability of Atlantic mackerel (Scomber scombrus) fillets during frozen storage
- 2020
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 321
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to evaluate the shelf-life of mechanically filleted well-fed Atlantic mackerel during frozen storage at −25 °C and effect of treatment with antioxidants (sodium erythorbate and a polyphosphate mixture) and different antioxidant application methods (dipping, spraying and glazing). Both physicochemical measurements and sensory analysis were applied. Antioxidant treatments prolonged shelf-life of mackerel. Sensory analysis indicated that untreated fillets had a shelf-life of less than 2.5 months, while all antioxidant treated fillets exceeded that. The most effective treatment, dipping fillets into a sodium erythorbate solution, yielding a shelf-life of 15 months. Physicochemical methods used to evaluate degradation of lipids in the fillets were free fatty acids (FFA), lipid hydroperoxides (PV) and thiobarbituric acid reactive substances (TBARS). They did not correlate with sensory results and might therefore be a questionable choice for evaluation of oxidation and development of rancid flavour and odour in complex matrixes such as Atlantic mackerel.
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| 11. |
- Tandstad, T., et al.
(författare)
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Treatment of stage I seminoma, with one course of adjuvant carboplatin or surveillance, risk-adapted recommendations implementing patient autonomy: a report from the Swedish and Norwegian Testicular Cancer Group (SWENOTECA)
- 2016
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Ingår i: Annals of Oncology. - : Elsevier BV. - 0923-7534 .- 1569-8041. ; 27:7, s. 1299-1304
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Tidskriftsartikel (refereegranskat)abstract
- A total of 1118 patients with clinical stage I seminoma one course of adjuvant carboplatin or managed by surveillance were included. Stromal invasion of rete testis and tumor size > 4 cm are confirmed as risk factors predicting relapse. Relapse rates following one course of adjuvant carboplatin is high and there is need to explore more effective adjuvant treatment options in patients with seminoma.The purpose of the protocol was to reduce the treatment burden in clinical stage I (CSI) seminoma by offering risk-adapted treatment. The protocol aimed to prospectively validate the proposed risk factors for relapse, stromal invasion of the rete testis and tumor diameter > 4 cm, and to evaluate the efficacy of one course of adjuvant carboplatin. From 2007 to 2010, 897 patients were included in a prospective, population-based, risk-adapted treatment protocol implementing one course of adjuvant carboplatin AUC7 (>n = 469) or surveillance (>n = 422). In addition, results from 221 patients receiving carboplatin between 2004 and 2007 are reported. At a median follow-up of 5.6 years, 69 relapses have occurred. Stromal invasion of the rete testis [hazard ratio (HR) 1.9, >P = 0.011] and tumor diameter > 4 cm (HR 2.7, >P < 0.001) were identified as risk factors predicting relapse. In patients without risk factors, the relapse rate (RR) was 4.0% for patients managed by surveillance and 2.2% in patients receiving adjuvant carboplatin. In patients with one or two risk factors, the RR was 15.5% in patients managed by surveillance and 9.3% in patients receiving adjuvant carboplatin. We found no increased RR in patients receiving carboplatin < 7 x AUC compared with that in patients receiving a parts per thousand yen7 x AUC. Stromal invasion in the rete testis and tumor diameter > 4 cm are risk factors for relapse in CSI seminoma. Patients without risk factors have a low RR and adjuvant therapy is not justified in these patients. The efficacy of adjuvant carboplatin is relatively low and there is need to explore more effective adjuvant treatment options in patients with high-risk seminoma. The data do not support the concept of a steep dose response for adjuvant carboplatin.
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