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Background: Neuropathy can lead not only to impaired function but also to sensory sensitization. We aimed to link reduced skin nerve fibre density in different levels to layer-specific functional impairment in neuropathic pain patients and tried to identify pain-specific functional and structural markers. Methods: In 12 healthy controls and 36 patients with neuropathic pain, we assessed clinical characteristics, thermal thresholds (quantitative sensory testing) and electrically induced pain and axon reflex erythema. At the most painful sites and at intra-individual control sites, skin biopsies were taken and innervation densities in the different skin layers were assessed. Moreover, neuronal calcitonin gene-related peptide staining was quantified. Results: Perception of warm, cold and heat pain and nerve fibre density were reduced in the painful areas compared with the control sites and with healthy controls. Warm and cold detection thresholds correlated best with epidermal innervation density, whereas heat and cold pain thresholds and axon reflex flare correlated best with dermal innervation density. Clinical pain ratings correlated only with epidermal nerve fibre density (r = 0.38, p < 0.05)andbetterpreservedcolddetectionthresholds(r = 0.39,p < 0.05), but not with other assessed functional and structural parameters. Conclusions: Thermal thresholds, axon reflex measurements and assessment of skin innervation density are valuable tools to characterize and quantify peripheral neuropathy and link neuronal function to different layers of the skin. The severity of small fibre neuropathy, however, did not correspond to clinical pain intensity and a specific parameter or pattern that would predict pain intensity in peripheral neuropathy could not be identified.

The rapidly increasing cost to develop new drugs calls for new tools that efficiently enable the demonstration of the safety and effectiveness of a new drug. When validating such a decision-enabling tool, a traditional approach is typically to apply the tool on a positive control, known to be effective, and ascertain that a statistically significant effect is obtained. We argue, however, that the validation study should be designed to show that the tool provides a variability that is small in relation to the treatment effect, which means that the tool has the capacity of providing decision-enabling results in small-sample studies in routine use. We give details on the relevant test to perform in the validation of a decision-enabling tool and use the development of a human pharmacological model, aimed at studying neuropathic pain in 2 × 2 crossover trials, as a motivating example. We also develop power and sample size calculations, and illustrate the implications on sample size needed for a validation study. Results show that to obtain pertinent evidence that the decision-enabling tool is useful, that is, to reject the relevant null hypothesis, a substantially increased sample size would often be needed in the validation study, as compared to traditional approaches.

In a multivariate framework, it is shown how the two treatments in a 2 × 2 crossover trial with multivariate response can be compared with respect to mean vectors, i.e. fixed treatment effects, as well as within-subject covariance matrices, marginally and simultaneously. No distributional assumption is made about the between-subject variability, whereas multivariate normality is assumed for the within-subject variability. The proposed exact statistical inferences are valid even with few subjects. Data from a crossover trial with bivariate response are analysed with the proposed multivariate methods as well as with univariate methods.

To conduct a psychometric analysis to determine the adequacy of instruments that measure cognition in Alzheimer's disease trials.Both the Alzheimer's Disease Assessment Scale - Cognition (ADAS-Cog) and the Neuropsychological Test Battery (NTB) are validated outcome measures for clinical trials in Alzheimer's disease and are approved also for regulatory purposes. However, it is not clear how comparable they are in measuring cognitive function. In fact, many recent trials in Alzheimer's disease patients have failed and it has been questioned if ADAS-Cog still is a sensitive measure.The present paper examines the psychometric properties of ADAS-Cog and NTB, based on a post hoc analysis of data from a clinical trial (NCT01024660), which was conducted by AstraZeneca, in mild-to-moderate Alzheimer's disease (AD) patients, with a Mini Mental State Examination (MMSE) Total score 16-24. Acceptability, reliability, different types of validity and ability to detect change were assessed using relevant statistical methods. Total scores of both tests, as well as separate domains of both tests, including the Wechsler Memory Scale (WMS), Rey Auditory Verbal Learning Test (RAVLT) and Delis-Kaplan Executive Function System (D-KEFS) Verbal Fluency Condition, were analyzed.Overall, NTB performed well, with acceptable reliability and ability to detect change, while ADAS-Cog had insufficient psychometric properties, including ceiling effects in 8 out of a total of 11 ADAS-Cog items in mild AD patients, as well as low test-retest reliability in some of the items.Based on a direct comparison on the same patient sample, we see advantages of the NTB compared with the ADAS-Cog for the evaluation of cognitive function in the population of mild-to-moderate AD patients. The results suggest that not all of ADAS-Cog items are relevant for both mild and moderate AD population.This validation study demonstrates satisfactory psychometric properties of the NTB, while ADAS-Cog was found to be psychometrically inadequate.

Introduction Perfusion measurement by arterial spin labeling (ASL) techniques is well suited for pharmaceutical magnetic resonance imaging (phMRI) studies to investigate how drugs change the cerebral perfusion status and further, neuronal activity. Materials and method Twelve healthy normal male volunteers participated in the study which was based on a double blinded design. Six subjects were randomly selected to receive a single oral dose of 20 mg d -amphetamine and six were given placebo. Perfusion measurements by pseudo-continuous ASL (pCASL) technique were repeatedly performed at 10 different time points with a 3T clinical MRI scanner during a 10 hour period after dose together with physiologic data and blood sample collections. The dynamic changes in cerebral perfusion in response to the plasma concentration variations of d -amphetamine were analyzed at voxel-level and for regions of interest. Results Compared to the placebo group a 20% reduction in cerebral blood flow (CBF) was observed in gray matter for the subjects that received d -amphetamine. The most significant reduction of regional CBF (rCBF) was detected in the basal ganglia, frontal region and insular cortex using voxel based analysis. A relation between d -amphetamine exposure and CBF response was found using PK/PD modeling, which predicted on average a 15% decrease of the CBF in gray matter at a plasma concentration of 30 ng/ml. Conclusion In this study we have demonstrated that repeated perfusion measurements by pCASL technique was sufficiently robust to differentiate the neurological response between the groups that received d -amphetamine and placebo. Quantitative and repetitive CBF measurements can be used for PK/PD modeling of CNS drug responses in humans.

Tesaglitazar was developed as a dual peroxisome proliferator–activated receptor (PPARα/γ). To support the clinical program, a hamster carcinogenicity study was performed. The only neoplastic findings possibly related to treatment with tesaglitazar were low incidences of hemangioma and hemangiosarcoma in the liver of male animals. A high-power, two-year investigative study with interim necropsies was performed to further elucidate these findings. Treatment with tesaglitazar resulted in changes typical for exaggerated PPARα pharmacology in rodents, such as hepatocellular hypertrophy and hepatocellular carcinoma, but not an increased frequency of hemangiosarcomas. At the highest dose level, there was an increased incidence of sinusoidal dilatation and hemangiomas. No increased endothelial cell (EC) proliferation was detected in vivo, which was confirmed by in vitro administration to ECs. Immunohistochemistry and gene expression analyses indicated increased cellular stress and vascular endothelial growth factor (VEGF) expression in the liver, which may have contributed to the sinusoidal dilatation. A two-fold increase in the level of circulating VEGF was detected in the hamster at all dose levels, whereas no effect on VEGF was observed in patients treated with tesaglitazar. In conclusion, investigations have demonstrated that tesaglitazar does not produce hemangiosarcomas in hamster despite a slight effect on vascular morphology in the liver.

immunogens in the culture media, DCs from As immunogens-immunized APP/PS1 transgenic mice showed stronger migration, endocytosis and higherMHC II expression than DCs from unimmunizedmice. Further, short As immunogens decreased the secretion of IL-12/IL-10, IL-6/IL-1s and increased the production of TGF-s by DCs from immunized APP/PS1 transgenic mice, but not those from unimmunized mice. Our data indicated that DCs from APP/PS1 transgenic mice were in low-response state to short As immunogens in vitro. Furthermore, immunization with short As immunogens in vivowaked up this abnormal state.Conclusions:Therefore, it is necessary to take abnormal DCs role into consideration in As immunotherapy.

As recommended by the mouse lymphoma assay (MLA) Workgroup of the International Workshop on Genotoxicity Testing (Aberdeen, 2003), a trend test is critical if an induced mutant frequency (MF) of at least 126 × 10(-6) (global evaluation factor, GEF) is achieved at one or more test concentrations. Only those responses that both achieve the GEF and a significant trend are biologically relevant. While no specific trend test was recommended by the Workshop, a trend test was recommended by the UK Environmental Mutagen Society (1989). The test uses MF (untransformed) averaged over replicate cultures following a consistency test (against a historical heterogeneity factor) in a weighted linear regression with chi-square (χ(2)) test for slope and returns significant results in virtually all cases that are positive for the GEF, including those with no apparent dose-response. We have explored an alternative method where the natural logarithm of MF and its variance are estimated for each replicate culture separately and used in a weighted ordinary linear regression with t-test for slope. Using test cases positive for the GEF, the P-value from this model is shown to be sensitive to changes in the number of replicates, the shape and magnitude of mutant induction, in contrast to the χ(2) model. Cases with no apparent dose-response and thereby questionable biological significance are tested negative by our method but positive by the χ(2) model. Our method is thus straight-forward and provides a meaningful complement to the GEF in assessing the biological significance of the MLA results.

We aimed to find functional and structural differences in neuropathy between patients with and without chronic pain following nerve injury. We included 30 patients requiring hand surgery after a trauma, with 21 reporting chronic pain for more than one year after the injury, while 9 did not suffer from injury-related chronic pain. We assessed mechanical sensitivity, thermal thresholds, electrically induced pain and axon reflex erythema and cutaneous nerve fiber density in skin biopsies of the injured site and its contralateral control. Epidermal fiber density of the injured site was reduced similarly in both patient groups. Thresholds for cold and heat pain and axon reflex areas were reduced in the injured site, but did not differ between the patient groups. Only warmth thresholds were better preserved in the pain patients (35.2 vs. 38.4°C). Neuronal CGRP staining did not reveal any difference between pain and non-pain patients. Epidermal innervation density correlated best to warmth detection thresholds and deeper dermal innervation density to the area of the axon reflex erythema. No specific pattern of subjective, functional or structural parameters was detected that would separate the neuropathy patients into pain and non-pain patients. Specific staining of additional targets may help to improve our mechanistic understanding of pain development.

The use of novel analytical techniques (such as data clustering and decision trees) that can model and predict patient disease outcomes has great potential for assessing disease process and progression in Alzheimer’s disease and mild cognitive impairment. For this study, 43 different variables (generated from image data, demographics and clinical data) have been compiled and analyzed using a modified clustering algorithm. Our aim was to determine the influence of these variables on the incidence of Alzheimer’s and mild cognitive impairment. Furthermore, we used a decision tree algorithm to model the level of “importance” of variants influencing this decision.

With the aim of evaluating the usefulness of an in vitro system for assessing the potential hepatotoxicity of compounds, the paper describes several methods of obtaining mathematical models for the prediction of compound-induced toxicity in vivo. These models are based on data derived from treating rat primary hepatocytes with various compounds, and thereafter using microarrays to obtain gene expression 'profiles' for each compound. Predictive models were constructed so as to reduce the number of 'probesets' (genes) required, and subjected to rigorous cross-validation. Since there are a number of possible approaches to derive predictive models, several distinct modelling strategies were applied to the same data set, and the outcomes were compared and contrasted. While all the strategies tested showed significant predictive capability, it was interesting to note that the different approaches generated models based on widely disparate probesets. This implies that while these models may be useful in ascribing relative potential toxicity to compounds, they are unlikely to provide significant information on underlying toxicity mechanisms. Improved predictivity will be obtained through the generation of more comprehensive gene expression databases, covering more 'toxicity space', and by the development of models that maximize the observation, and combination, of individual differences between compounds.

Integrative understanding of preclinical and clinical data is imperative to enable informed decisions and reduce the attrition rate during drug development. The volume and variety of data generated during drug development have increased tremendously. A new information model and visualization tool was developed to effectively utilize all available data and current knowledge. The Knowledge Plot integrates preclinical, clinical, efficacy and safety data by adding two concepts: knowledge from the different disciplines and protein binding. Internal and public available data were gathered and processed to allow flexible and interactive visualizations. The exposure was expressed as the unbound concentration of the compound and the treatment effect was normalized and scaled by including expert opinion on what a biologically meaningful treatment effect would be. The Knowledge Plot has been applied both retrospectively and prospectively in project teams in a number of different therapeutic areas, resulting in closer collaboration between multiple disciplines discussing both preclinical and clinical data. The Plot allows head to head comparisons of compounds and was used to support Candidate Drug selections and differentiation from comparators and competitors, back translation of clinical data, understanding the predictability of preclinical models and assays, reviewing drift in primary endpoints over the years, and evaluate or benchmark compounds in due diligence comparing multiple attributes. The Knowledge Plot concept allows flexible integration and visualization of relevant data for interpretation in order to enable scientific and informed decision-making in various stages of drug development. The concept can be used for communication, decision-making, knowledge management, and as a forward and back translational tool, that will result in an improved understanding of the competitive edge for a particular project or disease area portfolio. In addition, it also builds up a knowledge and translational continuum, which in turn will reduce the attrition rate and costs of clinical development by identifying poor candidates early.

ketamine, ketorolac nor tramadol altered tolerance time but in buprenorphine subjects, morphine with either ketamine or tramadol increased tolerance times by 22 and 40%, respectively. Conclusions: Hyperalgesia can be measured by the cold pressor test in patients taking opioids for a variety of indications. Chronic opioid administration not only causes tolerance but also increases pain sensitivity leading to opioid-induced hyperalgesia without allodynia. The mechanism(s) are poorly understood, appear not to be opioid drug or dosing regimen specific but may involve immune system modulators. Novel therapeutic strategies are therefore required for the management of persistent pain in patients receiving opioids that can attenuate hyperalgesia without causing additional or new adverse effects. The future will likely see combinations of analgesics and antihyperalgesics. Acknowledgement: the research was supported by grants from NIH (USA) and NHMRC(Australia).