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BACKGROUND: Growing evidence links brain-MRI enlarged perivascular spaces (EPVS) and multiple sclerosis (MS), but their role remains unclear. OBJECTIVE: This study aimed to investigate the cross-sectional associations of EPVS with several neuroinflammatory and neurodegenerative features in a large multicentric-MS cohort. METHODS: In total, 207 patients underwent 3T axial-T2-weighted brain-MRI for EPVS assessment (EPVS dichotomized into high/low according to ⩾ 2/< 2 rating categories). MRI biomarkers included brain-predicted age and brain-predicted age difference (brain-PAD), central vein sign (CVS)-positive lesion percentage (CVS%), paramagnetic rim and cortical lesions, T2-lesion load, and brain volumetry. The variable relative importance for EPVS-category prediction was explored using a classification random forest approach. RESULTS: High EPVS patients were older (49 vs 44 years, p = 0.003), had ⩾ 1 vascular risk factors (VRFs; p = 0.005), lower CVS% (67% vs 78%, p < 0.001), reduced brain volumes (whole brain: 0.63 vs 0.73, p = 0.01; gray matter: 0.36 vs 0.40; p = 0.002), and older brain-predicted age (58 vs 50 years, p < 0.001). No differences were found for neuroinflammatory markers. After adjusting for age and VFRs (multivariate analyses), the high EPVS category correlated with lower CVS% (odds ratio (OR) = 0.98, 95% confidence interval (CI) = 0.96-0.99; p = 0.02), lower whole brain (OR = 0.01, 95% CI = 0.0003-0.5; p = 0.02), gray matter (OR = 0.0004, 95% CI = 0.0000004-0.4; p = 0.03) volumes, and higher brain-PAD (OR = 1.05, 95% CI = 1.01-1.09; p = 0.02). Random forest identified brain-PAD as the most important predictor of high EPVS. CONCLUSION: EPVS in MS likely reflect microangiopathic disease rather than neuroinflammation, potentially contributing to accelerated neurodegeneration.
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Envejecimiento , Sistema Glinfático , Imagen por Resonancia Magnética , Esclerosis Múltiple , Humanos , Masculino , Femenino , Persona de Mediana Edad , Adulto , Sistema Glinfático/patología , Sistema Glinfático/diagnóstico por imagen , Esclerosis Múltiple/patología , Esclerosis Múltiple/diagnóstico por imagen , Envejecimiento/patología , Estudios Transversales , Encéfalo/patología , Encéfalo/diagnóstico por imagenRESUMEN
BACKGROUND AND OBJECTIVES: The diagnosis of multiple sclerosis (MS) can be challenging in clinical practice because MS presentation can be atypical and mimicked by other diseases. We evaluated the diagnostic performance, alone or in combination, of the central vein sign (CVS), paramagnetic rim lesion (PRL), and cortical lesion (CL), as well as their association with clinical outcomes. METHODS: In this multicenter observational study, we first conducted a cross-sectional analysis of the CVS (proportion of CVS-positive lesions or simplified determination of CVS in 3/6 lesions-Select3*/Select6*), PRL, and CL in MS and non-MS cases on 3T-MRI brain images, including 3D T2-FLAIR, T2*-echo-planar imaging magnitude and phase, double inversion recovery, and magnetization prepared rapid gradient echo image sequences. Then, we longitudinally analyzed the progression independent of relapse and MRI activity (PIRA) in MS cases over the 2 years after study entry. Receiver operating characteristic curves were used to test diagnostic performance and regression models to predict diagnosis and clinical outcomes. RESULTS: The presence of ≥41% CVS-positive lesions/≥1 CL/≥1 PRL (optimal cutoffs) had 96%/90%/93% specificity, 97%/84%/60% sensitivity, and 0.99/0.90/0.77 area under the curve (AUC), respectively, to distinguish MS (n = 185) from non-MS (n = 100) cases. The Select3*/Select6* algorithms showed 93%/95% specificity, 97%/89% sensitivity, and 0.95/0.92 AUC. The combination of CVS, CL, and PRL improved the diagnostic performance, especially when Select3*/Select6* were used (93%/94% specificity, 98%/96% sensitivity, 0.99/0.98 AUC; p = 0.002/p < 0.001). In MS cases (n = 185), both CL and PRL were associated with higher MS disability and severity. Longitudinal analysis (n = 61) showed that MS cases with >4 PRL at baseline were more likely to experience PIRA at 2-year follow-up (odds ratio 17.0, 95% confidence interval: 2.1-138.5; p = 0.008), whereas no association was observed between other baseline MRI measures and PIRA, including the number of CL. DISCUSSION: The combination of CVS, CL, and PRL can improve MS differential diagnosis. CL and PRL also correlated with clinical measures of poor prognosis, with PRL being a predictor of disability accrual independent of clinical/MRI activity.
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Imagen por Resonancia Magnética , Esclerosis Múltiple , Humanos , Femenino , Masculino , Adulto , Esclerosis Múltiple/diagnóstico por imagen , Esclerosis Múltiple/diagnóstico , Persona de Mediana Edad , Estudios Transversales , Pronóstico , Corteza Cerebral/diagnóstico por imagen , Corteza Cerebral/patología , Venas Cerebrales/diagnóstico por imagen , Venas Cerebrales/patología , Progresión de la Enfermedad , Estudios LongitudinalesRESUMEN
Malaria is a parasitic disease that remains a global concern and the subject of many studies. Metabolomics has emerged as an approach to better comprehend complex pathogens and discover possible drug targets, thus giving new insights that can aid in the development of antimalarial therapies. However, there is no standardized method to extract metabolites from in vitro Plasmodium falciparum intraerythrocytic parasites, the stage that causes malaria. Additionally, most methods are developed with either LC-MS or NMR analysis in mind, and have rarely been evaluated with both tools. In this work, three extraction methods frequently found in the literature were reproduced and samples were analyzed through both LC-MS and 1H NMR, and evaluated in order to reveal which is the most repeatable and consistent through an array of different tools, including chemometrics, peak detection and annotation. The most reliable method in this study proved to be a double extraction with methanol and methanol/water (80:20, v/v). Metabolomic studies in the field should move towards standardization of methodologies and the use of both LC-MS and 1H NMR in order to make data more comparable between studies and facilitate the achievement of biologically interpretable information.
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Antimaláricos , Malaria , Humanos , Plasmodium falciparum/metabolismo , Cromatografía Líquida con Espectrometría de Masas , Cromatografía Liquida/métodos , Espectroscopía de Protones por Resonancia Magnética , Metanol/metabolismo , Espectrometría de Masas en Tándem/métodos , Metabolómica/métodosRESUMEN
BACKGROUND: Chronic active lesions (CAL) in multiple sclerosis (MS) have been observed even in patients taking high-efficacy disease-modifying therapy, including B-cell depletion. Given that CAL are a major determinant of clinical progression, including progression independent of relapse activity (PIRA), understanding the predicted activity and real-world effects of targeting specific lymphocyte populations is critical for designing next-generation treatments to mitigate chronic inflammation in MS. METHODS: We analyzed published lymphocyte single-cell transcriptomes from MS lesions and bioinformatically predicted the effects of depleting lymphocyte subpopulations (including CD20 B-cells) from CAL via gene-regulatory-network machine-learning analysis. Motivated by the results, we performed in vivo MRI assessment of PRL changes in 72 adults with MS, 46 treated with anti-CD20 antibodies and 26 untreated, over â¼2 years. FINDINGS: Although only 4.3% of lymphocytes in CAL were CD20 B-cells, their depletion is predicted to affect microglial genes involved in iron/heme metabolism, hypoxia, and antigen presentation. In vivo, tracking 202 PRL (150 treated) and 175 non-PRL (124 treated), none of the treated paramagnetic rims disappeared at follow-up, nor was there a treatment effect on PRL for lesion volume, magnetic susceptibility, or T1 time. PIRA occurred in 20% of treated patients, more frequently in those with ≥4 PRL (p = 0.027). INTERPRETATION: Despite predicted effects on microglia-mediated inflammatory networks in CAL and iron metabolism, anti-CD20 therapies do not fully resolve PRL after 2-year MRI follow up. Limited tissue turnover of B-cells, inefficient passage of anti-CD20 antibodies across the blood-brain-barrier, and a paucity of B-cells in CAL could explain our findings. FUNDING: Intramural Research Program of NINDS, NIH; NINDS grants R01NS082347 and R01NS082347; Dr. Miriam and Sheldon G. Adelson Medical Research Foundation; Cariplo Foundation (grant #1677), FRRB Early Career Award (grant #1750327); Fund for Scientific Research (FNRS).
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Esclerosis Múltiple , Adulto , Humanos , Esclerosis Múltiple/metabolismo , Linfocitos B , Barrera Hematoencefálica/metabolismo , Imagen por Resonancia Magnética , HierroRESUMEN
Objective: To evaluate the residual effect of partial remission (PR) on immediate post-PR glycemic control according to its occurrence and duration in a cohort of children with type 1 diabetes mellitus (T1DM). Patients and Methods: Values of glycemic control parameters [i.e. HbA1C, insulin dose-adjusted hemoglobin A1C (IDAA1C), glycemic target-adjusted HbA1C (GTAA1C)] and data from glucose monitoring devices from 189 pediatric patients with new-onset type 1 diabetes were collected retrospectively from 24 months. Patients were characterized according to their remission status (PR+ and PR-). PR+ patients were subdivided into three subgroups regarding PR duration [i.e. short (⩾3-⩽6 months), intermediate (>6-⩽12 months), and long PR (>12-⩽14 months)]. We compared glycemic control data from each PR+ subgroup at +6 and +12 months post-PR with PR- patients at the same postdiagnosis time. Second, PR+ subgroups were compared with each other. Results: PR+ patients showed improved glycemic control (i.e. HbA1C, IDAA1C, and GTAA1C) at + 6 months post-PR when compared with nonremitters (PR-), independently of the PR duration subgroups (p < 0.05). Interestingly, patients in long PR+ subgroup exhibited higher positive residual effect than short PR+ subgroup with lower GTAA1C scores (p = 0.02), better time in range (TIR) (p = 0.003), less time in hypoglycemia (10.45 versus 16.13%, p = 0.03) and less glycemic variability (83.1 mg/dl versus 98.84 mg/dl, p = 0.03). No significant differences were found for glucose control between PR+ and PR- patients at +12 months post-PR. Conclusion: This study supports the positive impact of PR occurrence and duration on short-term metabolic control (better HbA1C levels, IDAA1C and GTAA1C scores, TIR, and less glycemic variability) with the residual effect increasing according to PR duration.
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Aims: New-onset type 1 diabetes mellitus (T1D) in pediatric patients represents a clinical challenge for initial total daily insulin dosing (TIDD) due to substantial heterogeneity in practice and lack of consensus on the optimal starting dose. Our INSENODIAB (INsulin SEnsitivity in New Onset type 1 DIABetes) study is aimed at (1) exploring the influence of patient-specific characteristics on insulin requirements in pediatric patients with new-onset T1D; (2) constructing a predictive model for the recommended TIDD tailored to individual patient profiles; and (3) assessing potential associations between TIDD and patient outcomes at follow-up intervals of 3 and 12 months. Methods: We conducted a comprehensive analysis of medical records for children aged 6 months to 18 years, hospitalized for new-onset T1D from 2013 to 2022. The study initially involved multivariable regression analysis on a retrospective cohort (rINSENODIAB), incorporating baseline variables. Subsequently, we validated the model robustness on a prospective cohort (pINSENODIAB) with a significance threshold of 5%. The model accuracy was assessed by Pearson's correlation. Results: Our study encompassed 103 patients in the retrospective cohort and 80 in the prospective cohort, with median TIDD at diagnosis of 1.1 IU/kg BW/day (IQR 0.5). The predictive model for optimal TIDD was established using baseline characteristics, resulting in the following formula: TIDD (IU/d) = ([0.09 × Age2] + [0.68 × %Weight Loss] + [28.60 × Veinous pH] - [1.03 × Veinous bicarbonates] + [0.81 × Weight] - 194.63). Validation of the model using the pINSENODIAB cohort demonstrated a significant Pearson correlation coefficient of 0.74. Notably, no significant correlation was observed between TIDD at diagnosis and partial remission markers (IDAA1C, C-peptide) at 3- and 12-months postdiagnosis time points. Conclusions: In the context of new-onset T1D in pediatric patients, we identified key influencing factors for determining optimal TIDD, including age, percentage of weight loss, weight, veinous pH, and bicarbonates. These findings have paved the way for the development of a dosing algorithm to potentially expedite glycemic control stabilization and facilitate a more individualized approach to treatment regimens.
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Diabetes Mellitus Tipo 1 , Hipoglucemiantes , Insulina , Humanos , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/diagnóstico , Adolescente , Niño , Masculino , Femenino , Insulina/administración & dosificación , Hipoglucemiantes/administración & dosificación , Preescolar , Estudios Retrospectivos , Lactante , Estudios Prospectivos , Glucemia/metabolismo , Glucemia/efectos de los fármacosRESUMEN
BACKGROUND: The central vein sign (CVS) is an imaging biomarker able to differentiate multiple sclerosis (MS) from other conditions causing similar appearance lesions on magnetic resonance imaging (MRI), including cerebral small vessel disease (CSVD). However, the impact of vascular risk factors (VRFs) for CSVD on the percentage of CVS positive (CVS+) lesions in MS has never been evaluated. OBJECTIVE: To investigate the association between different VRFs and the percentage of CVS+ lesions in MS. METHODS: In 50 MS patients, 3T brain MRIs (including high-resolution 3-dimensional T2*-weighted images) were analyzed for the presence of the CVS and MRI markers of CSVD. A backward stepwise regression model was used to predict the combined predictive effect of VRF (i.e. age, hypertension, diabetes, obesity, ever-smoking, and hypercholesterolemia) and MRI markers of CSVD on the CVS. RESULTS: The median frequency of CVS+ lesions was 71% (range: 35%-100%). In univariate analysis, age (p < 0.0001), hypertension (p < 0.001), diabetes (p < 0.01), obesity (p < 0.01), smoking (p < 0.05), and the presence of enlarged-perivascular-spaces on MRI (p < 0.005) were all associated with a lower percentage of CVS+ lesions. The stepwise regression model showed that age and arterial hypertension were both associated with the percentage of CVS+ lesions in MS (adjusted R2 = 0.46; p < 0.0001 and p = 0.01, respectively). CONCLUSION: The proportion of CVS+ lesions significantly decreases in older and hypertensive MS patients. Although this study was conducted in patients with an already established MS diagnosis, the diagnostic yield of the previously proposed 35% CVS proportion-based diagnostic threshold appears to be not affected. Overall these results suggest that the presence of VRF for CSVD should be taken into account during the CVS assessment.
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Enfermedades de los Pequeños Vasos Cerebrales , Esclerosis Múltiple , Anciano , Encéfalo/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Esclerosis Múltiple/diagnóstico por imagen , Esclerosis Múltiple/epidemiología , VenasRESUMEN
OBJECTIVES: To assess the value of a radiographic score for the detection of delayed union in nailed fractures. METHODS: The modified radiographic union score (mRUS) values were determined by three separate radiologists on 259 radiographic sets of 58 nailed tibial or femoral fractures obtained at different timepoints after fracture (mean of 4.5 radiographic sets per fracture). A surgeon determined fracture outcome (normal or delayed union) at a mean of 192days after injury. Mean radiographic scores obtained at different timepoints after fracture were compared between fractures with normal or abnormal healing at follow-up. RESULTS: The mean score values increased significantly over time for fractures with normal healing for all readers (p<0.001). The mean score values determined 11-14 weeks after injury were higher in fractures with normal healing than in fractures with delayed union at follow-up (p<0.05). Scoring of radiographs obtained at about 3 months after injury or later enabled detection of fractures with delayed union with a sensitivity of 0.63-0.77 and a specificity of 1.0 (area under curve: 0.77- 0.88). CONCLUSIONS: The mRUS score can contribute to the detection of delayed union at a delay of about 3 months after injury in nailed shaft fractures.
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Fracturas del Fémur/diagnóstico por imagen , Curación de Fractura , Fracturas de la Tibia/diagnóstico por imagen , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Fracturas del Fémur/terapia , Humanos , Masculino , Persona de Mediana Edad , Radiografía/métodos , Reproducibilidad de los Resultados , Estudios Retrospectivos , Fracturas de la Tibia/terapia , Resultado del Tratamiento , Adulto JovenRESUMEN
OBJECTIVES: To determine whether body fat distribution, measured by waist circumference (WC) and waist/hip ratio (WHR), is a better predictor of mortality and morbidity after colorectal surgery than body mass index (BMI) or body surface area (BSA). BACKGROUND: Obesity measured by BMI is not a consistent risk factor for postoperative mortality and morbidity after abdominal surgery. Studies in metabolic and cardiovascular diseases have shown WC and WHR to be better outcome predictors than BMI. METHODS: A prospective multicenter international study was conducted among patients undergoing elective colorectal surgery. The WHR, BMI, and BSA were derived from body weight, height, and waist and hip circumferences measured preoperatively. Uni- and multivariate analyses were performed to identify risk factors for postoperative outcomes. RESULTS: A total of 1349 patients (754 men) from 38 centers in 11 countries were included. Increasing WHR significantly increased the risk of conversion [odds ratio (OR) = 15.7, relative risk (RR) = 4.1], intraoperative complications (OR = 11.0, RR = 3.2), postoperative surgical complications (OR = 7.7, RR = 2.0), medical complications (OR = 13.2, RR = 2.5), anastomotic leak (OR = 13.7, RR = 3.3), reoperations (OR = 13.3, RR = 2.9), and death (OR = 653.1, RR = 21.8). Both BMI (OR = 39.5, RR = 1.1) and BSA (OR = 4.9, RR = 3.1) were associated with an increased risk of abdominal wound complication. In multivariate analysis, the WHR predicted intraoperative complications, conversion, medical complications, and reinterventions, whereas BMI was a risk factor only for abdominal wall complications; BSA did not reach significance for any outcome. CONCLUSIONS: The WHR is predictive of adverse events after elective colorectal surgery. It should be used in routine clinical practice and in future risk-estimating systems.
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Cirugía Colorrectal/mortalidad , Circunferencia de la Cintura , Relación Cintura-Cadera , Anciano , Índice de Masa Corporal , Superficie Corporal , Femenino , Mortalidad Hospitalaria , Humanos , Complicaciones Intraoperatorias/mortalidad , Masculino , Persona de Mediana Edad , Morbilidad , Complicaciones Posoperatorias/mortalidad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Factores de RiesgoRESUMEN
Polychlorobiphenyls (PCBs), polybromodiphenylethers (PBDEs) and organochlorine pesticides (OCPs), such as dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene (HCB), are considered as endocrine disruptors in laboratory and wild animals. This study investigated whether these compounds and their hydroxylated metabolites (HO-PCBs and HO-PBDEs) may affect the homoeostasis of vitamin A, a dietary hormone, in the blubber and serum of twenty lactating grey seals sampled at early and late lactation on the Isle of May, Scotland. The effect of naturally produced compounds such as the methoxylated (MeO)-PBDEs was also examined. Vitamin A levels in inner blubber (37±9 µg/g wet weight (ww) and 92±32 µg/g ww at early and late lactation, respectively) and serum (408±143 and 390±98 ng/ml at early and late lactation, respectively) appeared to be positively related to ΣPCBs, ΣPBDEs and several individual PCB and PBDE congeners in inner blubber and serum. These findings may suggest enhanced mobilisation of hepatic retinoid stores and redistribution in the blubber, a storage site for vitamin A in marine mammals. We have also reported that serum concentrations of ΣHO-PCBs and 4-OH-CB107 tended to increase with circulating vitamin A levels. Although the direction of the relationships may sometimes differ from those reported in the literature, our results are in agreement with previous findings highlighting a disruption of vitamin A homoeostasis in the blubber and bloodstream following exposure to environmental pollutants. The fact that vitamin A and PCBs appeared to share common mechanisms of mobilisation and transfer during lactation in grey seals (Debier et al., 2004; Vanden Berghe et al., 2010) may also play a role in the different relationships observed between vitamin A and lipophilic pollutants.
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Disruptores Endocrinos/efectos adversos , Hidrocarburos Halogenados/efectos adversos , Phocidae/sangre , Vitamina A/sangre , Tejido Adiposo/química , Animales , Femenino , Éteres Difenilos Halogenados/efectos adversos , Hidrocarburos Clorados/efectos adversos , Lactancia , Bifenilos Policlorados/efectos adversosRESUMEN
Twenty grey seal (Halichoerus grypus) mother-pup pairs from the colony of the Isle of May (Scotland) were sampled at early and late lactation in order to study the transfer of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and their metabolites (HO-PCBs and HO-PBDEs) as well as organochlorine pesticides (OCPs), such as DDT and metabolites (DDXs) and hexachlorobenzene (HCB). The transfer of the naturally produced MeO-PBDEs was also investigated. Generally, concentrations (on a lipid weight basis) of the sum of PCBs, PBDEs and DDXs tended to be higher in all tissues at late lactation (for maternal outer blubber ΣPCBs=3860±2091 ng/g, ΣPBDEs=120±74 ng/g and ΣDDXs=559±207 ng/g; for maternal inner blubber ΣPCBs=4229±3274 ng/g, ΣPBDEs=148±118 ng/g and ΣDDXs=704±353 ng/g; for maternal serum ΣPCBs=1271±796 ng/g, ΣPBDEs=27±16 ng/g and ΣDDXs=242±125 ng/g; for milk ΣPCBs=1190±747 ng/g, ΣPBDEs=55±36 ng/g and ΣDDXs=357±160 ng/g; for pup serum ΣPCBs=1451±901 ng/g, ΣPBDEs=48±31 ng/g and ΣDDXs=395±201 ng/g). In all tissues, ΣMeO-PBDEs were found at very low levels or even undetected and their concentrations appeared to increase at late lactation only in maternal inner blubber (2.7±1.3 to 5.3±2.9 ng/g for early and late lactation, respectively) and milk (0.6±0.3 to 1.1±0.5 ng/g for early and late lactation, respectively). The transfer from inner blubber to maternal serum was selective and strongly depended on the log K(ow) value of the compounds, with less lipophilic compounds being more efficiently released. Only a limited amount of HO-PCBs was transferred during lactation as 4-HO-CB-107 was the only metabolite detected in milk (29 to 40 pg/g lw). On the contrary, most of HO-PCB metabolites found in maternal serum were also detected in pup serum. These findings suggest not only a transplacental transfer of HO-PCBs from mothers to pups but also the possibility of endogenous biotransformation in suckling pups or accumulation of undetectable low amounts from milk.
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Éteres Difenilos Halogenados/análisis , Lactancia , Bifenilos Policlorados/análisis , Phocidae/metabolismo , Tejido Adiposo/química , Animales , Biotransformación , Diclorodifenil Dicloroetileno/sangre , Diclorodifenil Dicloroetileno/metabolismo , Femenino , Éteres Difenilos Halogenados/sangre , Éteres Difenilos Halogenados/metabolismo , Hexaclorobenceno/sangre , Hexaclorobenceno/metabolismo , Hidrocarburos Clorados/sangre , Hidrocarburos Clorados/metabolismo , Leche/química , Plaguicidas/sangre , Plaguicidas/metabolismo , Bifenilos Policlorados/sangre , Bifenilos Policlorados/metabolismo , Escocia , Phocidae/sangreRESUMEN
A functional ANOVA analysis of the thermal dissociation of RNA hybridized to DNA microarrays was used to improve discrimination between two soil microbial communities. Following hybridization of in vitro transcribed 16S rRNA derived from uncontaminated and 2,4,6-trinitrotoluene contaminated soils to an oligonucleotide microarray containing group- and species-specific perfect match (PM) probes and mismatch (MM) variants, thermal dissociation was used to analyze the nucleic acid bound to each PM-MM probe set. Functional ANOVA of the dissociation curves generally discriminated PM-MM probe sets when Td values (temperature at 50% probe-target dissociation) could not. Maximum discrimination for many PM and MM probes often occurred at temperatures greaterthan the Td. Comparison of signal intensities measured prior to dissociation analysis from hybridizations of the two soil samples revealed significant differences in domain-, group-, and species-specific probes. Functional ANOVA showed significantly different dissociation curves for 11 PM probes when hybridizations from the two soil samples were compared, even though initial signal intensities for 3 of the 11 did not vary.
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Pseudomonas putida/genética , Microbiología del Suelo , Contaminantes del Suelo , Trinitrotolueno , Análisis de Varianza , Análisis de Secuencia por Matrices de Oligonucleótidos , ARN Bacteriano/análisis , ARN Ribosómico 16S/análisisRESUMEN
The differential effects of basic visual or auditory stimuli on electroencephalograms (EEG), named event related potentials (ERPs), are often used to evaluate the impact of treatments on brain performances. In the present paper, we propose a P-splines based model that can be used to evaluate treatment effect on the timing and the amplitude of some peaks of the ERPs curves. Functional ANOVA is an adaptation of linear model or analysis of variance to analyse functional observations. The changes in the functional of interest effects are generally described using smoothing splines. Eilers and Marx proposed to work with P-splines, a combination of B-splines and difference penalties on coefficients. We define a P-splines model for ERPs curves combined with random effects. In particular, we show that it is a useful alternative to classical strategies requiring the visual and usually imprecise localization of specific ERP peaks from curves with a low signal-to-noise ratio.