Evaluation of two long synthetic merozoite surface protein 2 peptides as malaria vaccine candidates.

Merozoite surface protein 2 (MSP2) is a promising vaccine candidate against Plasmodium falciparum blood stages. A recombinant 3D7 form of MSP2 was a subunit of Combination B, a blood stage vaccine tested in the field in Papua New Guinea. A selective effect in favour of the allelic family not represented by the vaccine argued for a MSP2 vaccine consisting of both dimorphic variants. An alternative approach to recombinant manufacture of vaccines is the production of long synthetic peptides (LSP). LSP exceeding a length of well over 100 amino acids can now be routinely synthesized. Synthetic production of vaccine antigens cuts the often time-consuming steps of protein expression and purification short. This considerably reduces the time for a candidate to reach the phase of clinical trials. Here we present the evaluation of two long synthetic peptides representing both allelic families of MSP2 as potential vaccine candidates. The constructs were well recognized by human immune sera from different locations and different age groups. Furthermore, peptide-specific antibodies in human immune sera were associated with protection from clinical malaria. The synthetic fragments share major antigenic properties with native MSP2. Immunization of mice with these antigens yielded high titre antibody responses and monoclonal antibodies recognized parasite-derived MSP2. Our results justify taking these candidate poly-peptides into further vaccine development.

Unavailability of CD147 leads to selective erythrocyte trapping in the spleen.

Adhesive interactions with stromal cells and the extracellular matrix are essential for the differentiation and migration of hematopoietic progenitors. In the erythrocytic lineage, a number of adhesion molecules are expressed in the developing erythrocytes and are thought to play a role in the homing and maturation of erythrocytic progenitors. However, many of these molecules are lost during the final developmental stages leading to mature erythrocytes. One of the adhesion molecules that remains expressed in mature, circulating erythrocytes is CD147. This study shows that blockade of this molecule on the cell surface by treatment with F(ab')(2) fragments of anti-CD147 monoclonal antibody disrupts the circulation of erythrocytes, leading to their selective trapping in the spleen. Consequently, mice develop an anemia, and de novo, erythropoietin-mediated erythropoiesis in the spleen. In contrast, these changes were not seen in mice similarly treated with another antierythrocyte monoclonal antibody with a different specificity. These results suggest that the CD147 expressed on erythrocytes likely plays a critical role in the recirculation of mature erythrocytes from the spleen into the general circulation. (Blood. 2001;97:3984-3988)

Selective use of postoperative neck radiotherapy in oral cavity and oropharynx cancer: a prospective clinical study.

BACKGROUND In cervical postoperative radiotherapy, the target volume is usually the same as the extension of the previous dissection. We evaluated a protocol of selective irradiation according to the risk estimated for each dissected lymph node level. METHODS Eighty patients with oral/oropharyngeal cancer were included in this prospective clinical study between 2005 and 2008. Patients underwent surgery of the primary tumor and cervical dissection, with identification of positive nodal levels, followed by selective postoperative radiotherapy. Three types of selective nodal clinical target volume (CTV) were defined: CTV0, CTV1, and CTV2, with a subclinical disease risk of <10%, 10-25%, and 25% and a prescribed radiation dose of <35 Gy, 50 Gy, and 66-70 Gy, respectively. The localization of node failure was categorized as field, marginal, or outside the irradiated field. RESULTS A consistent pattern of cervical infiltration was observed in 97% of positive dissections. Lymph node failure occurred within a high-risk irradiated area (CTV1-CTV2) in 12 patients, marginal area (CTV1/CTVO) in 1 patient, and non-irradiated low-risk area (CTV0) in 2 patients. The volume of selective lymph node irradiation was below the standard radiation volume in 33 patients (mean of 118.6 cc per patient). This decrease in irradiated volume was associated with greater treatment compliance and reduced secondary toxicity. The three-year actuarial nodal control rate was 80%. CONCLUSION This selective postoperative neck irradiation protocol was associated with a similar failure pattern to that observed after standard neck irradiation and achieved a significant reduction in target volume and secondary toxicity.

CpG-ODN-induced sustained expression of BTLA mediating selective inhibition of human B cells.

BTLA (B- and T-lymphocyte attenuator) is a prominent co-receptor that is structurally and functionally related to CTLA-4 and PD-1. In T cells, BTLA inhibits TCR-mediated activation. In B cells, roles and functions of BTLA are still poorly understood and have never been studied in the context of B cells activated by CpG via TLR9. In this study, we evaluated the expression of BTLA depending on activation and differentiation of human B cell subsets in peripheral blood and lymph nodes. Stimulation with CpG upregulated BTLA, but not its ligand: herpes virus entry mediator (HVEM), on B cells in vitro and sustained its expression in vivo in melanoma patients after vaccination. Upon ligation with HVEM, BTLA inhibited CpG-mediated B cell functions (proliferation, cytokine production, and upregulation of co-stimulatory molecules), which was reversed by blocking BTLA/HVEM interactions. Interestingly, chemokine secretion (IL-8 and MIP1β) was not affected by BTLA/HVEM ligation, suggesting that BTLA-mediated inhibition is selective for some but not all B cell functions. We conclude that BTLA is an important immune checkpoint for B cells, as similarly known for T cells.

Comparison of a modified shell vial culture procedure with conventional mouse inoculation for rabies virus isolation

Rabies is a neurotropic disease that is often lethal. The early diagnosis of rabies infection is important and requires methods that allow for the isolation of the virus from animals and humans. The present study compared a modified shell vial (MSV) procedure using 24-well tissue culture plates with the mouse inoculation test (MIT), which is considered the gold standard for rabies virus isolation. Thirty brain samples (25 positive and 5 negative by the fluorescent antibody test) obtained from different animal species at the National Institute of Hygiene Rafael Rangel in Caracas, Venezuela, were studied by the MIT and MSV assays. Nine samples (36%) were positive at 24 h, 10 (40%) were positive at 48 h and six (24%) were positive at 72 h by the MSV assay. With the MIT assay, 76% were positive at six days post inoculation and 12% were positive at 12 and 18 days post inoculation. One sample that was negative according to the MSV assay was positive with MIT on the 12th day. The MSV procedure exhibited a sensitivity of 96.2%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value 80%. This procedure allowed for rapid rabies virus detection. MIT can be employed as an alternative method in laboratories without tissue culture facilities.

Selective integration of auditory-visual looming cues by humans.

An object's motion relative to an observer can confer ethologically meaningful information. Approaching or looming stimuli can signal threats/collisions to be avoided or prey to be confronted, whereas receding stimuli can signal successful escape or failed pursuit. Using movement detection and subjective ratings, we investigated the multisensory integration of looming and receding auditory and visual information by humans. While prior research has demonstrated a perceptual bias for unisensory and more recently multisensory looming stimuli, none has investigated whether there is integration of looming signals between modalities. Our findings reveal selective integration of multisensory looming stimuli. Performance was significantly enhanced for looming stimuli over all other multisensory conditions. Contrasts with static multisensory conditions indicate that only multisensory looming stimuli resulted in facilitation beyond that induced by the sheer presence of auditory-visual stimuli. Controlling for variation in physical energy replicated the advantage for multisensory looming stimuli. Finally, only looming stimuli exhibited a negative linear relationship between enhancement indices for detection speed and for subjective ratings. Maximal detection speed was attained when motion perception was already robust under unisensory conditions. The preferential integration of multisensory looming stimuli highlights that complex ethologically salient stimuli likely require synergistic cooperation between existing principles of multisensory integration. A new conceptualization of the neurophysiologic mechanisms mediating real-world multisensory perceptions and action is therefore supported.

Computational and Biological Evaluation of N-octadecyl-N'-propylsulfamide, a Selective PPARα Agonist Structurally Related to N-acylethanolamines.

To further understand the pharmacological properties of N-oleoylethanolamine (OEA), a naturally occurring lipid that activates peroxisome proliferator-activated receptor alpha (PPARα), we designed sulfamoyl analogs based on its structure. Among the compounds tested, N-octadecyl-N'-propylsulfamide (CC7) was selected for functional comparison with OEA. The performed studies include the following computational and biological approaches: 1) molecular docking analyses; 2) molecular biology studies with PPARα; 3) pharmacological studies on feeding behavior and visceral analgesia. For the docking studies, we compared OEA and CC7 data with crystallization data obtained with the reference PPARα agonist GW409544. OEA and CC7 interacted with the ligand-binding domain of PPARα in a similar manner to GW409544. Both compounds produced similar transcriptional activation by in vitro assays, including the GST pull-down assay and reporter gene analysis. In addition, CC7 and OEA induced the mRNA expression of CPT1a in HpeG2 cells through PPARα and the induction was avoided with PPARα-specific siRNA. In vivo studies in rats showed that OEA and CC7 had anorectic and antiobesity activity and induced both lipopenia and decreases in hepatic fat content. However, different effects were observed when measuring visceral pain; OEA produced visceral analgesia whereas CC7 showed no effects. These results suggest that OEA activity on the PPARα receptor (e.g., lipid metabolism and feeding behavior) may be dissociated from other actions at alternative targets (e.g., pain) because other non cannabimimetic ligands that interact with PPARα, such as CC7, do not reproduce the full spectrum of the pharmacological activity of OEA. These results provide new opportunities for the development of specific PPARα-activating drugs focused on sulfamide derivatives with a long alkyl chain for the treatment of metabolic dysfunction.

Turnover and accumulation of genetic diversity across large time-scale cycles of isolation and connection of populations.

Major climatic and geological events but also population history (secondary contacts) have generated cycles of population isolation and connection of long and short periods. Recent empirical and theoretical studies suggest that fast evolutionary processes might be triggered by such events, as commonly illustrated in ecology by the adaptive radiation of cichlid fishes (isolation and reconnection of lakes and watersheds) and in epidemiology by the fast adaptation of the influenza virus (isolation and reconnection in hosts). We test whether cyclic population isolation and connection provide the raw material (standing genetic variation) for species evolution and diversification. Our analytical results demonstrate that population isolation and connection can provide, to populations, a high excess of genetic diversity compared with what is expected at equilibrium. This excess is either cyclic (high allele turnover) or cumulates with time depending on the duration of the isolation and the connection periods and the mutation rate. We show that diversification rates of animal clades are associated with specific periods of climatic cycles in the Quaternary. We finally discuss the importance of our results for macroevolutionary patterns and for the inference of population history from genomic data.

Functional and molecular evolutionary analysis of the "Brevix Radix" gene family in mono-and dicotyledonous plants

ABSTRACTIn contrast to animals, plants cannot move from their place of birth and, therefore, need to adapt to their particular habitat in order to survive. Thus, plant development is remarkably plastic, making plants an ideal system for the isolation of genes that account for intraspecific natural variation and possibly environmental adaptation. However, to date, this approach mostly identified null alleles and missed mutations with subtle effects. For instance, BREVIS RADIX (BRX) has been isolated as a key regulator of root growth through a naturally occurring loss-of-function allele in the Arabidopsis thaliana accession Uk-1 and is the founding member of a highly-conserved plant-specific gene family.In this work, we show that a strong selective pressure is acting on the BRX gene family and dates back before the monocot-dicot divergence. However, functional diversification is observed mainly in dicotyledon BRX family genes and is correlated with acceleration in the evolutionary rates in the N-terminal regions. Population genetic data revealed that BRX is highly conserved across Arabidopsis accessions and presents signatures of adaptation. Interestingly, a seven amino acid deletion polymorphism in BRX sequence was found in a few accessions, which seems to be responsible for their enhanced primary root growth. Nevertheless, BRX might not only be active in the root, as suggested by its expression in the shoot. Indeed, leaves and cotyledons of brx mutants are significantly smaller than wild- type. This phenotype is a direct consequence of the absence of BRX function in the shoot rather than an indirect effect of an altered root system growth. Interestingly, cotyledons of brx plants reflect the same physiological defects as the root. Moreover, phenotypes in BRX gain-of-function plants, such as epinastic leaves and increased epidermal cell size, could be associated with an increase in leaf brassinosteroid content.Collectively, these results indicate that BRX contributes to local adaptation by ubiquitously regulating plant growth, probably through the modulation of brassinosteroid biosynthesis.RÉSUMÉContrairement à la plupart des animaux, les plantes ne peuvent se mouvoir et doivent ainsi s'adapter à leur environnement pour survivre. Pour cette raison, elles représentent un système idéal pour l'identification de gènes contribuant à la variation naturelle intra- spécifique, ainsi qu'à l'adaptation. Cependant, cette approche a, jusqu'à présent, surtout permis d'isoler des allèles nuls et non des mutations conférant des effets plus subtiles. C'est le cas du gène Β REVIS RADIX (BRX), un régulateur clé de la croissance racinaire, qui a été identifié grâce à un allèle non-fonctionnel présent dans l'accession naturelle d'Arabidopsis thaliana Uk-1. BRX et ses homologues des plantes mono- et dicotylédones forment une famille très conservée et spécifique aux plantes.Dans ce travail, nous démontrons que la famille de gènes BRX est soumise à une forte pression de sélection qui remonte avant la divergence entre mono- et dicotylédones. Cependant, une diversification fonctionnelle a été observée chez les gènes des dicotylédones et corrèle avec une accélération de la vitesse d'évolution dans leur région N- terminale. Une analyse génétique de différentes accessions naturelles d'Arabidopsis a révélé que BRX est hautement conservé et présente des signatures d'adaptation. Remarquablement, un polymorphisme de délétion de sept acides aminés a été détecté dans quelques accessions et a pour conséquence une plus forte croissance de la racine primaire. Néanmoins, il semble que le rôle de BRX ne se limite pas qu'à la racine, comme indiqué par son expression dans les parties aériennes de la plante. En effet, les mutants brx présentent des cotylédons et des feuilles significativement plus petits que le type sauvage, une conséquence directe de l'absence d'activité de BRX dans ces organes. Nous avons aussi noté que les cotylédons des mutants brx, à l'instar des racines, ont une perception altérée de l'auxine et peuvent être complémentés par l'application exogène de brassinostéroïdes. De plus, dans des plantes présentant un gain de fonction BRX, les feuilles sont épinastiques et les cellules de leur épiderme plus grandes. Ces phénotypes sont accompagnés d'une augmentation de la concentration de brassinostéroïdes dans les feuilles. Conjointement, ces résultats démontrent que BRX contribue à une adaptation locale de la plante par la régulation générale de sa croissance, probablement en modulant la biosynthèse des brassinostéroïdes.

The effect of host plant and isolation on the genetic structure of phytophagous insects: A preliminary study on a bruchid beetle

Genetic differentiation is a consequence of the combination of drift and restriction in gene flow between populations due to barriers to dispersal, or selection against individuals resulting from inter-population matings In phytophagous insects, local adaptation to different kinds of host plants can sometimes lead to reproductive isolation and thus to genetic structuring, or even to speciation Acanthoscelides. obtectus Say is a bean bruchid specialized on beans of the Phaseolus vulgaris group, attacking both wild and domesticated forms of P vulgaris., and P coccineus This study reveals that the genetic structure of populations of this bruchid is explained mainly by their geographical location and is not related to a particular kind (wild or domesticated) of bean In contrast, the species of bean might have led, to some extent, to genetic structuring in these bruchids, although our sampling is too limited to address such process unambiguously. If confirmed, it would corroborate preliminary results found for the parasitoid species that attack Acanthoscelides species, which might show a genetic structure depending on the species of host plant

Free-breathing renal magnetic resonance angiography with steady-state free-precession and slab-selective spin inversion combined with radial k-space sampling and water-selective excitation.

The impact of radial k-space sampling and water-selective excitation on a novel navigator-gated cardiac-triggered slab-selective inversion prepared 3D steady-state free-precession (SSFP) renal MR angiography (MRA) sequence was investigated. Renal MRA was performed on a 1.5-T MR system using three inversion prepared SSFP approaches: Cartesian (TR/TE: 5.7/2.8 ms, FA: 85 degrees), radial (TR/TE: 5.5/2.7 ms, FA: 85 degrees) SSFP, and radial SSFP combined with water-selective excitation (TR/TE: 9.9/4.9 ms, FA: 85 degrees). Radial data acquisition lead to significantly reduced motion artifacts (P < 0.05). SNR and CNR were best using Cartesian SSFP (P < 0.05). Vessel sharpness and vessel length were comparable in all sequences. The addition of a water-selective excitation could not improve image quality. In conclusion, radial k-space sampling reduces motion artifacts significantly in slab-selective inversion prepared renal MRA, while SNR and CNR are decreased. The addition of water-selective excitation could not improve the lower CNR in radial scanning.

Differential effects of selective HDAC inhibitors on macrophage inflammatory responses to the Toll-like receptor 4 agonist LPS.

Broad-spectrum inhibitors of HDACs are therapeutic in many inflammatory disease models but exacerbated disease in a mouse model of atherosclerosis. HDAC inhibitors have anti- and proinflammatory effects on macrophages in vitro. We report here that several broad-spectrum HDAC inhibitors, including TSA and SAHA, suppressed the LPS-induced mRNA expression of the proinflammatory mediators Edn-1, Ccl-7/MCP-3, and Il-12p40 but amplified the expression of the proatherogenic factors Cox-2 and Pai-1/serpine1 in primary mouse BMM. Similar effects were also apparent in LPS-stimulated TEPM and HMDM. The pro- and anti-inflammatory effects of TSA were separable over a concentration range, implying that individual HDACs have differential effects on macrophage inflammatory responses. The HDAC1-selective inhibitor, MS-275, retained proinflammatory effects (amplification of LPS-induced expression of Cox-2 and Pai-1 in BMM) but suppressed only some inflammatory responses. In contrast, 17a (a reportedly HDAC6-selective inhibitor) retained anti-inflammatory but not proinflammatory properties. Despite this, HDAC6(-/-) macrophages showed normal LPS-induced expression of HDAC-dependent inflammatory genes, arguing that the anti-inflammatory effects of 17a are not a result of inhibition of HDAC6 alone. Thus, 17a provides a tool to identify individual HDACs with proinflammatory properties.

In vitro biotransformation of the selective serotonin reuptake inhibitor citalopram, its enantiomers and demethylated metabolites by monoamine oxidase in rat and human brain preparations

This study was conducted to identify enzyme systems eventually catalysing a local cerebral metabolism of citalopram, a widely used antidepressant of the selective serotonin reuptake inhibitor type. The metabolism of citalopram, of its enantiomers and demethylated metabolites was investigated in rat brain microsomes and in rat and human brain mitochondria. No cytochrome P-450 mediated transformation was observed in rat brain. By analysing H2O2 formation, monoamine oxidase A activity in rat brain mitochondria could be measured. In rat whole brain and in human frontal cortex, putamen, cerebellum and white matter of five brains monoamine oxidase activity was determined by the stereoselective measurement of the production of citalopram propionate. All substrates were metabolised by both forms of MAO, except in rat brain, where monoamine oxidase B activity could not be detected. Apparent Km and Vmax of S-citalopram biotransformation in human frontal cortex by monoamine oxidase B were found to be 266 microM and 6.0 pmol min(-1) mg(-1) protein and by monoamine oxidase A 856 microM and 6.4 pmol min(-1) mg(-1) protein, respectively. These Km values are in the same range as those for serotonin and dopamine metabolism by monoamine oxidases. Thus, the biotransformation of citalopram in the rat and human brain occurs mainly through monoamine oxidases and not, as in the liver, through cytochrome P-450.

Selective distribution of lactate dehydrogenase isoenzymes in neurons and astrocytes of human brain.

In vertebrates, the interconversion of lactate and pyruvate is catalyzed by the enzyme lactate dehydrogenase. Two distinct subunits combine to form the five tetrameric isoenzymes of lactate dehydrogenase. The LDH-5 subunit (muscle type) has higher maximal velocity (Vmax) and is present in glycolytic tissues, favoring the formation of lactate from pyruvate. The LDH-1 subunit (heart type) is inhibited by pyruvate and therefore preferentially drives the reaction toward the production of pyruvate. There is mounting evidence indicating that during activation the brain resorts to the transient glycolytic processing of glucose. Indeed, transient lactate formation during physiological stimulation has been shown by 1H-magnetic resonance spectroscopy. However, since whole-brain arteriovenous studies under basal conditions indicate a virtually complete oxidation of glucose, the vast proportion of the lactate transiently formed during activation is likely to be oxidized. These in vivo data suggest that lactate may be formed in certain cells and oxidized in others. We therefore set out to determine whether the two isoforms of lactate dehydrogenase are localized to selective cell types in the human brain. We report here the production and characterization of two rat antisera, specific for the LDH-5 and LDH-1 subunits of lactate dehydrogenase, respectively. Immunohistochemical, immunodot, and western-blot analyses show that these antisera specifically recognize their homologous antigens. Immunohistochemistry on 10 control cases demonstrated a differential cellular distribution between both subunits in the hippocampus and occipital cortex: neurons are exclusively stained with the anti-LDH1 subunit while astrocytes are stained by both antibodies. These observations support the notion of a regulated lactate flux between astrocytes and neurons.

Selective inhibition of CTL activation by a dipalmitoyl-phospholipid that prevents the recruitment of signaling molecules to lipid rafts.

Antigen-specific T-cell activation implicates a redistribution of plasma membrane-bound molecules in lipid rafts, such as the coreceptors CD8 and CD4, the Src kinases Lek and Fyn, and the linker for activation of T cells (LAT), that results in the formation of signaling complexes. These molecules partition in lipid rafts because of palmitoylation of cytoplasmic, membrane proximal cysteines, which is essential for their functional integrity in T-cell activation. Here, we show that exogenous dipalmitoyl-phosphatidylethanolamine (DPPE), but not the related unsaturated dioleoyl-phosphatidylethanolamine (DOPE), partitions in lipid rafts. DPPE inhibits activation of CD8(+) T lymphocytes by sensitized syngeneic antigen-presenting cells or specific major histocompatibility complex (MHC) peptide tetramers, as indicated by esterase release and intracellular calcium mobilization. Cytotoxic, T lymphocyte (CTL)-target cell conjugate formation is not affected by DPPE, indicating that engagement of the T-cell receptor by its cognate ligand is intact in lipid-treated cells. In contrast to other agents known to block raft-dependent signaling, DPPE efficiently inhibits the MHC peptide-induced recruitment of palmitoylated signaling molecules to lipid rafts and CTL activation without affecting cell viability or lipid raft integrity.