Live-cell three-dimensional single-molecule tracking reveals modulation of enhancer dynamics by NuRD

To understand how the nucleosome remodeling and deacetylase (NuRD) complex regulates enhancers and enhancer-promoter interactions, we have developed an approach to segment and extract key biophysical parameters from live-cell three-dimensional single-molecule trajectories. Unexpectedly, this has revealed that NuRD binds to chromatin for minutes, decompacts chromatin structure and increases enhancer dynamics. We also uncovered a rare fast-diffusing state of enhancers and found that NuRD restricts the time spent in this state. Hi-C and Cut&Run experiments revealed that NuRD modulates enhancer-promoter interactions in active chromatin, allowing them to contact each other over longer distances. Furthermore, NuRD leads to a marked redistribution of CTCF and, in particular, cohesin. We propose that NuRD promotes a decondensed chromatin environment, where enhancers and promoters can contact each other over longer distances, and where the resetting of enhancer-promoter interactions brought about by the fast decondensed chromatin motions is reduced, leading to more stable, long-lived enhancer-promoter relationships.

Clinical evaluation of anaesthetic-like effect of two dermocosmetic formulations containing Aquaphilus dolomiae extract-G3 in subjects with sensitive facial skin

BACKGROUND

Sensitive skin is a common condition of hyper-reactivity to external stimuli, e.g. heat or abrasion. The symptoms are subjective but can be measured using validated emotional and technical methods. Avène water has several beneficial effects on the skin. In vitro studies indicated that the active component of this natural spring water, Aquaphilus dolomiae extract-G3 (ADE-G3), modulates cutaneous sensitivity via an anaesthetic-like mechanism.

OBJECTIVES

To assess facial skin reactivity after repeated application of two formulations containing ADE-G3.

METHODS

In open-label studies, healthy subjects with sensitive facial skin applied cream or balm twice daily for 84 days. The severity of skin sensitivity was measured using the Sensitive Scale (based on quantifying visible or subjective signs). Subjective responses associated with pain or uncomfortable feeling were assessed by measuring electrodermal response (EDR). This involves measuring variations in skin electrical resistance due to non-conscious physiological changes in activity of the sympathetic nervous system. Subjects were also evaluated for beneficial effects according to a quantitative approach using semantic assessment of a question regarding their skin quality. Evaluations were performed before and after the first application, and after 29/30, 56 and 84 days of twice daily use.

RESULTS

There was a significant decrease in the EDR after stimuli immediately after the application of both ADE-G3 formulations, which continued to decrease over 84 days (40-50% decrease by D85). Likewise, all physical and functional signs of the Sensitive Scale were significantly decreased immediately after the first application and at all time points tested after treatment. Verbatim analysis revealed a semantic shift, from mainly negative terms on D1 to mainly positive terms at D85 for both tested products.

CONCLUSIONS

These results demonstrated that two formulations containing ADE-G3 reduced skin sensitivity, indicating a decreased activation of the sympathetic nervous system associated with this condition.

Maternal dietary omega-3 deficiency worsens the deleterious effects of prenatal inflammation on the gut-brain axis in the offspring across lifetime

Maternal immune activation (MIA) and poor maternal nutritional habits are risk factors for the occurrence of neurodevelopmental disorders (NDD). Human studies show the deleterious impact of prenatal inflammation and low n-3 polyunsaturated fatty acid (PUFA) intake on neurodevelopment with long-lasting consequences on behavior. However, the mechanisms linking maternal nutritional status to MIA are still unclear, despite their relevance to the etiology of NDD. We demonstrate here that low maternal n-3 PUFA intake worsens MIA-induced early gut dysfunction, including modification of gut microbiota composition and higher local inflammatory reactivity. These deficits correlate with alterations of microglia-neuron crosstalk pathways and have long-lasting effects, both at transcriptional and behavioral levels. This work highlights the perinatal period as a critical time window, especially regarding the role of the gut-brain axis in neurodevelopment, elucidating the link between MIA, poor nutritional habits, and NDD.

Essential omega-3 fatty acids tune microglial phagocytosis of synaptic elements in the mouse developing brain

Omega-3 fatty acids (n-3 PUFAs) are essential for the functional maturation of the brain. Westernization of dietary habits in both developed and developing countries is accompanied by a progressive reduction in dietary intake of n-3 PUFAs. Low maternal intake of n-3 PUFAs has been linked to neurodevelopmental diseases in Humans. However, the n-3 PUFAs deficiency-mediated mechanisms affecting the development of the central nervous system are poorly understood. Active microglial engulfment of synapses regulates brain development. Impaired synaptic pruning is associated with several neurodevelopmental disorders. Here, we identify a molecular mechanism for detrimental effects of low maternal n-3 PUFA intake on hippocampal development in mice. Our results show that maternal dietary n-3 PUFA deficiency increases microglia-mediated phagocytosis of synaptic elements in the rodent developing hippocampus, partly through the activation of 12/15-lipoxygenase (LOX)/12-HETE signaling, altering neuronal morphology and affecting cognitive performance of the offspring. These findings provide a mechanistic insight into neurodevelopmental defects caused by maternal n-3 PUFAs dietary deficiency.

Dietary n-3 long chain PUFA supplementation promotes a pro-resolving oxylipin profile in the brain

The brain is highly enriched in long chain polyunsaturated fatty acids (LC-PUFAs) that display immunomodulatory properties in the brain. At the periphery, the modulation of inflammation by LC-PUFAs occurs through lipid mediators called oxylipins which have anti-inflammatory and pro-resolving activities when derived from n-3 LC-PUFAs and pro-inflammatory activities when derived from n-6 LC-PUFAs. However, whether a diet rich in LC-PUFAs modulates oxylipins and neuroinflammation in the brain has been poorly investigated. In this study, the effect of a dietary n-3 LC-PUFA supplementation on oxylipin profile and neuroinflammation in the brain was analyzed. Mice were given diets deficient or supplemented in n-3 LC-PUFAs for a 2-month period starting at post-natal day 21, followed by a peripheral administration of lipopolysaccharide (LPS) at adulthood. We first showed that dietary n-3 LC-PUFA supplementation induced n-3 LC-PUFA enrichment in the hippocampus and subsequently an increase in n-3 PUFA-derived oxylipins and a decrease in n-6 PUFA-derived oxylipins. In response to LPS, n-3 LC-PUFA deficient mice presented a pro-inflammatory oxylipin profile whereas n-3 LC-PUFA supplemented mice displayed an anti-inflammatory oxylipin profile in the hippocampus. Accordingly, the expression of cyclooxygenase-2 and 5-lipoxygenase, the enzymes implicated in pro- and anti-inflammatory oxylipin synthesis, was induced by LPS in both diets. In addition, LPS-induced pro-inflammatory cytokine increase was reduced by dietary n-3 LC-PUFA supplementation. These results indicate that brain n-3 LC-PUFAs increase by dietary means and promote the synthesis of anti-inflammatory derived bioactive oxylipins. As neuroinflammation plays a key role in all brain injuries and many neurodegenerative disorders, the present data suggest that dietary habits may be an important regulator of brain cytokine production in these contexts.

Dietary omega-3 deficiency exacerbates inflammation and reveals spatial memory deficits in mice exposed to lipopolysaccharide during gestation

Maternal immune activation (MIA) is a common environmental insult on the developing brain and represents a risk factor for neurodevelopmental disorders. Animal models of in utero inflammation further revealed a causal link between maternal inflammatory activation during pregnancy and behavioural impairment relevant to neurodevelopmental disorders in the offspring. Accumulating evidence point out that proinflammatory cytokines produced both in the maternal and fetal compartments are responsible for social, cognitive and emotional behavioral deficits in the offspring. Polyunsaturated fatty acids (PUFAs) are essential fatty acids with potent immunomodulatory activities. PUFAs and their bioactive derivatives can promote or inhibit many aspects of the immune and inflammatory response. PUFAs of the n-3 series ('n-3 PUFAs', also known as omega-3) exhibit anti-inflammatory/pro-resolution properties and promote immune functions, while PUFAs of the n-6 series ('n-6 PUFAs' or omega-6) favor pro-inflammatory responses. The present study aimed at providing insight into the effects of n-3 PUFAs on the consequences of MIA on brain development. We hypothesized that a reduction in n-3 PUFAs exacerbates both maternal and fetal inflammatory responses to MIA and later-life defects in memory in the offspring. Based on a lipopolysaccharide (LPS) model of MIA (LPS injection at embryonic day 17), we showed that n-3 PUFA deficiency 1) alters fatty acid composition of the fetal and adult offspring brain; 2) exacerbates maternal and fetal inflammatory processes with no significant alteration of microglia phenotype, and 3) induces spatial memory deficits in the adult offspring. We also showed a strong negative correlation between brain content in n-3 PUFA and cytokine production in MIA-exposed fetuses. Overall, our study is the first to address the deleterious effects of n-3 PUFA deficiency on brain lipid composition, inflammation and memory performances in MIA-exposed animals and indicates that it should be considered as a potent environmental risk factor for the apparition of neurodevelopmental disorders.

Light-switchable nanoparticles based on amphiphilic diblock, triblock and heterograft polyoxazoline

Photo-active nanoparticles (NP_D, NP_T, NP_H) were elaborated in water from amphiphilic diblock (D), triblock (T) and heterograft (H) copolymers based on a chromatic unit, coumarin, linked to an alkyl chain and a hydrophilic polyoxazoline chain.

Impact of Lactobacillus fermentum and dairy lipids in the maternal diet on the fatty acid composition of pups' brain and peripheral tissues

The aim of the study was to determine the effect of maternal diets administered since day 1 of gestation and containing dairy lipids or vegetable oils differing in the supply of n-3 polyunsaturated fatty acids (n-3 PUFAs) (equilibrated or deficient) and of Lactobacillus fermentum (L. fermentum) on the docosahexaenoic acid (DHA) accretion in the pups at postnatal day 14 in the prefrontal cortex (PFC) and hippocampus (HC) for brain structures and in the liver and adipose tissue for peripheral tissues. Maternal milk fatty acid composition was also assessed by analyzing the fatty acid composition of the gastric content of the pups. DHA was higher in mice supplemented with L. fermentum than in mice in the deficient group in HC and PFC and also in liver and adipose tissue. This increase could be linked to the slight but significant increase in C18:3n-3 in the maternal milk. This proportion was comparable in the dairy lipid group for which the brain DHA level was the highest. L. fermentum may have a key role in the protection of the brain during the perinatal period via the neuronal accretion of n-3 PUFAs, especially during n-3 PUFA deficiency.

Resolvin D1 and E1 promote resolution of inflammation in microglial cells in vitro

Sustained inflammation in the brain together with microglia activation can lead to neuronal damage. Hence limiting brain inflammation and activation of microglia is a real therapeutic strategy for inflammatory disease. Resolvin D1 (RvD1) and resolvin E1 (RvE1) derived from n-3 long chain polyunsaturated fatty acids are promising therapeutic compounds since they actively turn off the systemic inflammatory response. We thus evaluated the anti-inflammatory activities of RvD1 and RvE1 in microglia cells in vitro. BV2 cells were pre-incubated with RvD1 or RvE1 before lipopolysaccharide (LPS) treatment. RvD1 and RvE1 both decreased LPS-induced proinflammatory cytokines (TNF-α, IL-6 and IL-1β) gene expression, suggesting their proresolutive activity in microglia. However, the mechanisms involved are distinct as RvE1 regulates NFκB signaling pathway and RvD1 regulates miRNAs expression. Overall, our findings support that pro-resolving lipids are involved in the resolution of brain inflammation and can be considered as promising therapeutic agents for brain inflammation.

The Nucleosome Remodeling and Deacetylase Complex NuRD Is Built from Preformed Catalytically Active Sub-modules

The nucleosome remodeling deacetylase (NuRD) complex is a highly conserved regulator of chromatin structure and transcription. Structural studies have shed light on this and other chromatin modifying machines, but much less is known about how they assemble and whether stable and functional sub-modules exist that retain enzymatic activity. Purification of the endogenous Drosophila NuRD complex shows that it consists of a stable core of subunits, while others, in particular the chromatin remodeler CHD4, associate transiently. To dissect the assembly and activity of NuRD, we systematically produced all possible combinations of different components using the MultiBac system, and determined their activity and biophysical properties. We carried out single-molecule imaging of CHD4 in live mouse embryonic stem cells, in the presence and absence of one of core components (MBD3), to show how the core deacetylase and chromatin-remodeling sub-modules associate in vivo. Our experiments suggest a pathway for the assembly of NuRD via preformed and active sub-modules. These retain enzymatic activity and are present in both the nucleus and the cytosol, an outcome with important implications for understanding NuRD function.

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We have studied Drosophila nucleosome remodeling deacetylase (NuRD) assembly.

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NuRD consists of a core deacetylase complex, where MTA-like acts as the scaffold.

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This transiently associates with a chromatin remodeling sub-module including CHD4.

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Single-molecule imaging shows that the two sub-modules associate through MBD-like.

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NuRD comprises catalytically active sub-modules in both the cytosol and the nucleus.

Nutritional n-3 PUFAs deficiency during perinatal periods alters brain innate immune system and neuronal plasticity-associated genes

Low dietary intake of the n-3 polyunsaturated fatty acids (PUFAs) is a causative factor of neurodevelopmental disorders. However the mechanisms linking n-3 PUFAs low dietary intake and neurodevelopmental disorders are poorly understood. Microglia, known mainly for their immune function in the injured or infected brain, have recently been demonstrated to play a pivotal role in regulating maturation of neuronal circuits during normal brain development. Disruption of this role during the perinatal period therefore could significantly contribute to psychopathologies with a neurodevelopmental neurodevelopmental component. N-3 PUFAs, essential lipids and key structural components of neuronal membrane phospholipids, are highly incorporated in cell membranes during the gestation and lactation phase. We previously showed that in a context of perinatal n-3 PUFAs deficiency, accretion of these latter is decreased and this is correlated to an alteration of endotoxin-induced inflammatory response. We thus postulated that dietary n-3 PUFAs imbalance alters the activity of microglia in the developing brain, leading to abnormal formation of neuronal networks. We first confirmed that mice fed with a n-3 PUFAs deficient diet displayed decreased n-3 PUFAs levels in the brain at post-natal days (PND)0 and PND21. We then demonstrated that n-3 PUFAs deficiency altered microglia phenotype and motility in the post-natal developing brain. This was paralleled by an increase in pro-inflammatory cytokines expression at PND21 and to modification of neuronal plasticity-related genes expression. Overall, our findings show for the first time that a dietary n-3 PUFAs deficiency from the first day of gestation leads to the development of a pro-inflammatory condition in the central nervous system that may contribute to neurodevelopmental alterations.

Early morphofunctional plasticity of microglia in response to acute lipopolysaccharide

Within the central nervous system (CNS) the traditional role of microglia has been in brain infection and disease, phagocytosing debris and secreting factors to modify disease progression. This led to the concept of "resting" versus "activated" microglia. However, this is misleading because multiple phenotypic and morphological stages of microglia can influence neuronal structure and function in any condition and recent evidence extends their role to healthy brain homeostasis. The present work was thus aimed at reappraising the concept of morphofunctional activity of microglia in a context of peripheral acute immune challenge, where microglial activity is known to be modified, using the new state-of-the-art techniques available. To do so, mice were injected peripherally with lipopolysaccharide, a potent inducer of cerebral inflammation, and we assessed early cytokines production, phenotype, motility and morphology of microglial cells. Our results showed that LPS induced a widespread inflammatory response both peripherally and centrally, as revealed by the quantification of cytokines levels. We also found an alteration of microglial motility that was confirmed by in vivo studies showing an overall reduction of microglial processes length in the hippocampus of LPS-treated animals. Finally, analysis of various surface receptors expression revealed that LPS did not significantly impact microglial phenotype 2h after the injection but rather induced an increase of CD11b(+)/CD45(high) cells. These latter may be at the vasculature, at the CNS vicinity, or may have invaded the CNS.

Endoscopic ultrasound-guided fine-needle aspiration biopsy coupled with KRAS mutation assay to distinguish pancreatic cancer from pseudotumoral chronic pancreatitis

BACKGROUND AND STUDY AIMS

Differential diagnosis between pancreatic adenocarcinoma (PADC) and pseudotumoral forms of chronic pancreatitis remains difficult. Mutation of KRAS oncogene is present in 75% to 95% of PADC. This study aimed to evaluate whether the combined analysis of KRAS mutation with cytopathological findings from endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) might improve discrimination between PADC and chronic pancreatitis.

PATIENTS AND METHODS

This prospective multicenter study included 178 patients with solid pancreatic masses (men 104, women 74; mean age 64.5 years). Cytopathological examination and KRAS mutation analysis (codon-12 and codon-13, restriction fragment length polymorphism [RFLP] and direct sequencing) were performed on EUS-FNAB material. Final diagnoses were obtained on EUS-FNAB analysis and/or a second biopsy and/or clinical follow-up and/or surgery: PADC, n = 129; chronic pancreatitis, n = 27; other pancreatic neoplasms, n = 16; and benign lesions, n = 6.

RESULTS

KRAS status analysis was successful in all EUS-FNAB samples. Codon-12 KRAS point mutation was found in 66% of PADC samples. No case of chronic pancreatitis displayed KRAS mutation. Sensitivity, specificity, positive and negative predictive values, and overall accuracy of cytopathology alone for diagnosis of PADC versus chronic pancreatitis were 83%, 100%, 100%, 56% and 86%, respectively. When KRAS mutation analysis was combined with cytopathology, these values reached 88%, 100%, 100%, 63% and 90% respectively.

CONCLUSION

Although the value of KRAS analysis in addition to EUS-FNAB is limited for distinguishing pancreatic mass lesions, when chronic pancreatitis presented as a pseudotumor a negative finding (wild-type KRAS), was useful in strongly suggesting a benign lesion.

Modulation of social interactions by immune stimulation in honey bee, Apis mellifera, workers

Background

Immune response pathways have been relatively well-conserved across animal species, with similar systems in both mammals and invertebrates. Interestingly, honey bees have substantially reduced numbers of genes associated with immune function compared with solitary insect species. However, social species such as honey bees provide an excellent environment for pathogen or parasite transmission with controlled environmental conditions in the hive, high population densities, and frequent interactions. This suggests that honey bees may have developed complementary mechanisms, such as behavioral modifications, to deal with disease.

Results

Here, we demonstrate that activation of the immune system in honey bees (using bacterial lipopolysaccharides as a non-replicative pathogen) alters the social responses of healthy nestmates toward the treated individuals. Furthermore, treated individuals expressed significant differences in overall cuticular hydrocarbon profiles compared with controls. Finally, coating healthy individuals with extracts containing cuticular hydrocarbons of immunostimulated individuals significantly increased the agonistic responses of nestmates.

Conclusion

Since cuticular hydrocarbons play a critical role in nestmate recognition and other social interactions in a wide variety of insect species, modulation of such chemical profiles by the activation of the immune system could play a crucial role in the social regulation of pathogen dissemination within the colony.

Social management of LPS-induced inflammation in Formica polyctena ants

Invertebrates, and especially insects, constitute valuable and convenient models for the study of the evolutionary roots of immune-related behaviors. With stable conditions in the nest, high population densities, and frequent interactions, social insects such as ants provide an excellent system for examining the spread of pathogens. The evolutionary success of these species raises questions about the behavioral responses of social insects to an infected nestmate. In this experiment, we tested the behavioral changes of the red wood ant Formica polyctena toward an immune-stimulated nestmate. We used bacterial endotoxin (lipopolysaccharides, LPS) to active the innate immune system of individual worker ants without biasing our observation with possible cues or host-manipulation from a living pathogen. We show that LPS-induced immune activation in ants triggers behavioral changes in nestmates. Contrary to what would be expected, we did not find removal strategies (e.g. agonistic behaviors) or avoidance of the pathogenic source, but rather a balance between a limitation of pathogen dissemination (i.e. decreased trophallaxis and locomotion of the LPS-treated ant), and what could constitute the behavioral basis for a "social vaccination" (i.e. increased grooming). This supports the importance of social interactions in resistance to disease in social insects, and perhaps social animals in general.

Comorbidities and Charlson score in resected stage I nonsmall cell lung cancer

Patients with nonsmall cell lung cancer (NSCLC) have been shown to have a higher prevalence of comorbidity associated with age and tobacco consumption. The objective of the present study was to determine the impact of comorbidity on survival after surgery of stage I NSCLC. In total, 588 consecutive patients operated on for a pathological stage I NSCLC between January 1, 1979 and December 31, 2003 were studied. Comorbidities were analysed individually. Overall comorbidity was assessed using the Charlson index of comorbidity (CCI). Survival data were collected for each patient from the date of operation, with a median duration of follow-up of 104 months. Survival analyses and Cox proportional hazards model analyses were used. The mean age of patients was 62.7 yrs, and 529 (89%) patients were male. The distribution of overall comorbidity severity was as follows. CCI grade 0: 47.1%; grade 1-2: 43.7%; grade 3-4: 8.3%; and grade > or =5: 0.8%. The 2, 3 and 5 yrs survival were 69, 62 and 50%, respectively. Multivariable analysis showed that T stage, age, a concomitant history of moderate-to-severe liver disease, a past history of cured cancer, cerebrovascular disease and CCI were independent predictors of survival (Hazard Ratio for CCI grade >2: 1.81; 95% confidence interval 1.25-2.63). In conclusion, comorbidity has a significant impact on survival after surgical resection of patients with stage I nonsmall cell lung cancer. The use of a validated index of comorbidity in prognostic analyses of resected nonsmall cell lung cancer is recommended.

Protection against Leptospira interrogans sensu lato challenge by DNA immunization with the gene encoding hemolysin-associated protein 1

The use of DNA constructs encoding leptospiral proteins is a promising new approach for vaccination against leptospirosis. In previous work we determined that immunization with hemolysis-associated protein 1 (Hap1) (LipL32) expressed by adenovirus induced significant protection against a virulent Leptospira challenge in gerbils. To avoid the use of the adenovirus vector, we checked for clinical protection against lethal challenge by DNA vaccination. A DNA vaccine expressing Hap1 was designed to enhance the direct gene transfer of this protein into gerbils. A challenge was performed 3 weeks after the last immunization with a virulent strain of serovar canicola. Our results show that the cross-protective effect with pathogenic strains of Leptospira, shared by Hap1, could be mediated by the DNA plasmid vector. This finding should facilitate the design and development of a new generation of vaccines against bacteria, particularly Leptospira interrogans sensu lato.

Ethological validation and the assessment of anxiety-like behaviours: methodological comparison of classical analyses and structural approaches

The research on emotional reactivity usually implies the use of standardised behavioural tests that provide a quick idea of the effect of a treatment on the reactivity of subjects to potentially dangerous situations. Many validity criteria have been considered to evaluate these tests. This validity concept supports the idea that animals' behaviour in these tests model human anxiety. Generally, those criteria repeatedly labelled as "ethological validation" refer to the analogy between animals and human in the meaning of the test situation. Although the content of the ethological validation concept is heterogeneous, it is steadily related to a fixed interpretation of the behavioural items produced in a given experimental setting. The basic assumption of such reasoning is that the behavioural items would always be expressed in the same behavioural context whatever the subject, its gender, strain or species, thoroughly asserting a predefined subjective state. Using multivariate and textual analysis, we found evidence that the "ethological validation" recourse to an a priori interpretation for a given behavioural variable may be deceptive. We defend the idea that the meaning of a behavioural variable should be restricted to the general context where it arose. Theoretical propositions and methodological options are discussed.

Susceptibility to subchronic unpredictable stress is related to individual reactivity to threat stimuli in mice

As in many complex behavioral responses, inter-individual variability can be observed in the responses to a chronic mild stress. While some subjects exhibit more resilient behaviours, others appear more susceptible to stress. This study hypothesizes that this variability relies on the individual appraisal of the stressful event. To study this assumption, mice were first subjected to a conditioned task occurring in a circular arena. In this task, a mild air-puff (i.e. stressor) in a given quadrant of the arena was coupled with the presence or the absence of a light in the same quadrant. Half of mice were then submitted to a 15-day subchronic stress consisting in various environmental and social mild stressors randomly applied two or three times a day. At the end of this procedure, the occurrence of depressive-like behaviours in stressed mice was assessed using measures of the stress regime (i.e. physical state, choice test, grooming test). The physical state assessed the physical appearance of mice. The grooming test consisted in measuring the time spent in grooming after mice were sprayed upon with a viscous solution. The choice test consisted in measuring the time spent in an uncomfortable place (i.e. whose floor was covered with damp sawdust) versus a more comfortable one (i.e. with dry sawdust) to evaluate the reactivity to a negative stimulus previously encountered during the subchronic stress. Multiple regression analyses revealed a relationship between attention toward salient stressful stimuli in the conditioned task and susceptibility to the subchronic stress procedure. These results are discussed regarding their relevance for the understanding of aetiologies of depressive illnesses.

Modelling of the coupling between brain electrical activity and metabolism

In order to make an attempt at grouping the various aspects of brain functional imaging (fMRI, MRS, EEG-MEG, ...) within a coherent frame, we implemented a model consisting of a system of differential equations, that includes: (1) sodium membrane transport, (2) Na/K ATPase, (3) neuronal energy metabolism (i.e. glycolysis, buffering effect of phosphocreatine, and mitochondrial respiration), (4) blood-brain barrier exchanges and (5) brain hemodynamics, all the processes which are involved in the activation of brain areas. We assumed that the correlation between brain activation and metabolism could be due to either changes in the concentrations of ATP and ADP following activation of Na/K ATPase that result from the changes in ion concentrations, or the involvement, in different phases of metabolism, of a second messenger such as calcium. In this article, we show how this type of model enables interpretation of MRS and fMRI published data that were obtained during prolonged stimulations.

Identification of the hemolysis-associated protein 1 as a cross-protective immunogen of Leptospira interrogans by adenovirus-mediated vaccination

New vaccine strategies are needed for the prevention of leptospirosis, a widespread human and animal disease caused by pathogenic leptospires. Our previous work determined that a protein leptospiral extract conferred cross-protection in a gerbil model of leptospirosis. The 31- to 34-kDa protein fraction of Leptospira interrogans serovar autumnalis was shown sufficient for this purpose. In the present study, N-terminal sequencing of a 32-kDa fraction and Southern blotting of genomic DNA with corresponding degenerated oligonucleotide probes identified two of its constituents: hemolysis-associated protein 1 (Hap1) and the outer membrane Leptospira protein 1 (OmpL1). Adenovirus-mediated Hap1 vaccination induces significant protection against a virulent heterologous Leptospira challenge in gerbils, whereas a similar OmpL1 construct failed to protect the animals. These data indicate that Hap1 could be a good candidate for developing a new generation of vaccines able to induce broad protection against leptospirosis disease.

Hes1 and Hes5 activities are required for the normal development of the hair cells in the mammalian inner ear

The mammalian inner ear contains two sensory organs, the cochlea and vestibule. Their sensory neuroepithelia are characterized by a mosaic of hair cells and supporting cells. Cochlear hair cells differentiate in four rows: a single row of inner hair cells (IHCs) and three rows of outer hair cells (OHCs). Recent studies have shown that Math1, a mammalian homolog of Drosophila atonal is a positive regulator of hair cell differentiation. The basic helix-loop-helix (bHLH) genes Hes1 and Hes5 (mammalian hairy and Enhancer-of-split homologs) can influence cell fate determination by acting as negative regulators to inhibit the action of bHLH-positive regulators. We show by using reverse transcription-PCR analysis that Hes1, Hes5, and Math1 are expressed in the developing mouse cochleae. In situ hybridization revealed a widespread expression of Hes1 in the greater epithelial ridge (GER) and in lesser epithelial ridge (LER) regions. Hes5 is predominantly expressed in the LER, in supporting cells, and in a narrow band of cells within the GER. Examination of cochleae from Hes1(-/-) mice showed a significant increase in the number of IHCs, whereas cochleae from Hes5(-/-) mice showed a significant increase in the number of OHCs. In the vestibular system, targeted deletion of Hes1 and to a lesser extent Hes5 lead to formation of supernumerary hair cells in the saccule and utricle. The supernumerary hair cells in the mutant mice showed an upregulation of Math1. These data indicate that Hes1 and Hes5 participate together for the control of inner ear hair cell production, likely through the negative regulation of Math1.

[Fascioliasis of the common bile duct: endoscopic ultrasonographic diagnosis and endoscopic sphincterotomy]

Two cases of biliary fasciolasis are reported. The patients presented with biliary pain and/or acute pancreatitis. Pre-operative ultrasound endoscopy showed main bile duct dilation and linear elongated echogenic structures in the common bile duct lumen. Endoscopic retrograde cholangiography and endoscopic sphincterotomy were performed. Parasites were endoscopically removed resulting in disappearance of symptoms and biological abnormalities. Serological tests and pathological examination confirmed the presence of Fasciola hepatica. During follow-up, stool examination failed to show any Fasciola hepatica eggs, and in one case, serology became negative. This report emphasizes the value of ultrasound endoscopy in the diagnosis of unsuspected biliary fasciolasis. This report also confirms the therapeutic role of endoscopic sphincterotomy in patients with obstructive biliary fasciolasis.

Assessment of complications of EUS-guided fine-needle aspiration

BACKGROUND

EUS-guided fine-needle aspiration (EUS-FNA) permits both morphologic and cytologic analysis of lesions within or adjacent to the GI tract. Despite increasing use of this technique, the safety and overall complication rates remain poorly defined.

METHODS

During a period of 20 months, 322 consecutive patients underwent EUS-FNA in 2 centers. All procedures were performed with the patients under general anesthesia. All complications (including local complications resulting from endoscopy/aspiration or clinical complications after the procedure) were evaluated. Potential risk factors for the development of complications were also analyzed including site and nature of the lesion, presence of portal hypertension, and number of needle passes.

RESULTS

A total of 345 lesions were aspirated in 322 patients. EUS-FNA involved the pancreas in 248 cases. Pancreatic lesions included solid (134) and cystic (114) types, which required a mean of 2.5 and 1.4 needle passes, respectively. Complications were observed in 4 (1.2%) patients after aspiration of pancreatic cystic lesions (acute pancreatitis, n = 3; aspiration pneumonia, n = 1) and all cases of pancreatitis resulted from FNA of lesions in the head/uncinate process. No complications resulted from FNA of solid pancreatic lesions. Complications were not observed after FNA of lymph nodes (n = 62) and one case of aspiration pneumonia was observed after FNA of a stromal tumor. EUS-FNA was performed without complication in 16 patients (5%) with portal hypertension. The number of needle passes was not predictive of complications.

CONCLUSIONS

Because the overall risk of complications from EUS-FNA was relatively low (1.6%) with no severe or fatal incidents and although the risk appears slightly higher than that for standard EUS alone, the safety of EUS-FNA appears acceptable based on this analysis from an experienced center.

Immunization of cats against feline immunodeficiency virus (FIV) infection by using minimalistic immunogenic defined gene expression vector vaccines expressing FIV gp140 alone or with feline interleukin-12 (IL-12), IL-16, or a CpG motif

Four groups of cats, each containing four animals, were immunized at 0, 3, and 6 weeks with minimalistic immunogenic defined gene expression vector (MIDGE) vaccines containing the gene(s) for feline immunodeficiency virus (FIV) gp140, FIV gp140 and feline interleukin-12 (IL-12), FIV gp140 and feline IL-16, or FIV gp140 and a CpG motif. MIDGEs were coated onto gold beads and injected intradermally with a gene gun. A fifth group of four cats were immunized in an identical manner but with blank gold beads. All cats were challenge exposed to virulent FIV 4 weeks following the final immunization, and the course of infection was monitored. The two groups of cats immunized with the FIV gp140 gene alone or with blank gold particles became highly viremic and seroconverted as early as 4 weeks after infection. In contrast, three of four cats immunized with FIV gp140 in combination with feline IL-12 failed to become viremic or seropositive, as has been shown elsewhere (F. S. Boretti, C. M. Leutenegger, C. Mislin, et al., AIDS 14:1749-1757, 2000). Here we show the effect of IL-12 when used as an adjuvant on the viral RNA and DNA load and on the cytokine profile. In addition, the two groups of cats immunized either with gp140 and IL-16 or with gp140 and the CpG had greatly reduced viremia. Protection correlated weakly with cytotoxic T-lymphocyte activity and increased cytokine transcription of IL-12, gamma interferon, and IL-10 by peripheral blood mononuclear cells in the postchallenge period. This study extends the data on IL-12 and provides new results on CpG motifs and IL-16 used as adjuvants in the FIV cat model.

Protection against FIV challenge infection by genetic vaccination using minimalistic DNA constructs for FIV env gene and feline IL-12 expression

OBJECTIVE

To evaluate the efficacy of a genetic vaccination protocol based on minimalistic, immunogenic defined gene expression (MIDGE) vectors coding for domains of the feline immunodeficiency virus (FIV) env gene and feline IL-12.

METHODS

Three groups of four cats each were immunized three times within 6 weeks by the ballistic transfer of gold particles coated with MIDGE vectors. Group 1 received non-coated gold beads, groups 2 and 3 MIDGE vectors expressing FIV surface plus part of the transmembrane protein. In addition, group 3 received feline IL-12 DNA. All cats were challenged by intraperitoneal injection of 25 TCID50 of infectious FIV Z2. The following criteria were monitored: clinical signs, antibodies to transmembrane protein, antibodies to whole FIV, haematological parameters and kinetics of CD4 and CD8 cells, FIV proviral load (determined by quantitative polymerase chain reaction; PCR) and cytotoxic T lymphocyte (CTL) activity (in selected cats).

RESULTS

None of the cats developed a detectable antibody response during immunizations. Four weeks after challenge exposure, all cats in group 1 (control) and group 2 (FIV surface-transmembrane protein) had seroconverted and showed a high proviral load until week 19 (end of experiment). In contrast, only one of four cats in group 3 (surface-transmembrane protein and IL-12) showed antibodies; it was provirus positive at reduced virus load. Short-lived CTL activity was found in two cats in group 3.

CONCLUSION

Genetic vaccination using a MIDGE-based construct for the expression of the surface-transmembrane protein domain of FIV env and feline IL-12 DNA led to protection against homologous virus challenge in three out of four vaccinated cats.

Chest wall implantation of a mediastinal liposarcoma after thoracoscopy

We report a case of mediastinal liposarcoma resected by thoracoscopy. Despite the precautionary measures, chest wall implantations occurred rapidly at the port's sites in the chest wall and led to death within 24 months. We conclude that thoracoscopy is not a good approach for resection of anterior mediastinal masses in view of their possible malignant character.

Vaccination with feline immunodeficiency virus induces CD4 epitope masking by soluble factors

Soluble factors are important effector mechanisms to control for lentiviral replication. Vaccination of cats with recombinant outer surface proteins (SU) of the FIV envelope protein in combination with complete Freund adjuvant (CFA) and rabies nucleocapsid (NC) protein led to significantly reduced viral loads [Leutenegger, C.M., Hofmann-Lehmann, R., Holznagel, E., Cuisinier, A.M., Wolfensberger, C., Duquesne, V., Cronier, J., Allenspach, K., Aubert, A., Ossent, P. , Lutz, H., 1998. AIDS Res. Hum. Retroviruses, 14(3) 275-283]. Lymphocytes from vaccinated and non-vaccinated cats were stained with two monoclonal antibodies, Fel7 and CAT30A, directed against the feline CD4 antigen. Peripheral blood lymphocytes from cats vaccinated with the SU glycoprotein, CFA and rabies NC protein showed a significantly reduced number of cells after staining with CAT30A, while the number in Fel7 positive lymphocytes remained unchanged. This decreased CAT30A fluorescent staining could be reproduced in vitro by pre-incubating FIV-negative lymphocytes with immune sera from cats in which reduced CAT30A staining was detected. Neither experimental infection nor vaccination with the unglycosylated SU protein alone resulted in this epitope masking. Furthermore, this masking phenomenon was negatively correlated with a decreased susceptibility to activation-induced cell death (AICD). These findings will be discussed based on the current knowledge of CD8(+) T-cell antiviral factors and their involvement in lentiviral infection and/or replication.

Vaccination of Tunisian dogs with the lyophilised SAG2 oral rabies vaccine incorporated into the DBL2 dog bait

The protective effect of the lyophilised SAG2 oral vaccine bait DBL2, already demonstrated on laboratory dogs, needed to be verified on common Tunisian dogs. Seven Tunisian dogs consumed totally or partially one DBL2 bait containing 10(8.3) TCID50 of the highly attenuated rabies vaccine strain, SAG2. Five of the seven vaccinated animals survived a challenge administered 33 days later with a Tunisian canine street rabies virus to which five of the six controls that were not vaccinated and had no specific antibodies succumbed. The partial or total consumption of a single DBL2 bait thus conferred a protective immune response similar to that observed in laboratory dogs to dogs of poor health status. The sero-antibody response was, however, weak: only two vaccinated dogs exhibited a significant neutralising antibody response after vaccination and before the challenge, and four after the challenge.