Analysis of Notch1 signaling in mammalian sperm development

OBJECTIVE

A mammalian Delta-Notch signaling component, Notch1, has been suggested for its expression during the normal sperm development although its conditional deletion caused no apparent abnormalities. Since we established our original transgenic mouse system that enabled labeling of past and ongoing Notch1 signaling at a cellular level, we tried to validate that observation in vivo. Our transgenic mouse system used Cre/loxP system to induce tandem dsRed expression upon Notch1 signaling.

RESULTS

To our surprise, we were unable to observe tandem dsRed expression in the seminiferous tubules where the sperms developed. In addition, tandem dsRed expression was lacking in the somatic cells of the next generation in our transgenic mouse system, suggesting that sperms received no Notch1 signaling during their development. To validate this result, we conducted re-analysis of four single-cell RNA-seq datasets from mouse and human testes and showed that Notch1 expression was little in the sperm cell lineage. Collectively, our results posed a question into the involvement of Notch1 in the normal sperm development although this observation may help the interpretation of the previous result that Notch1 conditional deletion caused no apparent abnormalities in murine spermatogenesis.

Cu segregation in Au-Cu nanoparticles exposed to hydrogen atmospheric pressure: how is fcc symmetry maintained?

In a recent work [A. Nassereddine et al., Small 2021, 17, 2104571] we reported the atomic-scale structure and dynamics of sub-4 nm sized Au nanoparticles (NPs) supported on titania in H₂ at atmospheric pressure obtained by using aberration-corrected environmental transmission electron microscopy (ETEM), density functional theory (DFT) optimizations and ab initio molecular dynamic (AIMD) simulations. Our results showed unstable Au NPs losing their face-centred cubic (fcc) symmetry (from fcc to non-fcc symmetries) and revealed the drastic effect of hydrogen adsorption. In this work, we use the same approach to study the dynamics of equiatomic Au-Cu NPs in the same range of size and the results show an enhanced structural stability upon alloying by Cu. In spite of the morphology evolution from facetted to rounded shapes, the observed Au-Cu NPs are found to keep their fcc symmetry under atmospheric hydrogen pressure. AIMD simulation evidences a Cu segregation process from the sub-surface toward the upper surface layer, and a reversed segregation of Au atoms from the surface towards the sub-surface sites. The analysis of the chemical ordering in the core shows a tendency to a local chemical ordering where Au-Cu hetero-atomic bindings are favoured. The segregating Cu seems to play a major role in reducing the fluxionality of Au-Cu NPs in H₂ and thus, maintaining their fcc symmetry.

Juno Plasma Wave Observations at Ganymede

The Juno Waves instrument measured plasma waves associated with Ganymede's magnetosphere during its flyby on 7 June, day 158, 2021. Three distinct regions were identified including a wake, and nightside and dayside regions in the magnetosphere distinguished by their electron densities and associated variability. The magnetosphere includes electron cyclotron harmonic emissions including a band at the upper hybrid frequency, as well as whistler-mode chorus and hiss. These waves likely interact with energetic electrons in Ganymede's magnetosphere by pitch angle scattering and/or accelerating the electrons. The wake is accentuated by low-frequency turbulence and electrostatic solitary waves. Radio emissions observed before and after the flyby likely have their source in Ganymede's magnetosphere.

Magnetosphere-Ionosphere-Thermosphere Coupling Study at Jupiter Based on Juno's First 30 Orbits and Modeling Tools

The dynamics of the Jovian magnetosphere is controlled by the interplay of the planet's fast rotation, its solar-wind interaction and its main plasma source at the Io torus, mediated by coupling processes involving its magnetosphere, ionosphere, and thermosphere. At the ionospheric level, these processes can be characterized by a set of parameters including conductances, field-aligned currents, horizontal currents, electric fields, transport of charged particles along field lines including the fluxes of electrons precipitating into the upper atmosphere which trigger auroral emissions, and the particle and Joule heating power dissipation rates into the upper atmosphere. Determination of these key parameters makes it possible to estimate the net transfer of momentum and energy between Jovian upper atmosphere and equatorial magnetosphere. A method based on a combined use of Juno multi-instrument data and three modeling tools was developed by Wang et al. (2021, https://doi.org/10.1029/2021ja029469) and applied to an analysis of the first nine orbits to retrieve these parameters along Juno's magnetic footprint. We extend this method to the first 30 Juno science orbits and to both hemispheres. Our results reveal a large variability of these parameters from orbit to orbit and between the two hemispheres. They also show dominant trends. Southern current systems are consistent with the generation of a region of sub-corotating ionospheric plasma flows, while both super-corotating and sub-corotating plasma flows are found in the north. These results are discussed in light of the previous space and ground-based observations and currently available models of plasma convection and current systems, and their implications are assessed.

Synergistic enhancing-memory effect of donepezil and S 47445, an AMPA positive allosteric modulator, in middle-aged and aged mice

Positive allosteric modulators of AMPA receptors (AMPA-PAMs) are described to facilitate cognitive processes in different memory-based models. Among them, S 47445 is a novel potent and selective AMPA-PAM. In order to assess its efficacy after repeated administration, S 47445 effect was evaluated in two aging-induced memory dysfunction tasks in old mice, one short-term working memory model evaluated in a radial maze task and one assessing contextual memory performance. S 47445 was shown to improve cognition in both models sensitive to aging. In fact, administration of S 47445 at 0.3 mg/kg (s.c.) reversed the age-induced deficits of the working memory model whatever the retention interval. Moreover, in the contextual task, S 47445 also reversed the age-induced deficit at all tested doses (from 0.03 to 0.3 mg/kg, p.o.). Since donepezil, an acetylcholinesterase inhibitor, induces only moderate symptomatic effects on memory in Alzheimer's disease patients, an alternative strategy for treatment of cognitive symptoms could be to act simultaneously on both glutamatergic AMPA receptors and cholinergic pathways by combining pharmacological treatments. The present study further examined such effects by assessing combinations of S 47445 and donepezil given orally during 9 days in aged C57/Bl6J mice using contextual memory task (CSD) and the working memory model of serial alternation task (AT). Interestingly, a significant synergistic memory-enhancing effect was observed with the combination of donepezil at 0.1 mg/kg with S 47445 at 0.1 mg/kg p.o. in the CSD or with S 47445 at 0.1 and 0.3 mg/kg in AT in comparison to compounds given alone and without any pharmacokinetic interaction.

[Not Available]

PURPOSE OF THE STUDY

To evaluate the efficacy of fractionated stereotactic reirradiation with CyberKnife (CK) performed in 6 patients with high grade gliomas treated in Luxembourg with local recurrence (LR).

PATIENTS AND METHODS

Between 04.2014 and 06.2016, 6 patients with multiform grade IV gliomas LR were reirradiated with CK (protocol CNER re-RT CFB 1), as reirradiation. The mean time between primary radiotherapy and local recurrence (LR) is 14.1 months [4 - 38]. CK is performed with a dose of 36 Gy in 6 fractions (5 cases) and 30 Gy in 3 fractions (1 case) Results : LR after CK (progression free survival) is 3.4 months [2 - 7] (5 cases assessment). Mean survival after CK is 12 months [3 - 22] (3 cases assessment). Mean survival after initial diagnosis is 37 months [17 - 58] (3 cases assessment). No toxicity is noticed (4 cases assessment). Time to first progression after primary treatment is a strong predictor for survival. Fractionated stereotactic reirradiation with CK is well tolerated and effective (survival) in patients with LR high grade gliomas. In accordance with these results, the CFB Conseil Scientifique recommends a new paradigm for MRI follow-up high grade gliomas. After first line treatment, an MRI has to be performed every 3 months, to identify LR earlier, and to offer the patients a way of salvage with CK option, in order to increase his chances of better survival.

A new ER-specific photosensitizer unravels (1)O2-driven protein oxidation and inhibition of deubiquitinases as a generic mechanism for cancer PDT

Photosensitizers (PS) are ideally devoid of any activity in the absence of photoactivation, and rely on molecular oxygen for the formation of singlet oxygen ((1)O2) to produce cellular damage. Off-targets and tumor hypoxia therefore represent obstacles for the use of PS for cancer photodynamic therapy. Herein, we describe the characterization of OR141, a benzophenazine compound identified through a phenotypic screening for its capacity to be strictly activated by light and to kill a large variety of tumor cells under both normoxia and hypoxia. This new class of PS unraveled an unsuspected common mechanism of action for PS that involves the combined inhibition of the mammalian target of rapamycin (mTOR) signaling pathway and proteasomal deubiquitinases (DUBs) USP14 and UCH37. Oxidation of mTOR and other endoplasmic reticulum (ER)-associated proteins drives the early formation of high molecular weight (MW) complexes of multimeric proteins, the concomitant blockade of DUBs preventing their degradation and precipitating cell death. Furthermore, we validated the antitumor effects of OR141 in vivo and documented its highly selective accumulation in the ER, further increasing the ER stress resulting from (1)O2 generation upon light activation.

Oleate Abrogates Palmitate-Induced Lipotoxicity and Proinflammatory Response in Human Bone Marrow-Derived Mesenchymal Stem Cells and Osteoblastic Cells

Osteoporosis is a metabolic bone disease associated with unequilibrated bone remodeling resulting from decreased bone formation and/or increased bone resorption, leading to progressive bone loss. In osteoporotic patients, low bone mass is associated with an increase of bone marrow fat resulting from accumulation of adipocytes within the bone marrow. Marrow adipocytes are active secretory cells, releasing cytokines, adipokines and free fatty acids (FA) that influence the bone marrow microenvironment and alter the biology of neighboring cells. Therefore, we examined the effect of palmitate (Palm) and oleate (Ole), 2 highly prevalent FA in human organism and diet, on the function and survival of human mesenchymal stem cells (MSC) and MSC-derived osteoblastic cells. The saturated FA Palm exerted a cytotoxic action via initiation of endoplasmic reticulum stress and activation of the nuclear factor κB (NF-κB) and ERK pathways. In addition, Palm induced a proinflammatory response, as determined by the up-regulation of Toll-like receptor 4 expression as well as the increase of IL-6 and IL-8 expression and secretion. Moreover, we showed that MSC-derived osteoblastic cells were more sensitive to lipotoxicity than undifferentiated MSC. The monounsaturated FA Ole fully neutralized Palm-induced lipotoxicity by impairing activation of the pathways triggered by the saturated FA. Moreover, Ole promoted Palm detoxification by fostering its esterification into triglycerides and storage in lipid droplets. Altogether, our data showed that physiological concentrations of Palm and Ole differently modulated cell death and function in bone cells. We therefore propose that FA could influence skeletal health.

The use of theranostic gadolinium-based nanoprobes to improve radiotherapy efficacy

A new efficient type of gadolinium-based theranostic agent (AGuIX®) has recently been developed for MRI-guided radiotherapy (RT). These new particles consist of a polysiloxane network surrounded by a number of gadolinium chelates, usually 10. Owing to their small size (<5 nm), AGuIX typically exhibit biodistributions that are almost ideal for diagnostic and therapeutic purposes. For example, although a significant proportion of these particles accumulate in tumours, the remainder is rapidly eliminated by the renal route. In addition, in the absence of irradiation, the nanoparticles are well tolerated even at very high dose (10 times more than the dose used for mouse treatment). AGuIX particles have been proven to act as efficient radiosensitizers in a large variety of experimental in vitro scenarios, including different radioresistant cell lines, irradiation energies and radiation sources (sensitizing enhancement ratio ranging from 1.1 to 2.5). Pre-clinical studies have also demonstrated the impact of these particles on different heterotopic and orthotopic tumours, with both intratumoural or intravenous injection routes. A significant therapeutical effect has been observed in all contexts. Furthermore, MRI monitoring was proven to efficiently aid in determining a RT protocol and assessing tumour evolution following treatment. The usual theoretical models, based on energy attenuation and macroscopic dose enhancement, cannot account for all the results that have been obtained. Only theoretical models, which take into account the Auger electron cascades that occur between the different atoms constituting the particle and the related high radical concentrations in the vicinity of the particle, provide an explanation for the complex cell damage and death observed.

[Long-term fever after gastric banding]

We report a 65-year-old male, suffering from aspiration pneumonia after gastric banding revealed by intermittent fever inducing a delayed diagnosis. Several early and later pulmonary complications following laparoscopic gastric banding have been reported. Removal or deflation of the band should be considered in unexplained persistent fever to avoid more severe complications such as respiratory distress.

Effects of positive modulators of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors in a benzodiazepine-induced deficit of spatial discrimination in mice

Imbalance between GABAergic and glutamatergic neurotransmission has been recently hypothesized to trigger memory decline related either to ageing or to Alzheimer's disease (AD). Thereby, benzodiazepine-induced anterograde amnesia has been construed as a model of hippocampal-related cognitive dysfunctions. Since spatial memory is altered both by ageing and by benzodiazepines such as alprazolam, we investigated the pharmacological sensitivity of alprazolam-induced deficit in a delayed spatial discrimination (SD) task, notably with positive allosteric modulators of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors. We showed that alprazolam (0.1 mg/kg intraperitoneally) induced memory impairments as compared with vehicle-treated mice. The oral administration of modulators of AMPA receptors (IDRA-21: 10 mg/kg; S18986: 3 and 10 mg/kg) reversed the alprazolam-induced deficits. This study is first to show evidence that reference treatments of AD, such as memantine (a NMDA receptor antagonist) at 3 mg/kg per os (po) and donepezil (an acetylcholinesterase inhibitor) at 1 mg/kg po, also reversed the alprazolam-induced amnesia. Given such results, the SD task emerges as a valuable novel task to screen pro-cognitive compounds. Thus, we highlight the efficacy of modulators of AMPA-type glutamate receptors to counteract alprazolam-induced spatial deficits. These results could be viewed alongside the imbalance between excitation and inhibition observed during normal and pathological ageing.

Stereotactic radiotherapy of hepatocellular carcinoma: preliminary results

Stereotactic radiotherapy (SRT) offers a treatment option for hepatocellular carcinoma (HCC) patients that are not eligible for surgery, embolization, chemotherapy, or radiofrequency ablation. We have evaluated the feasibility, tolerance and toxicity of SRT for 25 HCC patients who were not eligible for these other modalities. The patients (6 women and 19 men) were treated with CyberKnife stereotactic radiotherapy using respiratory motion tracking. All patients had liver cirrhosis with an Eastern Cooperative Oncology Group (ECOG) performance score of less than 2 and pre-treatment Child scores ranging from A5 to B9. A total dose of 45 Gy in three fractions of 15 Gy each was prescribed to the 80% isodose line (95% of the PTV received 45 Gy) and delivered to the target volume over 10 to 12 days. Overall the treatment was well tolerated with two Grade 3 acute toxicities and no acute Grade 4 toxicities. Late toxicity was minimal with all observed late toxicities occurring within the first six months of follow-up. Three hepatic recurrences at a distance from the target and one metastasis were observed. The actuarial 1- and 2-year local control rate was 95% (95% CI: 69-95%). At a median overall follow-up of 12,7 months (range, 1-24 months), six of the twenty-five (24%) patients have died. Overall actuarial survival at 1- and 2-years was 79% (95% CI: 52-92%) and 52% (95% CI: 19-78%), respectively. Our results suggest promising therapeutic efficacy and good clinical tolerance to CyberKnife SRT treatment for HCC patients not eligible for other treatment modalities.

Multi-luminescent hybrid gadolinium oxide nanoparticles as potential cell labeling

This manuscript analyses the use of newly developed hybrid gadolinium oxide nanoparticles as cell-labeling tracers. The nanoparticles are core-shell particles composed of a core of gadolinium oxide of [2-4] nm and a protecting shell of polysiloxane [1-3 nm] where different organic dyes (fluoresceine isothiocyanate (FITC) or rhodamine B isothiocyanate (RBITC)) are embedded. They are functionalized with poly(ethylene glycol)bis(carboxymethyl) to ensure their colloidal stability in biological buffers. These particles are potential multi-labeling tracers (magnetic and optical). In this paper, we show by optical imaging that they can be efficiently internalized in cells without cell alteration. The in-vitro uptake of the nanoparticles was followed in two cell lines (human fibroblasts and a human adenocarnima cell lines MCF7 cells). Nanoparticles distribution within cells was analysed by confocal analysis, and gadolinium concentration within cells was quantified by mass spectrometry (ICP-MS analysis). Nanoparticles uptake is found to be fast and efficient for both cell lines, with fluorescent labeling visible after 10 min of incubation whatever the nature of the fluorophore. The fluorescent intensity is mainly found as concentrated dots in the perinuclear region of the cells and decreases with the number of days in culture, but is still easily detectable after 3 days in culture. No significant effect on cell growth was detected. Finally, we show in this study the protective effect of the polysiloxane layer: encapsulation of RBITC within the polysiloxane shell, leads to a better photostability of this low cost dye than Cy3 and even reach a level comparable to Alexa 595. With their high photostability and long-lasting contrast properties, these hybrid luminescent nanoparticles appears thus as a versatile solution to assess multiple cell fate both in in-vitro cell model as well as in-vivo.

Anatomical ontologies of mosquitoes and ticks, and their web browsers in VectorBase

VectorBase, an integrated, relational database that manages genomic and other genetic/biological data pertaining to arthropod vectors of disease, has recently embarked on the construction of ontologies and controlled vocabularies (CVs). It aims, thus, at providing all necessary tools for the complete annotation of vector genomes and, in particular, the annotation of functional genomic data. This task was initiated with the development of anatomical ontologies of mosquitoes and ticks, both of which were made compliant to CARO, the common anatomy reference ontology. The ontologies are complemented by the development of novel web-based browsers that can show figures for anatomical terms, something that is especially helpful for fully illustrating the controlled vocabularies of anatomy.

Cortico-limbic circuitry for conditioned nicotine-seeking behavior in rats involves endocannabinoid signaling

RATIONALE

The endocannabinoid system plays an important role in conditioned drug seeking, but the neuronal mechanisms involved in this behavior are unclear.

OBJECTIVES

Here, we evaluate the role of endogenous cannabinoids in the cortico-limbic circuitry in cue-induced nicotine-seeking behavior in rats.

METHODS

Animals were first trained to self-administer nicotine (0.03 mg/kg/injection, IV) under conditions in which responding was reinforced jointly by response-contingent nicotine injections and audiovisual stimuli. During subsequent sessions, nicotine was withdrawn and responding was reinforced by contingent presentation of the stimuli only. One month after nicotine removal, the cannabinoid CB1 receptor antagonist, rimonabant, was injected bilaterally into the shell of the nucleus accumbens (ShNAcc, 0.3, 3, or 30 ng/0.5 microl), the basolateral amygdala (BLA, 30 ng/0.5 microl), or the prelimbic cortex (PLCx, 30 ng/0.5 microl).

RESULTS

Rimonabant injected into the ShNAcc dose-dependently reduced nicotine-seeking behavior without modifying spontaneous locomotor activity. Similar results were obtained when the drug (30 ng) was injected into the BLA or the PLCx. The anatomical specificity was confirmed in a control experiment using [(3)H]rimonabant. Fifteen minutes after drug injection, when the behavioral effects of rimonabant were already achieved, radioactivity was detected at the site of injection and had not diffused to adjacent regions.

CONCLUSIONS

These findings demonstrate that increased endocannabinoid transmission critically triggers conditioned nicotine-seeking behavior in key cortico-limbic regions.

Late presentation for HIV care in central Haiti: factors limiting access to care

OBJECTIVE

Many patients with HIV infection present for care late in the course of their disease, a factor which is associated with poor prognosis. Our objective was to identify factors associated with late presentation for HIV care among patients in central Haiti.

METHODS/DESIGN

Thirty-one HIV-positive adults, approximately 10% of the HIV-infected population followed at a central Haiti hospital, participated in this research study. A two-part research tool that included a structured questionnaire and an ethnographic life history interview was used to collect quantitative as well as qualitative data about demographic factors related to presentation for HIV care.

RESULTS

Sixty-five percent of the patients in this study presented late for HIV care, as defined by CD4 cell count below 350 cells/mm3. Factors associated with late presentation included male sex, older age, patient belief that symptoms are not caused by a medical condition, greater distance from the medical clinic, lack of prior access to effective medical care, previous requirement to pay for medical care, and prior negative experience at local hospitals. Harsh poverty was a striking theme among all patients interviewed.

CONCLUSIONS

Delays in presentation for HIV care in rural Haiti are linked to demographic, socioeconomic and structural factors, many of which are rooted in poverty. These data suggest that a multifaceted approach is needed to overcome barriers to early presentation for care. This approach might include poverty alleviation strategies; provision of effective, reliable and free medical care; patient outreach through community health workers and collaboration with traditional healers.

Transcriptional analysis of insecticide resistance in Anopheles stephensi using cross-species microarray hybridization

A large scale microarray (20k MMC1) from the African malaria vector Anopheles gambiae was used to monitor gene expression in insecticide resistant and susceptible strains of the Asian mosquito Anopheles stephensi. Heterologous hybridization at slightly reduced stringency yielded approximately 7000 significant signals. Thirty-six putative genes were differentially transcribed between the pyrethroid-resistant (DUB-R) and the susceptible (BEECH) strains. The expression profiles of selected transcripts were verified by real-time PCR. A gene putatively involved in the thickening of the adult cuticle showed the most striking up-regulation in DUB-R. A more specialized microarray containing 231 An. gambiae genes putatively involved in insecticide detoxification was used to further analyse classical insecticide resistance genes. Three glutathione S-transferase (GST) transcripts, one esterase and a cytochrome P450 were up-regulated in the resistant strain, while two peroxidases were down-regulated.

[Innovative technologies in radiation oncology]

At present, radiation oncology is again flourishing thanks to the development of highly accurate techniques as intensity modulated radiation therapy, stereotactic radiation therapy and hadrontherapy. These therapeutic modalities are made possible by the advent of image guided radiation therapy and respiratory gating that allows a better patient repositioning during the irradiation and between fractions. Nowadays, thanks to these recent technological advances, one can more easily conceive dose escalation, hypofractionation and combined treatment of radiation with sensitizing drugs and this together with a better protection of normal tissue aiming at, simultaneously, improved tumour control and better quality of life. This article describes these innovative technologies that, when integrated to other anti-tumoral therapeutic modalities, seem to be very promising.

Evolution of Mesobuthus gibbosus (Brullé, 1832) (Scorpiones: Buthidae) in the northeastern Mediterranean region

Sequence data derived from two mitochondrial markers, 16S rRNA and COI genes, were used to infer the evolutionary history of 47 insular and mainland populations covering most of the distributional range of the northeastern Mediterranean scorpion species Mesobuthus gibbosus. Based on the estimated divergence times of Mesobuthus lineages, the temporal frame of the genus differentiation in the northeastern Mediterranean region is placed in middle Miocene (15 million years ago). The biogeographic affinities of M. gibbosus populations point towards a mainly vicariant pattern of differentiation of the species which is consistent with the geological events that transformed the Aegean region during the period from 12 to 5 million years ago. M. gibbosus is an old northeastern Mediterranean species that has retained valuable bits of genetic information, reflecting some of the oldest vicariant events that have occurred in the area. Most importantly, the history witnessed by M. gibbosus has not been obscured by more recent palaeoevents of the region. Therefore, the case of M. gibbosus is in favour of a taxon-oriented 'perception' of the natural history of a given area.

AnoBase: a genetic and biological database of anophelines

AnoBase (http://www.anobase.org) is an integrated, relational database of basic biological and genetic data on anopheline species, with a particular emphasis on Anopheles gambiae. It has been designed as an information source and research support tool for the broad vector biology community. Although AnoBase is not a primary genomic database that develops and provides tools to access the genome of the malaria mosquito, it nevertheless contains several sections that offer data of genomic interest such as in situ hybridization images, an integrated gene tool and direct online access to AnoXcel, the proteomic database of An. gambiae. Moreover, AnoBase also contains information on non-gambiae mosquito species and a novel section on studies related to insecticide resistance.

The annexin gene family in the malaria mosquito Anopheles gambiae

Annexins belong to a class of proteins that are known to bind to, and hold together structures such as membranes. Interestingly, Anopheles gambiae (and Drosophila melanogaster) annexins bind Plasmodium ookinetes in vitro. In the malaria mosquito three genes in two cytogenetic loci on chromosome arm 2R encode annexin homologues; their expression, monitored by quantitative real-time PCR during mosquito development, as well as in various tissues, revealed little fluctuation in patterns of expression during all life stages. A different mode of transcription was observed for the three genes in the midgut in relation to the uptake of a blood meal. Immunohistochemical staining of midguts and ovaries with polyclonal anti-annexin sera reveals that the Anopheles polypeptides are present in the epithelial cells of both tissues and associated with the plasma membrane.

Gene expression in insecticide resistant and susceptible Anopheles gambiae strains constitutively or after insecticide exposure

A microarray containing approximately 20 000 expressed sequence tags (ESTs; 11 760 unique EST clusters) from the malaria vector, Anopheles gambiae, was used to monitor differences in global gene expression in two insecticide resistant and one susceptible strains. Statistical analysis identified 77 ESTs that were differentially transcribed among the three strains. These include the cytochrome P450 CYP314A1, over-transcribed in the DDT resistant ZAN/U strain, and many genes that belong to families not usually associated with insecticide resistance, such as peptidases, sodium/calcium exchangers and genes implicated in lipid and carbohydrate metabolism. Short-term (6 and 10 h) effects of exposure of the pyrethroid resistant RSP strain to permethrin were also detected. Several genes belonging to enzyme families already implicated in insecticide or xenobiotic detoxification were induced, including the carboxylesterase COEAE2F gene and members of the UDP-glucuronosyl transferase and nitrilase families.

An insulin-like growth factor 2-derived self-antigen inducing a regulatory cytokine profile after presentation to peripheral blood mononuclear cells from DQ8+ type 1 diabetic adolescents: preliminary design of a thymus-based tolerogenic self-vaccination

This work aims to evaluate the potential use of insulin-like growth factor 2 (IGF-2) as the dominant thymic self-antigen precursor of the insulin family in designing a tolerogenic approach to type 1 diabetes (T1D) prevention. This evaluation was primarily based on cytokine profile driven by MHC presentation of insulin and IGF-2-derived antigens to PBMC cultures derived from 16 T1D DQ8(+) adolescents. Insulin B9-23, one dominant beta-cell autoantigen, and the homologous sequence B11-25 of IGF-2 display the same affinity and fully compete for binding to DQ8, a MHC-II allele conferring major genetic susceptibility to type 1 diabetes (T1D). However, compared to insulin B9-23, presentation of IGF-2 B11-25 elicits a suppressive/regulatory cytokine profile with a higher number of IL-10-secreting cells (P < 0.05), a much higher ratio of IL-10/IFN-gamma (P < 0.01), as well as a lower number of IL-4-secreting cells (P < 0.05). Thus, with regard to T1D prevention, administration of IGF-2-derived self-antigen(s) seems to be an efficient approach that combines both antagonism for binding to a major susceptibility MHC-II allele, as well as downstream promotion of an antigen-driven tolerogenic response.

[Importance of a thymus dysfunction in the pathophysiology of type 1 diabetes]

The autoimmune nature of the diabetogenic process and the major contribution of T lymphocytes stand now beyond any doubt. However, despite the identification of the three major type 1-diabetes-related autoantigens (insulin, GAD65 and phosphatase IA-2), the origin of this immune dysregulation still remains unknown. More and more evidence supports a thymic dysfunction in the establishment of central self-tolerance to the insulin family as a crucial factor in the development of the autoimmune response selective of pancreatic insulin-secreting islet beta cells. All the genes of the insulin family (INS, IGF1 and IGF2) are expressed in the thymus network. However, IGF-2 is the dominant member of this family first encountered by T cells in the thymus, and only IGFs control early T-cell differentiation. IGF2 transcription is defective in the thymus in one animal model of type 1 diabetes, the Bio-Breeding (BB) rat. The sequence B9-23, one dominant autoantigen of insulin, and the homologous sequence B11-25 derived from IGF-2 exibit the same affinity and fully compete for binding to DQ8, one class-II major histocompatibility complex (MHC-II) conferring major genetic susceptibility to type 1 diabetes. Compared to insulin B9-23, the presentation of IGF-2 B11-25 to peripheral mononuclear cells (PBMCs) isolated from type 1 diabetic DQ8+ adolescents elicits a regulatory/tolerogenic cytokine profile (*IL-10, *IL-10/IFN-g, *IL-4). Thus, administration of IGF-2 derived self-antigen(s) might constitute a novel form of vaccine/immunotherapy combining both an antagonism for the site of presentation of a susceptible MHC allele, as well as a downstream tolerogenic/regulatory immune response.

An Anopheles gambiae salivary gland promoter analysis in Drosophila melanogaster and Anopheles stephensi

Regulatory regions driving gene expression in specific target organs of the African malaria vector Anopheles gambiae are of critical relevance for studies on Plasmodium-Anopheles interactions as well as to devise strategies for blocking malaria parasite development in the mosquito. In order to identify an appropriate salivary gland promoter we analysed the transactivation properties of genomic fragments located just upstream of the An. gambiae female salivary gland-specific genes AgApy and D7r4. An 800 bp fragment from the AgApy gene directed specific expression of the LacZ reporter gene in the salivary glands of transgenic Anopheles stephensi. However, expression levels were lower than expected and the transgene was expressed in the proximal-rather than in the distal-lateral lobes of female glands. Surprisingly, a promoter fragment from the D7r4 gene conferred strong tissue-specific expression in Drosophila melanogaster but only low transcription levels in transgenic An. stephensi. These results imply a certain conservation of gland-specific control elements between the fruit fly and the mosquito suggesting that an increased degree of complexity, probably connected to the evolution of haematophagy, underlies the regulation of tissue-specific expression in mosquito female salivary glands.

Simulations of the mean chord length of a multi-element TEPC irradiated by monoenergetic neutrons

In recent years IRSN has developed tissue-equivalent proportional counters (TEPCs) for neutron monitoring. A detector with a multi-element geometry was studied for personal dosimetry purposes. The determination of the personal dose equivalent using a multi-element TEPC requires to calculate the mean chord length of the charged particles in the counter gas. This paper presents the results of the simulations using the MCNPX code and explains the influence of the gas parameters on the mean chord length and the consequences on the dose equivalent response.

AnoXcel: an Anopheles gambiae protein database

The proteome of the mosquito Anopheles gambiae was organized on a hyperlinked spreadsheet format containing one protein per row and several pieces of information in each column. The information for each protein ranges from the presence or absence of signal peptide indicative of secretion, presence of transmembrane domains, similarities to several databases, chromosomal location, and relatedness to other An. gambiae proteins, etc. Hosted by AnoBase (http://www.anobase.org/), the whole spreadsheet or segments of it can be downloaded or searched from http://www.anobase.org/AnoBase/Genes/Ano-Xcel by the scientist dealing with the annotation of proteome subsets such as those deriving from transcriptomes, nucleotide microarrays or high throughput mass spectrometry data.

SSR181507, a putative atypical antipsychotic with dopamine D2 antagonist and 5-HT1A agonist activities: improvement of social interaction deficits induced by phencyclidine in rats

Social behaviour is frequently impaired in schizophrenic patients, and current antipsychotics appear poorly effective in alleviating this deficit. SSR181507 is a selective dopamine D2 receptor antagonist and 5-HT1A receptor agonist [Neuropsychopharmacology 28 (2003) 2064] with an atypical antipsychotic profile and additional antidepressant/anxiolytic activities [Neuropsychopharmacology 28 (2003) 1889]. Here, we sought to assess the efficacy of SSR181507, and of reference antipsychotics and antidepressant/anxiolytics, to counteract phencyclidine (PCP)-induced social interaction deficit in rats. Pairs of unfamiliar rats were placed for 10 min each day into a dimly lit arena, during four consecutive days. On the test day (5th day), each pair was placed into the arena 30 min after i.p. treatment with PCP (or vehicle) and a challenge compound or vehicle (same for both rats, i.p. or s.c.). The time spent in social interaction was scored during 10 min. PCP (1 mg/kg) decreased social interaction time by about 35%. This effect was fully antagonized by pre-treatment with SSR181507 (1 mg/kg). In contrast, neither haloperidol (0.05 and 0.1 mg/kg) nor clozapine (0.3 and 1 mg/kg) antagonized this PCP-induced deficit. The selective 5-HT1A receptor agonist 8-OH-DPAT (0.025 and 0.05 mg/kg s.c.), but not the anxiolytic diazepam (0.75 and 1.5 mg/kg), also improved social interaction impairment in PCP-treated rats: this would indicate that the 5-HT1A receptor agonist properties of SSR181507 are responsible for the reversal of PCP-induced social deficit. These data suggest that, in addition to its atypical antipsychotic profile and antidepressant/anxiolytic activities, SSR181507 has a potential therapeutic activity in another key feature of schizophrenia poorly controlled by current antipsychotics, namely deterioration in social functioning.

Synthesis and properties of europium-based phosphors on the nanometer scale: Eu2O3, Gd2O3:Eu, and Y2O3:Eu

Nanocrystals of oxides containing europium as the main constituent or as a doping element in RE2O3 ( RE=Y, Gd) have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by high-resolution TEM, absorption spectroscopy, and luminescence spectroscopy. The samples obtained consisted of concentrated and colloidally stable suspensions of luminescent oxide nanoparticles with an average grain diameter in the range 2-5 nm. The nanoparticles were found to be highly crystalline despite their ultrasmall size and the low temperature of 180 degrees C applied during the synthesis. Upon UV excitation, the red luminescence relative to the 5D0-->7Fn transition within the cubic form of RE2O3 exhibits some important differences from that usually found in bulk materials.