The Fluorocycline TP-271 Is Efficacious in Models of Aerosolized Francisella tularensis SCHU S4 Infection in BALB/c Mice and Cynomolgus Macaques.

TP-271 is a novel, fully synthetic fluorocycline in development for complicated bacterial respiratory infections. TP-271 was active in vitro against a panel of 29 Francisella tularensis isolates, showing MICs against 50% and 90% of isolates of 0.25 and 0.5 µg/ml, respectively. In a mouse model of inhalational tularemia, animals were exposed by aerosol to 91 to 283 50% lethal doses (LD50)/mouse of F. tularensis SCHU S4. Following 21 days of once-daily intraperitoneal dosing with TP-271 at 3, 6, 12, and 18 mg/kg of body weight/day, initiating at 24 h postchallenge, survival was 80%, 100%, 100%, and 100%, respectively. When treatment was initiated at 72 h postchallenge, survival was 89%, 100%, 100%, and 100% in the 3-, 6-, 12-, and 18-mg/kg/day TP-271 groups, respectively. No mice treated with the vehicle control survived. Surviving mice treated with TP-271 showed little to no relapse during 14 days posttreatment. In a nonhuman primate model of inhalational tularemia, cynomolgus macaques received an average aerosol exposure of 1,144 CFU of F. tularensis SCHU S4. Once-daily intravenous infusion with 1 or 3 mg/kg TP-271, or vehicle control, for 21 days was initiated within 6 h of confirmed fever. All animals treated with TP-271 survived to the end of the study, with no relapse during 14 days after the last treatment, whereas no vehicle control-treated animals survived. The protection and low relapse afforded by TP-271 treatment in these studies support continued investigation of TP-271 for use in the event of aerosolized exposure to F. tularensis.

Better, worse, or different than expected: on the role of value and identity prediction errors in fear memory reactivation.

Although reconsolidation-based interventions constitute a promising new avenue to treating fear and anxieties disorders, the success of the intervention is not guaranteed. The initiation of memory reconsolidation is dependent on whether a mismatch between the experienced and predicted outcome-a prediction error (PE)-occurs during fear memory reactivation. It remains, however, elusive whether any type of PE renders fear memories susceptible to reconsolidation disruption. Here, we investigated whether a value PE, elicited by an outcome that is better or worse than expected, is necessary to make fear memories susceptible to reconsolidation disruption or whether a model-based identity PE, i.e., a PE elicited by an outcome equally aversive but different than expected, would be sufficient. Blocking beta-adrenergic receptors with propranolol HCl after reactivation did, however, not reduce the expression of fear after either type of PE. Instead, we observed intact fear memory expression 24 h after reactivation in the value-, identity- and a no-PE control group. The present results do not corroborate our earlier findings of reconsolidation disruption and point towards challenges that the field is currently facing in observing evidence for memory reconsolidation at all. We provide potential explanations for the unexpected failure of replicating reconsolidation disruption and discuss future directions.

Rapid in vivo transport and catabolism of human apolipoprotein A-IV-1 and slower catabolism of the apoA-IV-2 isoprotein.

Apolipoprotein (apo) A-IV is a polymorphic, intestinally derived apolipoprotein that is genetically linked to and similar in structure to apoA-I, the major apolipoprotein in high density lipoproteins (HDL). ApoA-IV plays a potentially important role in lipoprotein metabolism and reverse cholesterol transport, but its in vivo metabolism is poorly understood. In order to gain insight into factors modulating apoA-IV metabolism in humans, the in vivo kinetics of the two major human apoA-IV isoproteins apoA-IV-1 and apoA-IV-2 were investigated in normolipidemic human subjects. 131I-apoA-IV-1 and 125I-apoA-IV-2 were reassociated with autologous plasma and injected into study subjects. Analysis of the kinetic data revealed a rapid mean fractional catabolic rate (FCR) for apoA-IV-1 of 2.42 +/- 0.11 d-1. The mean production, or transport, rate of apoA-IV-1 was 16.3 +/- 1.4 mg/kg per d. Plasma apoA-IV concentrations were highly correlated with apoA-IV production rate (r = 0.84, P < 0.001) and not correlated with apoA-IV fractional catabolic rate (r = 0.25, P = NS). The mean FCR of apoA-IV-2 was 2.21 +/- 0.10 d-1. In the ten subjects in whom 131I-apoA-IV-1 and 125I-apoA-IV-2 were simultaneously injected, the FCR of apoA-IV-2 was significantly slower by paired t test (P = 0.003). The FCR of apoA-IV-2 in an apoA-IV-2/2 homozygote was only 1.49 d-1, substantially slower than in all other subjects. We conclude that: (a) apoA-IV is a rapidly catabolized apolipoprotein in humans, with a fractional catabolic rate more than 10 times greater than that of apoA-I; (b) apoA-IV has a high absolute transport rate similar to that of apoA-I; (c) plasma levels of apoA-IV are primarily determined by apoA-IV production rate in normolipidemic subjects; and (d) the fractional catabolic rate of the common variant apoA-IV-2 is slower than that of the wild-type apoA-IV-1.

Thyroxine binding to the apolipoproteins of high density lipoproteins HDL2 and HDL3.

Four preparations of high density lipoprotein HDL2, five of HDL3, and purified apolipoproteins apoA-I, apoA-IV, and apoE were photoaffinity labeled with [125I]T4 and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Gels were also immunoblotted with antiserum against apoA-I, apoA-II, apoA-IV, apoE, or apo(a), and the immunostained membrane was then autoradiographed. In HDL2, the two major radioactive bands migrated near the origin of the resolving gel and at 28-31 kilodaltons (kDa). The first band, stained by anti-apo(a) and anti-apoB-100, accounted for 40-96% of the total radioactivity and was attributed to lipoprotein(a), which is isolated in the same density range as HDL2. The second band, stained by anti-apoA-I, accounted for 1-57% [41-95% after correction for contaminating lipoprotein(a)] of the [125I]T4 in the resolving gel. In HDL3, the major radioactive band was identified as apoA-I and contained 93-94% of the [125I]T4 in the resolving gel. Minor radioactive bands in both HDL2 and HDL3 were identified as apoA-II (17-18 kDa), apoA-II monomer (7-10 kDa), apoE (36-38 kDa), and apoAII-apoE heterodimer (46 kDa). In addition, HDL3 contained apoA-IV (43 kDa). Photoaffinity labeling of isolated apoA-IV and apoE showed that each protein interacted with [125I]T4. In both HDL2 and HDL3, photoaffinity labeling in the presence of unlabeled L-T4 (1-10 microM) showed inhibition, suggesting a Kd in the micromolar range. This inhibition varied among different apo bands of the same HDL2 or HDL3 preparation and among the same bands of different preparations. Labeling in the presence of heparin or other inhibitors of T4 binding to plasma proteins (furosemide, diclofenac, and mefenamic acid) showed that HDL2-associated apoA-I was more sensitive to inhibition than HDL3-associated apoA-I. In conclusion, 1) HDL2 and HDL3 carry T4 mainly through apoA-I and secondarily through apoA-II and apoE. The inter- and intrasubclass variations in T4 binding and sensitivity to inhibitors can be explained by the known heterogeneity of HDL particles and possible differences in conformation of the apo. The findings reported here, that apo other than apoA-I and apoB exhibit saturable binding of T4, suggest that thyroid hormone-lipoprotein interactions may have even wider physiological implications than previously appreciated.

Role for monoamine oxidase-A (MAO-A) in the bioactivation and nigrostriatal dopaminergic neurotoxicity of the MPTP analog, 2'Me-MPTP.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration leads to the selective destruction of the dopaminergic neurons of the nigrostriatal pathway in experimental animals including monkeys and mice. The neurotoxicity of MPTP is dependent upon its monoamine oxidase-B (MAO-B)-catalyzed conversion to the 1-methyl-4-phenylpyridinium species (MPP+). A methylated analog of MPTP. A methylated analog of MPTP, namely 1-methyl-4-(2'-methylphenyl)-1,2,3,6-tetrahydropyridine (2'Me-MPTP), is a more potent dopaminergic neurotoxin than MPTP in mice. Although the selective inhibition of MAO-B is sufficient to protect mice against MPTP-induced neurotoxicity, it is reported here that complete inhibition of MAO-B failed to prevent 2'Me-MPTP-induced dopaminergic neurotoxicity. However, the neurotoxicity of 2'Me-MPTP was completely prevented and 2'Me-MPP+ formation was markedly attenuated in mice in which both MAO-A and MAO-B were almost totally inhibited. This information about the role of MAO-A in the bioactivation of 2'Me-MPTP may be of relevance to those who speculate that the MAO-B catalyzed bioactivation of MPTP or a similar compound may be the cause of idiopathic Parkinson's disease.

1-Methyl-4-(2'-methylphenyl)-1,2,3,6-tetrahydropyridine (2'-CH3-MPTP) is a more potent dopaminergic neurotoxin than MPTP in mice.

The administration to mice of 1-methyl-4-(2'-methylphenyl)-1,2,3, 6-tetrahydropyridine (2'-CH3-MPTP), a substituted analog of the dopaminergic neurotoxin MPTP caused even more dopaminergic toxicity than MPTP itself. Under conditions in which MPTP was relatively ineffective (i.e. two injections per day of 0.113 mmol/kg at an interval of 6 h for one or two days), 2'-CH3-MPTP caused a very large decrement in the neostriatal content of dopamine and its metabolites and a corresponding decrement in the capacity of a neostriatal synaptosomal preparation to take up [3H]dopamine. Moreover, 2'-CH3-MPTP administration (as few as four injections) caused a virtually complete loss of nerve cells in the zona compacta of the substantia nigra. This compound, like MPTP, may prove to be a valuable research tool.

The urge to smoke depends on the expectation of smoking.

AIMS: An earlier study (Dols et al. 2000) suggested that cue-induced urge to smoke depends on the expectation of smoking. The present study tried to replicate the findings under stringently controlled conditions. DESIGN: A 2 (context) x 2 (cues) x 6 (trial) within-subject design. Each smoker entered two different contexts; one context predicted the future occurrence of smoking (i.e. one puff of a cigarette) and one context predicted the non-occurrence of smoking. In each context smokers were exposed to smoking cues (i.e. cigarettes and lighter) or not. SETTING: Laboratory at Maastricht University. PARTICIPANTS: Thirty-two daily smokers, smoking at least five cigarettes a day for at least 2 years. MEASUREMENTS: Participants reported their urge to smoke in each context in the presence and absence of smoking cues using a computerized visual analogue scale (VAS). FINDINGS: The results revealed that the urge to smoke was higher in a context in which smoking was expected relative to a context in which it was not expected. As in the previous study the urge-inducing effect of smoking cues was larger in the smoking context than in the non-smoking context. Moreover, smoking cues did not have a significant effect in the non-smoking context. CONCLUSIONS: It was shown that smoking cues elicit craving due mainly to a generated expectation of the occurrence of smoking and less due to salience or long history of associative learning. Theoretical and practical implications of the results are discussed.

Phobia-related cognitive bias for pictorial and linguistic stimuli.

The purpose of this study was to examine whether anxiety-related cognitive bias for threat is stronger for threatening pictures than for threatening words. Spider-phobic participants (n = 31) and control participants (n = 33) performed a pictorial and linguistic spider Stroop task. Spider-phobic participants showed a marked bias for threat. However, this bias was similar for pictures and for words, although the spider-phobic group evaluated the pictures as being more aversive. The results suggest that automatic processing of threatening information in people with phobias is triggered in an on-off fashion, independent of subjective threat of the stimuli. This lack of distinction in automatic processing of weak and strong predictors of danger may be fundamental to the irrational nature of anxiety disorders.

Thyroid hormone binding to isolated human apolipoproteins A-II, C-I, C-II, and C-III: homology in thyroxine binding sites.

Thyroid hormone binding to lipid-free apolipoprotein (apo) A-II, C-I, C-II, and C-III isolated from human plasma was investigated by photoaffinity labeling with [125I]T4 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Both the monomeric and polymeric forms were specifically labeled. Inhibition by 10 microM unlabeled L-T4 was > or = 50%, suggesting affinity constants in the nM to microM range; the least inhibition was seen with apoA-II. Unlabeled D-T4 and reverse T3 (rT3) gave the same inhibition as unlabeled L-T4. Inhibitors of thyroid hormone binding to plasma proteins showed a different inhibitor potency with each apolipoprotein and a pattern different from that seen with T4 binding globulin (TBG) and transthyretin (TTR). Also in contrast to TBG, where only unsaturated nonesterified fatty acids (NEFA) are effective inhibitors, both unsaturated and saturated NEFA as well as other lipids inhibited T4 labeling. The flavonoid EMD 21388 was ineffective, confirming that it is a selective inhibitor of T4 binding to TTR. T4 binding to the apoCs was confirmed by the quenching of tryptophan fluorescence by unlabeled L-T4. (ApoA-II was not studied since it lacks tryptophan). Since the self-association of apolipoproteins involves interaction between amphipathic alpha-helices, and since the polymeric forms show specific T4 binding properties as in the parent monomer, the T4-binding domain appears to be outside the alpha-helical domain, as previously seen with apoA-I.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced dopaminergic toxicity in mice by MDL 72145, a selective inhibitor of MAO-B.

Pretreatment of mice with the potent and selective monoamine oxidase B (MAO-B) inhibitor MDL 72145 ((E)-2-(3',4'-dimethoxyphenyl)-3-fluoroallylamine) protected against the dopaminergic neurotoxicity of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Mice treated with MDL 72145 prior to MPTP did not exhibit the decrement in the neostriatal content of dopamine and its metabolites normally seen after MPTP administration. This observation adds further support to the concept that the oxidation of MPTP by MAO-B to its corresponding pyridinium analog, 1-methyl-4-phenylpyridinium (MPP+), is an important feature of the neurotoxic process.

MPTP, MPP+ and mitochondrial function.

1-Methyl-4-phenylpyridinium (MPP+), the putative toxic metabolite of the neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), inhibited NAD(H)-linked mitochondrial oxidation at the level of Complex I of the electron transport system. MPTP and MPP+ inhibited aerobic glycolysis in mouse striatal slices, as measured by increased lactate production; MPTP-induced effects were prevented by inhibition of monoamine oxidase B activity. Several neurotoxic analogs of MPTP also form pyridinium metabolites via MAO; these MPP+ analogs were all inhibitors of NAD(H)-linked oxidation by isolated mitochondria. 2'-Methyl-MPTP, a more potent neurotoxin in mice than MPTP, was also more potent than MPTP in inducing lactate accumulation in mouse brain striatal slices. Overall, the studies support the hypothesis that compromise of mitochondrial oxidative capacity is an important factor in the mechanisms underlying the toxicity of MPTP and similar compounds.

Different effects of monoamine oxidase inhibition on MPTP depletion of heart and brain catecholamines in mice.

Pargyline, an inhibitor of monoamine oxidase type B (MAO-B), did not prevent the depletion of heart norepinephrine 24 hr after a single dose of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) in mice. In mice killed 24 hr after the last of 4 daily doses of MPTP, the depletion of dopamine in the striatum and of norepinephrine in the frontal cortex was completely prevented by pargyline, but the depletion of heart norepinephrine was not prevented. These results with pargyline are the same as results obtained earlier with deprenyl, another selective inhibitor of MAO-B. The doses of pargyline and of deprenyl that were used resulted in almost complete inhibition of MAO-B activity (phenylethylamine as substrate) in brain, heart and liver of mice. Deprenyl did not inhibit MAO-A activity (serotonin as substrate) in brain, but pargyline caused some inhibition of MAO-A in brain. In heart and liver, serotonin was oxidized only at about 1/10 the rate of phenylethylamine oxidation, suggesting that MAO-B predominates in these tissues. Both pargyline and deprenyl caused some inhibition of serotonin deamination in heart and liver, suggesting that the oxidation may have been due partly to MAO-B. Experiments with selective MAO inhibitors in vitro showed that only about 20% of the oxidation of serotonin was occurring via MAO-B in heart and liver. The in vitro oxidation of MPTP by MAO in mouse brain, heart and liver was almost completely inhibited by pretreatment with either pargyline or deprenyl. Neither pargyline nor deprenyl had any significant effect on the concentrations of MPTP in brain or heart one-half hr after injection of MPTP into mice. The concentrations of the metabolite, MPP+ (1-methyl-4-phenyl-pyridinium), were markedly reduced in brain and in heart by pretreatment with either pargyline or deprenyl. The data suggest that MPP+ formation, which is necessary for the depletion of brain catecholamines after MPTP injection, may not be necessary for depletion of norepinephrine in heart. Since the oxidation of MPTP in vitro was inhibited more by pargyline or deprenyl pretreatment than was the appearance of MPP+ in vivo, the possibility exists that some MPP+ formation might occur by an enzyme other than MAO.

Spider phobia questionnaire for children (SPQ-C): a psychometric study and normative data.

The purpose of this study was to develop a reliable and valid questionnaire to assess spider fear in children. The Spider Phobia Questionnaire for adults was adapted for children by simplifying items and by assessing situations relevant to children. The SPQ for children (SPQ-C) was administered to two non-clinical samples of children aged 8-12. The first sample consisted of 586 Ss who filled in the SPQ-C twice, with a retest interval of 6-7 weeks. Internal consistency and test-retest reliability were high. The second sample consisted of 669 children of which 28 spider phobic and 30 nonphobic girls were selected for the Behavioural Approach Test (BAT). The SPQ-C predicted BAT scores, thus supporting the validity of the questionnaire as a measure of spider fear. Norms for the SPQ-C, based on the total sample of children, are provided.

Illusory correlation and social anxiety.

An illusory correlation (IC) experiment examined the presence of a phobia-relevant covariation bias in the context of social anxiety. Low (n = 28) and high (n = 32) social anxious women were shown a series of slides comprising pictures of angry, happy and neutral faces which were randomly paired with either a shock, a siren or nothing. One half of the participants were shown women faces, whereas the other half were shown men faces. Participants indicated outcome expectancies on a trial by trial basis. After the experiment proper they estimated the contingencies of all slide/outcome combinations. Participants showed both an a priori and an a posteriori IC between angry faces and shock. This covariation bias was similar for men and women faces and independent of prior fear. The pattern of results is consistent with the idea that ICs arise from initial expectancies that survive extinction.

Responding to subliminal threat cues is related to trait anxiety and emotional vulnerability: a successful replication of Macleod and Hagan (1992)

Macleod and Hagan (1992) [Behaviour Research and Therapy, 30, 151-161] reported that threat-relevant interference on a masked Stroop task, where neutral and negative words cannot be consciously perceived, is positively correlated with trait anxiety and emotional vulnerability to stressful life events. Their findings were obtained from subjects who were currently stressed. The aim of the present study was to determine whether the Macleod and Hagan findings could be replicated in a sample that was not currently stressed. Using a sample of 32 volunteers, we found a significant correlation between trait anxiety and threat-relevant interference on a masked Stroop. Furthermore, it was found that the single best predictor of vulnerability to life stress was the interference on the masked Stroop. The findings of the present study correspond quite closely to those reported by Macleod and Hagan (1992).

A reaction time paradigm to assess (implicit) complaint-specific dysfunctional beliefs.

We investigated whether an implicit association test (IAT) can be used to assess dysfunctional beliefs in the realm of psychopathology. As a first exploration we therefore constructed a IAT that was designed to differentiate between high and low social anxious individuals. Social situation and neutral words were the targets (e.g. date vs hall), and positive and negative outcomes (e.g. compliment vs rejection) the associated attributes. High social anxious women (N=32) showed the predicted deterioration of task performance if the required responses switched from compatible to incompatible with the idea that social situations are related to negative outcomes and vice versa, whereas the opposite was true for low anxious women (N=32). Thus a modified IAT seems a useful and highly flexible tool to implicitly assess complaint-specific dysfunctional associations and may be a valuable addition to the usual (explicit) self-report measures of patients' beliefs.

Cognitive inhibition in phobia.

OBJECTIVES: The purpose of this study was to investigate whether cognitive bias for threat in anxious individuals may be attributed to a defective inhibition. DESIGN: It was investigated whether phobics and not non-phobics would show a defective inhibition of threat words as compared to neutral words. METHOD: Inhibition was measured by a negative priming task, which was administered to spider phobic participants (N = 29) and non-phobic controls (N = 31). RESULTS: The phobics did not show less negative priming of threatening information. Instead, they showed a general delay on all probe displays that were presented after threatening primes. CONCLUSION: Anxiety is related to defective inhibition of threat, in the sense that this inhibition consumes extra cognitive resources.

Autobiographical memories become less vivid and emotional after eye movements.

OBJECTIVES: To test (1) whether eye movements during retrieval of emotional memories are followed by less vividness and less emotionality of future recollections, (2) whether this effect, if present, is stronger than the effects of a control activity (finger tapping), (3) whether the alleged effects of tapping and eye movements are stronger than a no-movement, control condition (mere imagery), (4) whether reductions in vividness and emotionality after eye movements (and finger tapping) are specific to negative memories or also occur in the case of positive memories. METHOD: Sixty healthy volunteers recalled either positive or negative memories and scored the vividness and emotionality of the recollections. Next, memories were recalled whilst the participant was performing rapid eye movements, finger tapping, or not performing a dual task. Then participants were asked to recall the event again and to rate its vividness and emotionality. RESULTS: Compared to finger tapping and the no-dual-task condition, recollections after eye movements made future recollections less vivid. After eye movements, but not after the other interventions, negative memories became less negative, and positive memories became less positive. CONCLUSION: The findings show that eye movements not only reduce vividness and emotionality of memories during the eye moving, but also affect future recollections, during which no eye movements are made. Some theoretical explanations are discussed. As to clinical implications, it is suggested that if there is a role for eye-movement-based treatments, it is very limited.

High-Level cognition in phobics: abstract anticipatory memory is associated with the attenuation of physiological reactivity to threat.

The extent to which anxious people benefit from exposure-based treatments seems to depend on the degree to which they activate their fear network during exposure. This study was designed to investigate whether the cognitive processing of threat in anxious individuals is dominated by abstract anticipatory memory, and whether this abstract memory mode is related to the incomplete activation of the fear network. Activation of the fear network was assessed during phobic exposure, as evidenced by the initial autonomic reaction. Spider phobics and controls were presented with a threatening imagery script. Half of them were exposed to a real-life spider. Spider phobics memorized relatively more abstract anticipatory descriptions than concrete sensory descriptions when compared with the control subjects. Only in phobic subjects. higher recognition of abstract anticipatory descriptions was inversely related to heart rate reactivity during exposure. A preferential memory mode for abstract information was related to an attenuated heart rate reactivity to threat in spider phobics. It is suggested that the preferential memory mode for abstract information may inhibit the activation of the subcortical affective memory system, which is crucial for the complete activation of the fear network. The absence of complete fear network activation may play a role in the persistence of anxiety disorders by hindering anxious individuals to learn that the stimuli they fear are not as dangerous as they assumed.

Levels of cellular glutathione and metallothionein affect the toxicity of oxidative stressors in an established carp cell line.

The comparative toxicity of a variety of oxidative stressors was studied in the epithelioma papulosum cyprini line from carp using the neutral red cytotoxicity assay. LC50's decreased in the order t-butylhydroperoxide > hydrogen peroxide > diquat > paraquat. The cytotoxicity of hydrogen peroxide was significantly reduced when the cells were grown in L-15 medium rather than MEM and this could be attributed to elevated cellular glutathione and metallothionein levels and higher activities of GSH-dependent detoxification systems. The protective effect of metallothionein in radical scavenging was demonstrated by decreased toxicity of the redox-cycling toxicants, diquat and menadione after metallothionein levels had been pre-induced by Cd-exposure. This study demonstrates the relationship between toxic effects of oxidative stressors and expression of detoxification systems in fish.