Conditioned taste aversion using four different means to deliver sucrose to rats

A solution of sucrose either to be drunk from a drinking tube-self-drinking procedure (SD)-or perfused intraorally as a consequence of nose-pokes-self-administration procedure (SA)-or perfused as a consequence of licking an empty tube (LA)-was paired with an LiCl-induced malaise in rats. The effects were compared to those of a procedure consisting of intraoral administration (IO) of sucrose not contingent to any specific action of the rat. Similar levels of conditioned taste aversion (CTA) were obtained but extinction in the IO procedure was quicker than in the SA procedure, which was itself quicker than in the SD procedure. Extinctions in the IO and LA procedures resembled one another and were quicker than in the SD procedure. A step towards deciding between several explanatory hypotheses of these differences was made by conducting two more experiments. The third experiment was based on reinstatement, or not, of the conditioning procedure for the test after standard IO extinction. CTA was produced only when SD was used both at conditioning and test. A fourth experiment was based on latent inhibition where the procedure was changed, or not, between preexposure and conditioning. Latent inhibition was absent only when the rats had been preexposed to sucrose with the SA procedure and conditioned with the SD procedure.     

Characterization of wild-type recombinant Bet v 1a as a candidate vaccine against birch pollen allergy

BACKGROUND: We describe the production in Escherichia coli as a recombinant protein of clinical grade wild-type Bet v 1a (rBet v 1a), to be used as a candidate vaccine against birch pollen allergy. METHODS: This recombinant protein was purified by hydrophobic interaction and ion exchange chromatography and characterized by SDS-PAGE, immunoprint and circular dichroism in parallel with natural Bet v 1 (nBet v 1) purified from a birch pollen extract. We also compared rBet v 1 and nBet v 1 for their capacity to induce histamine release from basophils and to stimulate T lymphocyte proliferation. RESULTS: rBet v 1a appears in SDS-PAGE as an 18-kDa monomeric protein, whereas purified nBet v 1 comprises a mixture of isoforms (resolving as three distinct bands and six spots after 1-dimensional and 2-dimensional electrophoresis, respectively). Both recombinant and natural purified Bet v 1 molecules are recognized by IgE from birch pollen-allergic patients as well as anti-Bet v 1 murine monoclonal antibodies, suggesting that the recombinant protein is correctly folded in a native configuration. Circular dichroism analysis confirmed that the two Bet v 1 molecules exhibit similar 3-dimensional structures, even if rBet v 1a appears more compact and stable in thermodenaturation/renaturation experiments. Both rBet v 1 and nBet v 1 induce the degranulation of sensitized basophils and proliferation of Bet v 1-specific T lymphocytes in a similar manner. CONCLUSIONS: On the basis of these structural and biological properties, rBet v 1a is a valid candidate vaccine against birch pollen allergy, currently evaluated in humans.     

Identification and characterization of a Neospora caninum microneme-associated protein (NcMIC4) that exhibits unique lactose-binding properties

Microneme proteins have been shown to play an important role in the early phase of host cell adhesion, by mediating the contact between the parasite and host cell surface receptors. In this study we have identified and characterized a lectin-like protein of Neospora caninum tachyzoites which was purified by alpha-lactose-agarose affinity chromatography. Upon separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, this lactose-binding protein migrated at 70 and 55 kDa under reducing and nonreducing conditions, respectively. Immunofluorescence and immunogold electron microscopy with affinity-purified antibodies showed that the protein was associated with the tachyzoite micronemes. Mass spectrometry analyses and expressed sequence tag database mining revealed that this protein is a member of the Neospora microneme protein family; the protein was named NcMIC4 (N. caninum microneme protein 4). Upon two-dimensional gel electrophoresis, NcMIC4 separated into seven distinct isoforms. Incubation of extracellular parasites at 37 degrees C resulted in the secretion of NcMIC4 into the medium as a soluble protein, and the secreted protein exhibited a slightly reduced M(r) but retained its lactose-binding properties. Immunofluorescence was used to investigate the temporal and spatial distribution of NcMIC4 in tachyzoites entering their host cells and showed that reexpression of NcMIC4 took place 30 min after entry into the host cell. Incubation of secreted fractions and purified NcMIC4 with Vero cells demonstrated binding of NcMIC4 to Vero cells as well as binding to chondroitin sulfate A glycosaminoglycans.     

Cell domain-dependent changes in the glutamatergic and GABAergic drives during epileptogenesis in the rat CA1 region

An increased ratio of the glutamatergic drive to the overall glutamatergic/GABAergic drive characterizes the chronic stage of temporal lobe epilepsy (TLE), but it is unclear whether this modification is present during the latent period that often precedes the epileptic stage. Using the pilocarpine model of TLE in rats, we report that this ratio is decreased in hippocampal CA1 pyramidal cells during the early phase of the latent period (3–5 days post pilocarpine). It is, however, increased during the late phase of the latent period (7–10 days post pilocarpine), via cell domain-dependent alterations in synaptic current properties, concomitant with the occurrence of interictal-like activity in vivo . During the late latent period, the glutamatergic drive was increased in somata via an enhancement in EPSC decay time constant and in dendrites via an increase in EPSC frequency and amplitude. The GABAergic drive remained unchanged in the soma but was decreased in dendrites, since the drop off in IPSC frequency was more marked than the increase in IPSC kinetics. Theoretical considerations suggest that these modifications are sufficient to produce interictal-like activity. In epileptic animals, the ratio of the glutamatergic drive to the overall synaptic drive was not further modified, despite additional changes in synaptic current frequency and kinetics. These results show that the global changes to more glutamatergic and less GABAergic activities in the CA1 region precede the chronic stage of epilepsy, possibly facilitating the occurrence and/or the propagation of interictal activity.     

Pathogenesis of antiphospholipid syndrome: recent insights and emerging concepts

Introduction: Even though our understanding of the antiphospholipid syndrome (APS) has improved tremendously over the last decades, we are still not in a position to replace symptomatic anticoagulation by pathogenesis based causal treatments.

Areas covered: Recent years have provided further insights into pathogenetically relevant mechanisms. These include a differentiation of pathogenic subtypes of antiphospholipid antibodies (aPL), novel mechanisms modulating disease activity, for example, extracellular vesicles and microRNA, and novel players in pathogenesis, for example, neutrophils and neutrophil extracellular traps (NETs).

Expert commentary: It is evident that aPL induce a proinflammatory and procoagulant state and recent data suggest that different aPL species activate different signaling pathways which sometimes converge into a common cellular response. This implies that presence of more than one aPL species may disproportionally increase the risk for the major manifestations of APS, that is, thrombosis and fetal loss. Further delineation of the pathogenic mechanisms will hopefully provide clues to causal rather than symptomatic treatments of APS.     

Localization of endogenous galactoside-binding lectin during morphogenesis ofXenopus laevis

Summary A monoclonal antibody has been produced againstXenopus laevis galactoside-binding neural-creststage lectin. This antibody inhibits lectin-mediated hemagglutination. Using this antibody in conjunction with immunohistochemical techniques, lectin deposition has been studied in embryos and tadpoles at different stages of morphogenesis, from initial neural crest migration, up to the formation of a swimming tadpole. Lectin levels change during development in different regions of the embryo and tadpole, decreasing in migratory cells, and increasing in sites where cells become more adhesive to one another. The results suggest that galactoside-binding lectins may be an important class of cellular adhesion molecules during these stages of development.     

Polymorphisms in the MAOA, MAOB, and COMT genes and aggressive behavior in schizophrenia.

Some studies have reported associations between COMT and MAO genotypes and aggression, though results have been inconsistent. We examined the relationship between Overt aggression scale (OAS) scores, and both MAOA and MAOB polymorphisms in a well-powered sample of 346 subjects with schizophrenia. We also examined COMT in a Stage II replication sample of 150 individuals, and combined these results with our previously reported (Stage I) findings for COMT. We found no evidence of any associations between OAS ratings and any of the polymorphisms investigated under different genetic models. There was no evidence of epistatic interaction between MAOA and COMT on OAS scores. These results fail to support the theory that functional polymorphisms within the MAOA, MAOB, or COMT genes, as determinants of catecholamine enzymatic activity, are risk factors for aggressive behavior.     

Comparison of the real-time PCR method and the Gen-Probe amplified Mycobacterium tuberculosis direct test for detection of Mycobacterium tuberculosis in pulmonary and nonpulmonary specimens

Real-time PCR was compared to Amplified Mycobacterium tuberculosis Direct Test (AMTDII) for 100 clinical specimens. The overall sensitivities of the real-time PCR method and AMTDII were similar for respiratory and nonrespiratory specimens. However, real-time PCR seemed to be less susceptible to amplification inhibitors than AMTDII.     

Interpretation of gas-blood ratio inP O 2polarography

Summary The differences inP _{O 2}readings between gas and blood were studied with a Clark-type electrode in the range of 38.5 to 713 mm HgP _{O 2}.The tonometered blood samples were taken in two different ways. The results showed that the gas-blood ratior _b(equilibrating gasP _{O 2}reading/equilibrated bloodP _{O 2}reading) depended not only on the sampling method but also on theP _{O 2}range: it varied from 1.005 to 1.032 for aP _{O 2}of 96.5 mm Hg, and from 1.040 to 1.081 for aP _{O 2}of 713 mm Hg according to the sampling procedure.A theoretical analysis demonstrated that the variation ofr _bwith the bloodP _{O 2}can be attributed to the influence of the degree of oxygen saturation of the hemoglobin on theP _{O 2}gradient existing in the blood diffusion boundary layer adhering to the electrode membrane.This work was supported by grants from the High Authority of the European Coal and Steel Community and from the Fonds de la Recherche Scientifique Médicale, Belgium.