Explaining the Sex Effect on Survival in Cystic Fibrosis: a Joint Modeling Study of UK Registry Data.

BACKGROUND: Male sex is associated with better lung function and survival in people with cystic fibrosis but it is unclear whether the survival benefit is solely due to the sex-effect on lung function. METHODS: This study analyzes data between 1996 and 2015 from the longitudinal registry study of the UK Cystic Fibrosis Registry. We jointly analyze repeated measurements and time-to-event outcomes to assess how much of the sex effect on lung function also explains survival. These novel methods allow examination of association between percent of forced expiratory volume in 1 second (%FEV1) and covariates such as sex and genotype, and survival, in the same modeling framework. We estimate the probability of surviving one more year with a probit model. RESULTS: The dataset includes 81,129 lung function measurements of %FEV1 on 9,741 patients seen between 1996 and 2015 and captures 1,543 deaths. Males compared with females experienced a more gradual decline in %FEV1 (difference 0.11 per year 95% confidence interval [CI] = 0.08, 0.14). After adjusting for confounders, both overall level of %FEV1 and %FEV1 rate of change are associated with the concurrent hazard for death. There was evidence of a male survival advantage (probit coefficient 0.15; 95% CI = 0.10, 0.19) which changed little after adjustment for %FEV1 using conventional approaches but was attenuated by 37% on adjustment for %FEV1 level and slope in the joint model (0.09; 95% CI = 0.06, 0.12). CONCLUSIONS: We estimate that about 37% of the association of sex on survival in cystic fibrosis is mediated through lung function

Manganese superoxide dismutase can reduce cellular damage mediated by oxygen radicals in transgenic plants

In plants, environmental adversity often leads to the formation of highly reactive oxygen radicals. Since resistance to such conditions may be correlated with the activity of enzymes involved in oxygen detoxification, we have generated transgenic tobacco plants which express elevated levels of manganese superoxide dismutase (MnSOD) within their chloroplasts or mitochondria. Leaf discs of these plants have been analyzed in conditions in which oxidative stress was generated preferentially within one or the other organelle. It was found that high level overproduction of MnSOD in the corresponding subcellular location could significantly reduce the amount of cellular damage which would normally occur. In contrast, small increases in MnSOD activity were deleterious under some conditions. A generally applicable model correlating the consequences of SOD with the magnitude of its expression is presented

The Nature of Surround-Induced Depolarizing Responses in Goldfish Cones

Cones in the vertebrate retina project to horizontal and bipolar cells and the horizontal cells feedback negatively to cones. This organization forms the basis for the center/surround organization of the bipolar cells, a fundamental step in the visual signal processing. Although the surround responses of bipolar cells have been recorded on many occasions, surprisingly, the underlying surround-induced responses in cones are not easily detected. In this paper, the nature of the surround-induced responses in cones is studied. Horizontal cells feed back to cones by shifting the activation function of the calcium current in cones to more negative potentials. This shift increases the calcium influx, which increases the neurotransmitter release of the cone. In this paper, we will show that under certain conditions, in addition to this increase of neurotransmitter release, a calcium-dependent chloride current will be activated, which polarizes the cone membrane potential. The question is, whether the modulation of the calcium current or the polarization of the cone membrane potential is the major determinant for feedback-mediated responses in second-order neurons. Depolarizing light responses of biphasic horizontal cells are generated by feedback from monophasic horizontal cells to cones. It was found that niflumic acid blocks the feedback-induced depolarizing responses in cones, while the shift of the calcium current activation function and the depolarizing biphasic horizontal cell responses remain intact. This shows that horizontal cells can feed back to cones, without inducing major changes in the cone membrane potential. This makes the feedback synapse from horizontal cells to cones a unique synapse. Polarization of the presynaptic (horizontal) cell leads to calcium influx in the postsynaptic cell (cone), but due to the combined activity of the calcium current and the calcium-dependent chloride current, the membrane potential of the postsynaptic cell will be hardly modulated, whereas the output of the postsynaptic cell will be strongly modulated. Since no polarization of the postsynaptic cell is needed for these feedback-mediated responses, this mechanism of synaptic transmission can modulate the neurotransmitter release in single synaptic terminals without affecting the membrane potential of the entire cell

Measures of body habitus are associated with lung function in adults with cystic fibrosis: a population-based study

Background Body habitus differences may explain some of the variation in lung function between individuals with cystic fibrosis (CF). We tested the hypothesis that measures of lean muscle mass and obesity are independently associated with lung function in CF. Methods Cross-sectional study design using UK CF registry data from 2096 clinically stable adults. Results Serum creatinine and BMI were positively and independently associated with FEV1 and FVC. One standard deviation increment in serum creatinine was associated with an FEV1 increase of 171 ml (95% confidence intervals CI: + 116 to + 227 ml) in males and 90 ml (95% CI: + 46 to + 133 ml) in females. Compared to the reference group of 20–24.9 kg/m2, those with a BMI < 20 kg/m2 had lower FEV1 with values of − 642 ml (95%CI: − 784 to − 500 ml) for males and − 468 ml (95%CI: − 564 to − 372 ml) for females. Conclusions Prospective studies and controlled trials are required to ascertain if these associations have therapeutic potential in modifying disease progression

Interactions immunoglobulines-lipides

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Négationnisme et logique du bouc émissaire : le rapport Leuchter

À travers l’étude théorique du négationnisme de la Shoah, de nombreuses questions se sont posées : pourquoi le négationniste utilise-t-il un rapport contesté scientifiquement pour appuyer ses thèses ? Quel est le but poursuivi par le négationnisme ? Quel est le processus s’opérant lors de la remise en cause de la Shoah ? C’est en vue de répondre à ces questions que nous avons tenté, dans le cadre de ce mémoire, d’observer le processus menant à charger un individu de tous les maux par son appartenance à un groupe déterminé. Pour cela, nous avons procédé à une analyse à partir de la logique du bouc émissaire. Cette analyse retrace l’histoire de la persécution du peuple « juif » dans un premier temps au regard de la psychologie sociale et dans un second temps dans une perspective plus psychanalytique.Master [120] en criminologie, Université catholique de Louvain, 201