What makes a host profitable? Parasites balance host nutritive resources against immunity

Numerous host qualities can modulate parasite fitness, and among these, host nutritive resources and immunity are of prime importance. Indeed, parasite fitness increases with the amount of nutritive resources extracted from the host body and decreases with host immune response. To maximize fitness, parasites have therefore to balance these two host components. Yet, because host nutritive resources and immunity both increase with host body condition, it is unclear whether parasites perform better on hosts in prime, intermediate, or poor condition. We investigated blood meal size and survival of the ectoparasitic louse fly Crataerina melbae in relation to body condition and cutaneous immune response of their Alpine swift (Apus melba) nestling hosts. Louse flies took a smaller blood meal and lived a shorter period of time when feeding on nestlings that were experimentally food deprived or had their cutaneous immune response boosted with methionine. Consistent with these results, louse fly survival was the highest when feeding on nonexperimental nestlings in intermediate body condition. Our findings emphasize that although hosts in poor condition had a reduced immunocompetence, parasites may have avoided them because individuals in poor condition did not provide adequate resources. These findings highlight the fact that giving host immunocompetence primary consideration can result in a biased appraisal of host-parasite interactions

The contractile properties of vaginal myofibroblasts: Is the myofibroblasts contraction force test a valuable indication of future prolapse development?

Using a specific myofibroblast contraction test, we try to predict future utero-vaginal prolapse development in young primiparae women. We compare myofibroblast cultures of the vaginal wall in primiparae women (group 1), young multiparae women (group 2) and older multiparae women (group 3) who were operated on for severe utero-vaginal prolapse. A myofibroblast-mediated collagen gel contraction assay determined a contraction factor that was compared in the three groups of women. The myofibroblasts contraction factor after 24 and 48 hours was significantly higher in group 1 women (2.4 ± 0.6/4.4 ± 1.9) compared to group 2 (1.6 ± 0.3/ 1.8 ± 0.1) andgroup 3 (1.6 ± 0.3/1.8 ± 0.3), but showed no differences in group 1 women without (2.1 ± 0.5/3.5 ± 1.9) and with (2.7 ± 0.6/5.1 ± 1.7) cystocoele. Vaginal myofibroblasts of young women show better contraction forces than young women with severe utero-vaginal prolapse. The latter have a myofibroblast contraction factor similar to those of older post-menopausal women operated for the same conditio

Notch Antagonists: Potential Modulators of Cancer and Inflammatory Diseases.

Notch is a key player in various developmental processes during the embryonic stage as well as in regulating tissue homeostasis, cell differentiation, and stem cell maintenance in adult life. Activation of Notch signaling occurs following Notch receptor-ligand interaction and subsequent enzymatic proteolysis by the gamma-secretase complex, resulting in the cytoplasmic release of a Notch intracellular domain, which translocates to the nucleus to initiate the downstream transcriptional machinery. Notch activation and its aberrant signaling have been broadly linked to the pathogenesis of cancer and some chronic inflammatory diseases resulting in pathologic fibrotic processes. This review focuses on the molecular basis of Notch-induced signaling and its interaction with other pathways to identify therapeutic targets. We also highlight current efforts to pharmacologically intervene in Notch signaling and discuss promising ongoing experimental and clinical studies

Processus psychologiques de gestion du stress et régulation neuroendocrinienne chez les adolescents délinquants en institution fermée : une étude pilote [Psychological processes of stress management and neuroendocrine regulation in incarcerated adolescent offenders: A pilot study]

Adolescence is a stressful period where important biological, psychological and social changes occur. Adolescents are particularly vulnerable during this developmental period and can use various strategies to deal with daily stress, such as substance use or externalizing behaviors. In previous studies, stress in adolescents with externalizing behaviors was often linked to ineffective cognitive coping strategies (i.e., constructive thinking) and overlooking the biological aspects involved in stress management such as neuroendocrine regulation. Indeed, repeated activation of the hypothalamic-pituitary-adrenal (HPA) axis in chronic stress situations may have long-term effects on subsequent cortisol regulation and lead to psychological difficulties. It was also shown that basal cortisol levels are lower in adolescents with externalizing behaviors. This study aims to assess the links between constructive thinking and neuroendocrine regulation in adolescent offenders and their association with externalizing symptoms (e.g., aggression, delinquency, psychopathic traits, substance use). Identifying particular biopsychological patterns can help to better understand stress management in youth with externalizing behaviors and to improve clinical treatments. Sixteen adolescent males aged from 12 to 18 years were recruited in an institution for juvenile offenders. Exclusion criteria were insufficient reasoning abilities assessed using the Raven Matrices Test. Regarding psychological dimensions, constructive thinking was assessed through the Constructive thinking inventory (CTI), psychopathic traits through the Youth psychopathic traits inventory (YPI), externalizing behaviors through 30 items (out of 113) and 2 subscales (aggressive behavior and delinquency problems) from the Child behavior checklist-youth self-report (CBCL), and substance use through the Dep-ado. Regarding biological dimensions, cortisol daily secretion and regulation were assessed through saliva samples that were collected during 3 consecutive days (4 samples per day: directly after awakening, at 10 a.m., at 4 a.m., and before going to bed). Adolescent offenders presented maladaptative thinking styles and a particular neuroendocrine regulation in their daily management with stress. In particular, their level of cortisol in the morning was higher than those expected in a general population (20.34 nmol/L while the norm is around 10 nmol/L). They also showed more agressive and delinquent behaviors (CBCL) as well as more psychopathic traits (YPI) than the general population. Moreover, constructive thinking style was associated with personality and behavioral dimensions. Indeed, results indicated positive and significant correlations between categorical thinking style (CTI), psychopathic traits (YPI) (r=0.57, P=0.021) and externalizing behaviors (CBCL) (r=0.55, P=0.028). In other words, the more adolescent offenders used categorical thinking, the more they presented psychopathic traits and externalizing behaviors. With respect to the association between psychological and biological dimensions in stress management, we observed a significant and positive correlation between cortisol regulation and esoteric thinking (r=0.57, P=0.028) and a trend with superstitious thinking (r=0.47, P=0.075). The more adolescent offenders used esoteric and superstitious thinking, the poorer was their cortisol regulation. We also observed a trend between the life style scale of the YPI (i.e., impulsive, irresponsible) and the daily secretion of cortisol (r=0.51; P=0.052) as well as cortisol regulation (r=0.49, P=0.065). The more adolescent offenders presented psychopathic traits, the higher tended to be their daily secretion of cortisol and the poorer their cortisol regulation. Finally, cortisol regulation (r=0.54, P=0.038) and secretion (r=0.73, P=0.002) were significantly correlated with the DEP-Ado score. In other words, a poor cortisol regulation and a high secretion of cortisol seem to be associated with substance use. Adolescent offenders face an important amount of daily stress and do not always have the appropriate skills to deal with it. Indeed, we know from clinical experience that they often report a sense of hopelessness toward their lack of professional perspectives as well as familial conflicts which can be important stressors in addition to the incarceration in itself. Therefore, treatment aiming to improve psychic elaboration can help these adolescents to make their thinking styles more flexible and use more appropriate ways of coping with stress instead of externalizing behaviors and substance use. Moreover, considering the complex cases of these adolescents and the many changes of caregivers and institutions where they have lived, which can be important stressors as well, professionals working with these youth should be aware of their emotional reactions toward them and try to encourage continuity of care

Growth of Single Unit-Cell Superconducting La2−x_{2-x}Srx_xCuO4_{4} Films

We have developed an approach to grow high quality ultrathin films of La$_{2-x}$Sr$_x$CuO$_{4}$ with molecular beam epitaxy, by adding a homoepitaxial buffer layer in order to minimize the degradation of the film structure at the interface. The advantage of this method is to enable a further reduction of the minimal thickness of a superconducting La$_{1.9}$Sr$_{0.1}$CuO$_{4}$ film. The main result of our work is that a single unit cell (only two copper oxide planes) grown on a SrLaAlO$_4$ substrate exhibits a superconducting transition at 12.5 K (zero resistance) and an in-plane magnetic penetration depth $\lambda_{ab}(0)$ = 535 nm.Comment: to be published in "Solid State Electonics" special issue, conference proceedings of the 9th Workshop on Oxide Electronics, St-Pete Beach, FL, 20-23 november 2002 : 12 pages 4 figures in preprint versio

Kinetic Inductance of Josephson Junction Arrays: Dynamic and Equilibrium Calculations

We show analytically that the inverse kinetic inductance $L^{-1}$ of an overdamped junction array at low frequencies is proportional to the admittance of an inhomogeneous equivalent impedance network. The $ij^{th}$ bond in this equivalent network has an inverse inductance $J_{ij}\cos(\theta_i^0-\theta_j^0-A_{ij})$, where $J_{ij}$ is the Josephson coupling energy of the $ij^{th}$ bond, $\theta_i^0$ is the ground-state phase of the grain $i$, and $A_{ij}$ is the usual magnetic phase factor. We use this theorem to calculate $L^{-1}$ for square arrays as large as $180\times 180$. The calculated $L^{-1}$ is in very good agreement with the low-temperature limit of the helicity modulus $\gamma$ calculated by conventional equilibrium Monte Carlo techniques. However, the finite temperature structure of $\gamma$, as a function of magnetic field, is \underline{sharper} than the zero-temperature $L^{-1}$, which shows surprisingly weak structure. In triangular arrays, the equilibrium calculation of $\gamma$ yields a series of peaks at frustrations $f = \frac{1}{2}(1-1/N)$, where $N$ is an integer $\geq 2$, consistent with experiment.Comment: 14 pages + 6 postscript figures, 3.0 REVTe

Sub MeV Particles Detection and Identification in the MUNU detector ((1)ISN, IN2P3/CNRS-UJF, Grenoble, France, (2)Institut de Physique, Neuch\^atel, Switzerland, (3) INFN, Padova Italy, (4) Physik-Institut, Z\"{u}rich, Switzerland)

We report on the performance of a 1 m$^{3}$ TPC filled with CF$_{4}$ at 3 bar, immersed in liquid scintillator and viewed by photomultipliers. Particle detection, event identification and localization achieved by measuring both the current signal and the scintillation light are presented. Particular features of $\alpha$ particle detection are also discussed. Finally, the ${54}$Mn photopeak, reconstructed from the Compton scattering and recoil angle is shown.Comment: Latex, 19 pages, 20 figure

Limits on the neutrino magnetic moment from the MUNU experiment

The MUNU experiment was carried out at the Bugey nuclear power reactor. The aim was the study of electron antineutrino-electron elastic scattering at low energy. The recoil electrons were recorded in a gas time projection chamber, immersed in a tank filled with liquid scintillator serving as veto detector, suppressing in particular Compton electrons. The measured electron recoil spectrum is presented. Upper limits on the neutrino magnetic moment were derived and are discussed.Comment: 9 pages, 7 figures Added reference: p.3, 1st col., TEXONO Added sentence: p.4, 1st col., electron attachement Modified sentence: p.5, 1st col., readout sequence Added sentence: p.5, 1st col., fast rise time cu

Fluctuation-dissipation theorem and flux noise in overdamped Josephson junction arrays

The form of the fluctuation-dissipation theorem for a resistively shunted Josephson juction array is derived with the help of the method which explicitely takes into acoount screening effects. This result is used to express the flux noise power spectrum in terms of frequency dependent sheet impedance of the array. The relation between noise amplitude and parameters of the detection coil is analysed for the simplest case of a single-loop coil.Comment: ReVTeX, 8 page