Factor analysis of responses to thermal, electrical, and mechanical painful stimuli supports the importance of multi-modal pain assessment

During the last decade, a multi-modal approach has been established in human experimental pain research for assessing pain thresholds and responses to various experimental pain modalities. Studies have concluded that differences in responses to pain stimuli are mainly related to variation between individuals rather than variation in response to different stimulus modalities. In a factor analysis of 272 consecutive volunteers (137 men and 135 women) who underwent tests with different experimental pain modalities, it was determined whether responses to different pain modalities represent distinct individual uncorrelated dimensions of pain perception. Volunteers underwent single painful electrical stimulation, repeated painful electrical stimulation (temporal summation), test for reflex receptive field, pressure pain stimulation, heat pain stimulation, cold pain stimulation, and a cold pressor test (ice water test). Five distinct factors were found representing responses to 5 distinct experimental pain modalities: pressure, heat, cold, electrical stimulation, and reflex-receptive fields. Each of the factors explained approximately 8% to 35% of the observed variance, and the 5 factors cumulatively explained 94% of the variance. The correlation between the 5 factors was near null (median ρ=0.00, range -0.03 to 0.05), with 95% confidence intervals for pairwise correlations between 2 factors excluding any relevant correlation. Results were almost similar for analyses stratified according to gender and age. Responses to different experimental pain modalities represent different specific dimensions and should be assessed in combination in future pharmacological and clinical studies to represent the complexity of nociception and pain experience.

Developing a model of library user education for freshman science students

Discusses the cooperative effort between librarians and science faculty at Bucknell University in developing an effective library use education course for incoming undergraduate science and engineering students. Describes course structure and activities, and includes a library instruction bibliography. (five references) (EA)

Impact of body mass index on the five-year outcome of patients having percutaneous coronary interventions with drug-eluting stents

The purpose of this study was to assess the impact of body mass index (BMI) on clinical outcome of patients treated by percutaneous coronary intervention (PCI) using drug-eluting stents. Patients were stratified according to BMI as normal (<25 kg/m(2)), overweight (25 to 30 kg/m(2)), or obese (>30 kg/m(2)). At 5-year follow-up all-cause death, myocardial infarction, clinically justified target vessel revascularization (TVR), and definite stent thrombosis were assessed. A complete dataset was available in 7,427 patients, of which 45%, 22%, and 33% were classified according to BMI as overweight, obese, and normal, respectively. Mean age of patients was significantly older in those with a normal BMI (p <0.05). Incidence of diabetes mellitus, hypertension, and dyslipidemia increased as BMI increased (p <0.05). Significantly higher rates of TVR (15.3% vs 12.8%, p = 0.02) and early stent thrombosis (1.5% vs 0.9%, p = 0.04) were observed in the obese compared to the normal BMI group. No significant difference among the 3 BMI groups was observed for the composite of death/myocardial infarction/TVR or for definite stent thrombosis at 5 years, whereas the normal BMI group was at higher risk for all-cause death at 5 years (obese vs normal BMI, hazard ratio 0.74, confidence interval 0.53 to 0.99, p = 0.05; overweight vs normal BMI, hazard ratio 0.73, confidence interval 0.59 to 0.94, p = 0.01) in the multivariate Cox proportional hazard model. Age resulted in a linearly dependent covariate with BMI in the all-cause 5-year mortality multivariate model (p = 0.001). In conclusion, the "obesity paradox" observed in 5-year all-cause mortality could be explained by the higher rate of elderly patients in the normal BMI group and the existence of colinearity between BMI and age. However, obese patients had a higher rate of TVR and early stent thrombosis and a higher rate of other risk factors such as diabetes mellitus, hypertension, and hypercholesterolemia.

Measurement Properties of the Short Multi-Dimensional Observation Scale for Elderly Subjects (MOSES)

This study evaluated the five-factor measurement model of the abbreviated Multidimensional Observation Scale for Elderly Subjects (MOSES), originally proposed by Pruchno, Kleban, and Resch in 1988. Modifications of the five-factor model were examined and evaluated with regard to their practical significance. A confirmatory second-order factor analysis was performed to examine whether the correlations among the first-order factors were adequately accounted for by a global dysfunction factor. Findings indicated that the proposed measurement model was replicated adequately. Although post hoc modifications resulted in significant improvements in overall model fit, the minor parameters had only a trivial influence on the major parameters of the baseline model. Results from the second-order factor analysis showed that a global dysfunc tion factor accounted adequately for the intercorrelations among the first-order factors.

Essential role of choline for pneumococcal virulence in an experimental model of meningitis

Objectives: The goal of the present study was to elucidate the contribution of the newly recognized virulence factor choline to the pathogenesis of Streptococcus pneumoniae in an animal model of meningitis. Results: The choline containing strain D39Cho(-) and its isogenic choline-free derivative D39Cho(-)licA64 -each expressing the capsule polysaccharide 2 - were introduced intracisternally at an inoculum size of 10(3) CFU into 11 days old Wistar rats. During the first 8 h post infection both strains multiplied and stimulated a similar immune response that involved expression of high levels of proinflammatory cytokines, the matrix metalloproteinase 9 (MMP-9), IL-10, and the influx of white blood cells into the CSF. Virtually identical immune response was also elicited by intracisternal inoculation of 10(7) CFU equivalents of either choline-containing or choline-free cell walls. At sampling times past 8 h strain D39Cho(-) continued to replicate accompanied by an intense inflammatory response and strong granulocytic pleiocytosis. Animals infected with D39Cho(-) died within 20 h and histopathology revealed brain damage in the cerebral cortex and hippocampus. In contrast, the initial immune response generated by the choline-free strain D39Cho(-)licA64 began to decline after the first 8 h accompanied by elimination of the bacteria from the CSF in parallel with a strong WBC response peaking at 8 h after infection. All animals survived and there was no evidence for brain damage. Conclusion: Choline in the cell wall is essential for pneumococci to remain highly virulent and survive within the host and establish pneumococcal meningitis.

Association between inflammatory mediators and response to inhaled nitric oxide in a model of endotoxin-induced lung injury

INTRODUCTION: Inhaled nitric oxide (INO) allows selective pulmonary vasodilation in acute respiratory distress syndrome and improves PaO2 by redistribution of pulmonary blood flow towards better ventilated parenchyma. One-third of patients are nonresponders to INO, however, and it is difficult to predict who will respond. The aim of the present study was to identify, within a panel of inflammatory mediators released during endotoxin-induced lung injury, specific mediators that are associated with a PaO2 response to INO. METHODS: After animal ethics committee approval, pigs were anesthetized and exposed to 2 hours of endotoxin infusion. Levels of cytokines, prostanoid, leucotriene and endothelin-1 (ET-1) were sampled prior to endotoxin exposure and hourly thereafter. All animals were exposed to 40 ppm INO: 28 animals were exposed at either 4 hours or 6 hours and a subgroup of nine animals was exposed both at 4 hours and 6 hours after onset of endotoxin infusion. RESULTS: Based on the response to INO, the animals were retrospectively placed into a responder group (increase in PaO2 > or = 20%) or a nonresponder group. All mediators increased with endotoxin infusion although no significant differences were seen between responders and nonresponders. There was a mean difference in ET-1, however, with lower levels in the nonresponder group than in the responder group, 0.1 pg/ml versus 3.0 pg/ml. Moreover, five animals in the group exposed twice to INO switched from responder to nonresponder and had decreased ET-1 levels (3.0 (2.5 to 7.5) pg/ml versus 0.1 (0.1 to 2.1) pg/ml, P < 0.05). The pulmonary artery pressure and ET-1 level were higher in future responders to INO. CONCLUSIONS: ET-1 may therefore be involved in mediating the response to INO.

A newly developed in vitro model of the human epithelial airway barrier to study the toxic potential of nanoparticles

The potential health effects of inhaled engineered nanoparticles are almost unknown. To avoid and replace toxicity studies with animals, a triple cell co-culture system composed of epithelial cells, macrophages and dendritic cells was established, which simulates the most important barrier functions of the epithelial airway. Using this model, the toxic potential of titanium dioxide was assessed by measuring the production of reactive oxygen species and the release of tumour necrosis factor alpha. The intracellular localisation of titanium dioxide nanoparticles was analyzed by energy filtering transmission electron microscopy. Titanium dioxide nanoparticles were detected as single particles without membranes and in membrane-bound agglomerates. Cells incubated with titanium dioxide particles showed an elevated production of reactive oxygen species but no increase of the release of tumour necrosis factor alpha. Our in vitro model of the epithelial airway barrier offers a valuable tool to study the interaction of particles with lung cells at a nanostructural level and to investigate the toxic potential of nanoparticles.

Effects of GDNF pretreatment on function and survival of transplanted fetal ventral mesencephalic cells in the 6-OHDA rat model of Parkinson's disease

Transplantation of fetal dopaminergic (DA) neurons offers an experimental therapy for Parkinson's disease (PD). The low availability and the poor survival and integration of transplanted cells in the host brain are major obstacles in this approach. Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor with growth- and survival-promoting capabilities for developing DA neurons. In the present study, we examined whether pretreatment of ventral mesencephalic (VM) free-floating roller tube (FFRT) cultures with GDNF would improve graft survival and function. For that purpose organotypic cultures of E14 rat VM were grown for 2, 4 or 8 days in the absence (control) or presence of GDNF [10 ng/ml] and transplanted into the striatum of 6-hydroxydopamine-lesioned rats. While all groups of rats showed a significant reduction in d-amphetamine-induced rotations at 6 weeks posttransplantation a significantly improved graft function was observed only in the days in vitro (DIV) 4 GDNF pretreated group compared to the control group. In addition, no statistical significant differences between groups were found in the number of surviving tyrosine hydroxylase-immunoreactive (TH-ir) neurons assessed at 9 weeks posttransplantation. However, a tendency for higher TH-ir fiber outgrowth from the transplants in the GDNF pretreated groups as compared to corresponding controls was observed. Furthermore, GDNF pretreatment showed a tendency for a higher number of GIRK2 positive neurons in the grafts. In sum, our findings demonstrate that GDNF pretreatment was not disadvantageous for transplants of embryonic rat VM with the FFRT culture technique but only marginally improved graft survival and function.

From school to work: A comprehensive model of work-related motivation in the transition to working life.

Motivation is a core concept to understand work related outcomes and vocational pursuits. However, existing research mostly focused on specific aspects of motivation, such as goals or self-efficacy beliefs, while falling short of adequately addressing more complex and integrative notions of motivation. Advancing the current state of research, we draw from Motivational Systems Theory and a model of proactive motivation to propose a comprehensive model of work-related motivation. Specifically, we define motivation as a system of mutually related factors consisting of goals, emotions, and personal agency beliefs, comprised by capability beliefs and context evaluations. Adapting this model of motivation to the school-to-work transition, we postulate that this motivational system is affected by different social, personal, and environmental variables, for example social support, the presence of role-models, personality traits, and scholastic achievement. We further expect that students with more autonomous work-related goals, expectations of more positive emotional experiences in their future working life, fewer perceived barriers to their career development, and higher work-related self-efficacy beliefs would be more successful in their transition from school to work. We also propose that goal-directed engagement acts as a partial mediator in the relationship between motivation and a successful transition. Finally, we hypothesize that work-related motivation while in school will have meaningful effects on positive outcomes while in vocational training, as represented by more work engagement, higher career commitment, job satisfaction, and lower intentions to quit training. In sum, we advance the point that the adaptation of a broader concept of work-related motivation in the school-to-work transition would result in more powerful predictions of success in this transition and would enhance scientific research and interventions in career development and counselling practice.

Biokinetics of nanoparticles and susceptibility to particulate exposure in a murine model of cystic fibrosis.

BACKGROUND Persons with cystic fibrosis (CF) are at-risk for health effects from ambient air pollution but little is known about the interaction of nanoparticles (NP) with CF lungs. Here we study the distribution of inhaled NP in a murine CF model and aim to reveal mechanisms contributing to adverse effects of inhaled particles in susceptible populations. METHODS Chloride channel defective CftrTgH (neoim) Hgu mice were used to analyze lung function, lung distribution and whole body biokinetics of inhaled NP, and inflammatory responses after intratracheal administration of NP. Distribution of 20-nm titanium dioxide NP in lungs was assessed on ultrathin sections immediately and 24 h after a one-hour NP inhalation. NP biokinetics was deduced from total and regional lung deposition and from whole body translocation of inhaled 30-nm iridium NP within 24 h after aerosol inhalation. Inflammatory responses were assessed within 7 days after carbon NP instillation. RESULTS Cftr mutant females had moderately reduced lung compliance and slightly increased airway resistance compared to wild type mice. We found no genotype dependent differences in total, regional and head deposition or in secondary-organ translocation of inhaled iridium NP. Titanium dioxide inhalation resulted in higher NP uptake by alveolar epithelial cells in Cftr mutants. Instillation of carbon NP induced a comparable acute and transient inflammatory response in both genotypes. The twofold increase of bronchoalveolar lavage (BAL) neutrophils in Cftr mutant compared to wild type mice at day 3 but not at days 1 and 7, indicated an impaired capacity in inflammation resolution in Cftr mutants. Concomitant to the delayed decline of neutrophils, BAL granulocyte-colony stimulating factor was augmented in Cftr mutant mice. Anti-inflammatory 15-hydroxyeicosatetraenoic acid was generally significantly lower in BAL of Cftr mutant than in wild type mice. CONCLUSIONS Despite lacking alterations in lung deposition and biokinetics of inhaled NP, and absence of significant differences in lung function, higher uptake of NP by alveolar epithelial cells and prolonged, acute inflammatory responses to NP exposure indicate a moderately increased susceptibility of lungs to adverse effects of inhaled NP in Cftr mutant mice and provides potential mechanisms for the increased susceptibility of CF patients to air pollution.

Synergism of peptide receptor-targeted Auger electron radiation therapy with anti-angiogenic compounds in a mouse model of neuroendocrine tumors.

BACKGROUND Neuroendocrine tumors are well vascularized and express specific cell surface markers, such as somatostatin receptors and the glucagon-like peptide-1 receptor (GLP-1R). Using the Rip1Tag2 transgenic mouse model of pancreatic neuroendocrine tumors (pNET), we have investigated the potential benefit of a combination of anti-angiogenic treatment with targeted internal radiotherapy. METHODS [Lys40(Ahx-DTPA-111In)NH2]-exendin-4, a radiopeptide that selectively binds to GLP-1R expressed on insulinoma and other neuroendocrine tumor cells, was co-administered with oral vatalanib (an inhibitor of vascular endothelial growth factor receptors (VEGFR)) or imatinib (a c-kit/PDGFR inhibitor). The control groups included single-agent kinase inhibitor treatments and [Lys40(Ahx-DTPA-natIn)NH2]-exendin-4 monotherapy. For biodistribution, Rip1Tag2 mice were pre-treated with oral vatalanib or imatinib for 0, 3, 5, or 7 days at a dose of 100 mg/kg. Subsequently, [Lys40(Ahx-DTPA-111In)NH2]-exendin-4 was administered i.v., and the biodistribution was assessed after 4 h. For therapy, the mice were injected with 1.1 MBq [Lys40(Ahx-DTPA-111In)NH2]-exendin-4 and treated with vatalanib or imatinib 100 mg/kg orally for another 7 days. Tumor volume, tumor cell apoptosis and proliferation, and microvessel density were quantified. RESULTS Combination of [Lys40(Ahx-DTPA-111In)NH2]-exendin-4 and vatalanib was significantly more effective than single treatments (p < 0.05) and reduced the tumor volume by 97% in the absence of organ damage. The pre-treatment of mice with vatalanib led to a reduction in the tumor uptake of [Lys40(Ahx-DTPA-111In)NH2]-exendin-4, indicating that concomitant administration of vatalanib and the radiopeptide was the best approach. Imatinib did not show a synergistic effect with [Lys40(Ahx-DTPA-111In)NH2]-exendin-4. CONCLUSION The combination of 1.1 MBq of [Lys40(Ahx-DTPA-111In)NH2]-exendin-4 with 100 mg/kg vatalanib had the same effect on a neuroendocrine tumor as the injection of 28 MBq of the radiopeptide alone but without any apparent side effects, such as radiation damage of the kidneys.

Investigation of retinal morphology alterations using spectral domain optical coherence tomography in a mouse model of retinal branch and central retinal vein occlusion.

Retinal vein occlusion is a leading cause of visual impairment. Experimental models of this condition based on laser photocoagulation of retinal veins have been described and extensively exploited in mammals and larger rodents such as the rat. However, few reports exist on the use of this paradigm in the mouse. The objective of this study was to investigate a model of branch and central retinal vein occlusion in the mouse and characterize in vivo longitudinal retinal morphology alterations using spectral domain optical coherence tomography. Retinal veins were experimentally occluded using laser photocoagulation after intravenous application of Rose Bengal, a photo-activator dye enhancing thrombus formation. Depending on the number of veins occluded, variable amounts of capillary dropout were seen on fluorescein angiography. Vascular endothelial growth factor levels were markedly elevated early and peaked at day one. Retinal thickness measurements with spectral domain optical coherence tomography showed significant swelling (p<0.001) compared to baseline, followed by gradual thinning plateauing two weeks after the experimental intervention (p<0.001). Histological findings at day seven correlated with spectral domain optical coherence tomography imaging. The inner layers were predominantly affected by degeneration with the outer nuclear layer and the photoreceptor outer segments largely preserved. The application of this retinal vein occlusion model in the mouse carries several advantages over its use in other larger species, such as access to a vast range of genetically modified animals. Retinal changes after experimental retinal vein occlusion in this mouse model can be non-invasively quantified by spectral domain optical coherence tomography, and may be used to monitor effects of potential therapeutic interventions.

Impaired Cell Cycle Regulation in a Natural Equine Model of Asthma.

Recurrent airway obstruction (RAO) is a common and potentially debilitating lower airway disease in horses, which shares many similarities with human asthma. In susceptible horses RAO exacerbation is caused by environmental allergens and irritants present in hay dust. The objective of this study was the identification of genes and pathways involved in the pathology of RAO by global transcriptome analyses in stimulated peripheral blood mononuclear cells (PBMCs). We performed RNA-seq on PBMCs derived from 40 RAO affected and 45 control horses belonging to three cohorts of Warmblood horses: two half-sib families and one group of unrelated horses. PBMCs were stimulated with hay dust extract, lipopolysaccharides, a recombinant parasite antigen, or left unstimulated. The total dataset consisted of 561 individual samples. We detected significant differences in the expression profiles between RAO and control horses. Differential expression (DE) was most marked upon stimulation with hay dust extract. An important novel finding was a strong upregulation of CXCL13 together with many genes involved in cell cycle regulation in stimulated samples from RAO affected horses, in addition to changes in the expression of several HIF-1 transcription factor target genes. The RAO condition alters systemic changes observed as differential expression profiles of PBMCs. Those changes also depended on the cohort and stimulation of the samples and were dominated by genes involved in immune cell trafficking, development, and cell cycle regulation. Our findings indicate an important role of CXCL13, likely macrophage or Th17 derived, and the cell cycle regulator CDC20 in the immune response in RAO.

CD4 T cells are required for both development and maintenance of disease in a new mouse model of reversible colitis

Current therapies to treat inflammatory bowel diseases have limited efficacy, significant side effects, and often wane over time. Little is known about the cellular and molecular mechanisms operative in the process of mucosal healing from colitis. To study such events, we developed a new model of reversible colitis in which adoptive transfer of CD4(+)CD45RB(hi) T cells into Helicobacter typhlonius-colonized lymphopenic mice resulted in a rapid onset of colonic inflammation that was reversible through depletion of colitogenic T cells. Remission was associated with an improved clinical and histopathological score, reduced immune cell infiltration to the intestinal mucosa, altered intestinal gene expression profiles, regeneration of the colonic mucus layer, and the restoration of epithelial barrier integrity. Notably, colitogenic T cells were not only critical for induction of colitis but also for maintenance of disease. Depletion of colitogenic T cells resulted in a rapid drop in tumor necrosis factor α (TNFα) levels associated with reduced infiltration of inflammatory immune cells to sites of inflammation. Although neutralization of TNFα prevented the onset of colitis, anti-TNFα treatment of mice with established disease failed to resolve colonic inflammation. Collectively, this new model of reversible colitis provides an important research tool to study the dynamics of mucosal healing in chronic intestinal remitting-relapsing disorders.Mucosal Immunology advance online publication 16 September 2015; doi:10.1038/mi.2015.93.

Improving residency training with the help of multisource feedback: Generation of a model of influencing factors

Background: Feedback is considered to be one of the most important drivers of learning. One form of structured feedback used in medical settings is multisource feedback (MSF). This feedback technique provides the opportunity to gain a differentiated view on a doctor’s performance from several perspectives using a questionnaire and a facilitating conversation, in which learning goals are formulated. While many studies have been conducted on the validity, reliability and feasibility of the instrument, little is known about the impact of factors that might influence the effects of MSF on clinical performance. Summary of Work: To study under which circumstances MSF is most effective, we performed a literature review on Google Scholar with focus on MSF and feedback in general. Main key-words were: MSF, multi-source-feedback, multi source feedback, and feedback each combined with influencing/ hindering/ facilitating factors, effective, effectiveness, doctors-intraining, and surgery. Summary of Results: Based on the literature, we developed a preliminary model of facilitating factors. This model includes five main factors influencing MSF: questionnaire, doctor-in-training, group of raters, facilitating supervisor, and facilitating conversation. Discussion and Conclusions: Especially the following points that might influence MSF have not yet been sufficiently studied: facilitating conversation with the supervisor, individual aspects of doctors-in-training, and the causal relations between influencing factors. Overall there are only very few studies focusing on the impact of MSF on actual and long-term performance. We developed a preliminary model of hindering and facilitating factors on MSF. Further studies are needed to better understand under which circumstances MSF is most effective. Take-home messages: The preliminary model might help to guide further studies on how to implement MSF to use it at its full potential.