80 research outputs found
Computational model of learning
The program described learns to improve its performance in
the playing of a game, from experience. The main objectives
of the project are that the system should observe the
following principles:
1) The program should not rely on any special evaluation
functions, which would embody domain-specific information.
2) Initial knowledge of the domain should be minimal,
and further knowledge gained should be assimilated in
terms of prior knowledge 3) The system of representation employed should as far
as possible be independent of the domain, again
avoiding the incorporation of domain-specific information.
In customary Artificial Intelligence terms, the program is
referred to as existing in a domain or environment. The
model has a goal within this domain and has available
certain actions which it may take in order to achieve its
goal. The goal is represented as a Structure. This term
will be used throughout to denote a set of objects from
the domain, constrained by various domain-pertinent relationships. The actions, goals and objects are the
initial known facts of the environment. The program has
an innate ability to plan simple sequences of actions to
achieve its goals. Inevitably, these plans do not take
into account enough of the nature of the domain and prove
inadequate. In such events the descriptive abilities of
the program are invoked to correct the deficiency, and the
program's model of its environment is enriched
Real World Experience With Brentuximab Vedotin in Relapsed/Refractory CD30 Positive Lymphoma:Outcomes in 33 Patients After Prolonged Follow-up At a Single UK Centre
30-day mortality after systemic anticancer treatment for breast and lung cancer in England: a population-based, observational study
Background: 30-day mortality might be a useful indicator of avoidable harm to patients from systemic anticancer treatments, but data for this indicator are limited. The Systemic Anti-Cancer Therapy (SACT) dataset collated by Public Health England allows the assessment of factors affecting 30-day mortality in a national patient population. The aim of this first study based on the SACT dataset was to establish national 30-day mortality benchmarks for breast and lung cancer patients receiving SACT in England, and to start to identify where patient care could be improved. Methods: In this population-based study, we included all women with breast cancer and all men and women with lung cancer residing in England, who were 24 years or older and who started a cycle of SACT in 2014 irrespective of the number of previous treatment cycles or programmes, and irrespective of their position within the disease trajectory. We calculated 30-day mortality after the most recent cycle of SACT for those patients. We did logistic regression analyses, adjusting for relevant factors, to examine whether patient, tumour, or treatment-related factors were associated with the risk of 30-day mortality. For each cancer type and intent, we calculated 30-day mortality rates and patient volume at the hospital trust level, and contrasted these in a funnel plot. Findings: Between Jan 1, and Dec, 31, 2014, we included 23 228 patients with breast cancer and 9634 patients with non-small cell lung cancer (NSCLC) in our regression and trust-level analyses. 30-day mortality increased with age for both patients with breast cancer and patients with NSCLC treated with curative intent, and decreased with age for patients receiving palliative SACT (breast curative: odds ratio [OR] 1·085, 99% CI 1·040–1·132; p<0·0001; NSCLC curative: 1·045, 1·013–1·079; p=0·00033; breast palliative: 0·987, 0·977–0·996; p=0·00034; NSCLC palliative: 0·987, 0·976–0·998; p=0·0015). 30-day mortality was also significantly higher for patients receiving their first reported curative or palliative SACT versus those who received SACT previously (breast palliative: OR 2·326 99% CI 1·634–3·312; p<0·0001; NSCLC curative: 3·371, 1·554–7·316; p<0·0001; NSCLC palliative: 2·667, 2·109–3·373; p<0·0001), and for patients with worse general wellbeing (performance status 2–4) versus those who were generally well (breast curative: 6·057, 1·333–27·513; p=0·0021; breast palliative: 6·241, 4·180–9·319; p<0·0001; NSCLC palliative: 3·384, 2·276–5·032; p<0·0001). We identified trusts with mortality rates in excess of the 95% control limits; this included seven for curative breast cancer, four for palliative breast cancer, five for curative NSCLC, and seven for palliative NSCLC. Interpretation: Our findings show that several factors affect the risk of early mortality of breast and lung cancer patients in England and that some groups are at a substantially increased risk of 30-day mortality. The identification of hospitals with significantly higher 30-day mortality rates should promote review of clinical decision making in these hospitals. Furthermore, our results highlight the importance of collecting routine data beyond clinical trials to better understand the factors placing patients at higher risk of 30-day mortality, and ultimately improve clinical decision making. Our insights into the factors affecting risk of 30-day mortality will help treating clinicians and their patients predict the balance of harms and benefits associated with SACT. Funding: Public Health England
Exploring severe mental illness and diabetes : protocol for a longitudinal observational and qualitative mixed methods study
Background: The average life expectancy for people with a severe mental illness (SMI) such as schizophrenia or bipolar disorder is 15-20 years less than for the population as a whole. Diabetes contributes significantly to this inequality, being 2-3 times more prevalent in people with SMI. Various risk factors have been implicated, including side effects of antipsychotic medication and unhealthy lifestyles, which often occur in the context of socio-economic disadvantage and healthcare inequality. However, little is known about how these factors interact to influence the risk of developing diabetes and poor diabetic outcomes, or how the organisation and provision of healthcare may contribute. Objective: The study aims to identify the determinants of diabetes and to explore variation in diabetes outcomes for people with SMI. Methods: This study will employ a concurrent mixed methods design combining the interrogation of electronic primary care health records from the Clinical Practice Research Datalink (CPRD GOLD) with qualitative interviews with adults with SMI and diabetes, their relatives/friends, and healthcare staff. The study has been funded for two years, from September 2017 to September 2019 and data collection has recently ended. Results: CPRD and linked health data will be used to explore the association of socio-demographic, illness and healthcarerelated factors with both the development and outcomes of Type 2 diabetes in people with SMI. Experiences of managing the comorbidity and accessing healthcare will be explored through qualitative interviews using topic guides informed by evidence synthesis and expert consultation. Findings from both datasets will be merged to develop a more comprehensive understanding of diabetes risks, interventions and outcomes for people with SMI. Findings will be translated into recommendations for interventions and services using co-design workshops. Conclusions: Improving diabetes outcomes for people with SMI is a high priority area nationally and globally. Understanding how risk factors combine to generate high prevalence of diabetes and poor diabetic outcomes for this population is a necessary first step in developing healthcare interventions to improve outcomes for people with diabetes and SMI
Risk of intracranial haemorrhage and ischaemic stroke after convexity subarachnoid haemorrhage in cerebral amyloid angiopathy : international individual patient data pooled analysis
Altres ajuts: JF reports grants from Instituto de Salud Carlos III, grants from Fundació Marató TV3, grants from NIH, grants from Departament de Salut de la Generalitat de Catalunya.To investigate the frequency, time-course and predictors of intracerebral haemorrhage (ICH), recurrent convexity subarachnoid haemorrhage (cSAH), and ischemic stroke after cSAH associated with cerebral amyloid angiopathy (CAA). We performed a systematic review and international individual patient-data pooled analysis in patients with cSAH associated with probable or possible CAA diagnosed on baseline MRI using the modified Boston criteria. We used Cox proportional hazards models with a frailty term to account for between-cohort differences. We included 190 patients (mean age 74.5 years; 45.3% female) from 13 centers with 385 patient-years of follow-up (median 1.4 years). The risks of each outcome (per patient-year) were: ICH 13.2% (95% CI 9.9-17.4); recurrent cSAH 11.1% (95% CI 7.9-15.2); combined ICH, cSAH, or both 21.4% (95% CI 16.7-26.9), ischemic stroke 5.1% (95% CI 3.1-8) and death 8.3% (95% CI 5.6-11.8). In multivariable models, there is evidence that patients with probable CAA (compared to possible CAA) had a higher risk of ICH (HR 8.45, 95% CI 1.13-75.5, p = 0.02) and cSAH (HR 3.66, 95% CI 0.84-15.9, p = 0.08) but not ischemic stroke (HR 0.56, 95% CI 0.17-1.82, p = 0.33) or mortality (HR 0.54, 95% CI 0.16-1.78, p = 0.31). Patients with cSAH associated with probable or possible CAA have high risk of future ICH and recurrent cSAH. Convexity SAH associated with probable (vs possible) CAA is associated with increased risk of ICH, and cSAH but not ischemic stroke. Our data provide precise risk estimates for key vascular events after cSAH associated with CAA which can inform management decisions. The online version contains supplementary material available at 10.1007/s00415-021-10706-3
Improving diabetes outcomes for people with severe mental illness : a longitudinal observational and qualitative study in England
Background: people with severe mental illness experience poorer health outcomes than the general population. Diabetes contributes significantly to this health gap.Objectives: the objectives were to identify the determinants of diabetes and to explore variation in diabetes outcomes for people with severe mental illness.Design: under a social inequalities framework, a concurrent mixed-methods design combined analysis of linked primary care records with qualitative interviews.Setting: the quantitative study was carried out in general practices in England (2000–16). The qualitative study was a community study (undertaken in the North West and in Yorkshire and the Humber).Participants: the quantitative study used the longitudinal health records of 32,781 people with severe mental illness (a subset of 3448 people had diabetes) and 9551 ‘controls’ (with diabetes but no severe mental illness), matched on age, sex and practice, from the Clinical Practice Research Datalink (GOLD version). The qualitative study participants comprised 39 adults with diabetes and severe mental illness, nine family members and 30 health-care staff.Data sources: the Clinical Practice Research Datalink (GOLD) individual patient data were linked to Hospital Episode Statistics, Office for National Statistics mortality data and the Index of Multiple Deprivation.Results: people with severe mental illness were more likely to have diabetes if they were taking atypical antipsychotics, were living in areas of social deprivation, or were of Asian or black ethnicity. A substantial minority developed diabetes prior to severe mental illness. Compared with people with diabetes alone, people with both severe mental illness and diabetes received more frequent physical checks, maintained tighter glycaemic and blood pressure control, and had fewer recorded physical comorbidities and elective admissions, on average. However, they had more emergency admissions (incidence rate ratio 1.14, 95% confidence interval 0.96 to 1.36) and a significantly higher risk of all-cause mortality than people with diabetes but no severe mental illness (hazard ratio 1.89, 95% confidence interval 1.59 to 2.26). These paradoxical results may be explained by other findings. For example, people with severe mental illness and diabetes were more likely to live in socially deprived areas, which is associated with reduced frequency of health checks, poorer health outcomes and higher mortality risk. In interviews, participants frequently described prioritising their mental illness over their diabetes (e.g. tolerating antipsychotic side effects, despite awareness of harmful impacts on diabetes control) and feeling overwhelmed by competing treatment demands from multiple morbidities. Both service users and practitioners acknowledged misattributing physical symptoms to poor mental health (‘diagnostic overshadowing’).Limitations: data may not be nationally representative for all relevant covariates, and the completeness of recording varied across practices.Conclusions: people with severe mental illness and diabetes experience poorer health outcomes than, and deficiencies in some aspects of health care compared with, people with diabetes alone.Future work: these findings can inform the development of targeted interventions aimed at addressing inequalities in this population.Study registration: National Institute for Health Research (NIHR) Central Portfolio Management System (37024); and ClinicalTrials.gov NCT03534921.Funding: this project was funded by the NIHR Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 9, No. 10. See the NIHR Journals Library website for further project information.<br/
Systemic chemotherapy with or without cetuximab in patients with resectable colorectal liver metastasis (New EPOC): long-term results of a multicentre, randomised, controlled, phase 3 trial.
BACKGROUND: The interim analysis of the multicentre New EPOC trial in patients with resectable colorectal liver metastasis showed a significant reduction in progression-free survival in patients allocated to cetuximab plus chemotherapy compared with those given chemotherapy alone. The focus of the present analysis was to assess the effect on overall survival. METHODS: New EPOC was a multicentre, open-label, randomised, controlled, phase 3 trial. Adult patients (aged ≥18 years) with KRAS wild-type (codons 12, 13, and 61) resectable or suboptimally resectable colorectal liver metastases and a WHO performance status of 0-2 were randomly assigned (1:1) to receive chemotherapy with or without cetuximab before and after liver resection. Randomisation was done centrally with minimisation factors of surgical centre, poor prognosis cancer, and previous adjuvant treatment with oxaliplatin. Chemotherapy consisted of oxaliplatin 85 mg/m2 administered intravenously over 2 h, l-folinic acid (175 mg flat dose administered intravenously over 2 h) or d,l-folinic acid (350 mg flat dose administered intravenously over 2 h), and fluorouracil bolus 400 mg/m2 administered intravenously over 5 min, followed by a 46 h infusion of fluorouracil 2400 mg/m2 repeated every 2 weeks (regimen one), or oxaliplatin 130 mg/m2 administered intravenously over 2 h and oral capecitabine 1000 mg/m2 twice daily on days 1-14 repeated every 3 weeks (regimen two). Patients who had received adjuvant oxaliplatin could receive irinotecan 180 mg/m2 intravenously over 30 min with fluorouracil instead of oxaliplatin (regimen three). Cetuximab was given intravenously, 500 mg/m2 every 2 weeks with regimen one and three or a loading dose of 400 mg/m2 followed by a weekly infusion of 250 mg/m2 with regimen two. The primary endpoint of progression-free survival was published previously. Secondary endpoints were overall survival, preoperative response, pathological resection status, and safety. Trial recruitment was halted prematurely on the advice of the Trial Steering Committee on Nov 1, 2012. All analyses (except safety) were done on the intention-to-treat population. Safety analyses included all randomly assigned patients. This trial is registered with ISRCTN, number 22944367. FINDINGS: Between Feb 26, 2007, and Oct 12, 2012, 257 eligible patients were randomly assigned to chemotherapy with cetuximab (n=129) or without cetuximab (n=128). This analysis was carried out 5 years after the last patient was recruited, as defined in the protocol, at a median follow-up of 66·7 months (IQR 58·0-77·5). Median progression-free survival was 22·2 months (95% CI 18·3-26·8) in the chemotherapy alone group and 15·5 months (13·8-19·0) in the chemotherapy plus cetuximab group (hazard ratio [HR] 1·17, 95% CI 0·87-1·56; p=0·304). Median overall survival was 81·0 months (59·6 to not reached) in the chemotherapy alone group and 55·4 months (43·5-71·5) in the chemotherapy plus cetuximab group (HR 1·45, 1·02-2·05; p=0·036). There was no significant difference in the secondary outcomes of preoperative response or pathological resection status between groups. Five deaths might have been treatment-related (one in the chemotherapy alone group and four in the chemotherapy plus cetuximab group). The most common grade 3-4 adverse events reported were: neutrophil count decreased (26 [19%] of 134 in the chemotherapy alone group vs 21 [15%] of 137 in the chemotherapy plus cetuximab group), diarrhoea (13 [10%] vs 14 [10%]), skin rash (one [1%] vs 22 [16%]), thromboembolic events (ten [7%] vs 11 [8%]), lethargy (ten [7%] vs nine [7%]), oral mucositis (three [2%] vs 14 [10%]), vomiting (seven [5%] vs seven [5%]), peripheral neuropathy (eight [6%] vs five [4%]), and pain (six [4%] vs six [4%]). INTERPRETATION: Although the addition of cetuximab to chemotherapy improves the overall survival in some studies in patients with advanced, inoperable metastatic disease, its use in the perioperative setting in patients with operable disease confers a significant disadvantage in terms of overall survival. Cetuximab should not be used in this setting. FUNDING: Cancer Research UK
Frontotemporal dementia and its subtypes: a genome-wide association study
SummaryBackground Frontotemporal dementia (FTD) is a complex disorder characterised by a broad range of clinical manifestations, differential pathological signatures, and genetic variability. Mutations in three genes—MAPT, GRN, and C9orf72—have been associated with FTD. We sought to identify novel genetic risk loci associated with the disorder. Methods We did a two-stage genome-wide association study on clinical FTD, analysing samples from 3526 patients with {FTD} and 9402 healthy controls. To reduce genetic heterogeneity, all participants were of European ancestry. In the discovery phase (samples from 2154 patients with {FTD} and 4308 controls), we did separate association analyses for each {FTD} subtype (behavioural variant FTD, semantic dementia, progressive non-fluent aphasia, and {FTD} overlapping with motor neuron disease FTD-MND), followed by a meta-analysis of the entire dataset. We carried forward replication of the novel suggestive loci in an independent sample series (samples from 1372 patients and 5094 controls) and then did joint phase and brain expression and methylation quantitative trait loci analyses for the associated (p<5 × 10−8) single-nucleotide polymorphisms. Findings We identified novel associations exceeding the genome-wide significance threshold (p<5 × 10−8). Combined (joint) analyses of discovery and replication phases showed genome-wide significant association at 6p21.3, \{HLA\} locus (immune system), for rs9268877 (p=1·05 × 10−8; odds ratio=1·204 95% \{CI\} 1·11–1·30), rs9268856 (p=5·51 × 10−9; 0·809 0·76–0·86) and rs1980493 (p value=1·57 × 10−8, 0·775 0·69–0·86) in the entire cohort. We also identified a potential novel locus at 11q14, encompassing RAB38/CTSC (the transcripts of which are related to lysosomal biology), for the behavioural \{FTD\} subtype for which joint analyses showed suggestive association for rs302668 (p=2·44 × 10−7; 0·814 0·71–0·92). Analysis of expression and methylation quantitative trait loci data suggested that these loci might affect expression and methylation in cis. Interpretation Our findings suggest that immune system processes (link to 6p21.3) and possibly lysosomal and autophagy pathways (link to 11q14) are potentially involved in FTD. Our findings need to be replicated to better define the association of the newly identified loci with disease and to shed light on the pathomechanisms contributing to FTD. Funding The National Institute of Neurological Disorders and Stroke and National Institute on Aging, the Wellcome/MRC Centre on Parkinson's disease, Alzheimer's Research UK, and Texas Tech University Health Sciences Center
Genome-wide meta-analysis identifies five new susceptibility loci for cutaneous malignant melanoma.
Thirteen common susceptibility loci have been reproducibly associated with cutaneous malignant melanoma (CMM). We report the results of an international 2-stage meta-analysis of CMM genome-wide association studies (GWAS). This meta-analysis combines 11 GWAS (5 previously unpublished) and a further three stage 2 data sets, totaling 15,990 CMM cases and 26,409 controls. Five loci not previously associated with CMM risk reached genome-wide significance (P < 5 × 10(-8)), as did 2 previously reported but unreplicated loci and all 13 established loci. Newly associated SNPs fall within putative melanocyte regulatory elements, and bioinformatic and expression quantitative trait locus (eQTL) data highlight candidate genes in the associated regions, including one involved in telomere biology.[Please see the Supplementary Note for acknowledgments.]This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/ng.337
Recommended from our members
Common genetic variants in the CLDN2 and PRSS1-PRSS2 loci alter risk for alcohol-related and sporadic pancreatitis
Pancreatitis is a complex, progressively destructive inflammatory disorder. Alcohol was long thought to be the primary causative agent, but genetic contributions have been of interest since the discovery that rare PRSS1, CFTR, and SPINK1 variants were associated with pancreatitis risk. We now report two significant genome-wide associations identified and replicated at PRSS1-PRSS2 (1×10-12) and x-linked CLDN2 (p < 1×10-21) through a two-stage genome-wide study (Stage 1, 676 cases and 4507 controls; Stage 2, 910 cases and 4170 controls). The PRSS1 variant affects susceptibility by altering expression of the primary trypsinogen gene. The CLDN2 risk allele is associated with atypical localization of claudin-2 in pancreatic acinar cells. The homozygous (or hemizygous male) CLDN2 genotype confers the greatest risk, and its alleles interact with alcohol consumption to amplify risk. These results could partially explain the high frequency of alcohol-related pancreatitis in men – male hemizygous frequency is 0.26, female homozygote is 0.07
- …