bluuebunny/crossref_metadata_2025 huggingface dataset:
The mental health of breast cancer survivors and their adolescent daughters
Authors: Inbar Cohen , Ety Berant , Ayala Hubert , Tamer Perez
Published: July 2012

Objective

This study examines associations between attachment orientations and mental health among breast cancer survivors and their adolescent daughters, while focusing on intergenerational transmission of emotional problems.

Methods

A total of 58 breast cancer survivors and their adolescent daughters were recruited 8 months following mothers' completion of treatment and were compared with a matched control group of 48 healthy mothers and their adolescent daughters. Measures included the Experiences in Close Relationships scale and the Mental Health Inventory.

Results

Hierarchical regressions revealed the following: First, breast cancer survivors reported higher levels of mental distress and lower levels of well‐being than control women, and the effect of breast cancer on well‐being was significant only among highly anxiously attached women. Second, daughters of breast cancer survivors reported higher levels of mental distress than daughters of control women only if they scored high on avoidant attachment. Third, daughters of breast cancer survivors reported higher levels of mental distress than daughters of control women only if their mothers scored high on anxious attachment.

Conclusions

Breast cancer had detrimental effects on survivors' well‐being and daughters' distress mainly when survivors scored high on attachment anxiety. Breast cancer had also detrimental effects of daughters' distress mainly when daughters scored high on avoidant attachment. These findings highlight the importance of attachment security as an inner resource for buffering detrimental mental health effects of breast cancer among survivors and their daughters.Copyright © 2012 John Wiley & Sons, Ltd.
Neutron resonance data exclude random matrix theory
Authors: Koehler P.E. , Bečvář F. , Krtička M. , Guber K.H. , Ullmann J.L.
Published: July 2012

Almost since the time it was formulated, the overwhelming consensus has been that random matrix theory (RMT) is in excellent agreement with neutron resonance data. However, over the past few years, we have obtained new neutron‐width data at Oak Ridge and Los Alamos National Laboratories that are in stark disagreement with this theory. We also have reanalyzed neutron widths in the most famous data set, the nuclear data ensemble (NDE), and found that it is seriously flawed, and, when analyzed carefully, excludes RMT with high confidence. More recently, we carefully examined energy spacings for these same resonances in the NDE using the Δ3 statistic. We conclude that the data can be found to either confirm or refute the theory depending on which nuclides and whether known or suspected p‐wave resonances are included in the analysis, in essence confirming results of our neutron‐width analysis of the NDE. We also have examined radiation widths resulting from our Oak Ridge and Los Alamos measurements, and find that in some cases they do not agree with RMT. Although these disagreements presently are not understood, they could have broad impact on basic and applied nuclear physics, from nuclear astrophysics to nuclear criticality safety.
Shape invariance in phase space
Authors: Rasinariu C.
Published: July 2012

Shape invariance is a powerful solvability condition, that allows for complete knowledge of the energy spectrum, and eigenfunctions of a system. After a short introduction into the deformation quantization formalism, this paper explores the implications of the supersymmetric quantum mechanics and shape invariance techniques to the phase space formalism. We show that shape invariance induces a new set of relations between the Wigner functions of the system, that allows for their direct calculation, once we know one of them. The simple harmonic oscillator and the Morse potential are solved as examples.
Novel approach for optimization of a ‘difficult’ peptide synthesis by utilizing quantitative reaction monitoring assays
Authors: Finneman Jari I. , Pozzo Mark J.
Published: July 2012

Three different synthetic strategies were tested to synthesize EGFRvIII peptide (1), which is a functional variant of the epidermal growth factor receptor, a protein that has been well validated as a target for cancer therapy. The initial synthesis was performed with Applied Biosystem (Carlsbad, CA, USA) 433A peptide synthesizer and it indicated that the last three amino acids coupling and Fmoc removal rates were lower than the rest of the sequence. Purity of the crude peptide was 54.5%. The second synthesis was performed manually utilizing C S Bio (Menlo Park, CA, USA) synthesizer and the Kaiser test for reaction monitoring. Because of non‐optimized reaction conditions and an unexpected by‐product, lower purity crude peptide (40.5%) was obtained. Quantitative assays to monitor reactions were developed and demonstrated in gram scale synthesis with C S Bio synthesizer. The optimized synthetic conditions improved the peptide purity to 68.1%. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.
Alternative Method for Determining O2 and CO2 Transmission Rates Through Microperforated Films for Modified Atmosphere Packs
Authors: González‐Buesa Jaime , Ferrer‐Mairal Ana , Oria Rosa , Salvador María L.
Published: July 2012

Most experimental systems for measuring the permeability of microperforated polymeric films are static, mainly because in dynamic systems the small differences in pressure on both sides of the perforation may result in serious errors in the measurements. The O2 and CO2 transmission rate through microperforations of different sizes (from 40 × 30 to 350 × 110 µm) were determined in a static and in a dynamic system. In the latter case, rather than the diffusive flow, the hydrodynamic flow generated by the difference in pressure was measured (between 5 and 90 mbar). This was determined by applying Bernouilli's theorem and an experimental equation potentially relating the area of the microperforation with the transmission rate. A comparison of the transmission rates obtained in both cases gives coefficients of determination close to one (>0.993). This means that measuring the hydrodynamic flow can be considered as an alternative for the quantification of the diffusive flow through a microperforation. This is a simple and quick methodology that does not require expensive equipment. Furthermore, this feature enables commercial leak detection equipment to be used to quantify diffusive transmission rates through microperforations. Copyright © 2012 John Wiley & Sons, Ltd.
GENOTOXICITY IN CHIRONOMUS KIIENSIS (CHIRONOMIDAE: DIPTERA) AFTER EXPOSURE TO POLLUTED SEDIMENTS FROM RIVERS OF NORTH PENINSULAR MALAYSIA: IMPLICATION FOR ECOTOXICOLOGICAL MONITORING
Authors: Al‐Shami Salman A. , Che Salmah Md Rawi , Mohd Nor Siti Azizah , Ahmad Abu Hassan , Mohd Ishadi Nur Adibah , Dieng Hamady
Published: July 2012

Rapid industrialization and urbanization has led to increasing input of chemical contaminants into the aquatic environment of Malaysia. Despite the threat civilization poses to the biota, there are still very few relevant studies on ecotoxicological testing of river ecosystems. To overcome this knowledge gap, we examined lethal and genotoxic effects of sediments from different rivers of the northern Malaysia against Chironomus kiiensis, a group well represented in the aquatic fauna of this region. We exposed the larvae to sediments from Selama River (SR), Permatang Rawa River (PRR) and Kilang Ubi River (KUR) at various durations (0, 6, 12, 24 and 48 h). The larval mortality was monitored, whereas DNA damage in survivors' cells was determined using the comet assay. Pollution level indexed by the amounts of heavy metals and other organic contaminants in the sediment showed progressive increases from SR to PRR to KUR. Highly polluted sediments (PRR to KUR) were detrimental to C. kiiensis larvae, most of which did not survive following exposure for long periods. DNA analyses revealed greater damages in nuclei derived from larvae maintained on polluted sediments, in particular, those from KUR. The effects on the genomic material of C. kiiensis larvae occurred in a time‐dependent manner, with damage level increasing as exposure time progressed. Our results highlight the genotoxic properties of polluted sediments. More importantly, this study showed that C. kiiensis larvae could respond to different levels of pollution with respect to exposure time. It is concluded that C. kiiensis larvae is a potential candidate for river ecotoxicological monitoring. Copyright © 2012 John Wiley & Sons, Ltd.
PATTERNS OF BENTHIC INVERTEBRATE RICHNESS AND DIVERSITY IN THE REGULATED MAGPIE RIVER AND NEIGHBOURING NATURAL RIVERS
Authors: Jones N. E.
Published: July 2012

Fluctuating flows common in hydropeaking operations present biota with contrasting and challenging environments. Taxa that require a narrow range of water velocity or are not adapted to withstand sudden changes in discharge will likely be eliminated or competitively disadvantaged under such circumstances, perhaps leading to reduced biodiversity. I investigated the whole river, longitudinal and lateral patterns of benthic invertebrate abundance, Shannon–Wiener diversity, and rarefied taxa density and richness in the hydropeaking Magpie River and 16 neighbouring natural rivers. The Magpie River had greater abundances of benthic invertebrates than natural rivers, particularly near the dam. General differences in benthic community characteristics were largely based on the near absence of Odonata and Plecoptera and an abundance of snails and worms in the Magpie River. Family density, richness and diversity were greater in the regulated Magpie River and unregulated upper Magpie River than found in natural rivers. Longitudinally, family density, diversity and particularly richness increased downstream in the Magpie River. Laterally, diversity did not show any trends with increasing depth along transects, except at near the dam where it decreased sharply with depth, velocity, and an abundance of filter feeding invertebrates. Taxa density did not show any lateral trends in natural rivers, whereas in the Magpie River, it increased with water velocity and depth. The results of this study are contradictory to the general findings of others implying reduced biodiversity below hydropower facilities. Possible explanations are examined and contrasted with other examinations of benthic invertebrate response below hydropeaking dams. © Her Majesty the Queen in Right of Canada 2012.
Secured and fast handoff in wireless mesh networks
Authors: Zarai Faouzi , Daly Ikbel , Obaidat Mohammad S. ,   Fellow of IEEE,   Fellow of SCS, Kamoun Lotfi
Published: July 2012

Wireless mesh networks are one of the most important improvements in the world of wireless technologies. In fact, they offer many advantages to ensure a free mobility and a self‐configuration of the various network equipment, a better quality of services, as well as an extensible domain and area. In spite of all of these contributions, mesh technology still suffers from some problems such as security especially in handoff phases. In this study, we propose an authentication scheme that is designed to reduce the authentication delay during a wireless mesh network handoff process. The proposed mechanism takes into account the mobility of clients as well as the router movements. This work takes advantage of some existing techniques such as Blom key predistribution scheme and Du key process generation method. Our simulation results prove the effectiveness of our proposed scheme. Our performance evaluation results shows that the suggested solution outperforms existing schemes in improving handoff latency values (<15 ms) and in the ability of satisfying the requirements of security as well as the quality of services in terms of having low loss rate (less than 1%) and having a low blocking rate. Copyright © 2012 John Wiley & Sons, Ltd.
Development of gas cluster ion beam irradiation system with an orthogonal acceleration TOF instrument
Authors: Ichiki K. , Tamura J. , Seki T. , Aoki T. , Matsuo J.
Published: July 2012

Surface damage induced on biomolecules with gas cluster ion beam (GCIB) irradiation is significantly lower than with atomic or small cluster ion beams, and for this reason, surface analysis techniques such as secondary ion mass spectrometry (SIMS) have become one of the most important applications of GCIB, particularly for microscale chemical imaging of biomolecular species. Because of the low duty‐cycle in time‐of‐flight (TOF)‐SIMS, only less than 0.1 % of the incident ion beam is used for analysis, meaning that analysis with high spatial resolution can practically be extremely lengthy. The duty cycle can be significantly improved with the orthogonal acceleration (oa) TOF method because with this method secondary ion mass spectra can be measured at high mass resolution without requiring a pulsed primary ion beam. In this study, we developed a gas cluster ion irradiation system mounted on an oa‐TOF instrument and investigated the sputtering yield and secondary ion yield of arginine. Copyright © 2012 John Wiley & Sons, Ltd.
Conductivity of ITO film amplified by multi‐step ion beam‐treatment on PET layers at room temperature
Authors: Son Phil Kook , Choi Suk‐Won , Kim Sung Soo , Gwag Jin Seog
Published: July 2012

In this paper, we investigate poly‐crystal indium tin oxide (ITO) film produced by a multi‐step ion beam treatment on polyethylene terephthalate (PET) at room temperature. In the process of ITO film deposition by a sputtering method, we perform an ion beam treatment after some quantity of ITO deposition is complete, and this process is carried out repeatedly until the required film thickness is achieved. X‐ray diffraction indicates that the ITO film deposited by our multi‐step ion beam treatment has an almost poly‐crystal structure with a morsel of amorphous structure in the PET layers. As a supplementary measurement, a contact angle method shows that the poly‐crystal structure is due to a surface charge effect. Consequently, the electrical conductivity of the ITO film (resistivity measurement error bar < 0.7%) with the multi‐step ion beam treatment is eight times higher than that of single‐treated ITO film, due to this poly‐crystal structure. Copyright © 2012 John Wiley & Sons, Ltd.
Generating survival times to simulate Cox proportional hazards models with time‐varying covariates
Authors: Austin Peter C.
Published: July 2012

Simulations and Monte Carlo methods serve an important role in modern statistical research. They allow for an examination of the performance of statistical procedures in settings in which analytic and mathematical derivations may not be feasible. A key element in any statistical simulation is the existence of an appropriate data‐generating process: one must be able to simulate data from a specified statistical model. We describe data‐generating processes for the Cox proportional hazards model with time‐varying covariates when event times follow an exponential, Weibull, or Gompertz distribution. We consider three types of time‐varying covariates: first, a dichotomous time‐varying covariate that can change at most once from untreated to treated (e.g., organ transplant); second, a continuous time‐varying covariate such as cumulative exposure at a constant dose to radiation or to a pharmaceutical agent used for a chronic condition; third, a dichotomous time‐varying covariate with a subject being able to move repeatedly between treatment states (e.g., current compliance or use of a medication). In each setting, we derive closed‐form expressions that allow one to simulate survival times so that survival times are related to a vector of fixed or time‐invariant covariates and to a single time‐varying covariate. We illustrate the utility of our closed‐form expressions for simulating event times by using Monte Carlo simulations to estimate the statistical power to detect as statistically significant the effect of different types of binary time‐varying covariates. This is compared with the statistical power to detect as statistically significant a binary time‐invariant covariate. Copyright © 2012 John Wiley & Sons, Ltd.
Quantifying the impact of between‐study heterogeneity in multivariate meta‐analyses
Authors: Jackson Dan , White Ian R. , Riley Richard D.
Published: July 2012

Measures that quantify the impact of heterogeneity in univariate meta‐analysis, including the very popular I2 statistic, are now well established. Multivariate meta‐analysis, where studies provide multiple outcomes that are pooled in a single analysis, is also becoming more commonly used. The question of how to quantify heterogeneity in the multivariate setting is therefore raised. It is the univariate R2 statistic, the ratio of the variance of the estimated treatment effect under the random and fixed effects models, that generalises most naturally, so this statistic provides our basis. This statistic is then used to derive a multivariate analogue of I2, which we call . We also provide a multivariate H2 statistic, the ratio of a generalisation of Cochran's heterogeneity statistic and its associated degrees of freedom, with an accompanying generalisation of the usual I2 statistic, . Our proposed heterogeneity statistics can be used alongside all the usual estimates and inferential procedures used in multivariate meta‐analysis. We apply our methods to some real datasets and show how our statistics are equally appropriate in the context of multivariate meta‐regression, where study level covariate effects are included in the model. Our heterogeneity statistics may be used when applying any procedure for fitting the multivariate random effects model. Copyright © 2012 John Wiley & Sons, Ltd.
A simulation study of predictive ability measures in a survival model II: explained randomness and predictive accuracy
Authors: Choodari‐Oskooei B. , Royston P. , Parmar Mahesh K.B.
Published: July 2012

Several R2‐type measures have been proposed to evaluate the predictive ability of a survival model. In Part I, we classified the measures into four categories and studied the measures in the explained variation category. In this paper, we study the remaining measures in a similar fashion, discussing their strengths and shortcomings. Simulation studies are used to examine the performance of the measures with respect to the criteria we set out in Part I. Our simulation studies showed that among the measures studied in this paper, the measures proposed by Kent and O'Quigley (and its approximation ) and Schemper and Kaider perform better with respect to our criteria. However, our investigations showed that is adversely affected by the distribution of covariate and the presence of influential observations. The results show that the other measures perform poorly, primarily because they are affected either by the degree of censoring or the follow‐up period. Copyright © 2012 John Wiley & Sons, Ltd.
A general approach for sample size calculation for the three‐arm ‘gold standard’ non‐inferiority design
Authors: Stucke Kathrin , Kieser Meinhard
Published: July 2012

In the three‐arm ‘gold standard’ non‐inferiority design, an experimental treatment, an active reference, and a placebo are compared. This design is becoming increasingly popular, and it is, whenever feasible, recommended for use by regulatory guidelines. We provide a general method to calculate the required sample size for clinical trials performed in this design. As special cases, the situations of continuous, binary, and Poisson distributed outcomes are explored. Taking into account the correlation structure of the involved test statistics, the proposed approach leads to considerable savings in sample size as compared with application of ad hoc methods for all three scale levels. Furthermore, optimal sample size allocation ratios are determined that result in markedly smaller total sample sizes as compared with equal assignment. As optimal allocation makes the active treatment groups larger than the placebo group, implementation of the proposed approach is also desirable from an ethical viewpoint. Copyright © 2012 John Wiley & Sons, Ltd.
Precipitation Behavior of Modified as Cast High Nitrogen Super Hard High‐Speed Tool Steel
Authors: Halfa Hossam , Mattar Taha , Eissa Mamdouh
Published: July 2012

The properties of high‐speed tool steels can be improved by modifying their chemical composition or the technology of production. Nitrogen alloying is an attractive technology to enhance the mechanical and physical properties of tool steels. In this work, modified super hard high‐speed tool steel was produced through nitrogen alloying and decreasing the level of cobalt content in investigated steels. This work aims to study the effect of nitrogen as alloying element on carbides and carbo‐nitrides precipitates type, shape, and size for investigated steels. From the results obtained from Thermo‐Calc, it was concluded that nitrogen alloying produced large amount of stable austenite, also eutectic carbides precipitates (M6C and M7C3) were stable at room temperature. Transmission electron microscope (TEM) images for traditional grade showed that the as cast structure contains beside the carbides network other single carbides precipitates. While on the other hand the selected area diffraction pattern (SADP) images of nitrogen alloyed grade shows fine carbides and carbo‐nitrides precipitates with more amount of retained austenite in the ferrite matrix, they showed also the presence of the eutectic precipitates as well as the dislocations.
Brief report: Does exposure to violent video games increase moral disengagement among adolescents?
Authors: Gabbiadini Alessandro , Andrighetto Luca , Volpato Chiara
Published: July 2012

Several studies have repeatedly shown that violent/action video games increase aggressive tendencies. The present study provides preliminary evidence that exposure to these games also affects the process of moral disengagement. High school students (N = 385) were recruited, and the impact of both recency and frequency of their exposure to the video game Grand Theft Auto IV (GTA; 2008) on moral disengagement was explored. Results showed that exposure to GTA predicted higher levels of moral disengagement. Recency of exposure had a primary impact on the considered mechanisms of moral disengagement. These findings provide insights into a relevant detrimental effect of exposure to video games, to our knowledge not explored yet. Future research is needed to provide evidence of the causal link in the observed relationships.
Fast microscopical dissection of action scenes played by Escherichia coli RNA polymerase
Authors: Suzuki Yuki , Shin Minsang , Yoshida Aiko , Yoshimura Shige H. , Takeyasu Kunio
Published: July 2012

Using fast‐scanning atomic force microscopy, we directly visualized the interaction of Escherichia coli RNA polymerase (RNAP) with DNA at the scan rate of 1–2 frames per second. The analyses showed that the RNAP can locate the promoter region not only by sliding but also by hopping and/or segmental transfer. Upon the addition of 0.05 mM NTPs to the stalled complex, the RNAP molecule pulled the template DNA uni‐directionally at the rates of 15 nucleotides/s on average. The present method is potentially applicable to examine a variety of protein–nucleic acid interactions, especially those involved in the process of gene regulation.
Characterizing the neurite outgrowth inhibitory effect of Mani
Authors: Mishra Manisha , Lee Sachiko , Lin Michelle K. , Yamashita Toshihide , Heese Klaus
Published: July 2012

MANI
physically interacts with
TMTC1
by two hybrid (View interaction)
Interferon‐β‐induced miR‐155 inhibits osteoclast differentiation by targeting SOCS1 and MITF
Authors: Zhang Jun , Zhao Hongying , Chen Jinping , Xia Bing , Jin Yongming , Wei Wei , Shen Jianjian , Huang Yazeng
Published: July 2012

IFN‐β is induced via a c‐fos dependent mechanism that is present downstream of the receptor activator of NF‐κB ligand (RANKL)‐RANK signal transduction cascade during osteoclast differentiation. Increased production of IFN‐β in turn inhibits osteoclastogenesis. However, the mechanism by which IFN‐β exerts its suppressive function remains unclear. In the present study, we found that miR‐155, an IFN‐β‐induced miRNA, mediated the suppressive effect of IFN‐β on osteoclast differentiation by targeting SOCS1 and MITF, two essential regulators of osteoclastogenesis. These findings have not only demonstrated that miR‐155 inhibits osteoclast differentiation, but also provided a new therapeutic target for treatment of osteoclast‐mediated diseases.
Cardiovascular responses to and modulation of pressure pain sensitivity in normotensive, pain-free women
Authors: Mohn Christine , Vassend Olav , Knardahl Stein
Published: July 2012

Background and purpose

The psychophysiological responses to and modulation of pressure pain stimulation are relatively new areas of investigation. The aims of the present study were to characterize subjective and cardiovascular (CV) responses to pressure pain stimulation, and to examine the relationship between CV responding and pain pressure pain sensitivity.

Methods

Thirty-nine pain-free, normotensive women were included in the study and tested during the follicular phase of their menstrual cycles. Pain threshold and tolerance were recorded at the right masseter muscle and the sternum, and visual analogue scales (VAS) were used to rate both pain intensity (the sensory dimension) and discomfort (the affective dimension). Mean arterial pressure (MAP), heart rate (HR), and facial and digital skin blood flux (SBF) were registered continuously.

Results

The pain threshold and tolerance were significantly higher at the sternum compared with the masseter, but the level of affective distress was higher at the masseter tolerance point. No associations emerged between pressure pain threshold and tolerance stimulation levels, and the corresponding VAS ratings. Pressure pain stimulation of the masseter induced significant increases in MAP, HR, and a decrease in digital SBF. During sternum pressure stimulation a significant change in HR and digital SBF was observed. There were no significant correlations between CV responding and pressure pain sensitivity.

Conclusion

Healthy women seem to display higher pressure pain sensitivity at the masseter region relative to the sternum. Pressure pain stimulation was associated with significant changes in MAP, HR, and SBF, but was not modulated by CV responses. The validity of these findings is strengthened by our control for menstrual cycle events, weekend-related changes in physiology, and CV changes during pain stimulation.

Implications

This study extends previous reports of SBF sensitivity to electrocutaneous pain into the field of pressure stimulation. Moreover, this study suggests that the often demonstrated association between high BP and low pain sensitivity may not apply to pressure pain specifically. Alternatively, this finding adds to the literature of gender differences in the relationship between CV responding and acute pain sensitivity in general.
The effect of a mental stressor on conditioned pain modulation in healthy subjects
Authors: Nilsen Kristian B. , Christiansen Sunniva E. , Holmen Line B. , Sand Trond
Published: July 2012

Background and purpose

In animal studies, enhanced sensitivity to painful stimuli succeeding chronic stress has been reported, while acute stress is reported to induce analgesia. Human studies on the effect of mental stress on pain are more equivocal. A disturbed stress-response resulting in an increased sensitivity to painful stimuli has also been discussed as a potential mechanism for e.g., the fibromyalgia syndrome. Endogenous analgesia may be studied in humans by measuring the analgesic effect of heterotopic noxious conditioning stimulation. In neurophysiological animal studies this phenomenon was originally denoted “diffuse noxious inhibitory controls” (DNIC), but for human studies it has been suggested to use the term conditioned pain modulation (CPM).

The clinical relevance of aberrances in CPM is not clear. Inhibitory CPM is reported as being reduced in several medically unexplained syndromes with musculoskeletal pain aggravated by mental stress. However, whether the reported reduced CPM effects are causally related to clinical pain is unknown.

In the present study the effect of a mental stressor on CPM is studied.

Methods

With tourniquet-induced pain as the conditioning stimulus we estimated the CPM effect in twenty healthy subjects. Heat pain threshold (HPT), supra-threshold heat pain level (SHPL) and pressure pain threshold (PPT) were used as test stimuli. Measurements were performed at baseline, after a stressful task and after a non-stressful task presented in a blinded cross-over design. We used repeated-measures ANOVAs in the analysis with simple contrasts for post hoc analysis.

Results

With a ANOVA repeated measures model we found a significant task effect (F = 18.5, p ≤ 0.001), indicating that CPM was successfully induced. In our ANOVA model, we found a significant effect of stress in the contrast analysis (F = 5.2, p = 0.037), indicating that CPM was affected by the stressful task. The effects on PPT could not be analyzed due to a significant carry-over effect (for PPT only).

Conclusions

In the present blinded crossover study, we found a significant small to medium inhibitory effect of mental stress upon the CPM of thermal pain.

Implications

Our results suggest that previously reported reduced inhibitory CPM in several medically unexplained syndromes with musculoskeletal pain aggravated by mental stress possibly can be related to confounding or clinically relevant stress level differences. However, the result might be modality-specific. Further studies in patients are obviously needed, and the impact of mental stress on CPM should be investigated also with other stressors.
Na+/K+-ATPase dependent regulation of astrocyte Ca2+ signalling: A novel mechanism for modulation of long-term pain?
Authors: Hansson Elisabeth , Block Linda , Forshammar Johan , Lundborg Christopher , Biber Björn
Published: July 2012

Background

Long-term or chronic pain represents a major health problem and is associated with significant socio-economic costs. During injury, pain can be dissociated from its normal physiological role. It can persist for a longer period of time, even after the primary noxious stimulus has more or less subsided. Analgesic drugs, with predominant neuronal sites of actions, seem to be relatively ineffective. Chronic pain is probably partly a consequence of ongoing neuroinflammation. The mechanisms behind these phenomena, and how the neuronal and non-neuronal activities evoked by painful stimuli and inflammation are processed in the brain and throughout the CNS, are not well understood.

Methods

Primary cultures, calcium imaging, immunocyto-chemistry, Western blotting, cytokine release.

Results

Following pain stimuli increased activity of inflammatory receptors and shifts in intra- and extracellular ion concentrations occur within the CNS. One signalling pathway in astrocytes propagates Ca2+ waves, which initially decrease and then increase in form of oscillations in the astrocyte networks. This causes dysfunction in the astrocytic Ca2+ signalling resulting in down-regulation of Na+ transporters, and increased release of pro-inflammatory cytokines. The neurons will then increase their excitability and, hypothetically, also increase the sensitivity for development or potentiation of neuropathic pain states. Low-dose of potential anti-inflammatory and analgesic drugs restore the disturbed astrocytic Ca2+ signalling, and modulate the activity of inflammatory receptors and Na+/K+-ATPase. We recently report, in patients with long-term pain, changes in neurotrophic factors and pro-inflammatory cytokines in blood and CSF.

Conclusions

Dysfunction in downregulation of Na+ transporters, changed Ca2+ signalling in the astrocyte networks and release of cytokines from glial cells can lead to pathogenic chronic neuroinflammation. Modulation of the Na+/K+-ATPase activity and restoration with anti-inflammatory substances will lead to a balance between inflammatory and anti-inflammatory mediators in inflammatory reactive cells. The pharmacological treatment of today is directed towards neuronal over-excitability, unfortunately with less success. A novel pharmacological treatment strategy would thus be directed towards the activated astrocytes and microglial cells, being the source of the neuroinflammation. This will be an important knowledge for treatment in clinical therapy.
Effect of specific trapezius exercises vs. coordination training on corticomotor control of neck muscles
Authors: Rittig-Rasmussen B. , Kasch H. , Fuglsang-Frederiksen A. , Jensen T.S. , Svensson P.
Published: July 2012

Objective

To test the effect of different neck training methods on motor evoked potentials (MEPs) from the trapezius muscle. We hypothesized that training of the trapezius muscle would significantly increase MEPs, indicating facilitation of the corticomotor pathways. Additional experiments investigated the influence of muscle strength, muscle fatigue, and correlations between MEP amplitudes and behavioral aspects of motor learning.

Methods

Transcranial magnetic stimulation (TMS) was used to elicit MEPs from the trapezius muscle and the abductor pollicis brevis (APB) muscle in 60 healthy subjects in three conditions: (1) specific trapezius training, (2) coordination training of the neck, and (3) no training.

Results

Specific training yielded an increase in MEPs 1 h (p = 0.001) and 7 days (p = 0.001) after training compared with baseline; no significant changes were seen after coordination training or no training. MEPs from the APB muscle did not change over time in any of the conditions. Muscle strength increased by 8% after specific training, but no subjective or objective measures of fatigue were observed.

Conclusions

The results showed that only specific training significantly increased trapezius MEPs for up to 7 days, indicating facilitation of the corticomotor pathways. These findings may help improve the future clinical management of neck pain.
Exercise and conditioned pain modulation have different effects on cuff pressure pain tolerance in humans
Authors: Madsen H.B. , Handberg G. , Graven-Nielsen T.
Published: July 2012

Background/aims

Exercise and experimental pain is known to cause an acute decrease of the pain sensitivity. Assessment of pain inhibitory mechanisms is often done by paradigms of exercise and experimental pain in both healthy subjects and pain patients. It is currently unknown whether pain and different types of exercise has similar effects on pain sensitivity. The aim of the present study was to investigate the effects of experimental pain and different types of exercise on deep tissue pain tolerance in healthy subjects.

Methods

On two separate days fifty-four healthy subjects (23 females, 33.8 ± 15.0 years) were assigned in random order to cold pressor tests (ice water at 1–2°C; 120 s duration) for the dominant hand and foot, bicycling exercises (100 W and 200 W; 20 min duration), and isometric contraction exercises (30% and 60% of maximal voluntary contraction, MVC; 180 s duration) of the dominant quadriceps and biceps brachii muscles. Before, immediately after, and 10 min after cold pressor tests and exercises, pressure pain tolerance (PTT) were assessed with computerized cuff-algometry at the non-dominant lower-leg and upper arm. Subjects reaching maximum stimulation intensity at baseline were excluded from the analysis. PTTs were analysed with repeated measures ANOVA and multiple comparisons.

Results

Immediately and 10 min after the cold pressor test in the dominant hand and foot significantly increased PTTs were found at the non-dominant upper arm and lower leg (P < 0.05). Both intensities of dominant biceps brachii isometric contractions produced a significant increase in the PTT at the non-dominant lower leg immediately after and 10 min after contractions (P < 0.05). After the 30% dominant quadriceps isometric contraction the PTT at the non-dominant lower leg was significantly increased (P < 0.05).

Conclusion

Cold pressor pain produced a contralateral and extrasegmental increase in deep tissue pain tolerance. Isometric arm exercise produced an extrasegmental increase in pain tolerance, whereas isometric leg contractions produced a contralateral effect. Aerobic exercise had no effect on pain tolerance. Thus, exercise and pain related inhibitory effects were not comparable.

Acknowledgment/disclosures

H.B. Madsen was supported by grants from the philanthropic foundation TrygFonden (7-11-0990), The Danish Rheumatism Association 8R95-A1871), The Research Foundation of the Danish Physiotherapy Association and The Fund for Physiotherapy in Private Practice.
Offset analgesia: A reproducibility study
Authors: Nilsson Matias , Nissen Thomas Dahl , Graversen Carina , Gazerani Parisa , Drewes Asbjørn Mohr , Brock Christina
Published: July 2012

Background and aims/objectives

Offset analgesia (OA) is a newly discovered pain-inhibiting mechanism, defined as a disproportionately large decrease in pain perception in response to a decrease in noxious stimulus intensity. Offset analgesia is usually evoked using heat as noxious stimulus (44–47 °C) and a slight decrease (1 °C) in stimulus intensity causes the volunteers to be pain-free for 5–10 s, despite the presence of a constant noxious stimulus. The aim of the present study was to evaluate whether the OA phenomenon is reproducible within the same day and between different days in order to evaluate whether the phenomenon can be used as a prognostic/diagnostic tool or as a potential therapeutic target in pain treatment.

Methods

Eighteen healthy volunteers were presented to painful thermal stimuli on the volar forearm, in three contiguous phases (first phase: 46 °C applied for 5 s; second phase: 47 °C applied for 5 s; third phase: 46 °C applied for 20 s). Continuous sensory ratings obtained with a handheld sliding VAS-scale and continuous 64-channel electroencephalographic (EEG) recordings were obtained throughout the three phases. Volunteers participated on two different days separated by a minimum of 7 days.

Results

Reproducibility was examined for numerous parameters (e.g. peak pain intensity, magnitude of pain-relief, AUC) related to the continuous pain ratings. Two-way ANOVA, ICC, and CV displayed a high degree of reproducibility both within the same day as well as between different days (P-values >0.05 and ICC values >0.6). EEG recordings were decomposed by spectral analysis, to obtain the normalized power in the delta, theta, alpha, beta and gamma frequency bands.

Conclusion

The present model displayed high reproducibility, making it suitable for further studies using OA. This may provide a unique approach to study basic pain and pharmacological intervention in healthy volunteers as well as in patients with dysfunctional pain inhibition. Continuous EEG recordings enable objective evaluation of dynamic changes in brainwave activity during OA, and can possibly be used as an objective biomarker to assess the underlying mechanisms of OA.
Visualization of painful process in peripheral tissue using positron emission tomography and [11C]-D-deprenyl
Authors: Aarnio Mikko , Appel Lieuwe , Fredrikson Mats , Gordh Torsten , Wolf Olof , Linnman Clas
Published: July 2012

Background/aims

An objective correlate of ongoing painful process in peripheral tissue would represent a progress in the analysis of pain. The aim of this study was to investigate if the extent of the injury and inflammation in musculoskeletal injuries can be visualized, quantified and followed over time using positron emission tomography (PET) with the radioligand [11C]-D-deprenyl.

Methods

Eight otherwise healthy patients with unilateral ankle sprain were PET-imaged acutely and followed up twice, first a month and then up to over one year after injury.

Results

Acutely [11C]-D-deprenyl uptake was significantly increased by a factor 10.7 (range 2.9–37.3) in the injury sites as compared to the intact ankle. During healing [11C]-D-deprenyl uptake was reduced, but not normalized until after 11 months.

Conclusions

Patients experiencing persistent pain showed prolonged [11C]-D-deprenyl uptake in the injury sites. Thus, PET can be used to visualize, quantify and follow painful processes in peripheral tissue.
Genetic variation in opioid receptor genes and sensitivity to experimental pain in male and female healthy volunteers
Authors: Olesen A.E. , Droney J. , Sato H. , Ross J.R. , Staahl C. , Andresen T. , Branford R. , Riley J. , Drewes A.M.
Published: July 2012

Background/aims

Pain is a common problem which significantly impacts on quality of life. Clinical pain is complicated to study due to numerous confounding variables. Normal volunteer models use standardised painful stimuli with resulting reduced phenotype variability. Current studies suggest an association between genetic variability and pain sensitivity.

Methods

Data from 50 healthy volunteers in three studies of multi-modal, multi-tissue experimental pain stimulation were included. Skin heat, muscle cuff pressure and visceral pressure were analysed. Genetic variants in the genes coding for the mu, delta and kappa opioid receptors (OPRM, OPRD and OPRK) were studied using multivariate regression modelling to investigate association with pain sensitivity.

Results

Reproducibility of baseline data for skin heat, muscle cuff pressure and visceral pressure between studies was confirmed (Cronbach’s α > 0.8). Gender differences in pain sensitivity were seen. Females were more sensitive to skin heat and muscle pressure (P =0.006 and 0.02 respectively). Genetic associations were also found. OPRK was associated with both skin heat pain (P =0.009) and muscle cuff pain (P =0.003). Visceral pressure pain was not associated with either gender or genotype.

Conclusion

Genetic variations in the kappa opioid receptor appear to mediate different pain modalities. Gender remains an independent predictor of pain sensitivity.
Chronic thoracic pain in children after cardiac surgery
Authors: Kristensen Anders Due , Lauridsen Mette Høj , Hjortdal Vibeke E. , Jensen Troels S. , Nikolajsen Lone
Published: July 2012

Background

Chronic pain after surgical procedures in children has gained limited attention. Chronic thoracic pain after cardiac surgery is common, and has a significant impact on daily life in adults. The study aim was to investigate the prevalence and etiology of chronic pain after cardiac surgery via sternotomy in children.

Methods

The study included a prospective clinical examination with quantitative sensory testing 3 months after surgery, and a retrospective survey of children, who underwent cardiac surgery 10-60 months earlier. Children were to be at least 4 years old at the time of completing the questionnaire. They were asked to recall the intensity of the post-operative pain. The questionnaire assessed pain descriptors, situations or activities that could worsen pain, and analgesic consumption. Faces pain scales (0–10) was used to rate the pain intensity.

Results

Ten children were examined three months after surgery. One child reported ongoing pain. Brush allodynia and pinprick hyperalgesia were present in 4 and 6 children respectively. Hypoesthesia to cold (20 °C) was present in 3 children, and cold allodynia was present in one child in the scar area. The average pressure pain threshold was 71.1 kPa (range 34.3–121 kPa).

One hundred and seventy one questionnaires were sent out, and 121 (70.8%) were eligible for analysis. Mean age at the time of surgery was 4.7 years and mean age at questionnaire completion was 8.4. Worst pain intensity in the week after surgery was 5.6 (mean). Any pain “during the recent week” was reported by 26 children, 12 children reported pain intensity ≥4. Two children (1.17%) reported pain intensity ≥4 at the time of questionnaire completion. Pain was evoked by local pressure in 23 (19.0%), and physical activity in 15 (12.4%) children. Itch and pressing were the most frequent pain descriptors chosen by 25 (20.7%) and 20 (16.5%) children, respectively. One child used paracetamol once a week.

Conclusions

The prevalence of chronic pain following cardiac surgery via median sternotomy in children is low. The pain may have a neuropathic component, but appears to be mild and does not significantly affect daily activities.
Is health related quality of life related to the pattern of chronic pain?
Authors: Jonsdottir Thorbjörg , Jonsdottir Helga , Gunnarsdottir Sigridur
Published: July 2012

Background/aims

When studying chronic pain in the general population, other factors besides prevalence may be equally important to establish the scope of the problem. Health related quality of life (HRQoL) is an important indicator for how chronic pain influences and interferes with the individual’s daily life. The relationships between different characteristics in the nature of pain and HRQoL have been investigated, showing number of pain locations and pain severity to be important. However, little is known about the relationship between pattern of chronic pain (constant/intermittent) and impact on HRQoL. The purpose of this study was to investigate the relationships between the pattern of chronic pain and impact on the individual’s HRQoL in a large nationwide population based sample.

Methods

A postal questionnaire on pain and HRQoL (SF-36), including information letter was sent to a sample of 4500 individuals, aged 20–70 years, randomly drawn from the Icelandic National Registry.

Results

Of 4500 questionnaires mailed 1586 were returned and completed (35.2%)

Majority of respondents were women (56.5%) and the majority were married or cohabitating (73.7%). The total sample mean age was 46.2 years (women 45.3, men 47.3) and respondents were significantly older than non-respondents.

The total prevalence of pain ≥3 months was 47.5% with mean duration of 9.3 years (SD = 9.96). One third (31.9%) of participants with pain ≥3 months reported constant pain and 21.4% daily intermittent. The rest reported frequent pain (27.8%) and periodical pain (18.9%).

There was a significant relationship between the pattern of pain and both physical and mental components of HRQoL. Participants experiencing constant pain had the lowest scores on both scales.

Conclusions

The results of this study show that both physical and mental components of HRQoL among individuals experiencing chronic pain are significantly related to the pattern of pain. Constant and daily pain is associated with poorer HRQoL than intermittent or periodical pain.
Splashing from drop impact into a deep pool: multiplicity of jets and the failure of conventional scaling
Authors: Zhang L. V. , Toole J. , Fezzaa K. , Deegan R. D.
Published: July 2012

We report high-speed optical and X-ray observations of jets formed during the impact of a drop with a deep pool of the same liquid. We show that a scaling that relies entirely on liquid properties, as is conventionally employed, is insufficient to determine the threshold for splashing. In order to determine if the gas properties could account for this deficit, we conducted experiments with different surrounding gases. We find that the splashing threshold depends on the gas’s dynamic viscosity, but not its density. We argue that these results are consistent with a thickening of the ejecta caused by the bubble trapped on impact between the drop and the pool. We also show that drop impact can generate a third jet, distinct from the lamella and the ejecta, that produces secondary droplets of an intermediate size.