The relationships between spinal amplitude of movement, pain and disability in low back pain: A systematic review and meta-analysis.

BACKGROUND AND OBJECTIVES: The role of spinal movement alterations in low back pain (LBP) remains unclear. This systematic review and meta-analyses examined the relationships between spinal amplitude of movement, disability and pain intensity in patients with LBP. DATABASES AND DATA TREATMENT: We searched PubMed, CINAHL, Embase, Pedro and Web of Science for relevant articles until 14th March 2023. Risk of bias was assessed with the Quality in Prognostic Studies Tool. We analysed the relationships between amplitude of movement, disability and pain intensity with standard correlational meta-analyses and meta-analytic structural equation modelling (MASEM) in cross-sectional and longitudinal data. RESULTS: A total of 106 studies (9001 participants) were included. In cross-sectional data, larger amplitude of movement was associated with lower disability (pooled coefficient: -0.25, 95% confidence interval: [-0.29 to -0.21]; 69/5899 studies/participants) and pain intensity (-0.13, [-0.17 to -0.09]; 74/5806). An increase in amplitude of movement was associated with a decrease in disability (-0.23, [-0.31 to -0.15]; 33/2437) and pain intensity (-0.25, [-0.33 to -0.17]; 38/2172) in longitudinal data. MASEM revealed similar results and, in addition, showed that amplitude of movement had a very small influence on the pain intensity-disability relationship. CONCLUSIONS: These results showed a significant but small association between amplitude of movement and disability or pain intensity. Moreover, they demonstrated a direct association between an increase in amplitude of movement and a decrease in pain intensity or disability, supporting interventions aiming to reduce protective spinal movements in patients with LBP. SIGNIFICANCE: The large meta-analyses performed in this work revealed an association between reductions in spinal amplitude of movement and increased levels of disability and pain intensity in people with LBP. Moreover, it highlighted that LBP recovery is associated with a reduction in protective motor behaviour (increased amplitude of movement), supporting the inclusion of spinal movement in the biopsychosocial understanding and management of LBP.

Somatosensory attentional modulations during pain-related movement execution.

Pain serves to protect against bodily threat, and therefore initiates protective responses such as attending toward threat-relevant information. Since pain is often exacerbated by executing movements, these motor actions may serve as cues for pain. Up to date, however, pain-related attention during movement remains largely unexplored. While it has been shown that the preparation of a pain-related movement leads to enhanced processing of somatosensory information, it is unclear how the actual execution of a movement interacts with somatosensory attention. In the current study, we examined whether somatosensory processing is enhanced at a moving body part when the movement is expected to be associated with pain. Participants were asked to execute hand movements which were occasionally followed by a pain stimulus. To measure somatosensory attention, a task-irrelevant, innocuous tactile probe was presented on either hand to evoke a somatosensory evoked potential (SEP). The results showed an elevation of the N120 SEP at the hand performing a potentially painful movement, indicating heightened attention toward tactile information at the threatened moving hand compared to the non-threatened hand. Additionally, the P200 SEP also showed enlarged responses when performing a pain-related movement compared to a no-pain-related movement. These results show that not only the anticipation, but also the execution of pain-related movements, may modulate the processing of somatosensory input, driven by attentional processes.

Attentional processing of itch.

Itch is a prevalent somatosensory symptom that can be highly disabling, because it is likely to draw attention and, as a result, may interfere with the performance of daily activities. Yet, research experimentally investigating attention to itch is lacking. In this study we aimed to investigate attentional processing of itch using multiple behavioral attention tasks. Forty-one healthy participants performed (1) a modified Stroop task with itch-related words, (2) a dot-probe task with itch-related pictures, and (3) a recently developed somatosensory attention task in which the effect of experimentally induced itch on the localization of visual targets was examined. Additionally, a number of self-report questionnaires related to somatosensory attentional processing were administered. Results indicated that participants' attention was biased toward itch-related words and pictures assessed by means of the dot-probe and modified Stroop task, respectively. For the somatosensory attention task, results showed that itch did not significantly influence the allocation of attention. However, when taking into account the time course of attention during the itch stimulus, data suggested that participants tended to disengage attention away during the itch stimulus. This is the first study that indicates an attentional bias for itch, using methods that have previously been validated for other sensations such as pain. In addition, the newly developed somatosensory attention task may reflect the time course of attention toward a tonic itch stimulus.

Hypervigilance for innocuous tactile stimuli in patients with fibromyalgia: an experimental approach.

BACKGROUND: Hypervigilance, i.e., excessive attention, is often invoked as a potential explanation for the observation that many individuals with fibromyalgia show a heightened sensitivity to stimulation in various sensory modalities, such as touch and hearing. Compelling evidence for this assumption is, however, lacking. The aim of the present study was to investigate the presence of somatosensory hypervigilance in patients with fibromyalgia. METHODS: Fibromyalgia patients (n = 41) and a matched control group (n = 40) performed a tactile change detection task in which they had to detect whether there was a change between two consecutively presented patterns of tactile stimuli presented to various body locations. The task was performed under two conditions: in the unpredictable condition, tactile changes occurred equally often at all possible body locations; in the predictable condition, the majority of tactile changes occurred at one specific body location. RESULTS: It was hypothesized that the fibromyalgia group would show better tactile change detection in the unpredictable condition and when changes ocurred at unexpected locations in the predictable condition. The results did not support this hypothesis. In neither condition was the fibromyalgia group better than the control group in detecting tactile changes. CONCLUSIONS: No evidence was found to support the claim that patients with fibromyalgia display somatosensory hypervigilance. This finding challenges the idea of hypervigilance as a static feature of fibromyalgia and urges for a more dynamic view in which hypervigilance emerges in situations when bodily threat is experienced.

Effects of mindfulness and distraction on pain depend upon individual differences in pain catastrophizing: an experimental study.

BACKGROUND: The aim of this study was to investigate whether the perception of experimental pain was different during a mindfulness manipulation than during a distraction manipulation. Furthermore, it was examined if effects were moderated by dispositional pain catastrophizing. METHODS: Undergraduate students (n = 51) completed self-report measures of pain catastrophizing and mindfulness. Subsequently, they were administered a series of mildly painful heat stimuli, which they had to rate. During pain induction, participants listened to either a pre-recorded mindfulness instruction (mindfulness group) or a pre-recorded story (distraction group). RESULTS: After controlling for baseline experimental pain ratings, we found no overall group effect, indicating that there was no difference in experienced pain between the mindfulness group and the distraction group. However, a significant moderation effect was found. When dispositional pain catastrophizing was high, pain was less pronounced in the mindfulness group than in the distraction group, whereas the opposite effect was found when the level of pain catastrophizing was low. CONCLUSIONS: The findings suggest that in persons with a high level of catastrophic thinking about pain, mindfulness-based coping may be a better approach than distraction.

Vicarious pain while observing another in pain: an experimental approach.

OBJECTIVE: This study aimed at developing an experimental paradigm to assess vicarious pain experiences. We further explored the putative moderating role of observer's characteristics such as hypervigilance for pain and dispositional empathy. METHODS: Two experiments are reported using a similar procedure. Undergraduate students were selected based upon whether they reported vicarious pain in daily life, and categorized into a pain responder group or a comparison group. Participants were presented a series of videos showing hands being pricked whilst receiving occasionally pricking (electrocutaneous) stimuli themselves. In congruent trials, pricking and visual stimuli were applied to the same spatial location. In incongruent trials, pricking and visual stimuli were in the opposite spatial location. Participants were required to report on which location they felt a pricking sensation. Of primary interest was the effect of viewing another in pain upon vicarious pain errors, i.e., the number of trials in which an illusionary sensation was reported. Furthermore, we explored the effect of individual differences in hypervigilance to pain, dispositional empathy and the rubber hand illusion (RHI) upon vicarious pain errors. RESULTS: RESULTS of both experiments indicated that the number of vicarious pain errors was overall low. In line with expectations, the number of vicarious pain errors was higher in the pain responder group than in the comparison group. Self-reported hypervigilance for pain lowered the probability of reporting vicarious pain errors in the pain responder group, but dispositional empathy and the RHI did not. CONCLUSION: Our paradigm allows measuring vicarious pain experiences in students. However, the prevalence of vicarious experiences of pain is low, and only a small percentage of participants display the phenomenon. It remains however unknown which variables affect its occurrence.

Keeping pain out of your mind: the role of attentional set in pain.

BACKGROUND: The involuntary capture of attention by pain may, to some extent, be controlled by psychological variables. In this paper, we investigated the effect of attentional set (i.e., the collection of task-related features that a person is monitoring in order to successfully pursue a goal) on pain. METHODS: Two experiments are reported in which the task relevance of the modality and spatial location of a target stimulus was manipulated. In both experiments, somatosensory and auditory stimuli were presented on each trial. In experiment 1, 29 participants were cued on each trial to localize either a somatosensory or an auditory target. In experiment 2, 37 participants were cued on each trial to identify either a somatosensory or an auditory target at a particular location. RESULTS: In experiment 1, self-reported pain intensity and unpleasantness were reduced when participants had to localize the auditory target. The location of the painful stimulus relative to the location of the auditory target did not affect pain. In experiment 2, again, pain intensity and unpleasantness ratings were reduced when participants identified the auditory target. Now, the location of the painful stimulus relative to the location of the auditory target moderated the effect. Pain intensity was less when the painful stimulus was at a different location than the auditory target. CONCLUSIONS: Results are discussed in terms of the attentional set hypothesis, and we argue that the effectiveness of distraction tasks depends on the degree to which the task-relevant features of the distraction task are distinct from pain-related features.

Molecular dynamics and umbrella sampling study of stabilizing factors in cyclic peptide-based nanotubes.

In this study, the dissociation mechanism of self-assembled cyclic peptides (CPs) has been investigated using classical/steered molecular dynamics simulations combined with umbrella sampling techniques in a polar and a nonpolar solvent. The stability of cyclic peptide nanotubes (CPNTs) with different surface polarity, {cyclo-[(D-Trp-L-Leu)(4)]}(8) and {cyclo-[(L-Gln-D-Ala-L-Glu-D-Ala)(2)]}(8), are explored in detail. It is observed from the results that the CPNTs are less dynamic in the nonpolar solvent than in the polar solvent. The dissociation of CPs from a lower oligomeric form is achieved by gradual breaking of interactions, requiring relatively little force. In higher oligomeric CPNTs, the dissociation takes place by collective breaking of interactions with significantly higher force. During the dissociation process, the tendency for collective breaking of various intermolecular interactions increases from the terminal to the core of the CPNT. The breaking of backbone-backbone hydrogen bonding is the critical point in the dissociation of CPs which is followed by the annihilation of various side chain-side chain interactions. The polarity of the solvent plays a decisive role in the dissociation mechanism of self-assembled CPs. It is evident from the calculated free energy of binding values that the overall stability of CPNT is higher in the nonpolar solvent than in the polar solvent.

Membrane bioreactor (MBR) sludge inoculation in a hybrid process scheme concept to assist overloaded conventional activated sludge (CAS) process operations.

This study analyzes the effect of inoculating membrane bioreactor (MBR) sludge in a parallel-operated overloaded conventional activated sludge (CAS) system. Modelling studies that showed the beneficial effect of this inoculation were confirmed though full scale tests. Total nitrogen (TN) removal in the CAS increased and higher nitrate formation rates were achieved. During MBR sludge inoculation, the TN removal in the CAS was proven to be dependent on MBR sludge loading. Special attention was given to the effect of inoculation on sludge quality. The MBR flocs, grown without selection pressure, were clearly distinct from the more compact flocs in the CAS system and also contained more filamentous bacteria. After inoculation the MBR flocs did not evolve into good-settling compact flocs, resulting in a decreasing sludge quality. During high flow conditions the effluent CAS contained more suspended solids. Sludge volume index, however, did not increase. Laboratory tests were held to determine the threshold volume of MBR sludge to be seeded into the CAS reactor. Above 16-30%, supernatant turbidity and scum formation increased markedly.

Long-term outcome after treatment of isolated pulmonary valve stenosis.

BACKGROUND: Few data are available on very long-term follow-up after treatment for isolated pulmonary valve stenosis (PVS), either surgically or by percutaneous balloon angioplasty (PBA). METHODS AND RESULTS: All patients with isolated PVS were selected from our database of congenital heart defects. Their records were reviewed systematically. We identified 79 surgically treated patients with a median follow-up of 22.5 years (range 0-45 years) and 139 PBA patients with median follow-up of 6.0 years (range 0-21 years). Echocardiographic and catheterization parameters indicate excellent results of both techniques in relieving the transpulmonary gradient. However, after initial surgery 20.3% of patients needed a cardiac re-intervention: 81% for severe pulmonary valve regurgitation, but none for residual pulmonary stenosis. After initial PBA a cardiac re-intervention was needed in 9.4% of patients. In 85% the indication was residual pulmonary stenosis, in none of them pulmonary regurgitation, although almost all patients developed a mild pulmonary regurgitation. Freedom of re-intervention after surgery was 98.4%, 93.5%, 87.7%, 70.9% and 55.7% at 5, 10, 20, 30 and 40 years postoperatively. Freedom of re-intervention in the PBA group was 95.1%, 87.5% and 84.4% at 5, 10 and 20 years post-procedure. CONCLUSIONS: Both surgery and PBA are safe and successful in relieving the acute transpulmonary gradient. Long-term results of surgery are worse than previously thought due to severe PR. After PBA re-interventions for residual stenosis are frequently needed and the incidence of mild PR is high. Very long-term results of PBA are still unknown.

Study of ion transport models for electroanalytical simulation. Part 2: experimental comparison.

Ion transport models are compared by simulating the limiting current density of copper deposition from aqueous CuSO(4) solutions on a rotating disk electrode. The first ion transport model is the pseudoideal solution model, on which many commercial electroanalytical simulation tools are built. The second, more rigorous model consists of the linear phenomenological equations for which the activity coefficients and Onsager coefficients are calculated locally with the mean spherical approximation (MSA). The influence of the formal association constant in the pseudoideal solution model is also investigated.

Ion transport models for electroanalytical simulation. 1. Theoretical comparison.

Ion transport models are compared by computing the limiting current density of an electrodeposition on a rotating disk electrode for various hypothetical electrolytes. The first ion transport model is the pseudoideal solution model, on which many commercial electroanalytical simulation tools are built. The second, more rigorous model consists of the linear phenomenological equations for which the activity coefficients and Onsager coefficients are calculated locally with the mean spherical approximation (MSA).

QSAR analysis of salicylamide isosteres with the use of quantum chemical molecular descriptors.

Quantitative relationships between the molecular structure and the biological activity of 49 isosteric salicylamide derivatives as potential antituberculotics with a new mechanism of action against three Mycobacterial strains were investigated. The molecular structures were represented by quantum chemical B3LYP/6-31G( *) based molecular descriptors. A resulting set of 220 molecular descriptors, including especially electronic properties, was statistically analyzed using multiple linear regression, resulting in acceptable and robust QSAR models. The best QSAR model was found for Mycobacterium tuberculosis (r(2)=0.92; q(2)=0.89), and somewhat less good QSAR models were found for Mycobacterium avium (r(2)=0.84; q(2)=0.78) and Mycobacterium kansasii (r(2)=0.80; q(2)=0.56). All QSAR models were cross-validated using the leave-10-out procedure.

Hemimyelomeningocele: a rare and complex spinal dysraphism.

We report a case of hemimyelomeningocele. This is a rare spinal dysraphism, consisting of the association of a split cord malformation with myelomeningocele. MRI demonstrates division of the spinal cord into two hemicords which are separated by a bony spur. The left hemicord forms a myelomeningocele, thus resulting in a hemimyelomeningocele. Accurate and early diagnosis of spinal dysraphisms is essential for optimal, individualised neurosurgical treatment.

Analyzing toxicity through electrophilicity.

The toxicological structure-activity relationships are investigated using conceptual DFT based descriptors like global and local electrophilicities. In the present work the usefulness of electrophilicity in predicting toxicity of several polyaromatic hydrocarbons (PAH) is assessed. The toxicity is expressed through biological activity data (pIC50) defined as molar concentration of those chemicals necessary to displace 50% of radiolabeled tetrachlorodibenzo-p-dioxin (TCDD) from the arylhydrocarbon (Ah) receptor. The experimental toxicity values (pIC50) for the electron acceptor toxin like polychlorinated dibenzofurans (PCDF) are taken as dependent variables and the DFT based global descriptor electrophilicity index (omega) is taken as independent variable in the training set. The same model is then tested on a test set of polychlorinated biphenyls (PCB). A good correlation is obtained which vindicates the importance of these descriptors in the QSAR studies on toxins. These toxins act as electron acceptors in the presence of biomolecules whereas aliphatic amines behave as electron donors some of which are also taken into account for the present work. The toxicity values of the aliphatic amines in terms of the 50% inhibitory growth concentration (IGC50) towards ciliate fresh-water protozoa Tetrahymena pyriformis are considered. Since there is no global nucleophilicity we apply local nucleophilicity (omegamax+) as the descriptor in this case of training set. The same regression model is then applied to a test set of amino alcohols. Although the correlation is very good the statistical analysis reflects some cross validation problem. As a further check the amines and amino alcohols are used together to form both the training and the test sets to provide good correlation. It is demonstrated that the toxicity of several toxins (both electron donors and acceptors) in the gas and solution phases can be adequately explained in terms of global and local electrophilicities. Amount of charge transfer between the toxin and the biosystem, simulated as nucleic acid bases and DNA base pairs, indicates the importance of charge transfer in the observed toxicity. The major strength of the present analysis vis-à-vis the existing ones rests on the fact that it requires only one descriptor having a direct relationship with toxicity to provide a better correlation. Importance of using the information from both the toxin and the biosystem is also analyzed.

The influence of PAX-14 on activated sludge systems and in particular on Microthrix parvicella.

The amount of wastewater treatment plants (WWTP) dealing with solid separation problems has significantly increased since the new requirements of the EU Directive 271/91 on nutrient removal. In Flanders a number of the nutrient removal WWTP are affected by solid separation problems mostly attributed to Microthrix parvicella being the most common dominant species. The effect of dosing polyaluminium chloride (PAX-14) on activated sludge is illustrated for WWTP solids separation problems, in particular because of Microthrix parvicella. The effects of the addition of PAX-14 on the microbiology and the morphology of Microthrix parvicella were studied in 9 full-scale WWTP. PAX-14 succeeded in reducing high SVI-values and controlled foaming problems whenever caused by Microthrix parvicella. Laboratory trials have shown that the dosage of PAX-14 should be less than 150 microL/L or 7 g Al3+/kg MLSS. At a dosage higher than 250 microL/L, an increase of free bacteria and a decrease of the protozoa activity are observed. In full-scale, PAX-14 is dosed at a concentration of 1.5 to 4.5 g Al3+/kg MLSS. Before addition, the mixed liquor scum layer--if present--should be removed. In our experience, the dosing should last for at least 3 weeks. During the first week, no drastic changes occur. At the end of the first week, an increase of SS and SVI is possible. The SVI and scum start to decrease after 10 to 15 days. The amount of filaments is reduced after 3 to 3 1/2 weeks. The morphological properties of Microthrix parvicella change, while other filaments such as Nostocoida limicola and Nocardia spp. are not affected. This study proves that PAX-14 is effective in controlling bulking and foaming problems at WWTPs when they are due to Microthrix parvicella. Prediction of when the SVI will decrease and when addition should be stopped is possible.

Heparin-induced thrombocytopenia and fat necrosis of the breast.

Fat necrosis of the breast is a well-known complication following trauma, surgery, or radiotherapy. The present paper describes a rare case of fat necrosis after heparin-induced thrombocytopenia. The mammographic, sonographic, and MR evaluation and pathologic correlation after a 1-year follow-up period are reported.

T-lymphoid extramedullary (lymphadenopathic) blast crisis in CML.

T-cells are only rarely involved in chronic myeloid leukemia. We report an unusual case of T-lymphoid extramedullary (lymphadenopathic) blast crisis in a 66-year-old patient with Philadelphia positive chronic myeloid leukemia. The lymph node morphological picture resembled that of a peripheral T-cell lymphoma. Immunohistochemical stainings showed most lymph node blasts to have T-phenotype (positivity for CD-2, CD-3 and CD-5). Flow cytometric phenotyping confirmed T-phenotype, with positivity for CD-7, CD-38 and TdT. Cytogenetic analysis of lymph node cells revealed Philadelphia chromosome with an additional chromosomal abnormality (add(6p)). The BCR-gene rearrangement in the lymph node blasts was identical to that in the bone marrow. This case adds to the growing evidence that CML may be a disorder of the common stem cell from which T-, B- and myeloid progenitors originate.

A monoclonal antibody directed against a human cell membrane antigen prevents cell substrate adhesion and tumor invasion.

It was the aim of this study to design mouse monoclonal antibodies (MAbs) that can inhibit the invasion of breast cancer cells in the host tissue. Therefore, MAbs were raised against epitopes on the extracellular domain of SK-BR-3 human breast cancer cells, and biological assays were performed to test the capability of the MAbs to inhibit cell substrate adhesion. MAb 14C5 bound an extracellular plasma membrane antigen of SK-BR-3 and MCF-7 human breast cancer cells and inhibited the cell substrate adhesion of these cells in vitro. The MAb delayed the adhesion of MCF-7 and SK-BR-3 cells on precultured embryonic heart fragments (PHFS). It inhibited the destruction of the PHF by MCF-7 cells and the invasion of the PHF by SK-BR-3 cells. The MAb reacted with an epitope on the cell membrane of in situ and invasive ductal carcinomas of the breast in immunohistochemistry. Poorly differentiated, highly invasive ductal carcinomas show extensive staining of long plasma membrane extensions. Normal multilayered epithelia, normal connective tissue, and tumors derived from these tissues as well as normal breast tissue were negative. From both cell lines a protein complex consisting of two subunits with molecular weight of 50 and 90 kd, respectively, was immunoprecipitated. It is concluded that the 14C5 antigen plays a role in cell substrate adhesion and subsequently also in invasion of breast cancer cells. The 14C5 MAb was able to inhibit cell substrate adhesion and invasion in vitro of breast cancer cells.