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1.
Nature ; 626(8000): 799-807, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38326615

RESUMEN

Linking variants from genome-wide association studies (GWAS) to underlying mechanisms of disease remains a challenge1-3. For some diseases, a successful strategy has been to look for cases in which multiple GWAS loci contain genes that act in the same biological pathway1-6. However, our knowledge of which genes act in which pathways is incomplete, particularly for cell-type-specific pathways or understudied genes. Here we introduce a method to connect GWAS variants to functions. This method links variants to genes using epigenomics data, links genes to pathways de novo using Perturb-seq and integrates these data to identify convergence of GWAS loci onto pathways. We apply this approach to study the role of endothelial cells in genetic risk for coronary artery disease (CAD), and discover 43 CAD GWAS signals that converge on the cerebral cavernous malformation (CCM) signalling pathway. Two regulators of this pathway, CCM2 and TLNRD1, are each linked to a CAD risk variant, regulate other CAD risk genes and affect atheroprotective processes in endothelial cells. These results suggest a model whereby CAD risk is driven in part by the convergence of causal genes onto a particular transcriptional pathway in endothelial cells. They highlight shared genes between common and rare vascular diseases (CAD and CCM), and identify TLNRD1 as a new, previously uncharacterized member of the CCM signalling pathway. This approach will be widely useful for linking variants to functions for other common polygenic diseases.


Asunto(s)
Enfermedad de la Arteria Coronaria , Células Endoteliales , Estudio de Asociación del Genoma Completo , Hemangioma Cavernoso del Sistema Nervioso Central , Humanos , Enfermedad de la Arteria Coronaria/genética , Enfermedad de la Arteria Coronaria/patología , Células Endoteliales/metabolismo , Células Endoteliales/patología , Predisposición Genética a la Enfermedad/genética , Hemangioma Cavernoso del Sistema Nervioso Central/genética , Hemangioma Cavernoso del Sistema Nervioso Central/patología , Polimorfismo de Nucleótido Simple , Epigenómica , Transducción de Señal/genética , Herencia Multifactorial
2.
EMBO J ; 42(5): e111519, 2023 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-36579501

RESUMEN

Nucleotide-binding domain leucine-rich repeat (NLR) immune receptors are important components of plant and metazoan innate immunity that can function as individual units or as pairs or networks. Upon activation, NLRs form multiprotein complexes termed resistosomes or inflammasomes. Although metazoan paired NLRs, such as NAIP/NLRC4, form hetero-complexes upon activation, the molecular mechanisms underpinning activation of plant paired NLRs, especially whether they associate in resistosome hetero-complexes, is unknown. In asterid plant species, the NLR required for cell death (NRC) immune receptor network is composed of multiple resistance protein sensors and downstream helpers that confer immunity against diverse plant pathogens. Here, we show that pathogen effector-activation of the NLR proteins Rx (confers virus resistance), and Bs2 (confers bacterial resistance) leads to oligomerization of their helper NLR, NRC2. Activated Rx does not oligomerize or enter into a stable complex with the NRC2 oligomer and remains cytoplasmic. In contrast, activated NRC2 oligomers accumulate in membrane-associated puncta. We propose an activation-and-release model for NLRs in the NRC immune receptor network. This points to a distinct activation model compared with mammalian paired NLRs.


Asunto(s)
Proteínas NLR , Inmunidad de la Planta , Animales , Proteínas NLR/química , Proteínas NLR/metabolismo , Plantas/metabolismo , Inmunidad Innata , Inflamasomas , Proteínas de Plantas/genética , Enfermedades de las Plantas , Mamíferos
3.
Plant Physiol ; 195(3): 2289-2308, 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38466723

RESUMEN

The production of glutamine (Gln) from NO3- and NH4+ requires ATP, reducing power, and carbon skeletons. Plants may redirect these resources to other physiological processes using Gln directly. However, feeding Gln as the sole nitrogen (N) source has complex effects on plants. Under optimal concentrations, Arabidopsis (Arabidopsis thaliana) seedlings grown on Gln have similar primary root lengths, more lateral roots, smaller leaves, and higher amounts of amino acids and proteins compared to those grown on NH4NO3. While high levels of Gln accumulate in Arabidopsis seedlings grown on Gln, the expression of GLUTAMINE SYNTHETASE1;1 (GLN1;1), GLN1;2, and GLN1;3 encoding cytosolic GS1 increases and expression of GLN2 encoding chloroplastic GS2 decreases. These results suggest that Gln has distinct effects on regulating GLN1 and GLN2 gene expression. Notably, Arabidopsis seedlings grown on Gln have an unexpected gene expression profile. Compared with NH4NO3, which activates growth-promoting genes, Gln preferentially induces stress- and defense-responsive genes. Consistent with the gene expression data, exogenous treatment with Gln enhances disease resistance in Arabidopsis. The induction of Gln-responsive genes, including PATHOGENESIS-RELATED1, SYSTEMIC ACQUIRED RESISTANCE DEFICIENT1, WRKY54, and WALL ASSOCIATED KINASE1, is compromised in salicylic acid (SA) biosynthetic and signaling mutants under Gln treatments. Together, these results suggest that Gln may partly interact with the SA pathway to trigger plant immunity.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Resistencia a la Enfermedad , Regulación de la Expresión Génica de las Plantas , Glutamina , Raíces de Plantas , Estrés Fisiológico , Arabidopsis/genética , Arabidopsis/fisiología , Arabidopsis/crecimiento & desarrollo , Arabidopsis/efectos de los fármacos , Glutamina/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Estrés Fisiológico/genética , Resistencia a la Enfermedad/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/inmunología , Plantones/genética , Plantones/crecimiento & desarrollo , Plantones/efectos de los fármacos , Glutamato-Amoníaco Ligasa/metabolismo , Glutamato-Amoníaco Ligasa/genética
4.
Stat Med ; 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38980954

RESUMEN

In clinical settings with no commonly accepted standard-of-care, multiple treatment regimens are potentially useful, but some treatments may not be appropriate for some patients. A personalized randomized controlled trial (PRACTical) design has been proposed for this setting. For a network of treatments, each patient is randomized only among treatments which are appropriate for them. The aim is to produce treatment rankings that can inform clinical decisions about treatment choices for individual patients. Here we propose methods for determining sample size in a PRACTical design, since standard power-based methods are not applicable. We derive a sample size by evaluating information gained from trials of varying sizes. For a binary outcome, we quantify how many adverse outcomes would be prevented by choosing the top-ranked treatment for each patient based on trial results rather than choosing a random treatment from the appropriate personalized randomization list. In simulations, we evaluate three performance measures: mean reduction in adverse outcomes using sample information, proportion of simulated patients for whom the top-ranked treatment performed as well or almost as well as the best appropriate treatment, and proportion of simulated trials in which the top-ranked treatment performed better than a randomly chosen treatment. We apply the methods to a trial evaluating eight different combination antibiotic regimens for neonatal sepsis (NeoSep1), in which a PRACTical design addresses varying patterns of antibiotic choice based on disease characteristics and resistance. Our proposed approach produces results that are more relevant to complex decision making by clinicians and policy makers.

5.
Arterioscler Thromb Vasc Biol ; 43(5): 600-608, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36994731

RESUMEN

Endothelial cells (EC) are an important mediator of atherosclerosis and vascular disease. Their exposure to atherogenic risk factors such as hypertension and serum cholesterol leads to endothelial dysfunction and many disease-associated processes. Identifying which of these multiple EC functions is causally related to disease risk has been challenging. There is evidence from in vivo models and human sequencing studies that dysregulation of nitric oxide production directly affects risk of coronary artery disease. Human genetics can help prioritize the other EC functions with causal relationships because germline mutations are acquired at birth and serve as a randomized test of which pathways affect disease risk. Though several coronary artery disease risk variants have been linked to EC function, this process has been slow and laborious. Unbiased analyses of EC dysfunction using multiomic approaches promise to identify the causal genetic mechanisms responsible for vascular disease. Here, we review the data from genomic, epigenomic, and transcriptomic studies that prioritize EC-specific causal pathways. New methods that CRISPR (clustered regularly interspaced short palindromic repeats) perturbation technology with genomic, epigenomic, and transcriptomic analysis promise to speed up the characterization of disease-associated genetic variation. We summarize several recent studies in ECs which use high-throughput genetic perturbation to identify disease-relevant pathways and novel mechanisms of disease. These genetically validated pathways can accelerate the identification of drug targets for the prevention and treatment of atherosclerosis.


Asunto(s)
Aterosclerosis , Enfermedad de la Arteria Coronaria , Recién Nacido , Humanos , Enfermedad de la Arteria Coronaria/genética , Enfermedad de la Arteria Coronaria/terapia , Enfermedad de la Arteria Coronaria/metabolismo , Células Endoteliales/metabolismo , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Multiómica , Aterosclerosis/genética , Aterosclerosis/terapia , Aterosclerosis/metabolismo
6.
BMC Med Res Methodol ; 24(1): 163, 2024 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-39080538

RESUMEN

BACKGROUND: A platform trial approach allows adding arms to on-going trials to speed up intervention discovery programs. A control arm remains open for recruitment in a platform trial while intervention arms may be added after the onset of the study and could be terminated early for efficacy and/or futility when early stopping is allowed. The topic of utilising non-concurrent control data in the analysis of platform trials has been explored and discussed extensively. A less familiar issue is the presence of heterogeneity, which may exist for example due to modification of enrolment criteria and recruitment strategy. METHOD: We conduct a simulation study to explore the impact of heterogeneity on the analysis of a two-stage platform trial design. We consider heterogeneity in treatment effects and heteroscedasticity in outcome data across stages for a normally distributed endpoint. We examine the performance of some hypothesis testing procedures and modelling strategies. The use of non-concurrent control data is also considered accordingly. Alongside standard regression analysis, we examine the performance of a novel method that was known as the pairwise trials analysis. It is similar to a network meta-analysis approach but adjusts for treatment comparisons instead of individual studies using fixed effects. RESULTS: Several testing strategies with concurrent control data seem to control the type I error rate at the required level when there is heteroscedasticity in outcome data across stages and/or a random cohort effect. The main parameter of treatment effects in some analysis models correspond to overall treatment effects weighted by stage wise sample sizes; while others correspond to the effect observed within a single stage. The characteristics of the estimates are not affected significantly by the presence of a random cohort effect and/ or heteroscedasticity. CONCLUSION: In view of heterogeneity in treatment effect across stages, the specification of null hypotheses in platform trials may need to be more subtle. We suggest employing testing procedure of adaptive design as opposed to testing the statistics from regression models; comparing the estimates from the pairwise trials analysis method and the regression model with interaction terms may indicate if heterogeneity is negligible.


Asunto(s)
Proyectos de Investigación , Humanos , Proyectos de Investigación/estadística & datos numéricos , Ensayos Clínicos como Asunto/métodos , Ensayos Clínicos como Asunto/estadística & datos numéricos , Simulación por Computador , Modelos Estadísticos , Interpretación Estadística de Datos , Análisis de Regresión , Resultado del Tratamiento
7.
Pediatr Blood Cancer ; : e31222, 2024 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-39054725

RESUMEN

BACKGROUND: Comprehensive guidelines for the management of iron deficiency anemia (IDA) in adolescents with heavy menstrual bleeding (HMB) presenting to the emergency department (ED) are lacking, leading to variability in care. We aimed to standardize the evaluation and management of these patients through the development and implementation of an evidence-based algorithm using quality improvement methodology. METHODS: Baseline data of the target population identified variability across four key measures of clinical management: therapy choice and administration, laboratory evaluation, hematology service consultation, and patient disposition. Literature review and consensus from pediatric hematology and gynecology providers informed a draft algorithm that was refined in an iterative multidisciplinary process. From December 2022 to July 2023, we aimed to achieve a 25% relative increase in patients to receive optimal management per the algorithm, while using sequential Plan-Do-Study-Act (PDSA) cycles. Process measures focusing on provider documentation and balancing measures, such as ED length of stay, were assessed concurrently. RESULTS: Forty-nine patients were evaluated during four PDSA cycles. Improvement of ≥40% above baseline regarding recommended therapy administration was achieved across four PDSA cycles. Adherence to recommended therapy choice improved from 57% (baseline) to 100%, minimal laboratory evaluation from 14% to 83%, hematology consultation from 36% to 100%, and appropriate disposition from 71% to 100%. ED length of stay remained stable. CONCLUSION: Implementation of a standardized algorithm for management of IDA secondary to HMB in adolescents in the ED increased adherence to evidence-based patient care.

8.
Plant J ; 111(5): 1383-1396, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35791282

RESUMEN

The THIAMIN REQUIRING2 (TH2) protein comprising a mitochondrial targeting peptide followed by a transcription enhancement A and a haloacid dehalogenase domain is a thiamin monophosphate (TMP) phosphatase in the vitamin B1 biosynthetic pathway. The Arabidopsis th2-3 T-DNA insertion mutant was chlorotic and deficient in thiamin diphosphate (TDP). Complementation assays confirmed that haloacid dehalogenase domain alone was sufficient to rescue the th2-3 mutant. In pTH2:TH2-GFP/th2-3 complemented plants, the TH2-GFP was localized to the cytosol, mitochondrion, and nucleus, indicating that the vitamin B1 biosynthetic pathway extended across multi-subcellular compartments. Engineered TH2-GFP localized to the cytosol, mitochondrion, nucleus, and chloroplast, could complement the th2 mutant. Together, these results highlight the importance of intracellular TMP and thiamin trafficking in vitamin B1 biosynthesis. In an attempt to enhance the production of thiamin, we created various constructs to overexpress TH2-GFP in the cytosol, mitochondrion, chloroplast, and nucleus. Unexpectedly, overexpressing TH2-GFP resulted in an increase rather than a decrease in TMP. While studies on th2 mutants support TH2 as a TMP phosphatase, analyses of TH2-GFP overexpression lines implicating TH2 may also function as a TDP phosphatase in planta. We propose a working model that the TMP/TDP phosphatase activity of TH2 connects TMP, thiamin, and TDP into a metabolic cycle. The TMP phosphatase activity of TH2 is required for TDP biosynthesis, and the TDP phosphatase activity of TH2 may modulate TDP homeostasis in Arabidopsis.


Asunto(s)
Arabidopsis , Tiamina , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Unión al ADN/metabolismo , Difosfatos/metabolismo , Homeostasis , Monoéster Fosfórico Hidrolasas/metabolismo , Tiamina/metabolismo , Tiamina Pirofosfato/metabolismo
9.
Plant Cell Physiol ; 64(12): 1466-1481, 2023 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-37243703

RESUMEN

Glutamine (Gln) is the first amino acid synthesized in nitrogen (N) assimilation in plants. Gln synthetase (GS), converting glutamate (Glu) and NH4+ into Gln at the expense of ATP, is one of the oldest enzymes in all life domains. Plants have multiple GS isoenzymes that work individually or cooperatively to ensure that the Gln supply is sufficient for plant growth and development under various conditions. Gln is a building block for protein synthesis and an N-donor for the biosynthesis of amino acids, nucleic acids, amino sugars and vitamin B coenzymes. Most reactions using Gln as an N-donor are catalyzed by Gln amidotransferase (GAT) that hydrolyzes Gln to Glu and transfers the amido group of Gln to an acceptor substrate. Several GAT domain-containing proteins of unknown function in the reference plant Arabidopsis thaliana suggest that some metabolic fates of Gln have yet to be identified in plants. In addition to metabolism, Gln signaling has emerged in recent years. The N regulatory protein PII senses Gln to regulate arginine biosynthesis in plants. Gln promotes somatic embryogenesis and shoot organogenesis with unknown mechanisms. Exogenous Gln has been implicated in activating stress and defense responses in plants. Likely, Gln signaling is responsible for some of the new Gln functions in plants.


Asunto(s)
Aminoácidos , Glutamina , Glutamina/metabolismo , Aminoácidos/metabolismo , Ácido Glutámico/metabolismo , Transducción de Señal , Plantas/metabolismo , Glutamato-Amoníaco Ligasa/metabolismo
10.
Stat Sci ; 38(2): 185-208, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37324576

RESUMEN

Response-Adaptive Randomization (RAR) is part of a wider class of data-dependent sampling algorithms, for which clinical trials are typically used as a motivating application. In that context, patient allocation to treatments is determined by randomization probabilities that change based on the accrued response data in order to achieve experimental goals. RAR has received abundant theoretical attention from the biostatistical literature since the 1930's and has been the subject of numerous debates. In the last decade, it has received renewed consideration from the applied and methodological communities, driven by well-known practical examples and its widespread use in machine learning. Papers on the subject present different views on its usefulness, and these are not easy to reconcile. This work aims to address this gap by providing a unified, broad and fresh review of methodological and practical issues to consider when debating the use of RAR in clinical trials.

11.
Stat Med ; 42(8): 1156-1170, 2023 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-36732886

RESUMEN

In some clinical scenarios, for example, severe sepsis caused by extensively drug resistant bacteria, there is uncertainty between many common treatments, but a conventional multiarm randomized trial is not possible because individual participants may not be eligible to receive certain treatments. The Personalised Randomized Controlled Trial design allows each participant to be randomized between a "personalised randomization list" of treatments that are suitable for them. The primary aim is to produce treatment rankings that can guide choice of treatment, rather than focusing on the estimates of relative treatment effects. Here we use simulation to assess several novel analysis approaches for this innovative trial design. One of the approaches is like a network meta-analysis, where participants with the same personalised randomization list are like a trial, and both direct and indirect evidence are used. We evaluate this proposed analysis and compare it with analyses making less use of indirect evidence. We also propose new performance measures including the expected improvement in outcome if the trial's rankings are used to inform future treatment rather than random choice. We conclude that analysis of a personalized randomized controlled trial can be performed by pooling data from different types of participants and is robust to moderate subgroup-by-intervention interactions based on the parameters of our simulation. The proposed approach performs well with respect to estimation bias and coverage. It provides an overall treatment ranking list with reasonable precision, and is likely to improve outcome on average if used to determine intervention policies and guide individual clinical decisions.


Asunto(s)
Ensayos Clínicos Controlados Aleatorios como Asunto , Proyectos de Investigación , Humanos , Medicina de Precisión , Participación del Paciente
12.
Anesthesiology ; 136(1): 148-161, 2022 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-34724559

RESUMEN

BACKGROUND: The relationship between late clinical outcomes after injury and early dynamic changes between fibrinolytic states is not fully understood. The authors hypothesized that temporal transitions in fibrinolysis states using rotational thromboelastometry (ROTEM) would aid stratification of adverse late clinical outcomes and improve understanding of how tranexamic acid modulates the fibrinolytic response and impacts mortality. METHODS: The authors conducted a secondary analysis of previously collected data from trauma patients enrolled into an ongoing prospective cohort study (International Standard Randomised Controlled Trial Number [ISRCTN] 12962642) at a major trauma center in the United Kingdom. ROTEM was performed on admission and at 24 h with patients retrospectively grouped into three fibrinolysis categories: tissue factor-activated ROTEM maximum lysis of less than 5% (low); tissue factor-activated ROTEM maximum lysis of 5 to 15% (normal); or tissue factor-activated ROTEM maximum lysis of more than 15% (high). Primary outcomes were multiorgan dysfunction syndrome and 28-day mortality. RESULTS: Seven-hundred thirty-one patients were included: 299 (41%) were treated with tranexamic acid and 432 (59%) were untreated. Two different cohorts with low-maximum lysis at 24 h were identified: (1) severe brain injury and (2) admission shock and hemorrhage. Multiple organ dysfunction syndrome was greatest in those with low-maximum lysis on admission and at 24 h, and late mortality was four times higher than in patients who remained normal during the first 24 h (7 of 42 [17%] vs. 9 of 223 [4%]; P = 0.029). Patients that transitioned to or remained in low-maximum lysis had increased odds of organ dysfunction (5.43 [95% CI, 1.43 to 20.61] and 4.85 [95% CI, 1.83 to 12.83], respectively). Tranexamic acid abolished ROTEM hyperfibrinolysis (high) on admission, increased the frequency of persistent low-maximum lysis (67 of 195 [34%]) vs. 8 of 79 [10%]; P = 0.002), and was associated with reduced early mortality (28 of 195 [14%] vs. 23 of 79 [29%]; P = 0.015). No increase in late deaths, regardless of fibrinolysis transition patterns, was observed. CONCLUSIONS: Adverse late outcomes are more closely related to 24-h maximum lysis, irrespective of admission levels. Tranexamic acid alters early fibrinolysis transition patterns, but late mortality in patients with low-maximum lysis at 24 h is not increased.


Asunto(s)
Fibrinólisis/fisiología , Hemorragia/sangre , Hemorragia/mortalidad , Heridas y Lesiones/sangre , Heridas y Lesiones/mortalidad , Adulto , Antifibrinolíticos/administración & dosificación , Pruebas de Coagulación Sanguínea/tendencias , Estudios de Cohortes , Femenino , Fibrinólisis/efectos de los fármacos , Hemorragia/prevención & control , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Estudios Retrospectivos , Tromboelastografía/efectos de los fármacos , Tromboelastografía/tendencias , Factores de Tiempo , Ácido Tranexámico/administración & dosificación , Reino Unido/epidemiología , Heridas y Lesiones/tratamiento farmacológico
13.
Stat Med ; 41(5): 877-890, 2022 02 28.
Artículo en Inglés | MEDLINE | ID: mdl-35023184

RESUMEN

Adapting the final sample size of a trial to the evidence accruing during the trial is a natural way to address planning uncertainty. Since the sample size is usually determined by an argument based on the power of the trial, an interim analysis raises the question of how the final sample size should be determined conditional on the accrued information. To this end, we first review and compare common approaches to estimating conditional power, which is often used in heuristic sample size recalculation rules. We then discuss the connection of heuristic sample size recalculation and optimal two-stage designs, demonstrating that the latter is the superior approach in a fully preplanned setting. Hence, unplanned design adaptations should only be conducted as reaction to trial-external new evidence, operational needs to violate the originally chosen design, or post hoc changes in the optimality criterion but not as a reaction to trial-internal data. We are able to show that commonly discussed sample size recalculation rules lead to paradoxical adaptations where an initially planned optimal design is not invariant under the adaptation rule even if the planning assumptions do not change. Finally, we propose two alternative ways of reacting to newly emerging trial-external evidence in ways that are consistent with the originally planned design to avoid such inconsistencies.


Asunto(s)
Amigos , Proyectos de Investigación , Humanos , Tamaño de la Muestra , Incertidumbre
14.
Int J Mol Sci ; 23(10)2022 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-35628505

RESUMEN

This paper aims to investigate the dielectric properties, i.e., dielectric constant (ε'), dielectric loss factor (ε″), dielectric tangent loss (tan δ), electrical conductivity (σ), and penetration depth (Dp), of the porous nanohydroxyapatite/starch composites in the function of starch proportion, pore size, and porosity over a broad band frequency range of 5 MHz−12 GHz. The porous nanohydroxyapatite/starch composites were fabricated using different starch proportions ranging from 30 to 90 wt%. The results reveal that the dielectric properties and the microstructural features of the porous nanohydroxyapatite/starch composites can be enhanced by the increment in the starch proportion. Nevertheless, the composite with 80 wt% of starch proportion exhibit low dielectric properties (ε', ε″, tan δ, and σ) and a high penetration depth because of its highly interconnected porous microstructures. The dielectric properties of the porous nanohydroxyapatite/starch composites are highly dependent on starch proportion, average pore size, and porosity. The regression models are developed to express the dielectric properties of the porous nanohydroxyapatite/starch composites (R2 > 0.96) in the function of starch proportion, pore size, and porosity from 1 to 11 GHz. This dielectric study can facilitate the assessment of bone scaffold design in bone tissue engineering applications.


Asunto(s)
Almidón , Porosidad , Análisis de Regresión , Almidón/química , Ingeniería de Tejidos/métodos
15.
Paediatr Child Health ; 27(2): 93-98, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35599680

RESUMEN

Background: Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in children. Primary-care physicians (PCPs) play a key role in identifying patients requiring specialist referral. In this study, we aim to determine PCPs' practice patterns for paediatric NAFLD, as knowledge gaps have been reported for adult NAFLD. Methods: A survey was sent to 60 PCPs in the Eastern Ontario Network from July 2019 to January 2020. Results: Thirty-seven (62%) PCPs responded to the survey. Twenty-one incorrectly considered the prevalence of paediatric NAFLD to be ≤10%. The majority (35/36) cared for less than five paediatric NAFLD patients. Thirty-four (92%) were only 'slightly familiar' or 'not familiar at all' with paediatric NAFLD. Only one PCP routinely screens for NAFLD. Only one PCP was aware of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) clinical guidelines for paediatric NAFLD. Twenty-five (68%) correctly selected lifestyle modifications as a treatment option. Lack of confidence in the knowledge of NAFLD was the most common barrier for managing paediatric cases. Conclusion: The majority of PCPs are not screening for paediatric NAFLD and are not familiar with its clinical spectrum, citing a lack of knowledge regarding NAFLD as the greatest barrier. This may cause delays in diagnosis and a presentation with advanced fibrosis at the time of specialist referral. Dissemination and implementation of clinical guidelines have the potential to improve knowledge and screening rates for NAFLD in children at the primary-care level.

16.
J Viral Hepat ; 28(5): 739-754, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33556225

RESUMEN

The long-term effects of direct-acting antiviral therapies (DAAs) for chronic hepatitis C (CHC) remain uncertain. The objective of this systematic review and meta-analysis was to assess the impact of DAAs on CHC progression and mortality. We searched Ovid MEDLINE, Ovid EMBASE and PubMed databases (January 2011 to March 2020) for studies that compared the efficacy of DAAs to a non-DAA control in patients with CHC. Main outcomes were the adjusted hazard ratios (HRs) for mortality, liver decompensation, HCC occurrence and recurrence. Pooled estimates of HRs were determined using random-effects meta-analyses with inverse variance weighting, with sensitivity analyses and meta-regression to explore the effects of clinical factors. We identified 39 articles for the primary analysis. Compared with unexposed individuals, patients treated with DAA had a reduced risk of death (HR; CI = 0.44; 0.38-0.52), decompensation (HR; CI = 0.54; 0.38- 0.76) and HCC occurrence (HR; CI = 0.72; 0.61- 0.86). The protective effect of DAA on HCC recurrence was less clear (HR; CI = 0.72; 0.44-1.16). Sustained virologic response (SVR) attainment was a significant predictor of reduced mortality (HR; CI = 0.33; 0.23-0.46), decompensation (HR; CI = 0.11; 0.05-0.24), HCC occurrence (HR; CI = 0.31; 0.27-0.37) and HCC recurrence (HR; CI = 0.32; 0.20-0.51). Meta-regression showed no evidence of effect modification by patient age, sex, presence of cirrhosis or length of follow-up. In conclusion, our findings show protective effects of DAA treatment and DAA-related SVR on CHC progression and mortality.


Asunto(s)
Carcinoma Hepatocelular , Hepatitis C Crónica , Neoplasias Hepáticas , Antivirales/uso terapéutico , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/epidemiología , Hepatitis C Crónica/complicaciones , Hepatitis C Crónica/tratamiento farmacológico , Humanos , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/epidemiología , Morbilidad , Recurrencia Local de Neoplasia , Respuesta Virológica Sostenida
17.
J Pediatr Hematol Oncol ; 43(2): e260-e263, 2021 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-32341261

RESUMEN

Congenital afibrinogenemia is a rare disorder characterized by a lack of detectable fibrinogen. The mainstay of treatment for acute bleeding episodes or perioperative management is replacement with fibrinogen concentrate or fibrinogen-containing blood products. The development of neutralizing antibodies and severe allergic reactions to fibrinogen replacement is rarely reported in afibrinogenemia patients. Here the treatment regimen is described for a 6-year-old girl with a severe allergic reaction to multiple fibrinogen-containing products who became refractory to treatment because of a presumed inhibitor to fibrinogen.


Asunto(s)
Afibrinogenemia/tratamiento farmacológico , Anafilaxia/etiología , Fibrinógeno/efectos adversos , Hipersensibilidad/etiología , Afibrinogenemia/inmunología , Afibrinogenemia/patología , Anafilaxia/patología , Niño , Femenino , Fibrinógeno/administración & dosificación , Fibrinógeno/antagonistas & inhibidores , Humanos , Hipersensibilidad/patología , Mutación , Pronóstico
18.
BMC Public Health ; 21(1): 28, 2021 01 06.
Artículo en Inglés | MEDLINE | ID: mdl-33407271

RESUMEN

BACKGROUND: Currently 1.9 billion adults worldwide are estimated to be overweight or obese. In Denmark the municipalities hold the responsibility to deliver weight loss programmes to overweight and obese citizens. There is a tendency to assume that weight loss programmes that show positive effects in specialized hospital settings are directly transferrable to municipal settings. However, municipality-based weight loss programmes have not produced clinically significant reductions in body weight. One reason for this may be that much research evidence regarding obesity programming neglects the perspectives of people with obesity. The first step in developing a weight loss programme designed for municipal settings is to understand what people with obesity want and need from a programme. The aim of this study was to examine what people with obesity find important in a weight loss programme for weight loss and weight maintenance. METHODS: We used a qualitative, explorative, descriptive design with individual interviews. We included men and women age 17 and older with a BMI ≥ 25 kg/m2. Participants were recruited from the wait lists of 13 municipality programmes and through Facebook posts. Data were analyzed using content analysis. RESULTS: Thirty-four participants with overweight or obesity were individually interviewed (ages between 19 and 74). Findings suggest that weight loss programmes should; a) support participants in structuring days; b) consider the use of replacement activities to reduce cognitive and emotional burden; c) aide individuals to increase self-efficacy and; d) include family and friends as well as health professionals and peers in the weight loss process. Diet and exercise, while important, should be balanced with other meaningful activities in everyday life. CONCLUSION: Participants in this study wished to balance weight loss related activities with overall everyday life as well as finding the believe in their ability to lose weight in social relations.


Asunto(s)
Programas de Reducción de Peso , Adolescente , Adulto , Anciano , Ejercicio Físico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Obesidad/terapia , Sobrepeso , Pérdida de Peso , Adulto Joven
19.
BMC Public Health ; 21(1): 1945, 2021 10 26.
Artículo en Inglés | MEDLINE | ID: mdl-34702247

RESUMEN

BACKGROUND: Informal caregiving is an integral part of post-stroke recovery with strenuous caregiving demands often resulting in caregiving burden, threatening sustainability of caregiving and potentially impacting stroke survivor's outcomes. Our study aimed to examine and quantify objective and subjective informal care burden after stroke; and to explore the factors associated with informal care burden in Singapore. METHODS: Stroke patients and their informal caregivers were recruited from all five tertiary hospitals in Singapore from December 2010 to September 2013. Informal care comprised of assistance provided by informal caregivers with any of the activities of daily living. Informal care burden was measured by patients' likelihood of requiring informal care, hours of informal care required, and informal caregivers' Zarit's Burden Score. We examined informal care burden at 3-months and 12-months post-stroke. Generalized linear regressions were applied with control variables including patients' and informal caregivers' demographic characteristics, arrangement of informal care, and patients' health status including stroke severity (measured using National Institute of Health Stroke Scale), functional status (measured using Modified Rankin Scale), self-reported depression, and common comorbidities. RESULTS: Three hundred and five patients and 263 patients were examined at 3-months and 12-months. Around 35% were female and 60% were Chinese. Sixty three percent and 49% of the patients required informal care at 3-months and 12-months point, respectively. Among those who required informal care, average hours required per week were 64.3 h at 3-months and 76.6 h at 12-months point. Patients with higher functional dependency were more likely to require informal care at both time points, and required more hours of informal care at 3-months point. Female informal caregivers and those caring for patients with higher functional dependency reported higher Zarit's Burden. While informal caregivers who worked full-time reported higher burden, those caring for married stroke patients reported lower burden at 3-months point. Informal caregivers who co-cared with foreign domestic workers, i.e.: stay-in migrant female waged domestic workers, reported lower burden. CONCLUSIONS: Informal care burden remains high up to 12-months post-stroke. Factors such as functional dependency, stroke severity, informal caregiver gender and co-caring with foreign domestic workers were associated with informal care burden.


Asunto(s)
Actividades Cotidianas , Accidente Cerebrovascular , Cuidadores , Costo de Enfermedad , Femenino , Humanos , Atención al Paciente , Calidad de Vida , Accidente Cerebrovascular/terapia , Sobrevivientes
20.
BMC Fam Pract ; 22(1): 74, 2021 04 14.
Artículo en Inglés | MEDLINE | ID: mdl-33853544

RESUMEN

BACKGROUND: Outpatient medical follow-up post-stroke is not only crucial for secondary prevention but is also associated with a reduced risk of rehospitalization. However, being voluntary and non-urgent, it is potentially determined by both healthcare needs and the socio-demographic context of stroke survivor-caregiver dyads. Therefore, we aimed to examine the role of caregiver factors in outpatient medical follow-up (primary care (PC) and specialist outpatient care (SOC)) post-stroke. METHOD: Stroke survivors and caregivers from the Singapore Stroke Study, a prospective, yearlong, observational study, contributed to the study sample. Participants were interviewed 3-monthly for data collection. Counts of PC and SOC visits were extracted from the National Claims Database. Poisson modelling was used to explore the association of caregiver (and patient) factors with PC/SOC visits over 0-3 months (early) and 4-12 months (late) post-stroke. RESULTS: For the current analysis, 256 stroke survivors and caregivers were included. While caregiver-reported memory problems of a stroke survivor (IRR: 0.954; 95% CI: 0.919, 0.990) and caregiver burden (IRR: 0.976; 95% CI: 0.959, 0.993) were significantly associated with lower early post-stroke PC visits, co-residing caregiver (IRR: 1.576; 95% CI: 1.040, 2.389) and negative care management strategies (IRR: 1.033; 95% CI: 1.005, 1.061) were significantly associated with higher late post-stroke SOC visits. CONCLUSION: We demonstrated that the association of caregiver factors with outpatient medical follow-up varied by the type of service (i.e., PC versus SOC) and temporally. Our results support family-centred care provision by family physicians viewing caregivers not only as facilitators of care in the community but also as active members of the care team and as clients requiring care and regular assessments.


Asunto(s)
Cuidadores , Accidente Cerebrovascular , Estudios de Seguimiento , Humanos , Pacientes Ambulatorios , Estudios Prospectivos , Singapur/epidemiología , Accidente Cerebrovascular/terapia
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