[The pain-emotion: Advocating pain as an emotion]

OBJECTIVES

Pain is a common experience, both physical and emotional. However we often feel powerless with our patients suffering pain. This paper aims to give a new heuristic and psychological understanding of pain.

METHODOLOGY

According to new theories, recent researches as well as different points of view, we form an analogy between pain and emotion. Throughout historical considerations pain has always been perceived through theories and beliefs, changing its definition. This is also the case for emotion. Could they be two ways of expressing a single phenomenon?

RESULTS

First, we must clarify the definition of emotion. In past, emotion was considered as a multiple-conditioned notion. To be considered as an emotion the pain had to fill numerous features, which differ according to the scientific opinions. The emotion may be considered as a physical expression or perceived only as the consequences of a real emotion, i.e., the subjective feeling. We propose as a way of thinking that emotion brings together these two concepts. We support a flexible vision of emotion. To investigate the field of the emotion different mental steps may be thought of: we should conceive of the emotion as a stimulus, as an emotional evaluation and as a tendency to action, which becomes an emotional response. These steps are colored by subjective feelings. It can be summarized in three levels: the situation decoding (1), the response organization (2) and the effectiveness of the response (3). Second pain can be considered as a complex notion involving personal and subjective feelings. We can use multidimensional patterns and consider emotion with its multiple features: the generating mechanisms, the pain perception, the pain behavior and the environment. Each stage can be divided in different ways. Hence pain treatment could be approached as an emotional treatment. Indeed, we can make a link between generating mechanisms and emotion situation decoding, between pain perception and emotion situation decoding and response organization, between pain behavior and environment and emotion response effectiveness and consequences. A heuristic analogy can be formed enriching therapeutic possibilities. First, emotion and pain could be considered as a unique phenomenon that can be expressed in different ways. We can let aside the opposition between psychological and physiological: these are two different levels of a same phenomenon. This point of view can be helpful to treat pain disorders because the skills to manage emotion disorders are well known.

An electrodynamics-Langevin dynamics (ED-LD) approach to simulate metal nanoparticle interactions and motion

Understanding the formation of electrodynamically interacting assemblies of metal nanoparticles requires accurate computational methods for determining the forces and propagating trajectories. However, since computation of electromagnetic forces occurs on attosecond to femtosecond timescales, simulating the motion of colloidal nanoparticles on milliseconds to seconds timescales is a challenging multi-scale computational problem. Here, we present a computational technique for performing accurate simulations of laser-illuminated metal nanoparticles. In the simulation, we self-consistently combine the finite-difference time-domain method for electrodynamics (ED) with Langevin dynamics (LD) for the particle motions. We demonstrate the ED-LD method by calculating the 3D trajectories of a single 100-nm-diameter Ag nanoparticle and optical trapping and optical binding of two and three 150-nm-diameter Ag nanoparticles in simulated optical tweezers. We show that surface charge on the colloidal metal nanoparticles plays an important role in their optically driven self-organization. In fact, these simulations provide a more complete understanding of the assembly of different structures of two and three Ag nanoparticles that have been observed experimentally, demonstrating that the ED-LD method will be a very useful tool for understanding the self-organization of optical matter.

Integrated copy number and gene expression analysis detects a CREB1 association with Alzheimer's disease

Genetic variation, both single-nucleotide variations and copy number variations (CNV), contribute to changes in gene expression. In some cases these variations are meaningfully correlated with disease states. We hypothesized that in a genetically heterogeneous disorder such as sporadic Alzheimer's disease (AD), utilizing gene expression as a quantitative trait and CNVs as a genetic marker map within the same individuals in the context of case-control status may increase the power to detect relevant loci. Using this approach an 8-kb deletion was identified that contains a PAX6-binding site on chr2q33.3 upstream of CREB1 encoding the cAMP responsive element-binding protein1 transcription factor. The association of the CNV to AD was confirmed by a case-control association study consisting of the Texas Alzheimer Research and Care Consortium and NIA-LOAD Family Study data sets.

Increased blood-brain barrier permeability with thymidine phosphorylase deficiency

Mitochondrial neurogastrointestinal encephalomyopathy is an autosomal recessive multisystemic disorder caused by thymidine phosphorylase deficiency. Whereas the pathomechanism of the secondary mitochondrial dysfunction has been extensively studied, that of the leukoencephalopathy has not been elucidated. We hypothesized that the white matter hyperintensities on T2-weighted magnetic resonance images reflect disturbance of blood-brain barrier function. Albumin immunohistochemistry disclosed quantitative (p < 0.01) and qualitative differences between the mitochondrial neurogastrointestinal encephalomyopathy and control brains, indicating that loss of thymidine phosphorylase function impairs the integrity of the blood-brain barrier.

Adrenergic and peptidergic control of the regulation of cAMP efflux and melatonin secretion from perifused rat pineal gland

Mammalian pineal gland receives peptidergic (e.g., vasoactive intestinal peptide [VIP]; peptide histidine isoleucine [PHI]; neuropeptide Y, NPY; substance P, calcitonin gene-related peptide [CGRP], arginine vasopressin [AVP] and oxytocin [OXT]) fibers in addition to sympathetic innervation. The dynamics of cAMP efflux and melatonin (MT) secretion were compared during the infusion of these peptides in our long-term perifusion system. VIP and PHI enhanced both pineal cAMP efflux and MT secretion in a dose-dependent manner (10 nM to 10 microM). However, the potency of PHI was slightly less. The peak of cAMP release always precedes that of MT production. The possible interactions between adrenergic and peptidergic compounds in the regulation of pineal cAMP efflux and MT secretion were also studied. VIP acts on specific peptidergic receptors, since its stimulatory effect could only be reduced by a VIP receptor antagonist. VIP has an additive effect at a lower (100 nM) concentration combined with norepinephrine (NE). NPY (100 nM) can completely block NE-induced MT secretion, but the decrease in cAMP efflux is less. However, NPY does not significantly influence VIP-stimulated cAMP efflux or MT secretion. These data suggest that NE, VIP, and NPY are differently involved in the cAMP and calcium signaling. The other neuropeptides are ineffective.