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| 4. |
- Ring, A., et al.
(författare)
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Bridging The Age Gap: observational cohort study of effects of chemotherapy and trastuzumab on recurrence, survival and quality of life in older women with early breast cancer
- 2021
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Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 125, s. 209-219
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Tidskriftsartikel (refereegranskat)abstract
- Background: Chemotherapy improves outcomes for high risk early breast cancer (EBC) patients but is infrequently offered to older individuals. This study determined if there are fit older patients with high-risk disease who may benefit from chemotherapy. Methods: A multicentre, prospective, observational study was performed to determine chemotherapy (±trastuzumab) usage and survival and quality-of-life outcomes in EBC patients aged ≥70 years. Propensity score-matching adjusted for variation in baseline age, fitness and tumour stage. Results: Three thousands four hundred sixteen women were recruited from 56 UK centres between 2013 and 2018. Two thousands eight hundred eleven (82%) had surgery. 1520/2811 (54%) had high-risk EBC and 2059/2811 (73%) were fit. Chemotherapy was given to 306/1100 (27.8%) fit patients with high-risk EBC. Unmatched comparison of chemotherapy versus no chemotherapy demonstrated reduced metastatic recurrence risk in high-risk patients(hazard ratio [HR] 0.36 [95% CI 0.19–0.68]) and in 541 age, stage and fitness-matched patients(adjusted HR 0.43 [95% CI 0.20–0.92]) but no benefit to overall survival (OS) or breast cancer-specific survival (BCSS) in either group. Chemotherapy improved survival in women with oestrogen receptor (ER)-negative cancer (OS: HR 0.20 [95% CI 0.08–0.49];BCSS: HR 0.12 [95% CI 0.03–0.44]).Transient negative quality-of-life impacts were observed. Conclusions: Chemotherapy was associated with reduced risk of metastatic recurrence, but survival benefits were only seen in patients with ER-negative cancer. Quality-of-life impacts were significant but transient. Trial Registration: ISRCTN 46099296. © 2021, The Author(s).
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| 5. |
- Battisti, N. M. L., et al.
(författare)
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Observational cohort study in older women with early breast cancer: Use of radiation therapy and impact on health-related quality of life and mortality
- 2021
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Ingår i: Radiotherapy and Oncology. - : Elsevier BV. - 0167-8140. ; 161, s. 166-176
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Tidskriftsartikel (refereegranskat)abstract
- Background: Radiotherapy reduces in-breast recurrence risk in early breast cancer (EBC) in older women. This benefit may be small and should be balanced against treatment effect and holistic patient assessment. This study described treatment patterns according to fitness and impact on health-related quality-of-life (HRQoL). Methods: A multicentre, observational study of EBC patients aged ≥ 70 years, undergoing breast-conserving surgery (BCS) or mastectomy, was undertaken. Associations between radiotherapy use, surgery, clinico-pathological parameters, fitness based on geriatric parameters and treatment centre were determined. HRQoL was measured using the European Organisation for the Research and Treatment of Cancer (EORTC) questionnaires. Results: In 2013–2018 2811 women in 56 UK study centres underwent surgery with a median follow-up of 52 months. On multivariable analysis, age and tumour risk predicted radiotherapy use. Among healthier patients (based on geriatric assessments) with high-risk tumours, 534/613 (87.1%) having BCS and 185/341 (54.2%) having mastectomy received radiotherapy. In less fit individuals with low-risk tumours undergoing BCS, 149/207 (72.0%) received radiotherapy. Radiotherapy effects on HRQoL domains, including breast symptoms and fatigue were seen, resolving by 18 months. Conclusion: Radiotherapy use in EBC patients ≥ 70 years is affected by age and recurrence risk, whereas geriatric parameters have limited impact regardless of type of surgery. There was geographical variation in treatment, with some fit older women with high-risk tumours not receiving radiotherapy, and some older, low-risk, EBC patients receiving radiotherapy after BCS despite evidence of limited benefit. The impact on HRQoL is transient. © 2021 Elsevier B.V.
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| 6. |
- Morgan, J. L., et al.
(författare)
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Observational cohort study to determine the degree and causes of variation in the rate of surgery or primary endocrine therapy in older women with operable breast cancer
- 2021
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Ingår i: European Journal of Surgical Oncology. - : Elsevier BV. - 0748-7983. ; 47:2, s. 261-268
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Tidskriftsartikel (refereegranskat)abstract
- Background: In the UK there is variation in the treatment of older women with breast cancer, with up to 40% receiving primary endocrine therapy (PET), which is associated with inferior survival. Case mix and patient choice may explain some variation in practice but clinician preference may also be important. Methods: A multicentre prospective cohort study of women aged >70 with operable breast cancer. Patient characteristics (health status, age, tumour characteristics, treatment allocation and decision-making preference) were analysed to identify whether treatment variation persisted following case-mix adjustment. Expected case-mix adjusted surgery rates were derived by logistic regression using the variables age, co-morbidity, tumour stage and grade. Concordance between patients’ preferred and actual decision-making style was assessed and associations between age, treatment and decision-making style calculated. Results: Women (median age 77, range 70–102) were recruited from 56 UK breast units between 2013 and 2018. Of 2854/3369 eligible women with oestrogen receptor positive breast cancer, 2354 were treated with surgery and 500 with PET. Unadjusted surgery rates varied between hospitals, with 23/56 units falling outside the 95% confidence intervals on funnel plots. Adjusting for case mix reduced, but did not eliminate, this variation between hospitals (10/56 units had practice outside the 95% confidence intervals). Patients treated with PET had more patient-centred decisions compared to surgical patients (42.2% vs 28.4%, p < 0.001). Conclusions: This study demonstrates variation in treatment selection thresholds for older women with breast cancer. Health stratified guidelines on thresholds for PET would help reduce variation, although patient preference should still be respected. © 2020 The Authors
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| 7. |
- Wyld, L., et al.
(författare)
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Bridging the age gap in breast cancer: cluster randomized trial of two decision support interventions for older women with operable breast cancer on quality of life, survival, decision quality, and treatment choices
- 2021
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Ingår i: The British journal of surgery. - : Oxford University Press (OUP). - 1365-2168 .- 0007-1323. ; 108:5, s. 499-510
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Rates of surgery and adjuvant therapy for breast cancer vary widely between breast units. This may contribute to differences in survival. This cluster RCT evaluated the impact of decision support interventions (DESIs) for older women with breast cancer, to ascertain whether DESIs influenced quality of life, survival, decision quality, and treatment choice. METHODS: A multicentre cluster RCT compared the use of two DESIs against usual care in treatment decision-making in older women (aged at least ≥70 years) with breast cancer. Each DESI comprised an online algorithm, booklet, and brief decision aid to inform choices between surgery plus adjuvant endocrine therapy versus primary endocrine therapy, and adjuvant chemotherapy versus no chemotherapy. The primary outcome was quality of life. Secondary outcomes included decision quality measures, survival, and treatment choice. RESULTS: A total of 46 breast units were randomized (21 intervention, 25 usual care), recruiting 1339 women (670 intervention, 669 usual care). There was no significant difference in global quality of life at 6 months after the baseline assessment on intention-to-treat analysis (difference -0.20, 95 per cent confidence interval (C.I.) -2.69 to 2.29; P=0.900). In women offered a choice of primary endocrine therapy versus surgery plus endocrine therapy, knowledge about treatments was greater in the intervention arm (94 versus 74 per cent; P=0.003). Treatment choice was altered, with a primary endocrine therapy rate among women with oestrogen receptor-positive disease of 21.0 per cent in the intervention versus 15.4 per cent in usual-care sites (difference 5.5 (95 per cent C.I. 1.1 to 10.0) per cent; P=0.029). The chemotherapy rate was 10.3 per cent at intervention versus 14.8 per cent at usual-care sites (difference -4.5 (C.I. -8.0 to 0) per cent; P=0.013). Survival was similar in both arms. CONCLUSION: The use of DESIs in older women increases knowledge of breast cancer treatment options, facilitates shared decision-making, and alters treatment selection. Trial registration numbers: EudraCT 2015-004220-61 (https://eudract.ema.europa.eu/), ISRCTN46099296 (http://www.controlled-trials.com). © The Author(s) 2021. Published by Oxford University Press on behalf of BJS Society Ltd.
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| 8. |
- Wyld, L., et al.
(författare)
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Bridging the age gap in breast cancer. Impacts of omission of breast cancer surgery in older women with oestrogen receptor positive early breast cancer. A risk stratified analysis of survival outcomes and quality of life
- 2021
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Ingår i: European Journal of Cancer. - : Elsevier BV. - 0959-8049. ; 142, s. 48-62
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Tidskriftsartikel (refereegranskat)abstract
- Background: Age-related breast cancer treatment variance is widespread with many older women having primary endocrine therapy (PET), which may contribute to inferior survival and local control. This propensity-matched study determined if a subgroup of older women may safely be offered PET. Methods: Multicentre, prospective, UK, observational cohort study with propensity-matched analysis to determine optimal allocation of surgery plus ET (S+ET) or PET in women aged ≥70 with breast cancer. Data on fitness, frailty, cancer stage, grade, biotype, treatment and quality of life were collected. Propensity-matching (based on age, health status and cancer stage) adjusted for allocation bias when comparing S+ET with PET. Findings: A total of 3416 women (median age 77, range 69–102) were recruited from 56 breast units—2854 (88%) had ER+ breast cancer: 2354 had S+ET and 500 PET. Median follow-up was 52 months. Patients treated with PET were older and frailer than patients treated with S+ET. Unmatched overall survival was inferior in the PET group (hazard ratio, (HR) 0.27, 95% confidence interval (CI) 0.23–0.33, P < 0.001). Unmatched breast cancer–specific survival (BCSS) was also inferior in patients treated with PET (HR: 0.41, CI: 0.29–0.58, P < 0.001 for BCSS). In the matched analysis, PET was still associated with an inferior overall survival (HR = 0.72, 95% CI: 0.53–0.98, P = 0.04) but not BCSS (HR = 0.74, 95% CI: 0.40–1.37, P = 0.34) although at 4–5 years subtle divergence of the curves commenced in favor of surgery. Global health status diverged at certain time points between groups but over 24 months was similar when adjusted for baseline variance. Interpretation: For the majority of older women with early ER+ breast cancer, surgery is oncologically superior to PET. In less fit, older women, with characteristics similar to the matched cohort of this study (median age 81 with higher comorbidity and functional impairment burdens, the BCSS survival differential disappears at least out to 4–5 year follow-up, suggesting that for those with less than 5-year predicted life-expectancy (>90 years or >85 with comorbidities or frailty) individualised decision making regarding PET versus S+ET may be appropriate and safe to offer. The Age Gap online decision tool may support this decision-making process (https://agegap.shef.ac.uk/). Trial registration number: ISRCTN: 46099296. © 2020 The Authors
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| 9. |
- Wyld, L., et al.
(författare)
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Improving outcomes for women aged 70 years or above with early breast cancer: Research programme including a cluster RCT
- 2022
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Ingår i: Programme Grants for Applied Research. - 2050-4322. ; 10:6
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Tidskriftsartikel (refereegranskat)abstract
- Background: In breast cancer management, age-related practice variation is widespread, with older women having lower rates of surgery and chemotherapy than younger women, based on the premise of reduced treatment tolerance and benefit. This may contribute to inferior outcomes. There are currently no age-and fitness-stratified guidelines on which to base treatment recommendations. Aim: We aimed to optimise treatment choice and outcomes for older women (aged > 70 years) with operable breast cancer. Objectives: Our objectives were to (1) determine the age, comorbidity, frailty, disease stage and biology thresholds for endocrine therapy alone versus surgery plus adjuvant endocrine therapy, or adjuvant chemotherapy versus no chemotherapy, for older women with breast cancer; (2) optimise survival outcomes for older women by improving the quality of treatment decision-making; (3) develop and evaluate a decision support intervention to enhance shared decision-making; and (4) determine the degree and causes of treatment variation between UK breast units. Design: A prospective cohort study was used to determine age and fitness thresholds for treatment allocation. Mixed-methods research was used to determine the information needs of older women to develop a decision support intervention. A cluster-randomised trial was used to evaluate the impact of this decision support intervention on treatment choices and outcomes. Health economic analysis was used to evaluate the cost-benefit ratio of different treatment strategies according to age and fitness criteria. A mixed-methods study was used to determine the degree and causes of variation in treatment allocation. Main outcome measures: The main outcome measures were enhanced age-and fitness-specific decision support leading to improved quality-of-life outcomes in older women (aged > 70 years) with early breast cancer. Results: (1) Cohort study: The study recruited 3416 UK women aged > 70 years (median age 77 years). Follow-up was 52 months. (a) The surgery plus adjuvant endocrine therapy versus endocrine therapy alone comparison: 2854 out of 3416 (88%) women had oestrogen-receptor-positive breast cancer, 2354 of whom received surgery plus adjuvant endocrine therapy and 500 received endocrine therapy alone. Patients treated with endocrine therapy alone were older and frailer than patients treated with surgery plus adjuvant endocrine therapy. Unmatched overall survival and breast-cancer-specific survival were higher in the surgery plus adjuvant endocrine therapy group (overall survival: Hazard ratio 0.27, 95% confidence interval 0.23 to 0.33; p < 0.001; breast-cancer-specific survival: Hazard ratio 0.41, 95% confidence interval 0.29 to 0.58; p < 0.001) than in the endocrine therapy alone group. In matched analysis, surgery plus adjuvant endocrine therapy was still associated with better overall survival (hazard ratio 0.72, 95% confidence interval 0.53 to 0.98; p = 0.04) than endocrine therapy alone, but not with better breast-cancer-specific survival (hazard ratio 0.74, 95% confidence interval 0.40 to 1.37; p = 0.34) or progression-free-survival (hazard ratio 1.11, 95% confidence interval 0.55 to 2.26; p = 0.78). (b) The adjuvant chemotherapy versus no chemotherapy comparison: 2811 out of 3416 (82%) women received surgery plus adjuvant endocrine therapy, of whom 1520 (54%) had high-recurrence-risk breast cancer [grade 3, node positive, oestrogen receptor negative or human epidermal growth factor receptor-2 positive, or a high Oncotype DX® (Genomic Health, Inc., Redwood City, CA, USA) score of > 25]. In this high-risk population, there were no differences according to adjuvant chemotherapy use in overall survival or breast-cancer-specific survival after propensity matching. Adjuvant chemotherapy was associated with a lower risk of metastatic recurrence than no chemotherapy in the unmatched (adjusted hazard ratio 0.36, 95% confidence interval 0.19 to 0.68; p = 0.002) and propensity-matched patients (adjusted hazard ratio 0.43, 95% confidence interval 0.20 to 0.92; p = 0.03). Adjuva t chemotherapy improved the overall survival and breast-cancer-specific survival of patients with oestrogen-receptor-negative disease. (2) Mixed-methods research to develop a decision support intervention: An iterative process was used to develop two decision support interventions (each comprising a brief decision aid, a booklet and an online tool) specifically for older women facing treatment choices (endocrine therapy alone or surgery plus adjuvant endocrine therapy, and adjuvant chemotherapy or no chemotherapy) using several evidence sources (expert opinion, literature and patient interviews). The online tool was based on models developed using registry data from 23,842 patients and validated on an external data set of 14,526 patients. Mortality rates at 2 and 5 years differed by < 1% between predicted and observed values. (3) Cluster-randomised clinical trial of decision support tools: 46 UK breast units were randomised (intervention, n = 21; usual care, n = 25), recruiting 1339 women (intervention, n = 670; usual care, n = 669). There was no significant difference in global quality of life at 6 months post baseline (difference-0.20, 95% confidence interval-2.7 to 2.3; p = 0.90). In women offered a choice of endocrine therapy alone or surgery plus adjuvant endocrine therapy, knowledge about treatments was greater in the intervention arm than the usual care arm (94% vs. 74%; p = 0.003). Treatment choice was altered, with higher rates of endocrine therapy alone than of surgery in the intervention arm. Similarly, chemotherapy rates were lower in the intervention arm (endocrine therapy alone rate: Intervention sites 21% vs. usual-care sites 15%, difference 5.5%, 95% confidence interval 1.1% to 10.0%; p = 0.02; adjuvant chemotherapy rate: Intervention sites 10% vs. usual-care site 15%, difference 4.5%, 95% confidence interval 0.0% to 8.0%; p = 0.013). Survival was similar in both arms. (4) Health economic analysis: A probabilistic economic model was developed using registry and cohort study data. For most health and fitness strata, surgery plus adjuvant endocrine therapy had lower costs and returned more quality-adjusted life-years than endocrine therapy alone. However, for some women aged > 90 years, surgery plus adjuvant endocrine therapy was no longer cost-effective and generated fewer quality-adjusted life-years than endocrine therapy alone. The incremental benefit of surgery plus adjuvant endocrine therapy reduced with age and comorbidities. (5) Variation in practice: analysis of rates of surgery plus adjuvant endocrine therapy or endocrine therapy alone between the 56 breast units in the cohort study demonstrated significant variation in rates of endocrine therapy alone that persisted after adjustment for age, fitness and stage. Clinician preference was an important determinant of treatment choice. Conclusions: This study demonstrates that, for older women with oestrogen-receptor-positive breast cancer, there is a cohort of women with a life expectancy of < 4 years for whom surgery plus adjuvant endocrine therapy may offer little benefit and simply have a negative impact on quality of life. The Age Gap decision tool may help make this shared decision. Similarly, although adjuvant chemotherapy offers little benefit and has a negative impact on quality of life for the majority of older women with oestrogen-receptor-positive breast cancer, for women with oestrogen-receptor-negative breast cancer, adjuvant chemotherapy is beneficial. The negative impacts of adjuvant chemotherapy on quality of life, although significant, are transient. This implies that, for the majority of fitter women aged > 70 years, standard care should be offered. Limitations: As with any observational study, despite detailed propensity score matching, residual bias cannot be excluded. Follow-up was at median 52 months for the cohort analysis. Longer-term follow-up will be required to validate these findings owing to the slow time course of oestrogen-receptor-positive breast cancer. Future work: The online algorithm is now available (URL: Https://ag gap.shef.ac.uk/; accessed May 2022). There are plans to validate the tool and incorprate quality-of-life and 10-year survival outcomes.
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| 10. |
- Leinonen, V., et al.
(författare)
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S- F-18 THK-5117-PET and C-11 PIB-PET Imaging in Idiopathic Normal Pressure Hydrocephalus in Relation to Confirmed Amyloid-beta Plaques and Tau in Brain Biopsies
- 2018
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Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 64:1, s. 171-179
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Tidskriftsartikel (refereegranskat)abstract
- Background: Detection of pathological tau aggregates could facilitate clinical diagnosis of Alzheimer's disease (AD) and monitor drug effects in clinical trials. S-[F-18] THK-5117 could be a potential tracer to detect pathological tau deposits in brain. However, no previous study have correlated S-[F-18] THK-5117 uptake in PET with brain biopsy verified tau pathology in vivo. Objective: Here we aim to evaluate the association between cerebrospinal fluid (CSF) AD biomarkers, S-[F-18] THK-5117, and [C-11] PIB PET against tau and amyloid lesions in brain biopsy. Methods: Fourteen patients with idiopathic normal pressure hydrocephalus (iNPH) with previous shunt surgery including right frontal cortical brain biopsy and CSF A beta(1-42), total tau, and P-tau(181) measures, underwent brain MRI, [C-11] PIB PET, and S-[F-18] THK-5117 PET imaging. Results: Seven patients had amyloid-beta(A beta, 4G8) plaques, two both A beta and phosphorylated tau (P tau, AT8) and one only P tau in biopsy. As expected, increased brain biopsy A beta was well associated with higher [C-11] PIB uptake in PET. However, S-[F-18] THK-5117 uptake did not show any statistically significant correlation with either brain biopsy P tau or CSF P-tau(181) or total tau. Conclusions: S-[F-18] THK-5117 lacked clear association with neuropathologically verified tau pathology in brain biopsy probably, at least partially, due to off-target binding. Further studies with larger samples of patients with different tau tracers are urgently needed. The detection of simultaneous A beta and tau pathology in iNPH is important since that may indicate poorer and especially shorter response for CSF shunt surgery compared with no pathology.
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| 13. |
- Collij, L. E., et al.
(författare)
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The amyloid imaging for the prevention of Alzheimer's disease consortium: A European collaboration with global impact
- 2023
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Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundAmyloid-beta (A beta) accumulation is considered the earliest pathological change in Alzheimer's disease (AD). The Amyloid Imaging to Prevent Alzheimer's Disease (AMYPAD) consortium is a collaborative European framework across European Federation of Pharmaceutical Industries Associations (EFPIA), academic, and 'Small and Medium-sized enterprises' (SME) partners aiming to provide evidence on the clinical utility and cost-effectiveness of Positron Emission Tomography (PET) imaging in diagnostic work-up of AD and to support clinical trial design by developing optimal quantitative methodology in an early AD population. The AMYPAD studiesIn the Diagnostic and Patient Management Study (DPMS), 844 participants from eight centres across three clinical subgroups (245 subjective cognitive decline, 342 mild cognitive impairment, and 258 dementia) were included. The Prognostic and Natural History Study (PNHS) recruited pre-dementia subjects across 11 European parent cohorts (PCs). Approximately 1600 unique subjects with historical and prospective data were collected within this study. PET acquisition with [F-18]flutemetamol or [F-18]florbetaben radiotracers was performed and quantified using the Centiloid (CL) method. ResultsAMYPAD has significantly contributed to the AD field by furthering our understanding of amyloid deposition in the brain and the optimal methodology to measure this process. Main contributions so far include the validation of the dual-time window acquisition protocol to derive the fully quantitative non-displaceable binding potential (BPND), assess the value of this metric in the context of clinical trials, improve PET-sensitivity to emerging A beta burden and utilize its available regional information, establish the quantitative accuracy of the Centiloid method across tracers and support implementation of quantitative amyloid-PET measures in the clinical routine. Future stepsThe AMYPAD consortium has succeeded in recruiting and following a large number of prospective subjects and setting up a collaborative framework to integrate data across European PCs. Efforts are currently ongoing in collaboration with ARIDHIA and ADDI to harmonize, integrate, and curate all available clinical data from the PNHS PCs, which will become openly accessible to the wider scientific community.
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| 14. |
- Holmes, G. R., et al.
(författare)
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Cost-Effectiveness Modeling of Surgery Plus Adjuvant Endocrine Therapy Versus Primary Endocrine Therapy Alone in UK Women Aged 70 and Over With Early Breast Cancer
- 2021
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Ingår i: Value in Health. - : Elsevier BV. - 1098-3015. ; 24:6, s. 770-779
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Approximately 20% of UK women aged 70+ with early breast cancer receive primary endocrine therapy (PET) instead of surgery. PET reduces surgical morbidity but with some survival decrement. To complement and utilize a treatment dependent prognostic model, we investigated the cost-effectiveness of surgery plus adjuvant therapies versus PET for women with varying health and fitness, identifying subgroups for which each treatment is cost-effective. Methods: Survival outcomes from a statistical model, and published data on recurrence, were combined with data from a large, multicenter, prospective cohort study of over 3400 UK women aged 70+ with early breast cancer and median 52-month follow-up, to populate a probabilistic economic model. This model evaluated the cost-effectiveness of surgery plus adjuvant therapies relative to PET for 24 illustrative subgroups: Age {70, 80, 90} × Nodal status {FALSE (F), TRUE (T)} × Comorbidity score {0, 1, 2, 3+}. Results: For a 70-year-old with no lymph node involvement and no comorbidities (70, F, 0), surgery plus adjuvant therapies was cheaper and more effective than PET. For other subgroups, surgery plus adjuvant therapies was more effective but more expensive. Surgery plus adjuvant therapies was not cost-effective for 4 of the 24 subgroups: (90, F, 2), (90, F, 3), (90, T, 2), (90, T, 3). Conclusion: From a UK perspective, surgery plus adjuvant therapies is clinically effective and cost-effective for most women aged 70+ with early breast cancer. Cost-effectiveness reduces with age and comorbidities, and for women over 90 with multiple comorbidities, there is little cost benefit and a negative impact on quality of life. © 2021 ISPOR–The Professional Society for Health Economics and Outcomes Research
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| 15. |
- Pemberton, T.J., et al.
(författare)
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Using population mixture to optimize the utility of genomic databases: linkage disequilibrium and association study design in India
- 2008
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Ingår i: Annals of Human Genetics. - : Wiley. - 0003-4800 .- 1469-1809. ; 72:4, s. 535-546
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Tidskriftsartikel (refereegranskat)abstract
- When performing association studies in populations that have not been the focus of large-scale investigations of haplotype variation, it is often helpful to rely on genomic databases in other populations for study design and analysis – such as in the selection of tag SNPs and in the imputation of missing genotypes. One way of improving the use of these databases is to rely on a mixture of database samples that is similar to the population of interest, rather than using the single most similar database sample. We demonstrate the effectiveness of the mixture approach in the application of African, European, and East Asian HapMap samples for tag SNP selection in populations from India, a genetically intermediate region underrepresented in genomic studies of haplotype variation.
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| 16. |
- Wang, Z.A., et al.
(författare)
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Comparing spatial maps of human population-genetic variation using Procrustes analysis
- 2010
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Ingår i: Statistical Applications in Genetics and Molecular Biology. - : Walter de Gruyter GmbH. - 1544-6115 .- 1544-6115. ; 9:1, s. e13-
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Tidskriftsartikel (refereegranskat)abstract
- Recent applications of principal components analysis (PCA) and multidimensional scaling (MDS) in human population genetics have found that "statistical maps" based on the genotypes in population-genetic samples often resemble geographic maps of the underlying sampling locations. To provide formal tests of these qualitative observations, we describe a Procrustes analysis approach for quantitatively assessing the similarity of population-genetic and geographic maps. We confirm in two scenarios, one using single-nucleotide polymorphism (SNP) data from Europe and one using SNP data worldwide, that a measurably high level of concordance exists between statistical maps of population-genetic variation and geographic maps of sampling locations. Two other examples illustrate the versatility of the Procrustes approach in population-genetic applications, verifying the concordance of SNP analyses using PCA and MDS, and showing that statistical maps of worldwide copy-number variants (CNVs) accord with statistical maps of SNP variation, especially when CNV analysis is limited to samples with the highest-quality data. As statistical maps with PCA and MDS have become increasingly common for use in summarizing population relationships, our examples highlight the potential of Procrustes-based quantitative comparisons for interpreting the results in these maps.
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| 17. |
- Eggers, Kai M., 1962-, et al.
(författare)
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Diagnostic and prognostic performance of the ratio between high-sensitivity cardiac troponin I and troponin T in patients with chest pain
- 2022
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 17:11
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Tidskriftsartikel (refereegranskat)abstract
- Background Elevations of high-sensitivity cardiac troponin (hs-cTn) concentrations not related to type 1 myocardial infarction are common in chest pain patients presenting to emergency departments. The discrimination of these patients from those with type 1 myocardial infarction (MI) is challenging and resource-consuming. We aimed to investigate whether the hs-cTn I/T ratio might provide diagnostic and prognostic increment in this context.Methods We calculated the hs-cTn I/T ratio in 888 chest pain patients having hs-cTnI (Abbott Laboratories) or hs-cTnT (Roche Diagnostics) concentrations above the respective 99(th) percentile at 2 hours from presentation. All patients were followed for one year regarding mortality.Results The median hs-cTn I/T ratio was 3.45 (25(th), 75(th) percentiles 1.80-6.59) in type 1 MI patients (n = 408 (sic) 46.0%]), 1.18 (0.81-1.90) in type 2 MI patients (n = 56 (sic) 6.3%]) and 0.67 (0.39-1.12) in patients without MI. The hs-cTn I/T ratio provided good discrimination of type 1 MI from no type 1 MI (area under the receiver-operator characteristic curve 0.89 (sic) 95% confidence interval 0.86-0.91]), of type 1 MI from type 2 MI (area under the curve 0.81 (sic) 95% confidence interval 0.74-0.87]), and was associated with type 1 MI in adjusted analyses. The hs-cTn I/T ratio provided no consistent prognostic value.Conclusions The hs-cTn I/T ratio appears to be useful for early diagnosis of type 1 MI and its discrimination from type 2 MI in chest pain patients presenting with elevated hs-cTn. Differences in hs-cTn I/T ratio values may reflect variations in hs-cTn release mechanisms in response to different types of myocardial injury.
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| 18. |
- Eggers, Kai M., 1962-, et al.
(författare)
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Diagnostic and prognostic performance of the ratio between high-sensitivity cardiac troponin I and troponin T in patients with chest pain.
- 2022
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 17:11
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Tidskriftsartikel (refereegranskat)abstract
- Elevations of high-sensitivity cardiac troponin (hs-cTn) concentrations not related to type 1 myocardial infarction are common in chest pain patients presenting to emergency departments. The discrimination of these patients from those with type 1 myocardial infarction (MI) is challenging and resource-consuming. We aimed to investigate whether the hs-cTn I/T ratio might provide diagnostic and prognostic increment in this context.We calculated the hs-cTn I/T ratio in 888 chest pain patients having hs-cTnI (Abbott Laboratories) or hs-cTnT (Roche Diagnostics) concentrations above the respective 99th percentile at 2 hours from presentation. All patients were followed for one year regarding mortality.The median hs-cTn I/T ratio was 3.45 (25th, 75th percentiles 1.80-6.59) in type 1 MI patients (n = 408 ☯46.0%]), 1.18 (0.81-1.90) in type 2 MI patients (n = 56 ☯6.3%]) and 0.67 (0.39-1.12) in patients without MI. The hs-cTn I/T ratio provided good discrimination of type 1 MI from no type 1 MI (area under the receiver-operator characteristic curve 0.89 ☯95% confidence interval 0.86-0.91]), of type 1 MI from type 2 MI (area under the curve 0.81 ☯95% confidence interval 0.74-0.87]), and was associated with type 1 MI in adjusted analyses. The hs-cTn I/T ratio provided no consistent prognostic value.The hs-cTn I/T ratio appears to be useful for early diagnosis of type 1 MI and its discrimination from type 2 MI in chest pain patients presenting with elevated hs-cTn. Differences in hs-cTn I/T ratio values may reflect variations in hs-cTn release mechanisms in response to different types of myocardial injury.
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| 19. |
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| 20. |
- Hansson, Bengt, et al.
(författare)
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Linkage mapping reveals sex-dimorphic map distances in a passerine bird
- 2005
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Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 272:1578, s. 2289-2298
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Tidskriftsartikel (refereegranskat)abstract
- Linkage maps are lacking for many highly influential model organisms in evolutionary research, including all passerine birds. Consequently, their full potential as research models is severely hampered. Here, we provide a partial linkage map and give novel estimates of sex-specific recombination rates in a passerine bird, the great reed warbler (Acrocephalus arundinaceus). Linkage analysis of genotypic data at 51 autosomal microsatellites and seven markers on the Z-chromosome (one of the sex chromosomes) from an extended pedigree resulted in 12 linkage groups with 2-8 loci. A striking feature of the map was the pronounced sex-dimorphism: males had a substantially lower recombination rate than females, which resulted in a suppressed autosomal map in males (sum of linkage groups: 110.2 cM) compared to females (237.2 cM; female/male map ratio: 2.15). The sex-specific recombination rates will facilitate the building of a denser linkage map and cast light on hypotheses about sex-specific recombination rates.
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| 21. |
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| 22. |
- Hughes, R. N., et al.
(författare)
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Paradoxical polyembryony? Embryonic cloning in an ancient order of marine bryozoans
- 2005
-
Ingår i: Biology Letters. - 1744-9561. ; 1:2, s. 178-180
-
Tidskriftsartikel (refereegranskat)abstract
- Prolific polyembryony is reported in few major taxa, but its occurrence has generated theoretical debate on potential conflict between sexual and asexual reproduction. It is, therefore, important to genetically confirm a widely cited inference, based on microscopy, that polyembryony characterizes marine bryozoans of the order Cyclostomata. Microsatellite genotyping of brooded embryos and maternal colonies conclusively demonstrated polyembryony, while genetic variation among broods within colonies indicated outcrossing via water-borne sperm, in the rocky-shore species Crisia denticulata. The characteristically voluminous brood chamber of cyclostomes is judged to be an adaptation linked to larval cloning and hence an indicator of polyembryony. We speculate that although the almost universal occurrence of polyembryony among crown-group Cyclostomata is probably attributable to phylogenetic constraint, adaptive consequences are likely to be significant.
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| 23. |
- Iwnicki, S., et al.
(författare)
-
The ‘FORESEE’ Prototype, Fully Active, Steered Two Axle Railway Vehicle
- 2020
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Ingår i: Lect. Notes Mech. Eng.. - Cham : Springer. ; , s. 3-15
-
Konferensbidrag (refereegranskat)abstract
- This paper reports on a novel project to develop a fully active, two axle railway vehicle which could provide reduced track forces and noise and improved ride comfort compared with existing vehicles. Computer simulations have been used to tune the suspension components and control systems to ensure good passenger comfort and safe operation even in failed control cases. A prototype of the vehicle has been constructed and tested on a full size roller rig. The test results confirm the computer simulations and demonstrate that for speeds up to 200 km/h and in all failure modes the vehicle was stable and with low track forces and high stability and passenger comfort.
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| 24. |
- Pemberton, A. J., et al.
(författare)
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Microscale genetic differentiation in a sessile invertebrate with cloned larvae: investigating the role of polyembryony
- 2007
-
Ingår i: Marine Biology. - 0025-3162. ; 153:1, s. 71-82
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Tidskriftsartikel (refereegranskat)abstract
- Microscale genetic differentiation of sessile organisms can arise from restricted dispersal of sexual propagules, leading to isolation by distance, or from localised cloning. Cyclostome bryozoans offer a possible combination of both: the localised transfer of spermatozoa between mates with limited dispersal of the resulting larvae, in association with the splitting of each sexually produced embryo into many clonal copies (polyembryony). We spatially sampled 157 colonies of Crisia denticulata from subtidal rock overhangs from one shore in Devon, England at a geographic scale of ca. 0.05 to 130 m plus a further 21 colonies from Pembrokeshire, Wales as an outgroup. Analysis of molecular variance (AMOVA) revealed that the majority (67%) of genetic variation was distributed among individuals within single rock overhangs, with only 16% of variation among different overhangs within each shore and 17% of variation between the ingroup and outgroup shores. Despite local genetic variation, pairwise genetic similarity analysed by spatial autocorrelation was greatest at the smallest inter-individual distance we tested (5 cm) and remained significant and positive across generally within-overhang comparisons (< 4 m). Spatial autocorrelation and AMOVA analyses both indicated that patches of C. denticulata located on different rock overhangs tended to be genetically distinct, with the switch from positive to negative autocorrelation, which is often considered to be the distance within which individuals reproduce with their close relatives or the radius of a patch, occurring at the 4-8 m distance class. Rerunning analyses with twenty data sets that only included one individual of each multilocus genotype (n = 97) or the single data set that contained just the unique genotypes (n = 67) revealed that the presence of repeat genotypes had an impact on genetic structuring (PhiPT values were reduced when shared genotypes were removed from the dataset) but that it was not great and only statistically evident at distances between individuals of 1-2 m. Comparisons to a further 20 randomisations of the data set that were performed irrespective of genotype (n = 97) suggested that this conclusion is not an artefact of reduced sample size. A resampling procedure using kinship coefficients, implemented by the software package GENCLONE gave broadly similar results but the greater statistical power allowed small but significant impacts of repeat genotypes on genetic structure to be also detected at 0.125-0.5 and 4-16 m. Although we predict that a proportion of the repeat multilocus genotypes are shared by chance, such generally within-overhang distances may represent a common distance of cloned larval dispersal. These results suggests that closely situated potential mates include a significant proportion of the available genetic diversity within a population, making it unlikely that, as previously hypothesised, the potential disadvantage of producing clonal broods through polyembryony is offset by genetic uniformity within the mating neighbourhood. We also report an error in the published primer note of Craig et al. (Mol Ecol Notes 1:281-282, 2001): loci Cd5 and Cd6 appear to be the same microsatellite.
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| 25. |
- Skeoch, S., et al.
(författare)
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Imaging atherosclerosis in rheumatoid arthritis: evidence for increased prevalence, altered phenotype and a link between systemic and localised plaque inflammation
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- In rheumatoid arthritis (RA), chronic inflammation is thought to drive increased cardiovascular risk through accelerated atherosclerosis. It may also lead to a more high-risk plaque phenotype. We sought to investigate carotid plaque phenotype in RA patients using Dynamic Contrast-Enhanced MRI (DCEMRI) and Fludeoxyglucose Positron Emission Tomography(FDG-PET). In this pilot study, RA patients and age/sex-matched controls were evaluated for cardiovascular risk factors and carotid plaque on ultrasound. Subjects with plaque >2 mm thick underwent DCE-MRI, and a subgroup of patients had FDG-PET. Comparison of MRI findings between groups and correlation between clinical, serological markers and imaging findings was undertaken. 130 patients and 62 controls were recruited. Plaque was more prevalent in the RA group (53.1% vs 37.0%, p = 0.038) and was independently associated with IL6 levels (HR[95% CI]: 2.03 [1.26, 3.26] per quartile). DCE-MRI data were available in 15 patients and 5 controls. Higher prevalence of plaque calcification was noted in RA, despite similar plaque size (73.3% vs 20%, p = 0.04). FDG-PET detected plaque inflammation in 12/13 patients scanned and degree of inflammation correlated with hs-CRP (r = 0.58, p = 0.04). This study confirms increased prevalence of atherosclerosis in RA and provides data to support the hypothesis that patients have a high-risk plaque phenotype.
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| 26. |
- Bollack, Ariane, et al.
(författare)
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Evaluation of novel data-driven metrics of amyloid β deposition for longitudinal PET studies
- 2023
-
Ingår i: NeuroImage. - 1053-8119. ; 280
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: Positron emission tomography (PET) provides in vivo quantification of amyloid-β (Aβ) pathology. Established methods for assessing Aβ burden can be affected by physiological and technical factors. Novel, data-driven metrics have been developed to account for these sources of variability. We aimed to evaluate the performance of four of these amyloid PET metrics against conventional techniques, using a common set of criteria. Methods: Three cohorts were used for evaluation: Insight 46 (N=464, [18F]florbetapir), AIBL (N=277, [18F]flutemetamol), and an independent test-retest data (N=10, [18F]flutemetamol). Established metrics of amyloid tracer uptake included the Centiloid (CL) and where dynamic data was available, the non-displaceable binding potential (BPND). The four data-driven metrics computed were the amyloid load (Aβ load), the Aβ-PET pathology accumulation index (Aβ index), the Centiloid derived from non-negative matrix factorisation (CLNMF), and the amyloid pattern similarity score (AMPSS). These metrics were evaluated using reliability and repeatability in test-retest data, associations with BPND and CL, variability of the rate of change and sample size estimates to detect a 25% slowing in Aβ accumulation. Results: All metrics showed good reliability. Aβ load, Aβ index and CLNMF were strong associated with the BPND. The associations with CL suggest that cross-sectional measures of CLNMF, Aβ index and Aβ load are robust across studies. Sample size estimates for secondary prevention trial scenarios were the lowest for CLNMF and Aβ load compared to the CL. Conclusion: Among the novel data-driven metrics evaluated, the Aβ load, the Aβ index and the CLNMF can provide comparable performance to more established quantification methods of Aβ PET tracer uptake. The CLNMF and Aβ load could offer a more precise alternative to CL, although further studies in larger cohorts should be conducted.
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| 27. |
- Bonnet, Timothee, et al.
(författare)
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Genetic variance in fitness indicates rapid contemporary adaptive evolution in wild animals
- 2022
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 376:6596, s. 1012-1016
-
Tidskriftsartikel (refereegranskat)abstract
- The rate of adaptive evolution, the contribution of selection to genetic changes that increase mean fitness, is determined by the additive genetic variance in individual relative fitness. To date, there are few robust estimates of this parameter for natural populations, and it is therefore unclear whether adaptive evolution can play a meaningful role in short-term population dynamics. We developed and applied quantitative genetic methods to long-term datasets from 19 wild bird and mammal populations and found that, while estimates vary between populations, additive genetic variance in relative fitness is often substantial and, on average, twice that of previous estimates. We show that these rates of contemporary adaptive evolution can affect population dynamics and hence that natural selection has the potential to partly mitigate effects of current environmental change.
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| 28. |
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| 29. |
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| 30. |
- Csillery, K, et al.
(författare)
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Performance of marker-based relatedness estimators in natural populations of outbred vertebrates
- 2006
-
Ingår i: Genetics. - : Oxford University Press (OUP). - 0016-6731 .- 1943-2631. ; 173:4, s. 2091-2101
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of relatedness between pairs of individuals plays an important role in many research areas including evolutionary biology, quantitative genetics, and conservation. Pairwise relatedness estimation methods based on genetic data from highly variable molecular markers are now used extensively as a substitute for pedigrees. Although the sampling variance of the estimators has been intensively studied for the most common simple genetic relationships, such as unrelated, half- and full-sib, or parent-offspring, little attention has been paid to the average performance of the estimators, by which we mean the performance across all pairs of individuals in a sample. Here we apply two measures to quantify the average performance: first, misclassification rates between pairs of genetic relationships and, second, the proportion of variance explained in the pairwise relatedness estimates by the true population relatedness composition (i.e., the frequencies of different relationships in the population). Using simulated data derived from exceptionally good quality marker and pedigree data from five long-term projects of natural populations, we demonstrate that the average performance depends mainly on the population relatedness composition and maybe improved by the marker data quality only within the limits of the population relatedness composition. Our five examples of vertebrate breeding systems suggest that due to the remarkably low variance in relatedness across the Population, marker-based estimates may often have low power to address research questions of interest.
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| 31. |
- Eichenlaub, Manuel, et al.
(författare)
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Comparator Data Characteristics and Testing Procedures for the Clinical Performance Evaluation of Continuous Glucose Monitoring Systems
- 2024
-
Ingår i: Diabetes Technology & Therapeutics. - : Mary Ann Liebert. - 1520-9156 .- 1557-8593. ; 26:4, s. 263-275
-
Tidskriftsartikel (refereegranskat)abstract
- Comparing the performance of different continuous glucose monitoring (CGM) systems is challenging due to the lack of comprehensive guidelines for clinical study design. In particular, the absence of concise requirements for the distribution of comparator (reference) blood glucose (BG) concentrations and their rate of change (RoC), that are used to evaluate CGM performance, impairs comparability. For this article, several experts in the field of CGM performance testing have collaborated to propose characteristics of the distribution of comparator measurements that should be collected during CGM performance testing. Specifically, it is proposed that at least 7.5% of comparator BG concentrations are <70 mg/dL (3.9 mmol/L) and >300 mg/dL (16.7 mmol/L), respectively and that at least 7.5% of BG-RoC combinations indicate fast BG changes with impending hypo- or hyperglycemia, respectively. These proposed characteristics of the comparator data can facilitate the harmonization of testing conditions across different studies and CGM systems and ensure that the most relevant scenarios representing real-life situations are established during performance testing. In addition, a study protocol and testing procedure for the manipulation of glucose levels is suggested that enables the collection of comparator data with these characteristics. This work is an important step towards establishing a future standard for the performance evaluation of CGM systems.
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| 32. |
- Hazan, J., et al.
(författare)
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Acceptability and feasibility of plasma phosphorylated-tau181 in two memory services
- 2023
-
Ingår i: International Journal of Geriatric Psychiatry. - : Wiley. - 0885-6230 .- 1099-1166. ; 38:3
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Plasma phosphorylated-tau181 (p-tau181) represents a novel blood-based biomarker of Alzheimer's disease pathology. We explored clinicians' experience of the utility of plasma p-tau181 in Camden and Islington Memory Services.Methods: Patients were identified by their clinician as appropriate for p-tau181. Their p-tau181 result was plotted on a reference range graph provided to clinicians. This was discussed with the patient at diagnostic feedback appointment.Results: Twenty-nine participants' plasma p-tau181 samples were included (mean age 74 SD 8.5, 65% female). Nine clinicians participated in the study. Eighty-six percent of clinicians found the p-tau181 result to be helpful and in 93% of cases it was clearly understandable. The p-tau181 result was useful in making the diagnosis in 44% of cases.Conclusions: Plasma p-tau181 is a feasible test for use in memory services and acceptable to clinicians. Clinician feedback on utility in dementia diagnoses was mixed. Further work is required to provide education and training in understanding and interpreting ambiguity in biomarker results.
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| 33. |
- Hedenström, Mattias, et al.
(författare)
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NMR studies of interactions between periplasmic chaperones from uropathogenic E-coli and pilicides that interfere with chaperone function and pilus assembly
- 2005
-
Ingår i: ORGANIC & BIOMOLECULAR CHEMISTRY. - : Royal Society of Chemistry (RSC). - 1477-0520 .- 1477-0539. ; 3:23, s. 4193-4200
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Tidskriftsartikel (refereegranskat)abstract
- Adherence of uropathogenic Escherichia coli to host tissue is mediated by pili, which are hair-like protein structures extending from the outer cell membrane of the bacterium. The chaperones FimC and PapD are key components in pilus assembly since they catalyse folding of subunits that are incorporated in type 1 and P pili, respectively, and also transport the subunits across the periplasmic space. Recently, compounds that inhibit pilus biogenesis and interfere with chaperone-subunit interactions have been discovered and termed pilicides. In this paper NMR spectroscopy was used to study the interaction of different pilicides with PapD and FimC in order to gain structural knowledge that would explain the effect that some pilicides have on pilus assembly. First relaxation-edited NMR experiments revealed that the pilicides bound to the PapD chaperone with mM affinity. Then the pilicide-chaperone interaction surface was investigated through chemical shift mapping using N-15-labelled FimC. Principal component analysis performed on the chemical shift perturbation data revealed the presence of three binding sites on the surface of FimC, which interacted with three different classes of pilicides. Analysis of structure-activity relationships suggested that pilicides reduce pilus assembly in E. coli either by binding in the cleft of the chaperone, or by influencing the orientation of the flexible F1-G1 loop, both of which are part of the surface by which the chaperone forms complexes with pilus subunits. It is suggested that binding to either of these sites interferes with folding of the pilus subunits, which occurs during formation of the chaperone-subunit complexes. In addition, pilicides that influence the F1-G1 loop also appear to reduce pilus formation by their ability to dissociate chaperone-subunit complexes.
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| 34. |
- Huang, Lucy, et al.
(författare)
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Haplotype variation and genotype imputation in African populations
- 2011
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Ingår i: Genetic Epidemiology. - : Wiley. - 0741-0395 .- 1098-2272. ; 35:8, s. 766-780
-
Tidskriftsartikel (refereegranskat)abstract
- Sub-Saharan Africa has been identified as the part of the world with the greatest human genetic diversity. This high level of diversity causes difficulties for genome-wide association (GWA) studies in African populationsfor example, by reducing the accuracy of genotype imputation in African populations compared to non-African populations. Here, we investigate haplotype variation and imputation in Africa, using 253 unrelated individuals from 15 Sub-Saharan African populations. We identify the populations that provide the greatest potential for serving as reference panels for imputing genotypes in the remaining groups. Considering reference panels comprising samples of recent African descent in Phase 3 of the HapMap Project, we identify mixtures of reference groups that produce the maximal imputation accuracy in each of the sampled populations. We find that optimal HapMap mixtures and maximal imputation accuracies identified in detailed tests of imputation procedures can instead be predicted by using simple summary statistics that measure relationships between the pattern of genetic variation in a target population and the patterns in potential reference panels. Our results provide an empirical basis for facilitating the selection of reference panels in GWA studies of diverse human populations, especially those of African ancestry.
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| 35. |
- Jahn, A., et al.
(författare)
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Arctic Ocean freshwater : How robust are model simulations?
- 2012
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 117, s. C00D16-
-
Tidskriftsartikel (refereegranskat)abstract
- The Arctic freshwater (FW) has been the focus of many modeling studies, due to the potential impact of Arctic FW on the deep water formation in the North Atlantic. A comparison of the hindcasts from ten ocean-sea ice models shows that the simulation of the Arctic FW budget is quite different in the investigated models. While they agree on the general sink and source terms of the Arctic FW budget, the long-term means as well as the variability of the FW export vary among models. The best model-to-model agreement is found for the interannual and seasonal variability of the solid FW export and the solid FW storage, which also agree well with observations. For the interannual and seasonal variability of the liquid FW export, the agreement among models is better for the Canadian Arctic Archipelago (CAA) than for Fram Strait. The reason for this is that models are more consistent in simulating volume flux anomalies than salinity anomalies and volume-flux anomalies dominate the liquid FW export variability in the CAA but not in Fram Strait. The seasonal cycle of the liquid FW export generally shows a better agreement among models than the interannual variability, and compared to observations the models capture the seasonality of the liquid FW export rather well. In order to improve future simulations of the Arctic FW budget, the simulation of the salinity field needs to be improved, so that model results on the variability of the liquid FW export and storage become more robust. Citation: Jahn, A., et al. (2012), Arctic Ocean freshwater: How robust are model simulations?, J. Geophys. Res., 117, C00D16, doi: 10.1029/2012JC007907.
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| 36. |
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| 37. |
- Mårtensson, Sebastian, et al.
(författare)
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Ridged sea ice characteristics in the arctic from a coupled multicategory sea ice model
- 2012
-
Ingår i: Journal of Geophysical Research: Oceans. - 2169-9291. ; 117:C8
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, a multicategory sea ice model with explicit ice classes for ridged and rafted ice was used to examine the evolution of deformed ice during the period 1980-2002. The results show that (1) ridged ice comprises roughly 45-60% of Arctic sea ice volume and 25-45% of the sea ice area, (2) most of the perennial ice consists of ridged ice, and (3) ridged ice exhibits a small seasonal variability. Our results also show an increase in mean ridged ice thickness of 4-6 cm yr(-1) during the summer in an area north of the Canadian Archipelago and a corresponding decrease in the East Siberian Sea and Nansen Basin. At the same time, Arctic sea ice age has been observed to decline and ice drift speed to increase during the simulation period. We connect these findings with a modeled regional increase in the production rate of ridged ice. Comparison of the multicategory model and a two category reference model shows a substantially increased ice production rate due to a more frequent occurrence of leads, resulting in an ice thickness increase of up to 0.8 m. Differences in ice physics between the multicategory and reference models also affect the freshwater content. The sum of liquid and solid freshwater content in the entire Arctic Ocean is about 10% lower and net precipitation (P-E) is about 7% lower as compared to the reference model.
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| 38. |
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| 39. |
- Pemberton, J. S., et al.
(författare)
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CGM accuracy: Contrasting CE marking with the governmental controls of the USA (FDA) and Australia (TGA): A narrative review
- 2023
-
Ingår i: Diabetes Obesity & Metabolism. - : Wiley. - 1462-8902 .- 1463-1326. ; 25:4, s. 916-939
-
Tidskriftsartikel (refereegranskat)abstract
- The National Institute for Clinical Excellence updated guidance for continuous glucose monitoring (CGM) in 2022, recommending that CGM be available to all people living with type 1 diabetes. Manufacturers can trade in the UK with Conformite Europeenne (CE) marking without an initial national assessment. The regulatory process for CGM CE marking, in contrast to the Food and Drug Administration (FDA) and Australian Therapeutic Goods Administration (TGA) process, is described. Manufacturers operating in the UK provided clinical accuracy studies submitted for CE marking. Critical appraisal of the studies shows several CGM devices have CE marking for wide-ranging indications beyond available data, unlike FDA and TGA approval. The FDA and TGA use tighter controls, requiring comprehensive product-specific clinical data evaluation. In 2018, the FDA published the integrated CGM (iCGM) criteria permitting interoperability. Applying the iCGM criteria to clinical data provided by manufacturers trading in the UK identified several study protocols that minimized glucose variability, thereby improving CGM accuracy on all metrics. These results do not translate into real-life performance. Furthermore, for many CGM devices available in the UK, accuracy reported in the hypoglycaemic range is below iCGM standards, or measurement is absent. We offer a framework to evaluate CGM accuracy studies critically. The review concludes that FDA- and TGA-approved indications match the available clinical data, whereas CE marking indications can have discrepancies. The UK can bolster regulation with UK Conformity Assessed marking from January 2025. However, balanced regulation is needed to ensure innovation and timely technological access are not hindered.
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| 40. |
- Pemberton, Nils, et al.
(författare)
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Cycloaddition of 2-thiazolines and acyl ketenes under acidic conditions results in bicyclic 1,3-oxazinones and not 6-acylpenams as earlier reported
- 2005
-
Ingår i: Organic Letters. - Washington, D.C. : American Chemical Society. - 1523-7060 .- 1523-7052. ; 7:6, s. 1019-1021
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Tidskriftsartikel (refereegranskat)abstract
- Optically active 2-thiazolines 4 were previously reported to react with acyl Meldrum's acid derivatives 5 under acidic conditions (HCl (g) in benzene) to stereoselectively give 6-acylpenams 1. Recently we have discovered that the structure elucidation of these compounds was incorrect. Thus, we report new data showing that instead of acyl -lactams, the optically active isomers 3R,9R-1,3-oxazinones 3a-g are obtained stereoselectively in 38-93% yields.
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| 41. |
- Pemberton, Nils, et al.
(författare)
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Functionalization of bicyclic 2-pyridones targeting pilus biogenesis in uropathogenic Escherichia coli
- 2007
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Ingår i: Tetrahedron Letters. - Oxford : Pergamon Press. - 0040-4039 .- 1359-8562. ; 48:26, s. 4543-4546
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Tidskriftsartikel (refereegranskat)abstract
- Substituted bicyclic 2-pyridones, termed pilicides, prevent pilus assembly in uropathogenic Escherichia coli. Based on the bioactive methyl ester protected 2-pyridone 4, further functionalization at C-6 has yielded a set of new compounds, which have been evaluated for their ability to inhibit pilus formation in uropathogenic E. coli. The key intermediate in the synthesis was formylated 2-pyridone 5, which could be obtained via a Vilsmeier reaction. This versatile intermediate was converted into secondary and tertiary amines via reductive amination and could also be converted to other interesting functionalities using simple chemical transformations.
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| 42. |
- Pemberton, Nils, et al.
(författare)
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Synthesis and evaluation of dihydroimidazolo and dihydrooxazolo ring-fused 2-pyridones - Targeting pilus biogenesis in uropathogenic bacteria
- 2008
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Ingår i: Tetrahedron. - : Elsevier. - 0040-4020 .- 1464-5416. ; 64:40, s. 9368-9376
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Tidskriftsartikel (refereegranskat)abstract
- Dihydrothiazolo ring-fused 2-pyridones have previously been shown to inhibit pilus assembly in uropathogenic Escherichia coli. Methods have now been developed to synthesize both dihydroimidazolo and dihydrooxazolo ring-fused 2-pyridones. To obtain the nitrogen analogs, Cbz-protected imidazolines were reacted with an acyl-Meldrum's acid derivative under acidic conditions. To prepare the oxygen analogs, a one-pot procedure was developed that allowed synthesis of dihydrooxazolo ring-fused 2-pyridones starting from acylated serine derivatives. After hydrolysis to their corresponding carboxylic acids and lithium carboxylates, biological evaluation revealed that the sulfur could be replaced by an oxygen atom and still maintains the ability to inhibit pilus assembly in uropathogenic E. coli. However, introducing a secondary amine instead of oxygen resulted in a substantial decrease in biological activity.
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| 43. |
- Pemberton, Trevor J., et al.
(författare)
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Sequence determinants of human microsatellite variability
- 2009
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Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 10, s. e612-
-
Forskningsöversikt (refereegranskat)abstract
- BackgroundMicrosatellite loci are frequently used in genomic studies of DNA sequence repeats and in population studies of genetic variability. To investigate the effect of sequence properties of microsatellites on their level of variability we have analyzed genotypes at 627 microsatellite loci in 1,048 worldwide individuals from the HGDP-CEPH cell line panel together with the DNA sequences of these microsatellites in the human RefSeq database.ResultsCalibrating PCR fragment lengths in individual genotypes by using the RefSeq sequence enabled us to infer repeat number in the HGDP-CEPH dataset and to calculate the mean number of repeats (as opposed to the mean PCR fragment length), under the assumption that differences in PCR fragment length reflect differences in the numbers of repeats in the embedded repeat sequences. We find the mean and maximum numbers of repeats across individuals to be positively correlated with heterozygosity. The size and composition of the repeat unit of a microsatellite are also important factors in predicting heterozygosity, with tetra-nucleotide repeat units high in G/C content leading to higher heterozygosity. Finally, we find that microsatellites containing more separate sets of repeated motifs generally have higher heterozygosity.ConclusionsThese results suggest that sequence properties of microsatellites have a significant impact in determining the features of human microsatellite variability.
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| 44. |
- Pickering, John W., et al.
(författare)
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Rapid Rule-out of Acute Myocardial Infarction With a Single High-Sensitivity Cardiac Troponin T Measurement Below the Limit of Detection A Collaborative Meta-analysis
- 2017
-
Ingår i: Annals of Internal Medicine. - 0003-4819 .- 1539-3704. ; 166:10, s. 715-724
-
Tidskriftsartikel (refereegranskat)abstract
- Background: High-sensitivity assays for cardiac troponin T (hs-cTnT) are sometimes used to rapidly rule out acute myocardial infarction (AMI). Purpose: To estimate the ability of a single hs-cTnT concentration below the limit of detection (<0.005 mu g/L) and a nonischemic electrocardiogram (ECG) to rule out AMI in adults presenting to the emergency department (ED) with chest pain. Data Sources: EMBASE and MEDLINE without language restrictions (1 January 2008 to 14 December 2016). Study Selection: Cohort studies involving adults presenting to the ED with possible acute coronary syndrome in whom an ECG and hs-cTnT measurements were obtained and AMI outcomes adjudicated during initial hospitalization. Data Extraction: Investigators of studies provided data on the number of low-risk patients (no new ischemia on ECG and hs-cTnT measurements <0.005 mu g/L) and the number who had AMI during hospitalization (primary outcome) or a major adverse cardiac event (MACE) or death within 30 days (secondary outcomes), by risk classification (low or not low risk). Two independent epidemiologists rated risk of bias of studies. Data Synthesis: Of 9241 patients in 11 cohort studies, 2825 (30.6%) were classified as low risk. Fourteen (0.5%) low-risk patients had AMI. Sensitivity of the risk classification for AMI ranged from 87.5% to 100% in individual studies. Pooled estimated sensitivity was 98.7% (95% CI, 96.6% to 99.5%). Sensitivity for 30-day MACEs ranged from 87.9% to 100%; pooled sensitivity was 98.0% (CI, 94.7% to 99.3%). No low-risk patients died. Limitation: Few studies, variation in timing and methods of reference standard troponin tests, and heterogeneity of risk and prevalence of AMI across studies. Conclusion: A single hs-cTnT concentration below the limit of detection in combination with a nonischemic ECG may successfully rule out AMI in patients presenting to EDs with possible emergency acute coronary syndrome.
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| 45. |
- Pinkner, Jerome S., et al.
(författare)
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Rationally designed small compounds inhibit pilus biogenesis in uropathogenic bacteria
- 2006
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - Washtington : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 103:47, s. 17897-17902
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Tidskriftsartikel (refereegranskat)abstract
- A chemical synthesis platform with broad applications and flexibility was rationally designed to inhibit biogenesis of adhesive pili assembled by the chaperone–usher pathway in Gram-negative pathogens. The activity of a family of bicyclic 2-pyridones, termed pilicides, was evaluated in two different pilus biogenesis systems in uropathogenic Escherichia coli. Hemagglutination mediated by either type 1 or P pili, adherence to bladder cells, and biofilm formation mediated by type 1 pili were all reduced by 90% in laboratory and clinical E. coli strains. The structure of the pilicide bound to the P pilus chaperone PapD revealed that the pilicide bound to the surface of the chaperone known to interact with the usher, the outer-membrane assembly platform where pili are assembled. Point mutations in the pilicide-binding site dramatically reduced pilus formation but did not block the ability of PapD to bind subunits and mediate their folding. Surface plasmon resonance experiments confirmed that the pilicide interfered with the binding of chaperone–subunit complexes to the usher. These pilicides thus target key virulence factors in pathogenic bacteria and represent a promising proof of concept for developing drugs that function by targeting virulence factors.
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| 46. |
- Preece, David A., et al.
(författare)
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Alexithymia profiles and depression, anxiety, and stress
- 2024
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Ingår i: Journal of Affective Disorders. - : Elsevier. - 0165-0327 .- 1573-2517. ; 357, s. 116-125
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Tidskriftsartikel (refereegranskat)abstract
- Background: Alexithymia is a multidimensional trait comprised of difficulties identifying feelings, difficulties describing feelings, and externally orientated thinking. It is regarded as an important risk factor for emotional disorders, but there are presently limited data on each specific facet of alexithymia, or the extent to which deficits in processing negative emotions, positive emotions, or both, are important. In this study, we address these gaps by using the Perth Alexithymia Questionnaire (PAQ) to comprehensively examine the relationships between alexithymia and depression, anxiety, and stress symptoms. Methods: University students (N = 1250) completed the PAQ and the Depression Anxiety Stress Scales-21. Pearson correlations, hierarchical regressions, and latent profile analysis were conducted. Results: All facets of alexithymia, across both valence domains, were significantly correlated with depression, anxiety, and stress symptoms (r = 0.27–0.40). Regression analyses indicated that the alexithymia facets, together, could account for a significant 14.6 %–16.4 % of the variance in depression, anxiety, and stress. Difficulties identifying negative feelings and difficulties identifying positive feelings were the strongest unique predictors across all symptom categories. Our latent profile analysis extracted eight profiles, comprising different combinations of alexithymia facets and psychopathology symptoms, collectively highlighting the transdiagnostic relevance of alexithymia facets. Limitations: Our study involved a student sample, and further work in clinical samples will be beneficial. Conclusions: Our data indicate that all facets of alexithymia, across both valence domains, are relevant for understanding depression, anxiety, and stress. These findings demonstrate the value of facet-level and valence-specific alexithymia assessments, informing more comprehensive understanding and more targeted treatments of emotional disorder symptoms.
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| 47. |
- Weston, Philip S J, et al.
(författare)
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Serum neurofilament light in familial Alzheimer disease: A marker of early neurodegeneration.
- 2017
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Ingår i: Neurology. - 1526-632X. ; 89:21, s. 2167-2175
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Tidskriftsartikel (refereegranskat)abstract
- To investigate whether serum neurofilament light (NfL) concentration is increased in familial Alzheimer disease (FAD), both pre and post symptom onset, and whether it is associated with markers of disease stage and severity.We recruited 48 individuals from families with PSEN1 or APP mutations to a cross-sectional study: 18 had symptomatic Alzheimer disease (AD) and 30 were asymptomatic but at 50% risk of carrying a mutation. Serum NfL was measured using an ultrasensitive immunoassay on the single molecule array (Simoa) platform. Cognitive testing and MRI were performed; 33 participants had serial MRI, allowing calculation of atrophy rates. Genetic testing established mutation status. A generalized least squares regression model was used to compare serum NfL among symptomatic mutation carriers, presymptomatic carriers, and noncarriers, adjusting for age and sex. Spearman coefficients assessed associations between serum NfL and (1) estimated years to/from symptom onset (EYO), (2) cognitive measures, and (3) MRI measures of atrophy.Nineteen of the asymptomatic participants were mutation carriers (mean EYO -9.6); 11 were noncarriers. Compared with noncarriers, serum NfL concentration was higher in both symptomatic (p < 0.0001) and presymptomatic mutation carriers (p = 0.007). Across all mutation carriers, serum NfL correlated with EYO (ρ = 0.81, p < 0.0001) and multiple cognitive and imaging measures, including Mini-Mental State Examination (ρ = -0.62, p = 0.0001), Clinical Dementia Rating Scale sum of boxes (ρ = 0.79, p < 0.0001), baseline brain volume (ρ = -0.62, p = 0.0002), and whole-brain atrophy rate (ρ = 0.53, p = 0.01).Serum NfL concentration is increased in FAD prior to symptom onset and correlates with measures of disease stage and severity. Serum NfL may thus be a feasible biomarker of early AD-related neurodegeneration.
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| 48. |
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| 49. |
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