Sensitivity analysis in a radiological impact assessment of a nuclear power plant discharge. A comparison of the Morris, Spearman and Sobol' approaches.

This paper compares the Morris, Spearman and Sobol' methods of sensitivity analysis in radiological risk assessment. The determination of the most influential parameters on model with regards to the propagation of their uncertainties to output variables, is of greatest interest. This study aims to determine the relative importance of parameters uncertainties on the dose calculation uncertainty in the framework of a scenario of routine discharges discussed in the context of an IAEA working group. The scenario considers atmospheric and liquid discharges of three different types of radionuclides (14C, tritium as HTO and 110mAg) from a nuclear power plant located by the side of a river. It is concluded that the most reliable and practical method according to the ability of ranking influential parameters and the easiness of its application is the Spearman method. As key result, the three first influential variables for annual total dose for all pathways and all radionuclides were the water dissolved inorganic carbon concentration, the volatilisation rate constant and the soil layer solid liquid distribution in 14C.

Clustering and Erratic Movement Patterns of Syringe-Injected versus Mosquito-Inoculated Malaria Sporozoites Underlie Decreased Infectivity.

Malaria vaccine candidates based on live, attenuated sporozoites have led to high levels of protection. However, their efficacy critically depends on the sporozoites' ability to reach and infect the host liver. Administration via mosquito inoculation is by far the most potent method for inducing immunity but highly impractical. Here, we observed that intradermal syringe-injected Plasmodium berghei sporozoites (syrSPZ) were 3-fold less efficient in migrating to and infecting mouse liver than mosquito-inoculated sporozoites (msqSPZ). This was related to a clustered dermal distribution (2-fold-decreased median distance between syrSPZ and msqSPZ) and, more importantly, a 1.4-fold (significantly)-slower and more erratic movement pattern. These erratic movement patterns were likely caused by alteration of dermal tissue morphology (>15-µm intercellular gaps) due to injection of fluid and may critically decrease sporozoite infectivity. These results suggest that novel microvolume-based administration technologies hold promise for replicating the success of mosquito-inoculated live, attenuated sporozoite vaccines.IMPORTANCE Malaria still causes a major burden on global health and the economy. The efficacy of live, attenuated malaria sporozoites as vaccine candidates critically depends on their ability to migrate to and infect the host liver. This work sheds light on the effect of different administration routes on sporozoite migration. We show that the delivery of sporozoites via mosquito inoculation is more efficient than syringe injection; however, this route of administration is highly impractical for vaccine purposes. Using confocal microscopy and automated imaging software, we demonstrate that syringe-injected sporozoites do cluster, move more slowly, and display more erratic movement due to alterations in tissue morphology. These findings indicate that microneedle-based engineering solutions hold promise for replicating the success of mosquito-inoculated live, attenuated sporozoite vaccines.

First full-length sequences of the S gene of European isolates reveal further diversity among turkey coronaviruses.

An increasing incidence of enteric disorders clinically suggestive of the poult enteritis complex has been observed in turkeys in France since 2003. Using a newly designed real-time reverse transcriptase-polymerase chain reaction assay specific for the nucleocapsid (N) gene of infectious bronchitis virus (IBV) and turkey coronaviruses (TCoV), coronaviruses were identified in 37% of the intestinal samples collected from diseased turkey flocks. The full-length spike (S) gene of these viruses was amplified, cloned and sequenced from three samples. The French S sequences shared 98% identity at both the nucleotide and amino acid levels, whereas they were at most 65% and 60% identical with North American (NA) TCoV and at most 50% and 37% identical with IBV at the nucleotide and amino acid levels, respectively. Higher divergence with NA TCoV was observed in the S1-encoding domain. Phylogenetic analysis based on the S gene revealed that the newly detected viruses form a sublineage genetically related with, but significantly different from, NA TCoV. Additionally, the RNA-dependent RNA polymerase gene and the N gene, located on the 5' and 3' sides of the S gene in the coronavirus genome, were partially sequenced. Phylogenetic analysis revealed that both the NA TCoV and French TCoV (Fr TCoV) lineages included some IBV relatives, which were however different in the two lineages. This suggested that different recombination events could have played a role in the evolution of the NA and Fr TCoV. The present results provide the first S sequence for a European TCoV. They reveal extensive genetic variation in TCoV and suggest different evolutionary pathways in North America and Europe.

Blood schizontocidal activity of methylene blue in combination with antimalarials against Plasmodium falciparum.

Methylene blue (MB) is the oldest synthetic antimalarial. It is not used anymore as antimalarial but should be reconsidered. For this purpose we have measured its impact on both chloroquine sensitive and resistant Plasmodium strains. We showed that around 5 nM of MB were able to inhibit 50% of the parasite growth in vitro and that late rings and early trophozoites were the most sensitive stages; while early rings, late trophozoites and schizonts were less sensitive. Drug interaction study following fractional inhibitory concentrations (FIC) method showed antagonism with amodiaquine, atovaquone, doxycycline, pyrimethamine; additivity with artemether, chloroquine, mefloquine, primaquine and synergy with quinine. These results confirmed the interest of MB that could be integrated in a new low cost antimalarial combination therapy.

Validation of use of a traditional antimalarial remedy from French Guiana, Zanthoxylum rhoifolium Lam.

Zanthoxylum rhoifolium bark (Rutaceae) is a medicinal plant, traditionally used in French Guiana to treat and prevent malaria. Bioassay-guided extractions of Zanthoxylum rhoifolium bark have shown that antiplasmodial activity is concentrated in the alkaloid fraction. Further fractionation of this extract has yielded seven benzophenanthridine alkaloids, dihydroavicine 1, dihydronitidine 2, oxyavicine 3, oxynitidine 4, fagaridine 5, avicine 6 and nitidine 7. Antimalarial activity of the last five compounds has been evaluated, and nitidine was the most potent, displaying an IC(50)<0.27microM against Plasmodium falciparum. Investigation of the traditional remedy, a trunk bark decoction in water, has shown that fagaridine 5, avicine 6 and nitidine 7 are also present in the decoction, therefore justifying the traditional use of Zanthoxylumrhoifolium bark as antimalarial.

Palatable fluids do not affect alcohol intake and its reduction by serotonergic compounds in alcohol-preferring cAA rats.

1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane (DOI) decreases alcohol intake by alcohol-preferring cAA rats more selectively than fluoxetine in a two-bottle alcohol vs. water paradigm. We report now that availability of sucrose or saccharin in a 3rd bottle does not affect (1) alcohol intake, supporting further the validity of this model of alcoholism, nor (2) the selectivity profile of the alcohol intake-reducing effects of these compounds. It is hypothesized that reduction of alcohol intake by DOI is not simply due to decreased intake of palatable fluids.

Contrasting mechanisms of action and sensitivity to antipsychotics of phencyclidine versus amphetamine: importance of nucleus accumbens 5-HT2A sites for PCP-induced locomotion in the rat.

In the present study, the comparative mechanisms of action of phencyclidine (PCP) and amphetamine were addressed employing the parameter of locomotion in rats. PCP-induced locomotion (PLOC) was potently blocked by the selective serotonin (5-HT)2A vs. D2 antagonists, SR46349, MDL100,907, ritanserin and fananserin, which barely affected amphetamine-induced locomotion (ALOC). In contrast, the selective D2 vs. 5-HT2A antagonists, eticlopride, raclopride and amisulpride, preferentially inhibited ALOC vs. PLOC. The potency of these drugs and 12 multireceptorial antipsychotics in inhibiting PLOC vs. ALOC correlated significantly with affinities at 5-HT2A vs. D2 receptors, respectively. Amphetamine and PCP both dose dependently increased dialysate levels of dopamine (DA) and 5-HT in the nucleus accumbens, striatum and frontal cortex (FCX) of freely moving rats, but PCP was proportionally more effective than amphetamine in elevating levels of 5-HT vs. DA in the accumbens. Further, whereas microinjection of PCP into the accumbens elicited locomotion, its introduction into the striatum or FCX was ineffective. The action of intra-accumbens PCP, but not intra-accumbens amphetamine, was abolished by SR46349 and clozapine. Parachloroamphetamine, which depleted accumbens pools of 5-HT but not DA, likewise abolished PLOC without affecting ALOC. In contrast, intra-accumbens 6-hydroxydopamine (6-OHDA), which depleted DA but not 5-HT, abolished ALOC but only partially attenuated PLOC. In conclusion, PLOC involves (indirect) activation of accumbens-localized 5-HT2A receptors by 5-HT. PLOC is, correspondingly, more potently blocked than ALOC by antipsychotics displaying marked affinity at 5-HT2A receptors.

5-HT receptor ligands differentially affect operant oral self-administration of ethanol in the rat.

The present study evaluated the effects of the selective serotonin (5-hydroxyhyptamine; 5-HT) reuptake inhibitor, fluoxetine, the 5-HT1B receptor agonist, tetrahydro-4-pyridyl[3,2-b]pyridine, CP-94,253 the preferential 5-HT2A receptor agonist, 1-(2,5-dimethoxy-4 iodophenyl)-2-aminopropane, DOI and the mixed 5-HT2C/1B receptor agonist, 1-(3-chlorophenyl)piperazine, mCPP, on oral ethanol (10% v/v) self-administration in a two-lever, fixed-ratio:1, water vs. ethanol choice procedure in the rat. All compounds affected operant behavior, with varying degrees of specificity, that is, the extent to which a reduction of ethanol-reinforced lever pressing coincided with a reduction of ethanol preference, and selectivity, that is, the extent to which a reduction of ethanol-reinforced lever pressing could be dissociated from an effect on total responding on both levers. Fluoxetine (5-20 mg/kg, i.p.) and CP-94,253 (1-10 mg/kg, i.p.) induced a nonselective disruption of operant behavior; the profile being weakly specific for CP-94,253. DOI (0.1-0.3 mg/kg, i.p.) and mCPP (0.3-1 mg/kg, i.p.) induced a specific effect; the profile being more selective for DOI. These findings suggest that operant ethanol self-administration can be suppressed in a specific manner by activation of 5-HT2A and, possibly, 5-HT2C receptors, and in a nonselective manner by activation of 5-HT1B receptors. As fluoxetine indirectly stimulates these receptors and its behavioral profile resembles more that of a 5-HT1B receptor agonist, activation of 5-HT1B receptors may underlie its effects on operant ethanol self-administration.

Comparison of the effects of the selective serotonin-reuptake inhibitors fluoxetine, paroxetine, citalopram and fluvoxamine in alcohol-preferring cAA rats.

Clinical studies indicate that selective serotonin-reuptake inhibitors (SSRIs) may decrease alcohol intake and craving in particular subgroups of alcoholics. The aim of the present study was to compare the behavioral profile of various SSRIs in alcohol-preferring cAA rats, a genetic model of alcoholism. The effects of acute IP administration of fluoxetine (doses in mg/kg 1-10), citalopram (3-30), fluvoxamine (3-30) and paroxetine (1-10) on ethanol (EtOH) intake and preference, as well as food and total fluid intake, were determined in a 12-h access, water vs. 10% v/v EtOH two-bottle choice paradigm. Each compound reduced EtOH intake [Minimal Effective Doses (MEDs) 5, 10, 30 and 1 mg/kg for fluoxetine, citalopram, fluvoxamine, and paroxetine, respectively]. The degree of selectivity, that is, the extent to which reductions in EtOH intake could be separated from reductions in food and/or total fluid intake varied across the compounds. Thus, whereas EtOH intake was more markedly affected than food intake by fluoxetine, both parameters were equally affected by citalopram, and food intake was more markedly affected than EtOH intake by fluvoxamine and paroxetine. The anti-alcohol effect also differed with respect to specificity, that is, the degree to which effects on EtOH intake coincided with effects on EtOH preference. Whereas fluoxetine showed the highest level of specificity, followed by citalopram and fluvoxamine, the effect of paroxetine was nonspecific. The observed variation in the degree of selectivity and specificity of the anti-alcohol effect of SSRIs suggests that reductions in EtOH intake are not merely a consequence of a general suppressive effect on consummatory behavior. It is hypothesized that differences between the behavioral profiles of these compounds reflect a differential involvement of 5-HT receptor subtypes.

5-HT2A and 5-HT2C/5-HT1B receptors are differentially involved in alcohol preference and consummatory behavior in cAA rats.

The present study aimed to investigate the role of serotonin 5-HT2A and 5-HT2C receptors in the control of alcohol preference and consummatory behavior in alcohol-preferring cAA rats. Effects of the 5-HT(2A/2C) receptor agonist, DOI, the 5-HT(2C/1B) receptor agonist, mCPP, the 5-HT(2A/2C) receptor antagonist, ritanserin, and the 5-HT2A receptor antagonist, MDL 100,907, on ethanol (EtOH, 10% v/v) preference and intake, as well as total fluid and food intake were evaluated in a 12-h limited-access two-bottle paradigm. DOI (0.3-3 mg/kg, i.p.) reduced EtOH intake and preference, but not total fluid or food intake; whereas mCPP (1-10 mg/kg, s.c.) reduced EtOH, total fluid, and food intake. Therefore, it is concluded that DOI induces a specific and selective antialcohol effect, whereas mCPP rather induces a general suppressive effect on consummatory behavior. Ritanserin (1-10 mg/kg, i.p.) did not affect EtOH intake and preference, nor total fluid and food consumption. MDL 100,907 (0.1-1 mg/kg, i.p.) induced only a small reduction of food intake at the highest dose tested. Pretreatment with ritanserin (3 mg/kg, i.p.) and MDL 100,907 (0.3 mg/kg, i.p.) blocked the effects of DOI (3 mg/kg, i.p.), but not those of mCPP (10 mg/kg, i.p.). It is suggested that activation of 5-HT2C and/or 5-HT1B receptors results in a general decrease of consummatory behavior, whereas activation of 5-HT2A receptors selectively decreases EtOH intake and preference, as assessed in the cAA rat model of alcoholism.

Comparison of hypericum extracts with imipramine and fluoxetine in animal models of depression and alcoholism.

Clinical evidence suggests that hypericum extracts (Hypericum perforatum L., St. John's wort) have antidepressive properties and may offer an interesting alternative for the treatment of mood disorders. In addition, hypericum extracts, as well as standard antidepressants such as the tricyclic, impramine, and the selective serotonin reuptake inhibitor, fluoxetine, have been reported to be of therapeutic benefit in the treatment of alcoholism, as these compounds may reduce alcohol craving and/or intake in particular subgroups of patients. It was the aim of the present study to compare the effects of hypericum extracts with those of imipramine and fluoxetine in the rat forced swimming test (RFST), a model of depression, as well as in cAA rats, a genetic model of alcoholism. In the RFST, triple i.p. administration of imipramine (3-30 mg/kg) and fluoxetine (3-30 mg/kg) induced a dose-dependent reduction in immobility: the minimal effective dose (MED) being 30 and 10 mg/kg, and the maximal effect being 50% and 57% immobility reduction, for imipramine and fluoxetine, respectively. In this test, the hypericum extracts Ze 117 (Remotiv) and LI 160 (Jarsin) also induced a statistically significant reduction of immobility when administered under the same application schedule (5-40 mg/kg, i.p., triple application). In the case of the hypericum extracts the dose-response relationship was inverted U-shaped with a MED value of 20 mg/kg and a maximal effect of 41% and 32% immobility reduction, for Ze 117 and LI 160, respectively. Interestingly, the anti-immobility effects tended to be more pronounced after subacute (1 week, B.I.D.) treatment with 10 mg/kg of imipramine, fluoxetine, or Ze 117, as compared with acute treatment. This phenomenon is in accordance with clinical experience and suggests that repeated treatment is required for full development of antidepressive effects. In the alcohol-preferring cAA rats, acute i.p. administration of imipramine (3-30 mg/kg), fluoxetine (1-10 mg/kg) and Ze 117 (10-40 mg/kg) dose-dependently reduced alcohol intake in a 12-h limited access two-bottle [ethanol 10% (v/v) versus water] choice procedure: with MED values of 30, 5 and 20 mg/kg, respectively. The anti-alcohol effects of fluoxetine and Ze 1-17 appeared to be specific, as reductions in alcohol intake coincided with reductions in alcohol preference. The present study suggests that hypericum extracts have antidepressant-like properties which resemble those of clinically established antidepressants, and that Remotiv may be an interesting adjunct for the treatment of alcoholism.

Role of 5-HT1B, 5-HT2A and 5-HT2C receptors in the generalization of 5-HT receptor agonists to the ethanol cue in the rat.

Although accumulating evidence suggests that serotonergic drugs are able to substitute for the ethanol (EtOH) cue in rats, it is still unclear which 5-HT receptor subtypes are responsible for this phenomenon, and whether these receptors are critically involved in the EtOH cue. In the present study, rats were trained to discriminate EtOH (1000 mg/kg, i.p., t-15 min) from saline in a two-lever food-reinforced procedure, and it was investigated to which extent serotonergic compounds with a certain level of specificity for either 5-HT1B, 5-HT2A or 5-HT2C receptors generalized to the EtOH cue. Subsequently, the involvement of these receptor subtypes was ascertained by the use of selected 5-HT receptor antagonists. The 5-HT1B receptor agonist CP 94,253 (0.3-5 mg/kg, i.p.) and the mixed 5-HT(2C/1B) receptor agonist mCPP (0.1-1 mg/kg, i.p.), but not the preferential 5-HT2A receptor agonist DOI (0.3-1 mg/kg, i.p.), completely generalized to the EtOH cue. Complete generalization of the former two compounds coincided with a decrease in response rate. In antagonism studies, it was shown that the 5-HT1B receptor antagonist GR 127935 (10 mg/kg, i.p.) completely blocked generalization of CP 94,253 to the EtOH cue, suggesting that stimulation of 5-HT1B receptors produces discriminative stimulus effects which are similar to those of EtOH. GR 127935 (10 mg/kg, i.p.), as well as the mixed 5-HT(1B/2C) receptor antagonist metergoline (1 mg/kg, i.p.), and the 5-HT2C receptor antagonist SB 206,553 (1 mg/kg, i.p.) completely blocked generalization of mCPP to the EtOH cue. This suggests that 5-HT1B and 5-HT2C receptors are required for the generalization of mCPP to the EtOH cue. The present findings indicate that activation of 5-HT1B and 5-HT2C, but not of 5-HT2A receptors, mimics the EtOH cue. However, the finding that neither metergoline, nor the 5-HT2A receptor antagonist MDL 100,907 blocked the EtOH cue, suggests that these receptors play only a minor role in the discriminative stimulus effects of a moderately low dose of EtOH.

Substitution of the selective serotonin reuptake inhibitors fluoxetine and paroxetine for the discriminative stimulus effects of ethanol in rats.

Rats trained to discriminate ethanol (EtOH, 1 g/kg IP) from saline in a two-lever procedure completely generalized to the selective serotonin reuptake inhibitors (SSRIs) fluoxetine and paroxetine. Substitution of fluoxetine was completely blocked by the selective 5-HT2A receptor antagonist MDL 100,907 and not affected by the selective 5-HT1A receptor antagonist WAY-100635. It is suggested that the previously reported effectiveness of SSRIs in reducing EtOH consumption could be based on similarities in discriminative stimulus effects of SSRIs and EtOH. Stimulation of 5-HT2A receptors may underlie these stimulus similarities and contribute to the EtOH intake-reducing effects of SSRIs.

Expanded polytetrafluoroethylene arterial prostheses in humans: histopathological study of 298 surgically excised grafts.

The expanded polytetrafluoroethylene vascular prosthesis is considered to be the best synthetic alternative for peripheral arterial reconstruction. Most studies on the healing characteristics of expanded polytetrafluoroethylene prostheses have been carried out on animals, and very few data are available on prosthesis implanted in humans long term. We implanted 298 expanded polytetrafluoroethylene grafts as arterial substitutes in humans. The mean duration of implantation was 523 d and the grafts were implanted mainly for infrainguinal or axillofemoral bypass. The cellular and collagen infiltration of the microporous expanded polytetrafluoroethylene structure was generally poor. Infiltration occurred mainly in the external region of the prosthetic wall and increased with the duration of implantation. The external reinforcement was not a major factor in limiting tissue infiltration. The luminal surfaces were covered with a thin, irregular layer of organized fibrin, interspersed with exposed expanded polytetrafluoroethylene areas. Mineral deposits were observed in five cases. Despite poor healing, the clinical performance of expanded polytetrafluoroethylene vascular prostheses is relatively good. Since the chief advantage of this material is good mechanical stability in vivo, any modifications of the graft to improve healing characteristics or thrombogenic properties should not be made at the expense of stability in vivo.

Expanded polytetrafluoroethylene arterial prostheses in humans: chemical analysis of 79 explanted specimens.

The expanded polytetrafluoroethylene (ePTFE) vascular prostheses are widely used as small and medium diameter blood conduits when an autologous venous material is not available or is not suitable. The long-term performance of a prosthesis is dependent on several factors, including its healing characteristics and its stability in vivo. This study was undertaken to assess whether chemical degradation of ePTFE occurs when such arterial substitutes are implanted in humans. Seventy-nine ePTFE grafts excised for complications were analysed using the following techniques: measurement of the contact angle (theta), electron spectroscopy for chemical analysis (ESCA or XPS), Fourier transform infra-red spectroscopy (FTIR) and differential scanning calorimetry (DSC). The results were compared with those obtained from virgin ePTFE and virgin ePTFE washed prostheses. The measurement of the contact angle (theta) permits the comparison of the level of hydrophobicity of material after in vivo residency. The contact angles of explanted ePTFE grafts are greater than those of virgin ones but remain close to those of washed virgin prostheses. The ESCA method allowed investigation of the chemical changes which occur on the surface of ePTFE prostheses after implantation because of the low penetration of the X-ray (about 50 A). This study did not reveal any chemical degradation of the ePTFE with time of implantation for periods up to 6.5 yr. Changes in the surface composition were probably related to lipid and/or protein uptake. The FTIR spectroscopy provides information about the chemical composition of material. Compared with the virgin ePTFE prostheses, the FTIR spectra of explanted prostheses showed specific bands which are characteristic of lipid and/or protein absorptions. The bulk properties of ePTFE studied by DSC did not show any significant changes with time of implantation. It is concluded that ePTFE grafts remain stable in vivo for periods up to 6.5 yr.