Psychosocial factors associated with chronic pain in adolescents

A number of psychosocial factors have been associated with the onset, exacerbation and/or maintenance of chronic pain in adolescents. The present study was conducted to evaluate the relative importance of vulnerability, reinforcement, and modeling. We compared 222 adolescents with chronic pain and no documented physiological etiology (headache, back, limb and abdominal pain) with 148 controls and their (respectively 183 vs. 127) parents. Analyses showed that adolescents with chronic pain are more vulnerable in terms of neuroticism, negative fear of failure, and (less) experienced social acceptance. Contrary to our expectations, the chronic pain group experienced less reinforcement for their pain behavior by both parents and peers than the control group. While the number of pain models was higher in the chronic pain group, no differences were found between their parents and those of the adolescents without chronic pain in pain experience, pain parameters, and pain coping. Regression analyses on the contribution of psychosocial factors to chronic pain and its parameters sustained the positive relation between vulnerability, (less) pain reinforcement, pain models and coping with pain. Furthermore, we also found evidence that gender differences have to be taken into account.     

New aspects of the Slug Mucosal Irritation assay: predicting nasal stinging, itching and burning sensations

Stinging, itching and/or burning (SIB) sensations cannot be detected by animal tests or in vitro models. In the past, the Slug Mucosal Irritation (SMI) assay demonstrated a relation between an increased mucus production in slugs and an elevated incidence of SIB sensations in humans. A new 1-day SMI test procedure was developed focusing on the prediction of these short-term sensations. The objective of this study was to verify whether this new procedure is capable predicting mucosal tolerance of several marketed nasal formulations using the slug Arion lusitanicus. Irritation and tissue damage were quantified with a 5-day repeated exposure study by means of the mucus produced and proteins and enzymes released. The new protocol predicted SIB sensations by means of mucus production. The effects of six liquid nasal formulations were tested with both protocols, while five physiologic saline solutions were only tested with the new protocol to optimize it. None of the tested liquid nasal formulations resulted in tissue damage; however, exposure to the different formulations had a clear effect on the mucus production of the slugs and moderate discomfort was observed in some cases. These effects were due to the active ingredient, the presence of benzalkonium chloride as a preservative or the hyperosmolality of the formulation. For the most part results agreed with clinical data found in literature. It was concluded that the SMI assay, and the new 1-day protocol in particular, is a good tool to predict nasal clinical discomfort.     

Controlled release of chlorhexidine antiseptic from microporous amorphous silica applied in open porosity of an implant surface

Amorphous microporous silica (AMS) serving as a reservoir for controlled release of a bioactive agent was applied in the open porosity of a titanium coating on a Ti-6Al-4V metal substrate. The pores of the AMS emptied by calcination were loaded with chlorhexidine diacetate (CHX) via incipient wetness impregnation with CHX solution, followed by solvent evaporation. Using this CHX loaded AMS system on titanium substrate sustained release of CHX into physiological medium was obtained over a 10 day-period. CHX released from the AMS coating was demonstrated to be effective in killing planktonic cultures of the human pathogens Candida albicans and Staphylococcus epidermidis. This surface modification of titanium bodies with AMS controlled release functionality for a bioactive compound potentially can be applied on dental and orthopaedic implants to abate implant-associated microbial infection.     

Transcutaneous Immunization Studies in Mice Using Diphtheria Toxoid-Loaded Vesicle Formulations and a Microneedle Array

Purpose  

To determine the immunogenicity of diphtheria toxoid (DT) formulated in two types of vesicles following transcutaneous immunization (TCI) of mice onto microneedle array-treated skin.     

Arthropod vectors and vector-borne bacterial pathogens in Yosemite National Park

Ticks, fleas, and vector-borne pathogens were surveyed in diverse small mammals in Yosemite National Park, California, from 2005 to 2007. A total of 450 unique captures of small mammals was collected during a 3-yr period and yielded 16 species of fleas and 10 species of ticks, including known vectors of Anaplasma phagocytophilum and Borrelia burgdorferi and plague. Serology was performed for A. phagocytophilum, spotted fever group Rickettsia spp., B. burgdorferi, and Yersinia pestis. A. phagocytophilum exposure was identified in 12.1% of all wild small mammals tested, with seropositive animals in 10 species, notably Belding's ground squirrels (Spermophilus beldingi), jumping mice (Zapus princeps), and voles (Microtus sp.). Spotted fever group Rickettsia spp. exposure was detected in 13.9% of all small mammals tested, with seropositive animals in eight species. Additionally, 37.0% of rodents in five species tested were seropositive for B. burgdorferi. No individuals were seropositive for Y. pestis. No animals were polymerase chain reaction positive for any pathogen tested. These results provide baseline data for future research and prediction of emerging vector-borne disease in Yosemite National Park, as well as adding to the known ranges and host species for tick and fleas in California.     

Coordination of gaze and hand movements for tracking and tracing in 3D

In this study we have investigated movements in three-dimensional space. Since most studies have investigated planar movements (like ellipses, cloverleaf shapes and “figure eights”) we have compared two generalizations of the two-thirds power law to three dimensions. In particular we have tested whether the two-thirds power law could be best described by tangential velocity and curvature in a plane (compatible with the idea of planar segmentation) or whether tangential velocity and curvature should be calculated in three dimensions. We defined total curvature in three dimensions as the square root of the sum of curvature squared and torsion squared. The results demonstrate that most of the variance is explained by tangential velocity and total curvature. This indicates that all three orthogonal components of movements in 3D are equally important and that movements are truly 3D and do not reflect a concatenation of 2D planar movement segments.In addition, we have studied the coordination of eye and hand movements in 3D by measuring binocular eye movements while subjects move the finger along a curved path. The results show that the directional component and finger position almost superimpose when subjects track a target moving in 3D. However, the vergence component of gaze leads finger position by about 250 msec. For drawing (tracing) the path of a visible 3D shape, the directional component of gaze leads finger position by about 225 msec, and the vergence component leads finger position by about 400 msec. These results are compatible with the idea that gaze leads hand position during drawing movement to assist prediction and planning of hand position in 3D space.     

Influence of Implant Connection Type on the Biomechanical Environment of Immediately Placed Implants – CT‐Based Nonlinear,Three‐Dimensional Finite Element Analysis

Purpose: The purpose of the present study was to evaluate the biomechanical environment of immediately placed implants, before and after osseointegration, by comparing three different implant‐abutment connection types. Materials and Methods: A computer tomography‐based finite element model of an upper central incisor extraction socket was constructed containing implants with either external hex, internal hex, or Morse‐taper connection. Frictional contact elements were used in the bone, implant, abutment, and abutment screw interfaces in the immediately placed simulations. In osseointegrated simulations, the repair of bone alveolar defect and a glued bone‐to‐implant interface were assumed. By analysis of variance, the influence was assessed of connection type, clinical situation, and loading magnitude on the peak equivalent strain in the bone, peak von Mises stress in the abutment screw, bone‐to‐implant relative displacement, and abutment gap. Results: The loading magnitudes had a significant contribution, regardless of the assessed variable. However, the critical clinical situation of an immediately placed implant itself was the main factor affecting the peak equivalent strain in the bone and bone‐to‐implant displacement. The largest influence of the connection type in this protocol was seen on the peak equivalent stress in the abutment screw. On the other hand, a higher influence of the various connection types on bone stress/strain could be noted in osseointegrated simulations. Conclusions: The implant‐abutment connection design did not significantly influence the biomechanical environment of immediately placed implants. Avoiding implant overloading and ensuring a sufficient initial intraosseous stability are the most relevant parameters for the promotion of a safe biomechanical environment in this protocol.     

Effective collaboration between marginal metallophilic macrophages and CD8+ dendritic cells in the generation of cytotoxic T cells

The spleen is the lymphoid organ that induces immune responses toward blood-borne pathogens. Specialized macrophages in the splenic marginal zone are strategically positioned to phagocytose pathogens and cell debris, but are not known to play a role in the activation of T-cell responses. Here we demonstrate that splenic marginal metallophilic macrophages (MMM) are essential for cross-presentation of blood-borne antigens by splenic dendritic cells (DCs). Our data demonstrate that antigens targeted to MMM as well as blood-borne adenoviruses are efficiently captured by MMM and exclusively transferred to splenic CD8⁺ DCs for cross-presentation and for the activation of cytotoxic T lymphocytes. Depletion of macrophages in the marginal zone prevents cytotoxic T-lymphocyte activation by CD8⁺ DCs after antibody targeting or adenovirus infection. Moreover, we show that tumor antigen targeting to MMM is very effective as antitumor immunotherapy. Our studies point to an important role for splenic MMM in the initial steps of CD8⁺ T-cell immunity by capturing and concentrating blood-borne antigens and the transfer to cross-presenting DCs which can be used to design vaccination strategies to induce antitumor cytotoxic T-cell immunity.