Person:
Sanz San Miguel, Luis

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First Name
Luis
Last Name
Sanz San Miguel
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Matemáticas
Department
Estadística e Investigación Operativa
Area
Estadística e Investigación Operativa
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UCM identifierScopus Author IDDialnet ID

Search Results

Now showing 1 - 10 of 12
  • Publication
    Function, oxidative, and inflammatory stress parameters in immune cells as predictive markers of lifespan throughout aging
    (Hindawi, 2019-06-02) Martínez de Toda Cabeza, Irene; Vida, Carmen; Sanz San Miguel, Luis; Fuente del Rey, Mónica de la
    According to the oxidative-inflammatory theory of aging, there is a link between the function, the oxidative-inflammatory stress state of immune cells, and longevity. However, it is unknown which immune cell parameters can predict lifespan and if there would be any changes in this prediction, depending on the age of the subject. Therefore, a longitudinal study in mice was performed analysing immune function (chemotaxis of macrophages and lymphocytes, phagocytosis of macrophages, natural killer (NK) activity, and lymphoproliferation capacity), antioxidant (catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities as well as reduced glutathione (GSH) concentrations), oxidant (oxidized glutathione (GSSG), superoxide anion, and malondialdehyde (MDA) concentrations), and inflammation-related markers (basal release of IL-1β, IL-6, TNF-α, and IL-10) in peritoneal leukocytes from mice at the adult, mature, old, very old, and long-lived ages (40, 56, 72, 96, and 120 ± 4 weeks of age, respectively). The results reveal that some of the investigated parameters are determinants of longevity at the adult age (lymphoproliferative capacity, lymphocyte chemotaxis, macrophage chemotaxis and phagocytosis, GPx activity, and GSH, MDA, IL-6, TNF-α, and IL-10 concentrations), and therefore, they could be proposed as markers of the rate of aging. However, other parameters are predictive of extreme longevity only at the very old age (NK activity, CAT and GR activities, and IL-6 and IL-1β concentrations), and as such, they could reflect some of the adaptive mechanisms underlying the achievement of high longevity. Nevertheless, although preliminary, the results of the present study provide a new perspective on the use of function, redox, and inflammatory parameters in immune cells as prognostic tools in aging research and represent a novel benchmark for future work aimed at prediction of lifespan.
  • Publication
    A Bayesian Test For The Mean Of The Power Exponential Distribution
    (Taylor & Francis, 2008) Gómez Villegas, Miguel A.; Portela García-Miguel, Javier; Sanz San Miguel, Luis
    In this article, we deal with the problem of testing a point null hypothesis for the mean of a multivariate power exponential distribution. We study the conditions under which Bayesian and frequentist approaches can match. In this comparison it is observed that the tails of the model are the key to explain the reconciliability or irreconciliability between the two approaches.
  • Publication
    A Bayesian decision procedure for testing multiple hypotheses in DNA microarray experiments
    (De Gruyter, 2014-02) Gómez Villegas, Miguel A.; Salazar, I.; Sanz San Miguel, Luis
    DNA microarray experiments require the use of multiple hypothesis testing procedures because thousands of hypotheses are simultaneously tested. We deal with this problem from a Bayesian decision theory perspective. We propose a decision criterion based on an estimation of the number of false null hypotheses (FNH), taking as an error measure the proportion of the posterior expected number of false positives with respect to the estimated number of true null hypotheses. The methodology is applied to a Gaussian model when testing bilateral hypotheses. The procedure is illustrated with both simulated and real data examples and the results are compared to those obtained by the Bayes rule when an additive loss function is considered for each joint action and the generalized loss 0-1 function for each individual action. Our procedure significantly reduced the percentage of false negatives whereas the percentage of false positives remains at an acceptable level.
  • Publication
    Epsilon contaminated priors in testing point null hypothesis: a procedure to determine the prior probability
    (North Holland, 2000-03-15) Gómez Villegas, Miguel A.; Sanz San Miguel, Luis
    In this paper the problem of testing a point null hypothesis from the Bayesian perspective and the relation between this and the classical approach is studied. A procedure to determine the mixed prior distribution is introduced and a justification for this construction based on a measure of discrepancy is given. Then, we compare a lower bound for the posterior probability, when the prior is in the class of -contaminated distributions, of the point null hypothesis with the p-value.
  • Publication
    A Bayesian Analysis For The Multivariate Point Null Testing Problem
    (Taylor & Francis, 2009-08) Gómez Villegas, Miguel A.; Main Yaque, Paloma; Sanz San Miguel, Luis
    A Bayesian test for the point null testing problem in the multivariate case is developed. A procedure to get the mixed distribution using the prior density is suggested. For comparisons between the Bayesian and classical approaches, lower bounds on posterior probabilities of the null hypothesis, over some reasonable classes of prior distributions, are computed and compared with the p-value of the classical test. With our procedure, a better approximation is obtained because the p-value is in the range of the Bayesian measures of evidence.
  • Publication
    A suitable Bayesian approach in testing point null hypothesis: some examples revisited
    (Marcel Dekker, 2002) Gómez Villegas, Miguel A.; Main Yaque, Paloma; Sanz San Miguel, Luis
    In the problem of testing the point null hypothesis H-0: theta = theta(0) versus H-1: theta not equal theta(0), with a previously given prior density for the parameter theta, we propose the following methodology: to fix an interval of radius epsilon around theta(0) and assign a prior mass, pi(0), to H-0 computed by the density pi(theta) over the interval (theta(0) - epsilon, theta(0) + epsilon), spreading the remainder, 1 - pi(0), over H-1 according to pi(theta). It is shown that for Lindley's paradox, the Normal model with some different priors and Darwin-Fisher's example, this procedure makes the posterior probability of H-0 and the p-value matching better than if the prior mass assigned to H-0 is 0.5.
  • Publication
    When will my mouse die? Life span prediction based on immune function, redox and behavioural parameters in female mice at the adult age
    (Elsevier, 2019-09) Martínez de Toda Cabeza, Irene; Vida, Carmen; Sanz San Miguel, Luis; Fuente del Rey, Mónica de la
    The identification of predictive markers of life span would help to unravel the underlying mechanisms influencing ageing and longevity. For this aim, 30 variables including immune functions, inflammatory-oxidative stress state and behavioural characteristics were investigated in ICR-CD1 female mice at the adult age (N = 38). Mice were monitored individually until they died and individual life spans were registered. Multiple linear regression was carried out to construct an Immunity model (adjusted R2 = 75.8%) comprising Macrophage chemotaxis and phagocytosis and Lymphoproliferation capacity, a Redox model (adjusted R2 = 84.4%) involving Reduced Glutathione and Malondialdehyde concentrations and Glutathione Peroxidase activity and a Behavioural model (adjusted R2 = 79.8%) comprising Internal Locomotion and Time spent in open arms indices. In addition, a Combined model (adjusted R2 = 92.4%) and an Immunity-Redox model (adjusted R2 = 88.7%) were also constructed by combining the above-mentioned selected variables. The models were also cross-validated using two different sets of female mice (N = 30; N = 40). Correlation between predicted and observed life span was 0.849 (P < 0.000) for the Immunity model, 0.691 (P < 0.000) for the Redox, 0.662 (P < 0.000) for the Behavioural and 0.840 (P < 0.000) for the Immunity-Redox model. Thus, these results provide a new perspective on the use of immune function, redox and behavioural markers as prognostic tools in ageing research.
  • Publication
    Sex-related differences in behavioural markers in adult mice for the prediction of lifespan
    (Springer, 2020-10-16) Kobayashi, Hikaru; Martínez de Toda Cabeza, Irene; Sanz San Miguel, Luis; Fuente del Rey, Mónica de la
    Finding biomarkers to assess the rate of ageing and consequently, to forecast individual lifespan is a challenge in ageing research. We recently published a mathematical model for lifespan prediction in adult female mice using behavioural parameters such as internal locomotion and time spent in open arms in the hole board (HB) and elevated plus maze (EPM) tests, respectively. Nevertheless, it is still not known if these behavioural variables could be useful in forecasting lifespan in male mice. Therefore, two groups of ICR-CD1 mice, male and female were subjected to the EPM, HB and T-maze tests at the adult age. Mice were monitored until they died and individual lifespans were registered. In general, adult male mice showed more anxiety-like behaviours than females. The mathematical model previously developed in females was validated with the female cohort, but found to be suboptimal for lifespan prediction in males. Thus, a new model for male lifespan prediction was constructed including the behavioural variables that were predictive of lifespan in males: time in the central platform of the EPM, inner locomotion, number of groomings and number and duration of head-dippings in the HB. These results confirm that the higher the anxiety-like behaviour at the adult age, the shorter the lifespan.
  • Publication
    Algunas relaciones entre la aproximación clásica y bayesiana en el contraste de hipótesis
    (Universidad Complutense de Madrid, Servicio de Publicaciones, 2002) Sanz San Miguel, Luis; Gómez Villegas, Miguel Ángel
    Para un problema de localización en una hipótesis nula puntual se relaciona el p-valor con la probabilidad final de la hipótesis nula, cuando la distribución inicial se escoge convenientemente. Se generalizan estos resultados al caso de distribuciones e-contaminadas.
  • Publication
    Asymptotic relationships between posterior probabilities and p-values using the hazard rate
    (North Holland, 2004-01) Gómez Villegas, Miguel A.; Main Yaque, Paloma; Sanz San Miguel, Luis; Navarro Veguillas, Hilario
    In this paper the asymptotic relationship between the classical p-value and the infimum (over all unimodal and symmetric distributions) of the posterior probability in the point null hypothesis testing problem is analyzed. It is shown that the ratio between the infimum and the classical p-value has an equivalent asymptotic behavior to the hazard rate of the sample model.