The role of uncertainty in regulating associative change

Rescorla (2000, 2001) interpreted his compound test results to show that both common and individual error terms regulate associative change such that the element of a conditioned compound with the greater prediction error undergoes greater associative change than the one with the smaller prediction error. However, it has recently been suggested that uncertainty, not prediction error, is the primary determinant of associative change in people (Spicer et al., 2020, 2022). The current experiments use the compound test in a continuous outcome allergist task to assess the role of uncertainty in associative change, using two different manipulations of uncertainty: outcome uncertainty (where participants are uncertain of the level of the outcome on a particular trial) and causal uncertainty (where participants are uncertain of the contribution of the cue to the level of the outcome). We replicate Rescorla's compound test results in the case of both associative gains (Experiment 1) and associative losses (Experiment 3) and then provide evidence for greater change to more uncertain cues in the case of associative gains (Experiments 2 and 4), but not associative losses (Experiments 3 and 5). We discuss the findings in terms of the notion of theory protection advanced by Spicer et al., and other ways of thinking about the compound test procedure, such as that proposed by Holmes et al. (2019). (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Unidirectional rating scales overestimate the illusory causation phenomenon

Illusory causation is a phenomenon in which people mistakenly perceive a causal relationship between a cue and outcome even though the contingency between them is actually zero. Illusory causation studies typically use a unidirectional causal rating scale, where one endpoint refers to no relationship and the other to a strongly positive causal relationship. This procedure may bias mean causal ratings in a positive direction, either by censoring negative ratings or by discouraging participants from giving the normative rating of zero which is at the bottom extreme of the scale. To test this possibility, we ran two experiments that directly compared the magnitude of causal illusions when assessed with a unidirectional (zero-positive) versus a bidirectional (negative-zero-positive) rating scale. Experiment 1 used high cue and outcome densities (both 75%), whereas Experiment 2 used neutral cue and outcome densities (both 50%). Across both experiments, we observed a larger illusory causation effect in the unidirectional group compared with the bidirectional group, despite both groups experiencing the same training trials. The causal illusions in Experiment 2 were observed despite participants accurately learning the conditional probabilities of the outcome occurring in both the presence and absence of the cue, suggesting that the illusion is driven by the inability to accurately integrate conditional probabilities to infer causal relationships. Our results indicate that although illusory causation is a genuine phenomenon that is observable with either a undirectional or a bidirectional rating scale, its magnitude may be overestimated when unidirectional rating scales are used.

Using unobserved causes to explain unexpected outcomes: The effect of existing causal knowledge on protection from extinction by a hidden cause

People often rely on the covariation between events to infer causality. However, covariation between cues and outcomes may change over time. In the associative learning literature, extinction provides a model to study updating of causal beliefs when a previously established relationship no longer holds. Prediction error theories can explain both extinction and protection from extinction when an inhibitory (preventive) cue is present during extinction. In three experiments using the allergist causal learning task, we found that protection could also be achieved by a hidden cause that was inferred but not physically present, so long as that cause was a plausible preventer of the outcome. We additionally showed complete protection by a physically presented cue that was neutral rather than inhibitory at the outset of extinction. Both findings are difficult to reconcile with dominant prediction error theories. However, they are compatible with the idea of theory protection, where the learner attributes the absence of the outcome to the added cue (when present) or to a hidden cause, and therefore does not need to revise causal beliefs about A. Our results suggest that prediction error encourages changes in causal beliefs, but the nature of the change is determined by reasoning processes that incorporate existing knowledge of causal mechanisms and may be biased toward preservation of existing beliefs. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

A cognitive pathway to punishment insensitivity

Individuals differ in their sensitivity to the adverse consequences of their actions, leading some to persist in maladaptive behaviors. Two pathways have been identified for this insensitivity: a motivational pathway based on excessive reward valuation and a behavioral pathway based on autonomous stimulus-response mechanisms. Here, we identify a third, cognitive pathway based on differences in punishment knowledge and use of that knowledge to suppress behavior. We show that distinct phenotypes of punishment sensitivity emerge from differences in what people learn about their actions. Exposed to identical punishment contingencies, some people (sensitive phenotype) form correct causal beliefs that they use to guide their behavior, successfully obtaining rewards and avoiding punishment, whereas others form incorrect but internally coherent causal beliefs that lead them to earn punishment they do not like. Incorrect causal beliefs were not inherently problematic because we show that many individuals benefit from information about why they are being punished, revaluing their actions and changing their behavior to avoid further punishment (unaware phenotype). However, one condition where incorrect causal beliefs were problematic was when punishment is infrequent. Under this condition, more individuals show punishment insensitivity and detrimental patterns of behavior that resist experience and information-driven updating, even when punishment is severe (compulsive phenotype). For these individuals, rare punishment acted as a "trap," inoculating maladaptive behavioral preferences against cognitive and behavioral updating.

Retardation of acquisition after conditioned inhibition and latent inhibition training in human causal learning

Inhibitory stimuli are slow to acquire excitatory properties when paired with the outcome in a retardation test. However, this pattern is also seen after simple nonreinforced exposure: latent inhibition. It is commonly assumed that retardation would be stronger for a conditioned inhibitor than for a latent inhibitor, but there is surprisingly little empirical evidence comparing the two in either animals or humans. Thus, retardation after inhibitory training could in principle be attributable entirely to latent inhibition. We directly compared the speed of excitatory acquisition after conditioned inhibition and matched latent inhibition training in human causal learning. Conditioned inhibition training produced stronger transfer in a summation test, but the two conditions did not differ substantially in a retardation test. We offer two explanations for this dissociation. One is that learned predictiveness attenuated the latent inhibition that otherwise would have occurred during conditioned inhibition training, so that retardation in that condition was primarily due to inhibition. The second explanation is that inhibitory learning in these experiments was hierarchical in nature, similar to negative occasion-setting. By this account, the conditioned inhibitor was able to negatively modulate the test excitor in a summation test, but was no more retarded than a latent inhibitor in its ability to form a direct association with the outcome. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Reduction in caffeine withdrawal after open-label decaffeinated coffee

BACKGROUND

Withdrawal from addictive drugs can be reduced by administering placebo deceptively, but in the clinic it is unethical to deceive the patient. Open-label placebo effects have been observed across a range of psychophysiological phenomena, and may also apply to drug withdrawal.

METHOD

24-hour abstinent heavy coffee drinkers (N = 61) rated their caffeine withdrawal symptoms before being allocated to one of three groups. The Deceptive group was given decaffeinated coffee (decaf) and told it was caffeinated, the Open-Label group given decaf and told it was decaf and the Control group given water and told it was water. After 45 min, caffeine withdrawal was measured again. All participants rated their expectancies of withdrawal reduction from caffeinated coffee, decaf and water prior to being randomised and the end of the study.

RESULTS

There was a significant 9.5-point reduction in caffeine withdrawal in the Open-Label group (95% confidence interval (CI): 4.7, 14.3; p = 0.002), which was 8.6 points less than the Deceptive group (95%CI: 0.4, 16.8; p = 0.014) but 8.9 points greater than the Control group (95%CI: 0.6, 17.2; p = 0.012). Pre-randomisation, participants expected caffeinated coffee to reduce their withdrawal symptoms the most, followed by water and decaf, Pre-randomisation expectancy of withdrawal was only associated with amount of withdrawal reduction in the Deceptive group.

CONCLUSION

It appears as if open-label placebo caffeine (i.e. decaf) can reduce caffeine withdrawal symptoms, even when people do not hold a conscious expectancy it will do so. There may be ways to integrate open-label placebo procedures into clinical interventions for drug dependence without violating informed consent.

Surgical challenges of giant parathyroid adenomas weighing 10 g or more

PURPOSE

An average parathyroid adenoma (PA) weighs < 1 g. This study aimed to characterise giant PAs ≥ 10 g (GPAs) to facilitate surgical management of primary hyperparathyroidism (PHPT).

METHODS

All patients with a GPA confirmed on histology were recruited from the Monash University Endocrine Surgery Unit database. Clinical and demographic data were collected and compared to a group of non-GPA patients.

RESULTS

A total of 14 GPAs were identified between 2007 and 2018 out of 863 patients (1.6%) with a single PA excised for PHPT. The GPA patients were compared to a control group of 849 non-GPA patients in the same period with similar mean age (62 ± 16 vs 63 ± 14, P = 0.66) and gender distribution (64% vs 75% female, P = 0.35). Pre-operative calcium (Ca) and parathyroid hormone (PTH) levels were significantly higher in GPA patients (P < 0.001). A higher percentage of GPA patients (79%) had concordant localisation studies (ultrasound and sestamibi) than control patients (59%), (P = 0.13), but they were significantly less likely to undergo MIP (55% vs 82%, P = 0.02). The median GPA weighed 12.5 g (IQR 10.5-24.3). Median serum Ca normalised by day 1 post-operatively, while PTH remained elevated. Both serum Ca and PTH levels were in the normal range at 3 months. All GPA lesions were benign on histopathology.

CONCLUSION

GPAs are rare and display severe clinical and biochemical abnormalities. Despite their large size, concordant pre-operative imaging was not always achieved, and a few patients were suitable for MIP.

Reversal of inhibition by no-modulation training but not by extinction in human causal learning

One of the many strengths of the Rescorla and Wagner (1972) model is that it accounts for both excitatory and inhibitory learning using a single error-correction mechanism. However, it makes the counterintuitive prediction that nonreinforced presentations of an inhibitory stimulus will lead to extinction of its inhibitory properties. Zimmer-Hart and Rescorla (1974) provided the first of several animal conditioning studies that contradicted this prediction. However, the human data are more mixed. Accordingly, we set out to test whether extinction of an inhibitor occurs in human causal learning after simultaneous feature negative training with a conventional unidirectional outcome. In 2 experiments with substantial sample sizes, we found no evidence of extinction after presentations of the inhibitory stimulus alone in either a summation test or causal ratings. By contrast, 2 "no-modulation" procedures that contradicted the original training contingencies successfully reversed inhibition. These results did not differ substantially as a function of participants' self-reported causal structures (configural/modulation/prevention). We hypothesize that inhibitory learning may be intrinsically modulatory, analogous to negative occasion-setting, even with simultaneous training. This hypothesis would explain why inhibition is reversed by manipulations that contradict modulation but not by simple extinction, as well as other properties of inhibitory learning such as imperfect transfer to another excitor. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Individual differences in stimulus identification, rule induction, and generalization of learning

In the field of stimulus generalization, an old yet unresolved discussion pertains to what extent stimulus misidentifications contribute to the pattern of conditioned responding. In this article, we perform cluster analysis on six datasets (four published datasets and two unpublished datasets, included N = 950) to examine the relationship between interindividual differences in (a) stimulus identification, (b) patterns of generalized responding, and (c) verbalized generalization rules. The datasets were obtained from online predictive learning tasks where participants learned associations between colored cues and the presence or absence of a hypothetical outcome. In these datasets, stimulus identification and expectancy ratings were assessed in separate phases to a range of colors varying between blue-green. Using cluster analyses on performance during stimulus identification, we identified different subgroups of participants (good vs. bad identifiers). In all six datasets, we found a close relationship between the pattern of stimulus identification and the shape of the expectancy gradient across the test dimension between the identified subgroups. Furthermore, participants classified as good identifiers were more likely to report a similarity generalization rule than a relational or linear rule, suggesting that individual differences in stimulus identification are related to individual differences in generalization rules. These findings suggest that greater consideration should be given to interindividual variability in stimulus identification, inductive rules, and their relationship in explaining patterns of generalized responses. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Generalization following symmetrical intradimensional discrimination training

A challenge for generalization models is to specify how excitation generated from a CS+ (i.e., positive evidence) should interact with inhibition from a CS- (i.e., negative evidence) to produce generalized responding. Empirically, many generalization phenomena are consistent with the monotonicity principle, which states that additional positive evidence should increase generalized responding, whereas additional negative evidence should decrease responding. However, a recent study (Lee et al.,, 2019) demonstrated that additional negative evidence can sometimes increase generalization, in direct contrast to animal data and associative accounts of generalization. The current study investigated whether a similar effect could be found in a symmetrical intradimensional discrimination procedure with two sources of negative evidence (CS-s) located on each side of a CS+. In three experiments, we compared generalization along a green-blue dimension between one group of participants who learned that an aqua-colored shape (CS+) predicted an outcome (Single Positive group) with another group who also learned that both a slightly greener and a slightly bluer shape led to no outcome (Double Negative group). Experiments 1A and 1B showed no effect of the additional negative evidence in increasing generalization around the CS+. However, changing a stimulus feature at test (shape) resulted in a higher gradient peak in the Double Negative group relative to the Single Positive group in Experiment 2. Although this result violates the monotonicity principle, an extended version of Blough's (1975) model applying cue competition to multiple stimulus dimensions (i.e., shape and color) successfully replicated the group differences. Our results suggest that associative mechanisms can account for some instances in which negative evidence increases generalization. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Inhibitory summation as a form of generalization

Inhibitory learning after feature negative training (A+/AB-) is typically measured by combining the Feature B with a separately trained excitor (e.g., C) in a summation test. Reduced responding to C is taken as evidence that B has properties directly opposite to those of C. However, in human causal learning, transfer of B's inhibitory properties to another excitor is modest and depends on individual differences in inferred causal structure. Here we ask whether instead of opposing processes, a summation test might instead be thought of in terms of generalization. Using an allergist task, we tested whether inhibitory transfer would be influenced by similarity. We found that transfer was greater when the test stimuli were from the same semantic category as the training stimuli (Experiments 1 and 2) and when the test excitor had previously been associated with the same outcome (Experiment 3). We also found that the similarity effect applied across all self-reported causal structures. We conclude it may be more helpful to consider transfer of inhibition as a form of conceptual generalization rather than the arithmetic summation of opposing processes. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Nonreactive testing: Evaluating the effect of withholding feedback in predictive learning

Learning of cue-outcome relationships in associative learning experiments is often assessed by presenting cues without feedback about the outcome and informing participants to expect no outcomes to occur. The rationale is that this "no-feedback" testing procedure prevents new learning during testing that might contaminate the later test trials. We tested this assumption in 4 predictive learning experiments where participants were tasked with learning which foods (cues) were causing allergic reactions (the outcome) in a fictitious patient. We found that withholding feedback in a block of trials had no effect on causal ratings (Experiments 1 and 2), but it led to regression toward intermediate ratings when the missing feedback was embedded in the causal scenario and information about the outcome replaced by a "?" (Experiment 3). A factorial experiment manipulating cover story and feedback revealed that the regression-to-baseline effect was primarily driven by presentation of the "?" feedback (Experiment 4). We conclude that the procedure of testing without feedback, used widely in studies of human cognition, is an appropriate way of assessing learning, as long as the missing data are attributed to the experimenter and the absence of feedback is not highlighted in a way that induces uncertainty. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Second-Order Conditioning in Humans

In contrast to the large body of work demonstrating second-order conditioning (SOC) in non-human animals, the evidence for SOC in humans is scant. In this review, I examine the existing literature and suggest theoretical and procedural explanations for why SOC has been so elusive in humans. In particular, I discuss potential interactions with conditioned inhibition, whether SOC is rational, and propose critical parameters needed to obtain the effect. I conclude that SOC is a real but difficult phenomenon to obtain in humans, and suggest directions for future research.

Punishment insensitivity in humans is due to failures in instrumental contingency learning

Punishment maximises the probability of our individual survival by reducing behaviours that cause us harm, and also sustains trust and fairness in groups essential for social cohesion. However, some individuals are more sensitive to punishment than others and these differences in punishment sensitivity have been linked to a variety of decision-making deficits and psychopathologies. The mechanisms for why individuals differ in punishment sensitivity are poorly understood, although recent studies of conditioned punishment in rodents highlight a key role for punishment contingency detection (Jean-Richard-Dit-Bressel et al., 2019). Here, we applied a novel ‘Planets and Pirates’ conditioned punishment task in humans, allowing us to identify the mechanisms for why individuals differ in their sensitivity to punishment. We show that punishment sensitivity is bimodally distributed in a large sample of normal participants. Sensitive and insensitive individuals equally liked reward and showed similar rates of reward-seeking. They also equally disliked punishment and did not differ in their valuation of cues that signalled punishment. However, sensitive and insensitive individuals differed profoundly in their capacity to detect and learn volitional control over aversive outcomes. Punishment insensitive individuals did not learn the instrumental contingencies, so they could not withhold behaviour that caused punishment and could not generate appropriately selective behaviours to prevent impending punishment. These differences in punishment sensitivity could not be explained by individual differences in behavioural inhibition, impulsivity, or anxiety. This bimodal punishment sensitivity and these deficits in instrumental contingency learning are identical to those dictating punishment sensitivity in non-human animals, suggesting that they are general properties of aversive learning and decision-making.

Inhibitory causal structures in serial and simultaneous feature negative learning

We have previously reported that human participants trained with a simultaneous feature negative discrimination (intermixed A+/AB− trials) show only modest transfer of inhibitory properties of feature B to a separately trained excitor in a summation test. Their self-reported causal structure suggested that many participants learned that the effect of feature B was somewhat specific to the excitor it had been trained with (modulation), rather than learning that the feature prevented the outcome (prevention). This pattern is reminiscent of the distinction between negative occasion-setting and conditioned inhibition in the animal conditioning literature. However, in animals, occasion-setting is more commonly seen with a serial procedure, in which the feature (B) precedes the training excitor (A). Accordingly, we ran three experiments to compare serial with simultaneous training in an allergist causal judgement task. Transfer in a summation test was stronger to a previously modulated test excitor compared to a simple excitor after both simultaneous and serial training. There was a numerical trend towards a larger effect in the serial group, but it failed to reach significance and the Bayes Factor indicated support for the null. Serial training had no differential effect on the self-reported causal structure and did not significantly reduce overall transfer. After both simultaneous and serial training, transfer was strongest in participants who reported a prevention structure, replicating and extending our previous results to a previously modulated excitor. These results suggest that serial feature negative training does not promote a qualitatively different inhibitory causal structure compared to simultaneous training in humans.

Differences in perceptual memory determine generalization patterns

Although memory of past experiences is crucial for the ability to transfer knowledge to new situations, surprisingly little research has directly investigated the relationship between memory and generalization. The present study sought to investigate how the perceptual memory of a trained stimulus influences generalization to similar stimuli. Forty participants underwent a fear conditioning procedure on Day 1, and separate memory recall and generalization tests on Day 2. We focused on two aspects of perceptual memory: namely memory bias (i.e., over- or underestimation of stimulus magnitude) and uncertainty. We found that memory bias predicted the pattern of generalized self-reported (expectancy ratings) and psychophysiological responses (fear-potentiated startle responses). Memory uncertainty was measured in two ways: self-reported uncertainty ratings and variability in stimulus recall. We found that higher levels of self-reported memory uncertainty corresponded with a broader generalization gradient on US expectancy, while greater variability in memory recall was associated with a broader generalization gradient on fear-potentiated startle responses. Taken together, our findings suggest that memory is an important determinant of generalized behavior and illustrate the need to account for these interindividual differences in perceptual memory when examining the generalization of learned responses.

Acute Bilateral Uveitis, Hypotony, and Cataracts Associated with Ipilimumab and Nivolumab Therapy: Optical Coherence Tomography Angiography Findings

Immune checkpoint inhibitors are increasingly being used for the treatment of several malignancies. In rare cases, patients develop disabling ophthalmic side effects such as dry eyes, episcleritis, keratitis, uveitis, inflammatory orbitopathy, myasthenia gravis, macular edema, and serous retinal detachment. We present a case of acute bilateral anterior uveitis, prolonged hypotony, and cataracts following the use of dual therapy ipilimumab and nivolumab. Physicians should be aware of these immune-mediated ocular adverse events and should have a management plan to deal with these side effects that range from mild to vision threatening.

Individual differences in causal structures inferred during feature negative learning

Traditional associative learning theories predict that training with feature negative (A+/AB-) contingencies leads to the feature B acquiring negative associative strength and becoming a conditioned inhibitor (i.e., prevention learning). However, feature negative training can sometimes result in negative occasion setting, where B modulates the effect of A. Other studies suggest that participants learn about configurations of cues rather than their individual elements. In this study, we administered simultaneous feature negative training to participants in an allergist causal learning task and tested whether evidence for these three types of learning (prevention, modulation, configural) could be captured via self-report in the absence of any procedural manipulation. Across two experiments, we show that only a small subset of participants endorse the prevention option, suggesting that traditional associative models that predict conditioned inhibition do not completely capture how humans learn about negative contingencies. We also show that the degree of transfer in a summation test corresponds to the implied causal structure underlying conditioned inhibition, occasion-setting, and configural learning, and that participants are only partially sensitive to explicit hints about causal structure. We conclude that feature negative training is an ambiguous causal scenario that reveals individual differences in the representation of inhibitory associations, potentially explaining the modest group-level inhibitory effects often found in humans.

Modelling generalisation gradients as augmented Gaussian functions

Studying generalisation of associative learning requires analysis of response gradients measured over a continuous stimulus dimension. In human studies, there is often a high degree of individual variation in the gradients, making it difficult to draw conclusions about group-level trends with traditional statistical methods. Here, we demonstrate a novel method of analysing generalisation gradients based on hierarchical Bayesian curve-fitting. This method involves fitting an augmented (asymmetrical) Gaussian function to individual gradients and estimating its parameters in a hierarchical Bayesian framework. We show how the posteriors can be used to characterise group differences in generalisation and how classic generalisation phenomena such as peak shift and area shift can be measured and inferred. Estimation of descriptive parameters can provide a detailed and informative way of analysing human generalisation gradients.

Polymicrobial infection confined to Ahmed glaucoma shunt

Purpose

To present a case of a unique complication of an Ahmed glaucoma shunt. The pathological and immunohistochemical findings will also be discussed.

Observations

A 58-year-old woman with glaucoma secondary to Marfan syndrome and cataract surgery developed exposure of an Ahmed glaucoma tube, intraluminal white inflammatory material, and low-grade endophthalmitis five years after insertion. The patient was treated with topical and oral antibiotics and successfully underwent removal and replacement of the shunt. Pathologic analysis of the intraluminal contents revealed a bacterial infiltrate of mixed morphology.

Conclusions and Importance

Concurrent tube exposure, intraluminal exudates, and endophthalmitis is a rare but potentially serious complication of glaucoma drainage device surgery. When this complication is encountered, prompt medical and surgical intervention is necessary to prevent significant vision loss. Ultimately, the glaucoma shunt may be revised, replaced, or removed altogether from the eye.

Comparison of 1-field, 2-fields, and 3-fields fundus photography for detection and grading of diabetic retinopathy

AIM

To evaluate the sensitivity and specificity of 1-, 2-, and 3-fields, nonmydriatic (NM), 45° color photography compared with mydriatic ophthalmoscopy for detection of diabetic retinopathy (DR).

METHODS

Masked, comparative case series was performed utilizing a group of 128 diabetic patients (256 eyes) with various stages of DR who underwent both 3-fields NM color photography and ophthalmologic examination. In a blinded manner, the same optometrist who read the original 3-fields images for a patient read the 1- and 2-fields photographs on separate dates later.

RESULTS

The sensitivity and specificity of digital retinal photography compared with dilated ophthalmoscopy were, respectively: 88% and 76% for 1-field; 94% and 69% for 2-fields; and 100% and 79% for 3-fields. The proportion of agreement between fundus photography reading and exam DR diagnosis were 58% for 1-field, 58% for 2-fields, and 77% for 3-fields. Kappa and Cramer's V statistics for 1-, 2-, and 3-fields were 0.55 and 0.60, 0.52 and 0.57, and 0.72 and 0.74, respectively. Three-fields measurement of DR was most similar to the dilated ophthalmological exam overall and across all DR severity levels.

CONCLUSIONS

Compared to 1- and 2-fields fundus photography, 3-fields is superior for detecting vision-threatening DR. One- and 2-fields have reasonable sensitivity for DR screening.

P6155Early computed tomographic evaluation for out-of-hospital cardiac arrest survivors: the CT-FIRST trial

Background

Patients surviving an out-of-hospital cardiac arrest (OHCA) commonly present without an obvious etiology, but computed tomography (CT) can provide rapid, comprehensive anatomic evaluation of potential OHCA causes.

Purpose

To assess the diagnostic capabilities of whole body CT imaging in OHCA survivors.

Methods

From 11/2015 to 2/2018, the CT-FIRST (CT Feasibility In Resuscitated patient for Sudden death Triage) protocol enrolled 104 OHCA survivors without obvious OHCA cause to an early (<6 hours from hospital arrival) dual source Sudden Death CT (SDCT) scan protocol that included a non-contrast head, ECG-gated cardiac/thoracic angiography, and non-gated venous phase abdominal CT's. Cardiac CT analysis was blinded, but other SDCT findings were clinically available. Patients needing urgent cardiac catheterization or hemodynamically unable to tolerate CT were excluded. Primary endpoints were SDCT diagnosis compared to OHCA causes from adjudicated record review, and any significantly altered therapy based on SDCT. Acute coronary syndrome by SDCT was conservatively assumed if >50% stenosis was identified in major coronary artery(ies).

Results

SDCT scans identified 39% (41/104) of all OHCA causes and 95% (41/43) of causes potentially identifiable with SDCT (Table). No inappropriate treatments resulted from SDCT findings. SDCT changed or expedited treatments in 21/23 (95%) patients, including antibiotics, anticoagulants, and invasive evaluations or treatments. SDCT found or confirmed resuscitation complications including liver/spleen laceration (n=5), pneumothorax (n=7), and hemopericardium (n=1).

N=104 OHCA Cause SDCT Diagnosis of OHCA Cause N (%) N (%) Acute coronary syndrome 13 (13%) 13 (100%) Cardiomyopathy 8 (8%) 7 (88%) Pneumonia 11 (11%) 11 (100%) Hemorrhagic stroke 3 (3%) 3 (100%) Pulmonary embolism 4 (3%) 4 (100%) Perforated viscus 2 (2%) 2 (100%) Gut necrosis 1 (1%) 1 (100%) Pulmonary hemorrhage 1 (1%) 1 (100%) Substance use 22 (21%) 0 (0%) Unknown 7 (7%) 0 (0%) Other 32 (31%) 0 (0%)

Conclusion

This pilot study suggests the SDCT protocol has considerable promise to diagnose OHCA causes and complications of resuscitation, as well as change clinical treatment.

Acknowledgement/Funding

Medic One Foundation

Evidential diversity increases generalisation in predictive learning

In property induction tasks, encountering a diverse range of instances (e.g., hippos and hamsters) with a given property usually increases our willingness to generalise that property to a novel instance, relative to non-diverse evidence (e.g., hippos and rhinos). Although generalisation in property induction and predictive learning tasks share conceptual similarities, it is unknown whether this diversity principle applies to generalisation of a predictive association. We tested this hypothesis in two predictive learning experiments using differential training where one category of stimuli (e.g., fruits) predicted an outcome and another category (e.g., vegetables) predicted no outcome. We compared generalisation between a Non-Diverse group who were presented with non-diverse evidence in both positive (predicted the outcome) and negative (predicted no outcome) categories, and two groups who received the same training as the Non-Diverse group but with a more diverse range of exemplars in the positive (Diverse+ group) or negative (Diverse– group) category. Diversity effects were found for both positive and negative categories, in that learning about a diverse range of exemplars increased generalisation of a predictive association to novel exemplars from that same category. The results suggest that diversity, a key principle describing how we reason inductively, also applies to generalisation in associative learning tasks.

Rule-based generalization and peak shift in the presence of simple relational rules

After discrimination learning between two stimuli that lie on a continuum, animals typically exhibit generalization on the basis of similarity to the physical features of the stimuli, often producing a peak-shifted gradient. However, post-discrimination generalization in humans usually resembles a monotonically increasing (e.g., linear) gradient that is better characterized as following a relational rule describing the difference between the stimuli. The current study tested whether rule-based generalization could be disrupted by reducing the applicability of a relational rule on test. We compared generalization following a difficult categorization task between a group who could use their rule consistently throughout test (Group Consistent), and a group who could only apply their rule effectively on 50% of test trials and thus could only use it inconsistently (Group Inconsistent). Across two experiments, a peak shift was found in the Inconsistent group and a monotonic gradient in the Consistent group. A post-hoc sequential analysis revealed that the Inconsistent group produced both peak-shifted and monotonic gradients as a function of whether or not the relevant rule was applicable on the previous trial. Reducing the applicability of a rule on test thus appeared to lead participants to revert to generalizing on the basis of similarity. Our results suggest that humans learn about the physical features of the stimuli alongside relational rules, and that rule- and similarity-based learning can interact in determining generalization.

Beyond disease susceptibility-Leveraging genome-wide association studies for new insights into complex disease biology

Genetic studies in complex diseases have been highly successful, but have also been largely one-dimensional: predominantly focusing on the genetic contribution to disease susceptibility. While this is undoubtedly important-indeed it is a pre-requisite for understanding the mechanisms underlying disease development-there are many other important aspects of disease biology that have received comparatively little attention. In this review, I will discuss how existing genetic data can be leveraged to provide new insights into other aspects of disease biology, why such insights could change the way we think about complex disease, and how this could provide opportunities for better therapies and/or facilitate personalised medicine. To do this, I will use the example of Crohn's disease-a chronic form of inflammatory bowel disease that has been one of the main success stories in complex disease genetics. Indeed, thanks to genetic studies, we now have a much more detailed understanding of the processes involved in Crohn's disease development, but still know relatively little about what determines the subsequent disease course (prognosis) and why this differs so considerably between individuals. I will discuss how we came to realise that genetic variation plays an important role in determining disease prognosis and how this has changed the way we think about Crohn's disease genetics. This will illustrate how phenotypic data can be used to leverage new insights from genetic data and will provide a broadly applicable framework that could yield new insights into the biology of multiple diseases.

Development of a New Pulsatile Extracorporeal Life Support Device Incorporating a Dual Pulsatile Blood Pump

A new pulsatile extracorporeal life support device (ECLS) has been developed, designed to sustain pulsatile blood flow during emergency cardiopulmonary resuscitations and cardiopulmonary operations. This device features two identical pulsatile pumps that operate alternately and can therefore provide blood inflow in a more uniform manner than similar systems featuring a single-pump configuration. In order to confirm the presumed benefits of this newly-developed dual pulsatile pump configuration, we have conducted a series of in vitro experiments designed to compare the properties of the new system with a single pump system, specifically with regard to pump delivery rate and active filling efficiency. Our results reveal that the dual pump configuration can, indeed, deliver a higher flow than can the single-pump system, and exhibits an active filling efficiency superior to that of the single-pump configuration. We performed a series of animal experiments to measure the pulsatility of the dual-pump configuration in terms of equivalent energy pressure (EEP). In order to measure EEP, we measured femoral arterial pressure and pump outflow. The results of our animal experiments revealed that the newly-developed pulstile ECLS exhibits sufficient pulsatility in terms of the EEP considerations.

Severe hyperkalaemia complicating parathyroidectomy in patients with end-stage renal disease

We evaluated the incidence of perioperative hyperkalaemia in end-stage renal disease (ESRD) patients undergoing parathyroidectomy and investigated possible contributors to this phenomenon. This was a retrospective cohort study looking at patients who had undergone parathyroidectomy for chronic kidney disease-associated mineral bone disease (CKD-MBD) at The Alfred Hospital, Melbourne, since 2001. Baseline demographics including age, gender, aetiology of renal failure and mode of renal replacement therapy as well as anaesthetic technique and duration of surgery were studied as possible contributors. Perioperative potassium values were compared to preoperative baseline. Following stratification into normokalaemic and hyperkalaemic groups, demographic and operative data were compared. Twenty-two patients met the inclusion criteria with a median (interquartile range, IQR) age of 48.5 (42-59) years. There was a male predominance of 68%. The median (IQR) surgical time was 131 (115-164) minutes. Potassium levels rose perioperatively, with a 27.3% incidence of perioperative hyperkalaemia. Median duration of surgery was longer in the hyperkalaemic patients (167 minutes versus 125 minutes). Following the withdrawal of cinacalcet, parathyroidectomy is increasingly required in ESRD patients with CKD-MBD. Potentially life-threatening hyperkalaemia poses a significant risk in the perioperative period. Serial electrolyte monitoring is crucial to safety in this patient group. A multidisciplinary approach to perioperative management is required to ensure optimal timing of renal replacement therapy and appropriate means of serial blood sampling.

A probiotic combination attenuates experimental colitis through inhibition of innate cytokine production

Inflammatory bowel disease (IBD) is a severe immune cell-mediated syndrome characterised by extensive inflammatory and effector mucosal responses leading to tissue destruction in the colon and small intestine. The leading hypothesis is that dysbiosis of the gut flora causes an excessive immune response and inflammation in the gastrointestinal track. Lactic acid bacteria (LAB) can correct dysbiosis of the normal microbiota. In the current study, the therapeutic potential of seven LAB strains in combination to treat IBD was evaluated using experimental colitis model. This LAB cocktail, designated GI7, includes four strains of Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactococcus lactis, two strains of Bifidobacterium bifidum, Bifidobacterium breve, and one strain of Streptococcus thermophilus. We confirmed that GI7 suppressed pro-inflammatory cytokines in Raw264.7 macrophages. When dextran sulphate sodium-induced colitic mice were treated with GI7, their symptoms of colitis, as assessed by body weight, colon length, myeloperoxidase activity, intestinal bleeding, and histological damage, were reduced compared to untreated mice. In addition, GI7 treatment significantly inhibited the production of innate pro-inflammatory cytokines during colitic progression. Therefore, we suggest that GI7, a combination of seven LAB, has a potential role in the treatment of IBD.

Sequential effects and sequence learning in a three-choice serial reaction time task

The recent history of events can influence responding despite there being no contingent relationship between those events. These 'sequential effects' are ubiquitous in cognitive psychology, yet their study has been dominated by two-choice reaction time tasks in which sequences necessarily comprise simple response repetitions and alternations. The current study explored sequential effects in a three-choice reaction time task where the target was constrained to either move clockwise or anticlockwise on each trial, allowing for assessment of sequential effects involving the direction of target transitions rather than target location. Across two experiments, a reliable pattern of sequential effects was found in the absence of contingencies, whereby the most notable feature was that participants were fastest to respond to subsequences where the target moved in a consistent direction on consecutive trials, compared to when the target direction alternated. In Experiment 2, the direction of motion was biased to move in one direction 75% of the time and in a subsequent transfer phase, participants showed evidence of learning this probabilistic sequence but still exhibited the same pattern of sequential effects on trials where the target moved in the more prevalent or less prevalent direction. Simulations with a connectionist model of sequence learning (the Augmented Serial Recurrent Network, Cleeremans & McClelland, 1991) produced an adequate replication of the sequential effects in both experiments in addition to an effect of sequence learning in Experiment 2. We propose that sequential effects may represent learning about transient contingencies and may be described using the same associative learning mechanisms intended for sequence learning.

Photoprotective Effect of Carpomitra costata Extract against Ultraviolet B-Induced Oxidative Damage in Human Keratinocytes

Natural marine products show various biological properties such as antiphotoaging, antioxidant, anticancer, and anti-inflammation. This study evaluated the protective effects of the brown alga Carpomitra costata (Stackhouse) Batters (Sporochnaceae) against ultraviolet B (UVB)-provoked damage in human HaCaT keratinocytes. C. costata extract (CCE) effectively reduced superoxide anion, hydroxyl radical, and UVB-stimulated intracellular reactive oxygen species (ROS) levels. CCE also restored the expression and activity of UVB-suppressed antioxidant enzymes. Furthermore, CCE decreased UVB-triggered oxidative damage to cellular components including DNA, protein, and lipid and defended the cells against mitochondrial membrane depolarization-medicated apoptosis. The results of this study indicate that CCE can safeguard human keratinocytes against UVB-induced cellular damage via a potent antioxidant mechanism. CCE may find utility as part of a therapeutic arsenal against the damaging effects of UVB radiation on the skin.

Safety, bioavailability, and pharmacokinetics of VGX-1027-A novel oral anti-inflammatory drug in healthy human subjects

VGX-1027, a novel oral immune modulator, is under development for the treatment of rheumatoid arthritis. The safety, tolerability, and pharmacokinetics of single (1-800 mg) and multiple (40-400 mg) oral doses were evaluated in 2 clinical studies. The doses were well tolerated up to 800 mg in a single dose and 200 mg twice daily in multiple doses. Adverse events were mild to moderate in severity with no identifiable dose-related pattern. There were no clinically significant physical or laboratory findings. The pharmacokinetic data indicated that increases in Cmax and AUC0-inf were dose-proportional, and AUC0- τ was approximately dose-proportional. For the single-dose study, median Tmax ranged from 0.5 to 2 hours and mean t1/2 ranged from 4.9 to 8.7 hours. For the multiple-dose study, median Tmax ranged from 0.5 to 2.0 hours and mean t1/2 ranged from 7.05 to 10.05 hours. No accumulation of the drug was observed after day 1, indicating that steady-state concentrations were attained with single and multiple dosing for 5 days. Approximately 90% of the administered dose was excreted in urine as unchanged drug.

Astrocytes regulate α-secretase-cleaved soluble amyloid precursor protein secretion in neuronal cells: Involvement of group IIA secretory phospholipase A2

Astrocytes are major supportive cells in brains with important functions including providing nutrients and regulating neuronal activities. In this study, we demonstrated that astrocytes regulate amyloid precursor protein (APP) processing in neuronal cells through secretion of group IIA secretory phospholipase A2 (sPLA2-IIA). When astrocytic cells (DITNC) were mildly stimulated with the pro-inflammatory cytokines, such as TNF α and IL-1β, sPLA2-IIA was secreted into the medium. When conditioned medium containing sPLA2-IIA was applied to human neuroblastoma (SH-SY5Y) cells, there was an increase in both cell membrane fluidity and secretion of α-secretase-cleaved soluble amyloid precursor protein (sAPPα). These changes were abrogated by KH064, a selective inhibitor of sPLA2-IIA. In addition, exposing SH-SY5Y cells to recombinant human sPLA2-IIA also increased membrane fluidity, accumulation of APP at the cell surface, and secretion of sAPPα, but without altering total expressions of APP, α-secretases and β-site APP cleaving enzyme (BACE1). Taken together, our results provide novel information regarding a functional role of sPLA2-IIA in astrocytes for regulating APP processing in neuronal cells.

Long noncoding RNA profiles of adrenocortical cancer can be used to predict recurrence

Adrenocortical carcinoma (ACC) is an aggressive malignancy with high rates of recurrence following surgical resection. Long noncoding RNAs (lncRNAs) play an important role in cancer development. Pathogenesis of adrenal tumours have been characterised by mRNA, microRNA and methylation expression signatures, but it is unknown if this extends to lncRNAs. This study describes lncRNA expression signatures in ACC, adrenal cortical adenoma (ACA) and normal adrenal cortex (NAC) and presents lncRNAs associated with ACC recurrence to identify novel prognostic and therapeutic targets. RNA was extracted from freshly frozen tissue with confirmation of diagnosis by histopathology. Focused lncRNA and mRNA transcriptome analysis was performed using the ArrayStar Human LncRNA V3.0 microarray. Differentially expressed lncRNAs were validated using quantitative reverse transcriptase-PCR and correlated with clinical outcomes. Microarray of 21 samples (ten ACCs, five ACAs and six NACs) showed distinct patterns of lncRNA expression between each group. A total of 956 lncRNAs were differentially expressed between ACC and NAC, including known carcinogenesis-related lncRNAs such as H19, GAS5, MALAT1 and PRINS (P≤0.05); 85 lncRNAs were differentially expressed between ACC and ACA (P≤0.05). Hierarchical clustering and heat mapping showed ACC samples correctly grouped compared with NAC and ACA. Sixty-six differentially expressed lncRNAs were found to be associated with ACC recurrence (P≤0.05), one of which, PRINS, was validated in a group of 20 ACCs and also found to be associated with metastatic disease on presentation. The pathogenesis of adrenal tumours extends to lncRNA dysregulation and low expression of the lncRNA PRINS is associated with ACC recurrence.

Wntless regulates dentin apposition and root elongation in the mandibular molar

Wnt signaling plays an essential role in the dental epithelium and mesenchyme during tooth morphogenesis. However, it remains unclear if Wnt ligands, produced from dental mesenchyme, are necessary for odontoblast differentiation and dentin formation. Here, we show that odontoblast-specific disruption of Wntless (Wls), a chaperon protein that regulates Wnt sorting and secretion, leads to severe defects in dentin formation and root elongation. Dentin thickness decreased remarkably and pulp chambers enlarged in the mandibular molars of OC-Cre;Wls(CO/CO) mice. Although the initial odontoblast differentiation was normal in the mutant crown, odontoblasts became cuboidal and dentin thickness was reduced. In immunohistochemistry, Wnt10a, β-catenin, type I collagen, and dentin sialoprotein were significantly down-regulated in the odontoblasts of mutant crown. In addition, roots were short and root canals were widened. Cell proliferation was reduced in the developing root apex of mutant molars. Furthermore, Wnt10a and Axin2 expression was remarkably decreased in the odontoblasts of mutant roots. Deletion of the Wls gene in odontoblasts appears to reduce canonical Wnt activity, leading to inhibition of odontoblast maturation and root elongation.

Osterix regulates tooth root formation in a site-specific manner

Bone and dentin share similar biochemical compositions and physiological properties. Dentin, a major tooth component, is formed by odontoblasts; in contrast, bone is produced by osteoblasts. Osterix (Osx), a zinc finger-containing transcription factor, has been identified as an essential regulator of osteoblast differentiation and bone formation. However, it has been difficult to establish whether Osx functions in odontoblast differentiation and dentin formation. To understand the role of Osx in dentin formation, we analyzed mice in which Osx was subjected to tissue-specific ablation under the control of either the Col1a1 or the OC promoter. Two independent Osx conditional knockout mice exhibited similar molar abnormalities. Although no phenotype was found in the crowns of these teeth, both mutant lines exhibited short molar roots due to impaired root elongation. Furthermore, the interradicular dentin in these mice showed severe hypoplastic features, which were likely caused by disruptions in odontoblast differentiation and dentin formation. These phenotypes were closely related to the temporospatial expression pattern of Osx during tooth development. These findings indicate that Osx is required for root formation by regulating odontoblast differentiation, maturation, and root elongation. Cumulatively, our data strongly indicate that Osx is a site-specific regulator in tooth root formation.

Seasonal phenology of Amphorophora agathonica (Hemiptera: Aphididae) and spread of viruses in red raspberry in Washington

Amphorophora agathonica (Hottes) is the primary vector of aphid-transmitted viruses in red raspberry in the Pacific Northwest region of the United States. To better understand the biology of the aphid, we estimated the lower developmental threshold and studied the seasonal activity of A. agathonica in commercial fields in northern Washington state. In addition, we monitored the spread of raspberry viruses (raspberry latent virus and raspberry leaf mottle virus, RLMV) to determine how rapidly fields became infected and whether there was a relationship between aphid presence and infection. The lower developmental threshold of A. agathonica was estimated to be 2.7°C. In the field, apterous and alate aphid populations began rapidly increasing at ≍800 growing degree-days and peaked at 1,050 growing degree-days. RLMV spread rapidly, with 30-60% of plants in four different commercial fields testing positive after three growing seasons. There was no discernible relationship between the presence or abundance of aphids based on 10 leaves sampled per plant location, and the odds of that plant becoming infected with RLMV.

Development of biological control of Tetranychus urticae (Acari: Tetranychidae) and Phorodon humuli (Hemiptera: Aphididae) in Oregon hop yards

The temporal development of biological control of arthropod pests in perennial cropping systems is largely unreported. In this study, the development of biological control of twospotted spider mite, Tetranychus urticae Koch, and hop aphid, Phorodon humuli (Schrank), in a new planting of hop in Oregon is described over a period of 9 yr (2005-2013). Both the abundance and diversity of natural enemies increased over time. Known predators of hop aphid (Coccinellidae and Anthocoridae) were present in all years; however, stable biological control of hop aphid was not achieved in most years and aphicides were required to suppress populations at commercially acceptable levels in 5 of 9 yr. Populations of aphidophagous coccinellids developed synchronously with hop aphid populations, and temporal correlations indicated these are the primary predatory insect associated with hop aphid regulation. However, sampling methods did not assess levels of aphid parasitoids and hyperparasitoids and their contribution to biological control was unquantified. Spider mite biological control was associated primarily with predatory mites (Phytoseiidae) and Stethorus spp. (Coccinellidae). The magnitude of temporal correlations of abundance of these predators with spider mites was found to be greatest on the same sampling dates and at lags of 7-14 d. Stable biological control of spider mites occurred after four field seasons, suppressing spider mites to levels similar to those commonly achieved with chemical control. A survey of 11 commercial hop yards in Oregon documented pest and natural enemy densities under commercial management practices over a period of 4 yr (2008-2011). Natural enemy abundance in commercial hop yards was similar to that of a 2- to 3-yr-old hop yard with limited disturbance. Whereas total reliance on biological control for hop aphid is unlikely to be successful, there appears to be unrealized potential for biological control of spider mites in commercial production. Dynamic action thresholds that consider the value of natural enemies are needed for both pests.

Acapsular clinical Staphylococcus aureus isolates lack agr function

Staphylococcus aureus is a major human pathogen causing community- and hospital-acquired infections. Capsule production of S. aureus confers protection against host defence. There is a lack of information concerning the association of capsular polysaccharide (CP) expression and activity of the accessory gene regulator (agr) in clinical S. aureus isolates. Production of CP and agr expression were assessed in 195 S. aureus isolates from infected patients at a German University Hospital. Northern blot analysis revealed that S. aureus strains with a non-functional agr locus were more likely to be CP-negative than strains with a functional agr locus.

The role of contingency awareness in single-cue human eyeblink conditioning

Single-cue delay eyeblink conditioning is presented as a prototypical example of automatic, nonsymbolic learning that is carried out by subcortical circuits. However, it has been difficult to assess the role of cognition in single-cue conditioning because participants become aware of the simple stimulus contingency so quickly. In this experiment (n = 166), we masked the contingency to reduce awareness. We observed a strong relationship between contingency awareness and conditioned responding, with both trace and delay procedures. This finding suggests that explicit associative knowledge and anticipatory behavior are regulated by a coordinated system rather than by functionally and neurally distinct systems.

Tolerability of intramuscular and intradermal delivery by CELLECTRA(®) adaptive constant current electroporation device in healthy volunteers

DNA vaccines are being developed as a potentially safe and effective immunization platform. However, translation of DNA vaccines into a clinical setting has produced results that have fallen short of those generated in a preclinical setting. Various strategies are being developed to address this lack of potency, including improvements in delivery methods. Electroporation (EP) creates transient increases in cell membrane permeability, thus enhancing DNA uptake and leading to a more robust immune response. Here, we report on the safety and tolerability of delivering sterile saline via intramuscular (IM) or intradermal (ID) injection followed by in vivo electroporation using the CELLECTRA(®) adaptive constant current device in healthy adults from two open-label studies. Pain, as assessed by VAS, was highest immediately after EP but diminishes by about 50% within 5 min. Mean VAS scores appear to correlate with the amount of energy delivered and depth of needle insertion, especially for intramuscular EP. Mean scores did not exceed 7 out of 10 or 3 out of 10 for IM and ID EP, respectively. The majority of adverse events included mild to moderate injection site reactions that resolved within one day. No deaths or serious adverse events were reported during the course of either study. Overall, injection followed by EP with the CELLECTRA(®) device was well-tolerated and no significant safety concerns were identified. These studies support the further development of electroporation as a vaccine delivery method to enhance immunogenicity, particularly for diseases in which traditional vaccination approaches are ineffective.

Immunotherapy against HPV16/18 generates potent TH1 and cytotoxic cellular immune responses

Despite the development of highly effective prophylactic vaccines against human papillomavirus (HPV) serotypes 16 and 18, prevention of cervical dysplasia and cancer in women infected with high-risk HPV serotypes remains an unmet medical need. We report encouraging phase 1 safety, tolerability, and immunogenicity results for a therapeutic HPV16/18 candidate vaccine, VGX-3100, delivered by in vivo electroporation (EP). Eighteen women previously treated for cervical intraepithelial neoplasia grade 2 or 3 (CIN2/3) received a three-dose (intramuscular) regimen of highly engineered plasmid DNA encoding HPV16 and HPV18 E6/E7 antigens followed by EP in a dose escalation study (0.3, 1, and 3 mg per plasmid). Immunization was well tolerated with reports of mild injection site reactions and no study-related serious or grade 3 and 4 adverse events. No dose-limiting toxicity was noted, and pain was assessed by visual analog scale, with average scores decreasing from 6.2/10 to 1.4 within 10 min. Average peak interferon-γ enzyme-linked immunospot magnitudes were highest in the 3 mg cohort in comparison to the 0.3 and 1 mg cohorts, suggesting a trend toward a dose effect. Flow cytometric analysis revealed the induction of HPV-specific CD8(+) T cells that efficiently loaded granzyme B and perforin and exhibited full cytolytic functionality in all cohorts. These data indicate that VGX-3100 is capable of driving robust immune responses to antigens from high-risk HPV serotypes and could contribute to elimination of HPV-infected cells and subsequent regression of the dysplastic process.

Early plasma soluble receptor for advanced glycation end-product levels are associated with bronchiolitis obliterans syndrome

Early epithelial injury after lung transplantation may contribute to development of bronchiolitis obliterans syndrome (BOS). We evaluated the relationship between early postoperative soluble receptor for advanced glycation end-product (sRAGE) levels, a marker of type I alveolar cell injury and BOS. We performed a cohort study of 106 lung transplant recipients between 2002 and 2006 at the University of Pennsylvania with follow-up through 2010. Plasma sRAGE was measured 6 and 24 h after transplantation. Cox proportional hazards models were used to evaluate the association between sRAGE and time to BOS, defined according to ISHLT guidelines. Sixty (57%) subjects developed BOS. The average time to BOS was 3.4 years. sRAGE levels measured at 6 h (HR per SD of sRAGE: 1.69, 95% CI: 1.11, 2.57, p = 0.02) and 24 h (HR per SD of sRAGE: 1.74, 95% CI: 1.14, 2.65, p = 0.01) were associated with an increased hazard of BOS. Multivariable Cox regression indicated this relationship was independent of potential confounders. Elevated plasma sRAGE levels measured in the immediate postoperative period are associated with the development of BOS. Early epithelial injury after transplantation may contribute to the development of fibrosis in BOS.

Second-order conditioning and conditioned inhibition: influences of speed versus accuracy on human causal learning

In human causal learning, excitatory and inhibitory learning effects can sometimes be found in the same paradigm by altering the learning conditions. This study aims to explore whether learning in the feature negative paradigm can be dissociated by emphasising speed over accuracy. In two causal learning experiments, participants were given a feature negative discrimination in which the outcome caused by one cue was prevented by the addition of another. Participants completed training trials either in a self-paced fashion with instructions emphasising accuracy, or under strict time constraints with instructions emphasising speed. Using summation tests in which the preventative cue was paired with another causal cue, participants in the accuracy groups correctly rated the preventative cue as if it reduced the probability of the outcome. However, participants in the speed groups rated the preventative cue as if it increased the probability of the outcome. In Experiment 1, both speed and accuracy groups later judged the same cue to be preventative in a reasoned inference task. Experiment 2 failed to find evidence of similar dissociations in retrospective revaluation (release from overshadowing vs. mediated extinction) or learning about a redundant cue (blocking vs. augmentation). However in the same experiment, the tendency for the accuracy group to show conditioned inhibition and the speed group to show second-order conditioning was consistent even across sub-sets of the speed and accuracy groups with equivalent accuracy in training, suggesting that second-order conditioning is not merely a consequence of poorer acquisition. This dissociation mirrors the trade-off between second-order conditioning and conditioned inhibition observed in animal conditioning when training is extended.