Visual search in spatial neglect studied with a preview paradigm.

Impaired visual search is a hallmark of spatial neglect. When searching for an unique feature (e.g., color) neglect patients often show only slight visual field asymmetries. In contrast, when the target is defined by a combination of features (e.g., color and form) they exhibit a severe deficit of contralesional search. This finding suggests a selective impairment of the serial deployment of spatial attention. Here, we examined this deficit with a preview paradigm. Neglect patients searched for a target defined by the conjunction of shape and color, presented together with varying numbers of distracters. The presentation time was varied such that on some trials participants previewed the target together with same-shape/different-color distracters, for 300 or 600 ms prior to the appearance of additional different-shape/same-color distracters. On the remaining trials the target and all distracters were shown simultaneously. Healthy participants exhibited a serial search strategy only when all items were presented simultaneously, whereas in both preview conditions a pop-out effect was observed. Neglect patients showed a similar pattern when the target was presented in the right hemifield. In contrast, when searching for a target in the left hemifield they showed serial search in the no-preview condition, as well as with a preview of 300 ms, and partly even at 600 ms. A control experiment suggested that the failure to fully benefit from item preview was probably independent of accurate perception of time. Our results, when viewed in the context of existing literature, lead us to conclude that the visual search deficit in neglect reflects two additive factors: a biased representation of attentional priority in favor of ipsilesional information and exaggerated capture of attention by ipsilesional abrupt onsets.

Work motivation and pro-social behavior in the delivery of public services : theoretical and empirical insights

This Ph.D. dissertation seeks to study the work motivation of employees in the delivery of public services. The questioning on work motivation in public services in not new but it becomes central for governments which are now facing unprecedented public debts. The objective of this research is twofold : First, we want to see if the work motivation of employees in public services is a continuum (intrinsic and extrinsic motivations cannot coexist) or a bi-dimensional construct (intrinsic and extrinsic motivations coexist simultaneously). The research in public administration literature has focused on the concept of public service motivation, and considered motivation to be uni-dimensional (Perry and Hondeghem 2008). However, no study has yet tackled both types of motivation, the intrinsic and extrinsic ones, in the same time. This dissertation proposes, in Part I, a theoretical assessment and an empirical test of a global work motivational structure, by using a self-constructed Swiss dataset with employees from three public services, the education sector, the security sector and the public administrative services sector. Our findings suggest that work motivation in public services in not uni-dimensional but bi-dimensional, the intrinsic and extrinsic motivations coexist simultaneously and can be positively correlated (Amabile et al. 1994). Our findings show that intrinsic motivation is as important as extrinsic motivation, thus, the assumption that employees in public services are less attracted by extrinsic rewards is not confirmed for this sample. Other important finding concerns the public service motivation concept, which, as theoretically predicted, represents the major motivational dimension of employees in the delivery of public services. Second, the theory of public service motivation makes the assumption that employees in public services engage in activities that go beyond their self-interest, but never uses this construct as a determinant for their pro-social behavior. In the same time, several studies (Gregg et al. 2011 and Georgellis et al. 2011) bring evidence about the pro-social behavior of employees in public services. However, they do not identify which type of motivation is at the origin of this behavior, they only make the assumption of an intrinsically motivated behavior. We analyze the pro-social behavior of employees in public services and use the public service motivation as determinant of their pro-social behavior. We add other determinants highlighted by the theory of pro-social behavior (Bénabou and Tirole 2006), by Le Grand (2003) and by fit theories (Besley and Ghatak 2005). We test these determinants on Part II and identify for each sector of activity the positive or the negative impact on pro-social behavior of Swiss employees. Contrary to expectations, we find, for this sample, that both intrinsic and extrinsic factors have a positive impact on pro-social behavior, no crowding-out effect is identified in this sample. We confirm the hypothesis of Le Grand (2003) about the positive impact of the opportunity cost on pro-social behavior. Our results suggest a mix of action-oriented altruism and out-put oriented altruism of employees in public services. These results are relevant when designing incentives schemes for employees in the delivery of public services.

Effect of single nucleotide polymorphisms in cytochrome P450 isoenzyme and N-acetyltransferase 2 genes on the metabolism of artemisinin-based combination therapies in malaria patients from Cambodia and Tanzania.

The pharmacogenetics of antimalarial agents are poorly known, although the application of pharmacogenetics might be critical in optimizing treatment. This population pharmacokinetic-pharmacogenetic study aimed at assessing the effects of single nucleotide polymorphisms (SNPs) in cytochrome P450 isoenzyme genes (CYP, namely, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5) and the N-acetyltransferase 2 gene (NAT2) on the pharmacokinetics of artemisinin-based combination therapies in 150 Tanzanian patients treated with artemether-lumefantrine, 64 Cambodian patients treated with artesunate-mefloquine, and 61 Cambodian patients treated with dihydroartemisinin-piperaquine. The frequency of SNPs varied with the enzyme and the population. Higher frequencies of mutant alleles were found in Cambodians than Tanzanians for CYP2C9*3, CYP2D6*10 (100C → T), CYP3A5*3, NAT2*6, and NAT2*7. In contrast, higher frequencies of mutant alleles were found in Tanzanians for CYP2D6*17 (1023C → T and 2850C → T), CYP3A4*1B, NAT2*5, and NAT2*14. For 8 SNPs, no significant differences in frequencies were observed. In the genetic-based population pharmacokinetic analyses, none of the SNPs improved model fit. This suggests that pharmacogenetic data need not be included in appropriate first-line treatments with the current artemisinin derivatives and quinolines for uncomplicated malaria in specific populations. However, it cannot be ruled out that our results represent isolated findings, and therefore more studies in different populations, ideally with the same artemisinin-based combination therapies, are needed to evaluate the influence of pharmacogenetic factors on the clearance of antimalarials.

The borehole-fluid effect in electrical resistivity imaging

Fluid that fills boreholes in crosswell electrical resistivity investigations provides the necessary electrical contact between the electrodes and the rock formation but it is also the source of image artifacts in standard inversions that do not account for the effects of the boreholes. The image distortions can be severe for large resistivity contrasts between the rock formation and borehole fluid and for large borehole diameters. We have carried out 3D finite-element modeling using an unstructured-grid approach to quantify the magnitude of borehole effects for different resistivity contrasts, borehole diameters, and electrode configurations. Relatively common resistivity contrasts of 100:1 and borehole diameters of 10 and 20 cm yielded, for a bipole length of 5 m, apparent resistivity underestimates of approximately 12% and 32% when using AB-MN configurations and apparent resistivity overestimates of approximately 24% and 95% when using AM-BN configurations. Effects are generally more severe at shorter bipole spacings. We report the results obtained by either including or ignoring the boreholes in inversions of 3D field data from a test site in Switzerland, where approximately 10,000 crosswell resistivity-tomography measurements were made across six acquisition planes among four boreholes. Inversions of raw data that ignored the boreholes filled with low-resistivity fluid paradoxically produced high-resistivity artifacts around the boreholes. Including correction factors based on the modeling results fora ID model with and without the boreholes did not markedly improve the images. The only satisfactory approach was to use a 3D inversion code that explicitly incorporated the boreholes in the actual inversion. This new approach yielded an electrical resistivity image that was devoid of artifacts around the boreholes and that correlated well with coincident crosswell radar images.

Effect of moderate hyperventilation and induced hypertension on cerebral tissue oxygenation after cardiac arrest and therapeutic hypothermia.

AIM: Improving cerebral perfusion is an essential component of post-resuscitation care after cardiac arrest (CA), however precise recommendations in this setting are limited. We aimed to examine the effect of moderate hyperventilation (HV) and induced hypertension (IH) on non-invasive cerebral tissue oxygenation (SctO2) in patients with coma after CA monitored with near-infrared spectroscopy (NIRS) during therapeutic hypothermia (TH). METHODS: Prospective pilot study including comatose patients successfully resuscitated from out-of-hospital CA treated with TH, monitored with NIRS. Dynamic changes of SctO2 upon HV and IH were analyzed during the stable TH maintenance phase. HV was induced by decreasing PaCO2 from ∼40 to ∼30 mmHg, at stable mean arterial blood pressure (MAP∼70 mmHg). IH was obtained by increasing MAP from ∼70 to ∼90 mmHg with noradrenaline. RESULTS: Ten patients (mean age 69 years; mean time to ROSC 19 min) were studied. Following HV, a significant reduction of SctO2 was observed (baseline 74.7±4.3% vs. 69.0±4.2% at the end of HV test, p<0.001, paired t-test). In contrast, IH was not associated with changes in SctO2 (baseline 73.6±3.5% vs. 74.1±3.8% at the end of IH test, p=0.24). CONCLUSIONS: Moderate hyperventilation was associated with a significant reduction in SctO2, while increasing MAP to supra-normal levels with vasopressors had no effect on cerebral tissue oxygenation. Our study suggests that maintenance of strictly normal PaCO2 levels and MAP targets of 70mmHg may provide optimal cerebral perfusion during TH in comatose CA patients.

Measuring an effect size from dichotomized data : contrasted results whether using a correlation or an odds-ratio

It is well known that dichotomizing continuous data has the effect to decrease statistical power when the goal is to test for a statistical association between two variables. Modern researchers however are focusing not only on statistical significance but also on an estimation of the "effect size" (i.e., the strength of association between the variables) to judge whether a significant association is also clinically relevant. In this article, we are interested in the consequences of dichotomizing continuous data on the value of an effect size in some classical settings. It turns out that the conclusions will not be the same whether using a correlation or an odds ratio to summarize the strength of association between the variables: Whereas the value of a correlation is typically decreased by a factor pi/2 after each dichotomization, the value of an odds ratio is at the same time raised to the power 2. From a descriptive statistical point of view, it is thus not clear whether dichotomizing continuous data leads to a decrease or to an increase in the effect size, as illustrated using a data set to investigate the relationship between motor and intellectual functions in children and adolescents

Mise en oeuvre de protocoles spatiaux pour analyser la modulation de processus cognitifs en fonction de la dimension émotionnelle chez le rongeur

Résumé : Emotion et cognition sont deux termes généralement employés pour désigner des processus psychiques de nature opposée. C'est ainsi que les sciences cognitives se sont longtemps efforcées d'écarter la composante «chaude »des processus «froids »qu'elles visaient, si ce n'est pour montrer l'effet dévastateur de la première sur les seconds. Pourtant, les processus cognitifs (de collecte, maintien et utilisation d'information) et émotioAnels (d'activation subjective, physiologique et comportementale face à ce qui est attractif ou aversif) sont indissociables. Par l'approche neuro-éthologique, à l'interface entre le substrat biologique et les manifestations comportementales, nous nous sommes intéressés à une fonction cognitive essentielle, la fonction mnésique, classiquement exprimée chez le rongeur par l'orientation spatiale. Au niveau du substrat, McDonald et White (1993) ont montré la dissociation de trois systèmes de mémoire, avec les rôles de l'hippocampe, du néostriatum et de l'amygdale dans l'encodage des informations respectivement épisodiques, procédurales et émotionnelles. Nous nous sommes penchés sur l'interaction entre ces systèmes en fonction de la dimension émotionnelle par l'éclairage du comportement. L'état émotionnel de l'animal dépend de plusieurs facteurs, que nous avons tenté de contrôler indirectement en comparant leurs effets sur l'acquisition, dans diverses conditions, de la tâche de Morris (qui nécessite la localisation dans un bassin de la position d'une plate-forme submergée), ainsi que sur le style d'exploration de diverses arènes, ouvertes ou fermées, plus ou moins structurées par la présence de tunnels en plexiglas transparent. Nous avons d'abord exploré le rôle d'un composant du système adrénergique dans le rapport à la difficulté et au stress, à l'aide de souris knock-out pour le récepteur à la noradrénaline a-1 B dans un protocole avec 1 ou 4 points de départ dans un bassin partitionné. Ensuite, nous nous sommes penchés, chez le rat, sur les effets de renforcement intermittent dans différentes conditions expérimentales. Dans ces conditions, nous avons également tenté d'analyser en quoi la situation du but dans un paysage donné pouvait interférer avec les effets de certaines formes de stress. Finalement, nous avons interrogé les conséquences de perturbations passées, y compris le renforcement partiel, sur l'organisation des déplacements sur sol sec. Nos résultats montrent la nécessité, pour les souris cont~ô/es dont l'orientation repose sur l'hippocampe, de pouvoir varier les trajectoires, ce qui favoriserait la constitution d'une carte cognitive. Les souris a->B KO s'avèrent plus sensibles au stress et capables de bénéficier de la condition de route qui permet des réponses simples et automatisées, sous-tendues par l'activité du striatum. Chez les rats en bassin 100% renforcé, l'orientation apparaît basée sur l'hippocampe, relayée par le striatum pour le développement d'approches systématiques et rapides, avec réorientation efficace en nouvelle position par réactivation dépendant de l'hippocampe. A 50% de renforcement, on observe un effet du type de déroulement des sessions, transitoirement atténué par la motivation Lorsque les essais s'enchaînent sans pause intrasession, les latences diminuent régulièrement, ce qui suggère une prise en charge possible par des routines S-R dépendant du striatum. L'organisation des mouvements exploratoires apparaît dépendante du niveau d'insécurité, avec différents profils intermédiaires entre la différentiation maximale et la thigmotaxie, qui peuvent être mis en relation avec différents niveaux d'efficacité de l'hippocampe. Ainsi, notre travail encourage à la prise en compte de la dimension émotionnelle comme modulatrice du traitement d'information, tant en phase d'exploration de l'environnement que d'exploitation des connaissances spatiales. Abstract : Emotion and cognition are terms widely used to refer to opposite mental processes. Hence, cognitive science research has for a long time pushed "hot" components away from "cool" targeted processes, except for assessing devastating effects of the former upon the latter. However, cognitive processes (of information collection, preservation, and utilization) and emotional processes (of subjective, physiological, and behavioral activation roue to attraction or aversion) are inseparable. At the crossing between biological substrate and behavioral expression, we studied a chief cognitive function, memory, classically shown in animals through spatial orientation. At the substrate level, McDonald et White (1993) have shown a dissociation between three memory systems, with the hippocampus, neostriatum, and amygdala, encoding respectively episodic, habit, and emotional information. Through the behavior of laboratory rodents, we targeted the interaction between those systems and the emotional axis. The emotional state of an animal depends on different factors, that we tried to check in a roundabout way by the comparison of their effects on acquisition, in a variety of conditions, of the Morris task (in which the location of a hidden platform in a pool is required), as well as on the exploration profile in different apparatus, open-field and closed mazes, more or less organized by clear Plexiglas tunnels. We first tracked the role, under more or less difficult and stressful conditions, of an adrenergic component, with knock-out mice for the a-1 B receptor in a partitioned water maze with 1 or 4 start positions. With rats, we looked for the consequences of partial reinforcement in the water maze in different experimental conditions. In those conditions, we further analyzed how the situation of the goal in the landscape could interfere with the effect of a given stress. At last, we conducted experiments on solid ground, in an open-field and in radial mazes, in order to analyze the organization of spatial behavior following an aversive life event, such as partial reinforcement training in the water maze. Our results emphasize the reliance of normal mice to be able to vary approach trajectories. One of our leading hypotheses is that such strategies are hippocampus-dependent and are best developed for of a "cognitive map like" representation. Alpha-1 B KO mice appear more sensitive to stress and able to take advantage of the route condition allowing simple and automated responses, most likely striatum based. With rats in 100% reinforced water maze, the orientation strategy is predominantly hippocampus dependent (as illustrated by the impairment induced by lesions of this structure) and becomes progressively striatum dependent for the development of systematic and fast successful approaches. Training towards a new platform position requires a hippocampus based strategy. With a 50% reinforcement rate, we found a clear impairment related to intersession disruption, an effect transitorily minimized by motivation enhancement (cold water). When trials are given without intrasession interruption, latencies consistently diminish, suggesting a possibility for striatum dependent stimulus-response routine to occur. The organization of exploratory movements is shown to depend on the level of subjective security, with different intermediary profiles between maximum differentiation and thigmotaxy, which can be considered in parallel with different efficiency levels of the hippocampus dependent strategies. Thus, our work fosters the consideration of emotion as a cognitive treatment modulator, during spatial exploration as well as spatial learning. It leads to a model in which the predominance of hippocampus based exploration is challenged by training conditions of various nature.

Main results of the Monte Carlo studies carried out for nuclear medicine practices within the ORAMED project

The aim of ORAMED work package 4 was the optimization of the medical practices in nuclear medicine during the preparation of radiopharmaceuticals and their administration to the patient. During the project a wide campaign of measurements was performed in the nuclear medicine departments of the collaborating hospitals. Such data were intrinsically characterized by a large variability that depended on the procedure, the employed techniques and the operator's habits. That variability could easily hide some important parameter, for example, the effectiveness of the adopted shielding (for syringe and vial) or the effect of the distances from the source. This information is necessary for a valuable optimization purpose of radiation protection. To this end a sensitivity analysis was carried out through Monte Carlo simulations employing voxel models, representing operator's hand during the considered practices. Such analysis allowed understanding at what extent the range of personal dose equivalent evaluated during measurements can be considered intrinsically related to the procedures. Furthermore, with the Monte Carlo simulations it was possible to study the appropriateness of the shielding usually utilized in these practices.

Sub-acute delayed failure of subthalamic DBS in Parkinson's disease: the role of micro-lesion effect.

OBJECTIVE: To study delayed failure after subthalamic nucleus (STN) deep brain stimulation in Parkinson's disease (PD) patients. METHODS: Out of 56 consecutive bilaterally STN-implanted PD patients, we selected subjects who, after initial clinical improvement (1 month after surgery), lost benefit (delayed failure, DF). RESULTS: Five patients developed sub-acutely severe gait disorders (DF). In 4/5 DF patients, a micro-lesion effect, defined as improvement without stimulation, was observed; immediate post-operative MRI demonstrated electrode located above or behind to the STN. CONCLUSIONS: Patients presenting micro-lesion effect should be carefully monitored, as this phenomenon can mask electrodes misplacement and evolution in DF

Effect of Lactobacillus paracasei ST11 on a nasal provocation test with grass pollen in allergic rhinitis.

Cite this as: J. Wassenberg, S. Nutten, R. Audran, N. Barbier, V. Aubert, J. Moulin, A. Mercenier and F. Spertini, Clinical & Experimental Allergy, 2011 (41) 565-573. SUMMARY: Background Probiotics have been associated with prevention and improvement of symptoms in atopic diseases such as atopic dermatitis. However, few studies exist that document their efficacy for upper airways allergies such as allergic rhinitis. Objective To investigate the effect of short-term oral administration of Lactobacillus paracasei ST11 on a nasal provocation test (NPT) with grass pollen. Methods Thirty-one adult volunteers with allergic rhinitis were enrolled in a randomized, double-blind, placebo-controlled study, based on two 4-week cross-over periods of product consumption (ST11-fermented milk vs. placebo), separated by a wash-out period of 6-8 weeks. Objective and subjective clinical parameters of NPT as well as systemic and nasal immunological parameters were compared between the two treatment periods (registration number: NCT 011 50 253). Results Subjects that received ST11-fermented milk had lower nasal congestion than subjects under placebo (visual analogical scale; P<0.05). Nasal pruritus followed the same trend. However, no significant change in combined nasal reaction threshold was observed between the two periods. IL-5 secretion by peripheral blood mononuclear cells and serum allergen-specific IgG4 were significantly lower in ST11-fermented milk group compared to placebo group. IL-8 and IL-10 secretion followed the same trend. Conclusion and Clinical Relevance Short-term treatment with ST11-fermented milk before NPT significantly improved a clinical marker of NPT (subjective nasal congestion) and down-regulated systemic immune markers (IL-5 from peripheral blood mononuclear cells and serum IgG4). These data strongly suggest that probiotics may down modulate key parameters of allergic rhinitis and warrant future evaluation in seasonal trials.

Adverse events to antiretrovirals in the Swiss HIV Cohort Study: effect on mortality and treatment modification.

BACKGROUND: Antiretroviral therapy (ART) decreases morbidity and mortality in HIV-infected patients but is associated with considerable adverse events (AEs). METHODS: We examined the effect of AEs to ART on mortality, treatment modifications and drop-out in the Swiss HIV Cohort Study. A cross-sectional evaluation of prevalence of 13 clinical and 11 laboratory parameters was performed in 1999 in 1,078 patients on ART. AEs were defined as abnormalities probably or certainly related to ART. A score including the number and severity of AEs was defined. The subsequent progression to death, drop-out and treatment modification due to intolerance were evaluated according to the baseline AE score and characteristics of individual AEs. RESULTS: Of the 1,078 patients, laboratory AEs were reported in 23% and clinical AEs in 45%. During a median follow up of 5.9 years, laboratory AEs were associated with higher mortality with an adjusted hazard ratio (HR) of 1.3 (95% confidence interval [CI] 1.2-1.5; P < 0.001) per score point. For clinical AEs no significant association with increased mortality was found. In contrast, an increasing score for clinical AEs (HR 1.11,95% CI 1.04-1.18; P = 0.002), but not for laboratory AEs (HR 1.07, 95% CI 0.97-1.17; P = 0.17), was associated with antiretroviral treatment modification. AEs were not associated with a higher drop-out rate. CONCLUSIONS: The burden of laboratory AEs to antiretroviral drugs is associated with a higher mortality. Physicians seem to change treatments to relieve clinical symptoms, while accepting laboratory AEs. Minimizing laboratory drug toxicity seems warranted and its influence on survival should be further evaluated.

The evolution of helping and harming on graphs: the return of the inclusive fitness effect.

Evolutionary graph theory has been proposed as providing new fundamental rules for the evolution of co-operation and altruism. But how do these results relate to those of inclusive fitness theory? Here, we carry out a retrospective analysis of the models for the evolution of helping on graphs of Ohtsuki et al. [Nature (2006) 441, 502] and Ohtsuki & Nowak [Proc. R. Soc. Lond. Ser. B Biol. Sci (2006) 273, 2249]. We show that it is possible to translate evolutionary graph theory models into classical kin selection models without disturbing at all the mathematics describing the net effect of selection on helping. Model analysis further demonstrates that costly helping evolves on graphs through limited dispersal and overlapping generations. These two factors are well known to promote relatedness between interacting individuals in spatially structured populations. By allowing more than one individual to live at each node of the graph and by allowing interactions to vary with the distance between nodes, our inclusive fitness model allows us to consider a wider range of biological scenarios leading to the evolution of both helping and harming behaviours on graphs.

Mirror me : the effect of the voting advice application smartvote on voting preferences and behavior of Swiss voters

Voting Advice Applications (VAAs) have become a central component of election campaigns worldwide. Through matching political preferences of voters to parties and candidates, the web application grants voters a look into their political mirror and reveals the most suitable political choices to them in terms of policy congruence. Both the dense and concise information on the electoral offer and the comparative nature of the application make VAAs an unprecedented information source for electoral decision making. In times where electoral choices are found to be highly individualized and driven by political issue positions, an ever increasing number of voters turn to VAAs before casting their ballots. With VAAs in high demand, the question of their effects on voters has become a pressing research topic. In various countries, survey research has been used to proclaim an impact of VAAs on electoral behavior, yet practically all studies fail to provide the scientific evidence that would allow for making such claims. In this thesis, I set out to systematically establish the causal link between VAA use and electoral behavior, using various data sources and appropriate statistical techniques in doing so. The focus lies on the Swiss VAA smartvote, introduced in the forefront of the 2003 Swiss federal elections and meanwhile an integral part of the national election campaign, smartvote has produced over a million voting recommendations in the last Swiss federal elections to an active electorate of two million, potentially guiding a vast amount of voters in their choices on the ballot. In order to determine the effect of the VAA on electoral behavior, I analyze both voting preferences and choice among Swiss voters during two consecutive election periods. First, I introduce statistical techniques to adequately examine VAA effects in observational studies and use them to demonstrate that voters who used smartvote prior to the 2007 Swiss federal elections were significantly more likely to swing vote in the elections than non- users. Second, I analyze preference voting during the same election and show that the smartvote voting recommendation inclines politically knowledgeable voters to modify their ballots and cast candidate specific preference votes. Third, to further tackle the indication that smartvote use affects the preference structure of voters, I employ an experimental research design to demonstrate that voters who use the application tend to strengthen their vote propensities for their most preferred party and adapt their overall party preferences in a way that they consider more than one party as eligible vote options after engaging with the application. Finally, vote choice is examined for the 2011 Swiss federal election, showing once more that the VAA initiated a change of party choice among voters. In sum, this thesis presents empirical evidence for the transformative effect of the Swiss VAA smartvote on the electoral behavior.

Comparison of two oral probiotic preparations in a randomized crossover trial highlights a potentially beneficial effect of Lactobacillus paracasei NCC2461 in patients with allergic rhinitis.

BACKGROUND: There is promising but conflicting evidence to recommend the addition of probiotics to foods for prevention and treatment of allergy. Based on previous studies with fermented milk containing Lactobacillus paracasei NCC2461, we aimed to compare the effect of a powder form of the latter probiotic with the effect of a blend of Lactobacillus acidophilus ATCC SD5221 and Bifidobacterium lactis ATCC SD5219 in patients with allergic rhinitis. METHODS: A double-blind, randomized, cross-over study, involving 31 adults with allergic rhinitis to grass pollen, was performed outside the grass pollen season (registration number: NCT01233154). Subjects received each product for 4-weeks in two phases separated by a wash-out period of 6 to 8 weeks. A nasal provocation test was performed before and after each 4-week product intake period, and outcome parameters (objective and subjective clinical symptoms; immune parameters) were measured during and/or 24 hours after the test. RESULTS: Out of the 31 subject enrolled, 28 completed the study. While no effect was observed on nasal congestion (primary outcome), treatment with NCC2461 significantly decreased nasal pruritus (determined by VAS), and leukocytes in nasal fluid samples, enhanced IL-5, IL-13 and IL-10 production by peripheral blood mononuclear cells in an allergen specific manner and tended to decrease IL-5 secretion in nasal fluid, in contrast to treatment with the blend of L. acidophilus and B. lactis. CONCLUSIONS: Despite short-term consumption, NCC2461 was able to reduce subjective nasal pruritus while not affecting nasal congestion in adults suffering from grass pollen allergic rhinitis. The associated decrease in nasal fluid leukocytes and IL-5 secretion, and the enhanced IL-10 secretion in an allergen specific manner may partly explain the decrease in nasal pruritus. However, somewhat unexpected systemic immune changes were also noted. These data support the study of NCC2461 consumption in a seasonal clinical trial to further demonstrate its potentially beneficial effect.