bluuebunny/crossref_metadata_2025 huggingface dataset:
Concurrent metabolism of pentose and hexose sugars by the polyextremophile Alicyclobacillus acidocaldarius
Authors: Lee Brady D , Apel William A , DeVeaux Linda C , Sheridan Peter P
Published: August 2017

Alicyclobacillus acidocaldarius is a thermoacidophilic bacterium capable of growth on sugars from plant biomass. Carbon catabolite repression (CCR) allows bacteria to focus cellular resources on a sugar that provides efficient growth, but also allows sequential, rather than simultaneous use when more than one sugar is present. The A. acidocaldarius genome encodes all components of CCR, but transporters encoded are multifacilitator superfamily and ATP-binding cassette-type transporters, uncommon for CCR. Therefore, global transcriptome analysis of A. acidocaldarius grown on xylose or fructose was performed in chemostats, followed by attempted induction of CCR with glucose or arabinose. Alicyclobacillus acidocaldarius grew while simultaneously metabolizing xylose and glucose, xylose and arabinose, and fructose and glucose, indicating that CCR did not control carbon metabolism. Microarrays showed down-regulation of genes during growth on one sugar compared to two, and occurred primarily in genes encoding: (1) regulators; (2) enzymes for cell wall synthesis; and (3) sugar transporters.
White Bass (Morone chrysops) Preferentially Retain n‐3 PUFA in Ova When Fed Prepared Diets with Varying FA Content
Authors: Fuller S. Adam , Rawles Steven D. , McEntire Matthew E. , Bader Troy J. , Riche Marty , Beck Benjamin H. , Webster Carl D.
Published: August 2017

We evaluated the fatty acid (FA) composition of broodstock white bass ova fed one of six commercial diets with increasing polyunsaturated FA content (n‐6/n‐3 ratio; 0.36, 0.39, 0.46, 0.83, 1.07, 1.12) eight weeks prior to sampling. Fatty acid profiles of ova from brooders fed each of the six diets were significantly altered according to canonical discriminant analysis. Ova FA profiles resulting from the 0.39 diet separated those from the 0.36 diet based on lower 18:2n‐6 (LNA) and higher 20:1n‐9 concentrations from the 0.36 diet. Ova profiles were further separated based on lower concentrations of 22:5n‐3 (DPA) from the 0.46 diet, lower concentrations of 20:5n‐3 (EPA) in the 1.12 and 0.83 diets, and lower concentrations of 22:6n‐3 (DHA) in all other diets relative to the 0.46 diet. Changes in ova FA profile at four and eight weeks were consistent with dietary intake with an approximate 2% increase in any given FA class with increasing time on individual diet. There was no correlation between dietary ARA concentrations (0.7–1.1 mol%), or dietary EPA/ARA ratios (7–15), and the concentrations (1.4–1.7 mol%) or ratios (3.3–4.4) found in the ova by diet. Our results suggest that white bass females have the ability to preferentially incorporate n‐3 PUFA, particularly DHA, suggesting mobilization of this FA from other tissues for ova deposition or preferential dietary incorporation of PUFA into ova. These results will add to the limited FA information available in white bass and enable nutritionists to formulate broodstock diets that maximize reproductive potential in this species.
Application of β‐Sitosterol + γ‐Oryzanol‐Structured Organogel as Migration Barrier in Filled Chocolate Products
Authors: Wendt Alexandra , Abraham Karin , Wernecke Christin , Pfeiffer Julia , Flöter Eckhard
Published: August 2017

Oil migration in filled pralines is a phenomenon that is highly correlated with the occurrence of chocolate bloom. In this study the potential to suppress or prevent oil migration by incorporation of sterol/sterolster‐structured organogels was evaluated. Different quantities, 2.5 or 14% (w/w), of gel with structurant levels of either 10 or 25% (w/w) were studied in a layered model system. The gel was either a part of the nougat or of the chocolate phase, or as a separate layer. Samples were monitored regularly for a period of 24 weeks at storage temperatures of 10, 18 and 28 °C. The amount of migrated oil was determined via DSC analysis of a surface sample. The results indicate that, despite the additional oil brought into the system via the oleogel, the level of oil found in the chocolate layer is reduced through the presence of the gel. In particular, the three‐layer system and gelled chocolate appear to be promising routes to either suppress oil migration or improve nutritional profiles by incorporation of liquid oils.
Materialism pathways: The processes that create and perpetuate materialism
Authors: Richins Marsha L.
Published: August 2017

Materialism has been examined in many social science disciplines from multiple perspectives. This review synthesizes this extensive literature into two organizing frameworks that describe how materialism develops in children and how materialism is reinforced and perpetuated in adulthood. The major components of the developmental model are the daily event cycle, developmental tasks, cultural influence, and family environment, all of which interact to influence how materialistic a child becomes. The reinforcement model describes how personal qualities that materialists tend to possess make them more vulnerable to threats in daily events, resulting in psychological discomfort. The desire to reduce this discomfort, in conjunction with the transformative powers that materialists ascribe to acquisition, results in actions and outcomes that reinforce materialistic tendencies. Suggestions for furthering the study of materialism are also included.
Processing and strengthening mechanisms of boron-carbide-reinforced aluminum matrix composites
Authors: Guo Hao , Zhang Zhongwu
Published: August 2017

Boron-carbide-reinforced aluminum matrix composites are widely used as various function materials. This paper aims at reviewing theoretical and experimental background related to boron-carbide-reinforced aluminum matrix composites. The powder milling processing, solid sintering, thermo-mechanical processing and the effects of reinforcement particle size on the microstructure and morphology evolution of the aluminum matrix composites are reviewed. The formation of interface between boron carbide and matrix and strengthening mechanisms of the boron-carbide-reinforced aluminum matrix composites are discussed.
Correlation between quality of pain and depression: A post-operative assessment of pain after caesarian section among women in Ghana
Authors: Adzika V.A. , Glozah F.N. , Ayim-Aboagye D. , Ahorlu C.S.K. , Ekuban M.
Published: August 2017

Background and aims

Post-operative pain after caesarean operation remains one of the major complains after delivery. With the rising rate of caesarean deliveries, the assessment and management of acute pain has become a major concern for medical professionals in Ghana. The aim was to determine the association between the neuroplasticity of pain and depression using a postoperative pain assessment among women after caesarean section in Ghana.

Methods

A descriptive pilot studies consisting of 54 women who have undergone caesarean operations and reported of acute pain after three months were conducted in King David Hospital and Neptune Medical centre. A purposeful sampling was used to complete the Numeric Pain Scale (NPS) and the Wong-Baker FACES Pain Rating Scale to justify the inclusion criteria. While the Pain Quality Assessment Scale (PQAS) and the Beck Depression Inventory (BDI) were completed by participant.

Results

On the characteristics of their pain respondents scored above 7, on average, for hot pains (7.04 ±2.028, minimum of 5 and maximum of 10), unpleasant pains (7.33±1.907, minimum of 5 and maximum of 10), intense and deep pain (7.35 ±1.825, minimum of 5 and maximum of 10) and intense but surface (7.38 ±1.784, minimum of 5 and maximum of 10), each with a minimum of 5 and a maximum of 10. This implies that for each of those types of pain, respondents scored very high levels of intensity. Similarly, on intensity of pain sensation (6.43 ±1.814, minimum of 5 and maximum of 10), sharpness of pain (6.53±1.772, minimum of 5 and maximum of 10), how dull their pains felt (6.38 ±2.603, minimum of 0 and maximum of 10) sensitiveness of their skins (6.75 ±1.9, minimum of 4 and maximum of 10) and how itchy (6.98±2.137, minimum of 4 and maximum of 10) their skins felt with their respective standard deviations. On the depression scale, more than half of the respondents (51.9%) captured in this study had moderate depression.

Conclusions

We ultimately sought to conduct a test of association between ten indicators of quality of pain and depression. There turned out to be significant association between intensity of pain and depression (χ2 = 21.507; p < 0.001) simply implying that where there is a rise in intensity of pain, there is likely going to be depression. There was also a significant association between sharp sensation and depression (χ2 =31.256).
The link between chronic musculoskeletal pain and sperm quality in overweight orthopedic patients
Authors: Dardmeh F. , Alipour H. , Nielsen H.I. , Rasmussen S. , Der Horst G. Van , Gazerani P.
Published: August 2017

Aims

The association between low fertility potential and an overweight is well recognized. In addition, a link between pain and overweight condition has been identified. However, it is not known whether overweight pain patients present any alterations in fertility potentials. Hence, the current study provided a profounder vision into the possible relation between an overweight condition, chronic musculoskeletal pain, and fertility potential in overweight male patients.

Methods

This “observational study” was based on 10 overweight chronic pain patients (OP and 10 healthy matched controls (OC) from the referrals to the orthopedic department at Aalborg University Hospital, Aalborg, Denmark. The study was approved by the regional Ethics Committee of the Northern Jutland, Denmark and conducted from June 2014 to December 2015. Semen samples were obtained from all participants and assessed for sperm concentration, motility, and kinematic parameters with the Sperm Class Analyzer (SCA®, Spain). Pressure pain thresholds (PPT) were also measured by a handheld pressure algometer in 16 pre-defined points of the subjects in both groups.

Results

The OP group demonstrated a decline in PPT values compared to the (OC); however, difference between the two was insignificant. But, the OP group showed a lower percentage of static and non-progressive motile sperm (P < 0.05). The sperm kinematic parameters (progressive motility, VCL, VSL, VAP and BCF) also demonstrated a lower trend in OP group in comparison with the controls.

Conclusions

This study presented that sperm quality declines in overweight chronic pain patients. Since the control group consisted of pain free overweight individuals, we propose that chronic musculoskeletal pain could potentially affect sperm quality, distinct from what an overweight alone does to the male fertility potential. However, further investigation in overweight chronic pain patients of different types is required before a general conclusion can be made. In addition, mechanisms underlying such effects need further clarification.
Cell-based platform for studying trigeminal satellite glial cells under normal and inflammatory conditions
Authors: Vinterhøj H.S.H. , Duroux M. , Gazerani P.
Published: August 2017

Aims

Satellite glial cells (SGCs) in sensory ganglia contribute to the pathogenesis of chronic pain. In vitro, providing enough fresh primary SGCs poses some practical limitations; hence, frozen stocks of primary cells for culture could be an attractive alternative for cell-based studies or drug screening. This study was designed to investigate the morphology and marker expression of frozen and freshly isolated trigeminal SGCs under normal and inflammatory conditions.

Methods

SGCs from trigeminal ganglia of three male Sprague–Dawley rats and three frozen (sub cultured and passaged) batches of stored primary SGCs were cultured. Their morphology was observed by phase microscopy and the phenotype was characterized by immunocytochemistry of glutamine synthetase (GS) and glial fibrillary acidic protein (GFAP). Lipopolysaccharide (LPS) was used to simulate a state of neurogenic inflammation in vivo. A pilot test was performed to determine the optimal concentration of LPS to activate SGCs based on GFAP expression. A long-term activation of the SGCs with 50 ng/mL LPS was chosen for further characterization.

Results

The fresh and frozen primary SGCs elicited similar phenotypes based on GS marker expression. However, frozen primary SGCs differed in terms of size and morphology. GFAP was constantly expressed in frozen primary SGCs regardless of LPS stimulation. Activation of primary fresh SGCs with LPS spread the GFAP expression from around the cell body throughout the longer processes and activation was only seen in the LPS treatment.

Conclusions

The phenotypic marker, GS was independent of culture conditions. There was no difference in upregulation of GFAP in thawed SGCs regardless of LPS stimulation. This indicates that freeze-thawing might activate SGCs and therefore frozen and passaged cells cannot be suitable for use in cell-based models for inflammation. Fresh primary cells are therefore optimal for studying SGCs under normal and inflammatory conditions.
The encoding of the thermal grill illusion in the human spinal cord
Authors: Fardo F. , Finnerup N. , Haggard P.
Published: August 2017

Aims

The spatial alternation of innocuous cold and warm stimuli on the skin can paradoxically provoke a hot, burning sensation, known as the thermal-grill illusion (TGI). Whether the TGI depends on spinal or supraspinal integration mechanisms is still debated. To assess whether the TGI can be accounted by integration of cold and warm afferent signals in the spinal cord, we leveraged anatomical knowledge on the spatial arrangement of dermatomes and spinal segmental projections.

Methods

We stimulated a series of skin locations on the right arm using one cold (∼20 °C) and one warm thermode (∼40°C). The two stimulus locations had identical physical distance on the skin. However, the distance between the cold and heat projection signals in the spinal cord varied across three conditions. Cold and warm inputs were delivered (1) within the same dermatome (e.g., C5–C5); (2) across the dermatome boundary of two adjacent spinal segments (e.g., C5–C6); (3) across the dermatome boundary of two non-adjacent spinal segments (e.g., C5–T1). In two experiments, we obtained an estimate of the strength of the TGI by asking 32 healthy participants to complete a temperature matching task.

Results

Participants overestimated the actual average temperature of the two thermodes (Exp. 1) and the cold temperature of one of the two thermodes (Exp. 2). However, this effect was significantly larger when cold and heat stimuli were delivered within the same dermatome (+6.57 ± 3.99°C and +9.88 ± 5.60 °C) or between dermatomes projecting to adjacent spinal segments (+6.26 ±4.44°C and +9.48 ± 5.83 °C), compared to when cold and heat stimuli projected to non-adjacent spinal segments (+3.46 ± 4.46 °C and +4.80 ± 3.21 °C).

Conclusions

These results demonstrate that the strength of the illusion is modulated by the segmental distance between cold and heat spinal signals, and show that the perceived quality and intensity of thermal stimuli depends upon low-level spatial summation mechanisms in the spinal cord.
Effect of cocoa on endorphin levels and craniofacial muscle sensitivity in healthy individuals
Authors: Simoni A.H. , Randers A. , Jønsson K. , Arpe S. , Poulsen J.N. , Gazerani P.
Published: August 2017

Aims

Migraine headache is a recurrent incapacitating neurovascular disorder. A combination of events occurring within the trigeminovascular system has been suggested to underlie migraine pathogenesis, including release of inflammatory neuropeptides with subsequent effects on meningeal vessels and sensory transmission. Increased craniofacial muscle tenderness is also present in patients with migraine and a lower β-endorphin concentration has been observed in these patients. Several external factors have been identified, which can modulate migraine. One such factor is cocoa, though controversies still exist whether this substance exerts pro-algesic or analgesic effects. The present study evaluated effects of pure cocoa on a mechanically-induced headache model in healthy individuals. Serum β-endorphin concentrations were also measured to identify if any changes occurred in response to cocoa consumption.

Methods

Healthy volunteers (8 men and 7 women, average age: 22±1.8 years) participated in a crossover study (approval number: N-20160015) consisting of two sessions with consumption of water or cocoa. A mechanical headband (custom-made, Aalborg University) was utilized to induce a moderate headache with pain rated as 4 on a Visual Analogue Scale (VAS0–10). In each session Pressure Pain Threshold (PPT) was measured by a hand held algometer at temporalis muscles and blood samples were collected to assess β-endorphin levels by ELISA. ANOVA analysis and independent two-sample t-tests were performed for comparisons. P < 0.05 was considered as significant.

Results

Consumption of cocoa compared to water did not change the pressure sensitivity in the craniofacial region without mechanical headband. No changes occurred in PPT with the mechanical headband either.Regardless of substance consumption (water/cocoa), endorphin levels remained unchanged.

Conclusions

Findings demonstrated that pure cocoa in the applied concentration and within the timeline of this study did not seem to exert any analgesic or pro-algesic effect on the mechanical sensitivity of craniofacial muscles or β-endorphin levels.
The impact of naloxegol treatment on gastrointestinal transit and colonic volume
Authors: Grønlund D. , Olesen A.E. , Poulsen J.L. , Brock C. , Drewes A.M.
Published: August 2017

Aims

Opioid treatment is associated with gastrointestinal (GI) side effects, known as opioid-induced bowel dysfunction (OIBD). Symptoms of OIBD are caused by opioid receptor activation in the enteric nervous system, which results in increased GI transit time and increased faecal volume in the colon. OIBD can be experimentally induced in healthy participants through oral oxycodone treatment. The aim of this study was to investigate whether administration of naloxegol, a peripherally restricted opioid antagonist, could reduce GI symptoms, GI transit time, and colorectal volume, using an experimental model of OIBD.

Methods

In a double blind crossover trial, twenty-five healthy males were randomly assigned to a six day treatment of oral oxycodone in combination with either oral naloxegol or placebo. At baseline and at day six, participants filled in the Patient Assessment of Constipation Symptom questionnaire, and colorectal volume was quantified with a magnetic resonance imaging method. Participants swallowed a small electromagnetic capsule, which allowed determination of total and segmental GI transit times, using the 3D-Transit system.

Results

In the established model of oxycodone induced OIBD, fewer GI symptoms were observed during naloxegol treatment, compared to placebo (P <0.01). Naloxegol decreased median total transit time by 27% (56 vs 71 h, P < 0.05) and decreased colorectal transit time by 33% (45 vs 59 h, P < 0.01), compared to placebo. No difference in colorectal volume was found between the two treatments.

Conclusions

In an experimental model of OIBD, GI symptoms and GI transit time were reduced during treatment with naloxegol, compared to placebo. However, naloxegol treatment did not reduce colorectal volume. These findings add information on the potential of naloxegol to be used in prevention and treatment of OIBD.
Painful diabetic polyneuropathy and quality of life in Danish type 2 diabetic patients
Authors: Gylfadottir Sandra Sif , Christensen Diana Hedevang , Nicolaisen Sia Kromann , Thomsen Reimar Wernich , Nielsen Jens Steen , Itani Mustapha , Sindrup Søren , Jensen Troels Staehelin , Finnerup Nanna Brix
Published: August 2017

Background and aims

Painful polyneuropathy (PPN) is a disabling complication of diabetes. This study aims to determine its prevalence and relationship with Quality of Life (QoL) in a nationwide prospective cohort of incident recently diagnosed Danish type 2 diabetic patients.

Methods

We sent a detailed questionnaire on neuropathy, pain and QoL to 6726 patients prospectively enrolled from general practitioners and hospital specialist outpatient clinics into the Danish Centre for Strategic Research in Type 2 Diabetes (DD2) cohort. Patients who reported pain in both feet and a score ≥3 on the Douleur Neuropathique (DN4) questionnaire were considered to have possible PPN. QoL and pain intensity were measured on a numeric rating scale (NRS, 0–10). The Michigan Neuropathy Screening Instrument (MNSI) was used to assess neuropathy.

Results

A total of 5371 (79.8%) returned a complete questionnaire. 848 (15.8%) recently diagnosed type 2 diabetic patients reported pain in both feet. Of the 619 patients with pain who completed the DN4 questionnaire, 404 (65.2%) had a DN4 score ≥ 3, corresponding to a prevalence in the total population of possible PPN of 10.3%. Mean pain intensity was 5.2 (SD 2.2) and 89% had a MNSI score ≥ 3. Patients with possible PPN had a substantially lower QoL score than those without PPN (median QoL score 6 versus 8 (p < 0.001)), also when correcting for MNSI score.

Conclusions

Ten percent of newly diagnosed type 2 diabetic patients in Denmark had possible PPN. Patients with PPN had lower QoL than patients without PPN.
“What about me?”: A qualitative explorative study on perspectives of spouses living with complex chronic pain patients
Authors: Thrysøe Hansen L. , Nielsen L.I. , Gazerani P. , Petrini L.
Published: August 2017

Aims

Being a close relative of a chronic pain patient affects family life. No study has been carried out in Denmark to explore relatives’ life experiences and challenges while living with complexchronic pain patients. Hence, the aim of the study was to investigate the experiences of living with chronic pain patients from their spouses’ perspectives. In particular, this study focused on how spouses describe: (i) their everyday tasks and roles as a spouse; (ii) the types of changes and challenges that the pain condition brings into their partnership lives; (iii) a gender difference in these experiences; and (iv) the type of help they wish to receive from the healthcare system.

Methods

Two focus group interviews were conducted in Multidisciplinary Pain Center, Køge, including a total of 11 spouses (6 men). The spouses were contacted via their partners who were referred to public pain clinics. Focus group interview was chosen because is a suitable method for exploratory studies. The approach was phenomenological and transcriptions of interview records were used for analysis.

Results

Eight categories emerged from the data analysis: psychological burden, physical burden, the pain invisibility, roles, loss, worries concerning medicine, self-care, and needs concerning help and support. The differences between gender were vague. Spouses for whom the patient pain condition was a new situation (<1 year) appeared to worry more.

Conclusions

The study demonstrated that the spouses’ lives were dramatically affected. They had to support the family financially, do most of the household chores, be optimistic, a parent, and a pain care giver. The spouses experienced daily worries about several points including pain medicine by the patients. This study also highlighted an essential need for psychological support for coping with the changing life situation, the point that is currently neglected to a great extent.
Increased postural stiffness in patients with knee osteoarthritis who are highly sensitized
Authors: Hirata R.P. , Skou S.T. , Simonsen O. , Rasmussen S. , Graven-Nielsen T.
Published: August 2017

Aims

To evaluate the effect of widespread pain sensitization on postural stability during quiet standing tasks in patients with knee osteoarthritis.

Methods

Patients (56) stood quietly on a force platform for 1 min in 4 conditions (each repeated 3 times): (i) firm surface (FS) with open eyes (OE), (ii) FS with closed eyes (CE), (iii) soft foam surface (SS) with OE, and (iv) SS with CE. Postural stability was quantified by Center of Pressure (CoP) variables extracted from the force platform. Pressure pain thresholds (PPTs), were assessed bilaterally with a handheld pressure algometer (1 cm2 probe) at: (i) four sites in the knee region (3 cm medial to the midpoint of the medial edge of the patella; 2 cm proximal to the superior edge of the patella; 3 cm lateral to the mid-point of the lateral edge of the patella; and centre of the patella), (ii) tibialis anterior muscle, and (iii) extensor carpi radialis longus muscle. The PPT values from tibialis anterior and extensor carpi radialis longus muscles were used to divide the patients in high and low sensitization groups (two-steps clustering).

Results

PPT values at bilateral knees sites were lower in the high sensitivity [median (range) of all sites: 423 (153, 1129) kPa] compared with low sensitivity group [822 (305, 2051) kPa] (P < 0.05). CoP range in the anterior–posterior direction was reduced in high sensitivity group (41±16 mm) compared with the low sensitivity group (51±16 mm) during the SS with CE (P < 0.05) condition.

Conclusions

The lower CoP Range suggests stiffer postural strategy in patients with higher widespread pain sensitivity compared with low sensitivity patients during sensory restrictions. The lack of mobility found in high sensitivity patients under such restrictions might be related to the impaired integration of sensory information due to the parallel processing of the nociceptive information.
Efficacy of dry needling on latent myofascial trigger points in male subjects with neck/shoulders musculoskeletal pain. A case series
Authors: Heredia-Rizo A.M. , Navarro-Carmona I. , Piña-Pozo F.
Published: August 2017

Aims

To assess the impact of dry needling on neural mechanosensitivity and grip strength in male subjects with a history of persistent pain in the neck/shoulder area.

Methods

Case series study. Eight male subjects (mean age 25±6.24 years) with a recurrent history of bilateral neck/shoulder pain for at least 6 months, and with symptoms provoked by neck/shoulder postures or movement were recruited from a University-based clinical research center. Measurements were taken at baseline, immediately after intervention, and fifteen days later, of the pressure pain threshold (PPT) over the median, ulnar, and radial nerves, and the tibialis anterior (TA) muscle. Secondary measures included free-pain grip strength with a hydraulic dynamometer. A therapist assessed the presence of latent (not spontaneously painful, but painful upon palpation) myofascial trigger points (MTrP) over the scalene, subclavius, pectoralis minor, infraspinatus and serratus posterior superior muscles, on the most painful side. Deep dry needling was then performed on the latent MtrP by quickly inserting and partially removing the needle from the MTrP until 2 local twitch responses were provoked.

Results

PPT over the nerve trunks significantly increased after intervention (p < 0.05 for all locations). These changes remained constant in the second assessment, both in the treated (p < 0.001 for median and ulnar nerves, and p = 0.004 for radial nerve), and the non-treated upper limb (median nerve p < 0.001, ulnar nerve p = 0.003, and radial nerve p = 0.006). No statistical significance was found for PPT over the TA muscle (p > 0.05) or for grip strength (p = 0.153 on the treated side, and p = 0.564 on the non-treated upper limb).

Conclusions

Dry needling on the cervicothoracic and shoulder areas may help to improve peripheral neural features over the brachial plexus nerve trunks in subjects with recurrent neck/shoulder pain. No effect was observed for grip strength.
Renal function estimations and dose recommendations for Gabapentin, Ibuprofen and Morphine in acute hip fracture patients
Authors: Houlind M.B. , Treldal C. , Aakjær M. , Palm H. , Malmquist B. , Andersen O. , Christrup L.L. , Petersen K.K.
Published: August 2017

Aims

Optimization of pain management is essential for fasttrack surgery and safety in acute hip fracture (AHF) patients. Kidney function determines the doses of several postoperative painkillers, but previous studies have shown the standard Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation overestimate glomerular filtration rate (GFR) in elderly and underweight patients. The optimized Cockcroft Gault (CGop) equation might be more accurate in this patient group. The study aims to (1) investigate the differences in estimated GFR (eGFR) based on CKD-EPI and CGop and (2) to simulate this impact on recommended dosing of standard painkillers in AHF patients.

Methods

Patients admitted with AHF from January to April 2015 were included. eGFR was calculated for each patient by CKD-EPI and CGop based on the lowest measured serum creatinine between 1 and 4 days postoperatively. CKD-classification (1–5) was performed based on both eGFR values. If patients were classified differently based on the two eGFR values, then drug dosages were simulated for Morphine, Ibuprofen and Gabapentin according to prescribing recommendations in Renbase®.Two-sided Mann–Whitney test was used to compare median values between groups.

Results

176 patients (62% women) with a median age of 76 years were included. CKD-EPI (78.0mL/min/m2) estimated eGFR significantly higher compared with GGop (58.9, P < 0.001). Depending on the equation used to estimate GFR, CKD ≥ 3 (eGFR < 60 mL/min/m2) occurred in 23–53% all patients. Using CGop to estimate GFR resulted in CKD re-classification for 63% of all patients. Using CKD-EPI to estimate GFR resulted in significantly higher doses of Morphine, Ibuprofen and Gabapentin (P < 0.0001) in re-classified patients.

Conclusions

GFR estimates are significantly higher when calculated by CKD-EPI compared to CGop, and this difference results in significantly higher recommended doses of painkillers in AHF patients. Future studies should include a gold standard for measuring GFR and maybe alternative biomarkers for the renal function.
Evaluating the ability of non-rectangular electrical pulse forms to preferentially activate nociceptive fibers by comparing perception thresholds
Authors: Hugosdottir R. , Mørch C.D. , Andersen O.K. , Helgason T. , Arendt-Nielsen L.
Published: August 2017

Aims

Selective activation of nociceptive fibers is difficult using electrical stimulation as the activation threshold is higher than for non-nociceptive fibers. It remains unclear to what extent accommodation of non-nociceptive fibers during slowly rising electrical pulses can be utilized to reverse this activation order. The aim of this study was to evaluate the ability of different pulse forms to activate nociceptive fibers with minimal co-activation of non-nociceptive fibers by comparing subjective perception thresholds (PT).

Methods

Electrical pulses were applied on the volar forearm of 25 subjects with (1) small diameter pin electrodes providing high current density in the skin epidermis, where primarily nociceptive fibers terminate and (2) standard patch electrodes (2.63 cm2). PTs were obtained for exponential current increase, linear current increase, increasing form of exponential current decay (ED), and standard rectangular current pulses. All pulse forms were tested at two relatively long durations (5 and 50 ms). The PT ratio between patch- and pin electrode was calculated as an estimate of the ability of a pulse form to preferentially activate nociceptive fibers. The short form McGill pain questionnaire (SF-MPQ) was used to assess perceived quality of pain for all pulse forms.

Results

For the pin electrode, PT tended to decrease with increasing pulse area. Patch electrode PT tended to increase for increasing pulse area for non-rectangular 50 ms pulses, in contrast to 5 ms pulses, indicating accommodation of non-nociceptive fibers. Largest PT ratio was obtained for the 50 ms ED. SF-MPQ scores were higher for the pin- compared to the patch electrode. Pin electrode pain qualities were mainly described as stabbing and sharp. SF-MPQ scores did not differ between pulse forms.

Conclusions

Long duration ED pulses seem to activate nociceptive fibers better than regular, short duration pulses; most likely reflecting accommodation of non-nociceptive fibers.
Acute muscle pain alters corticomotor output of the affected muscle stronger than a synergistic, ipsilateral muscle
Authors: Larsen Dennis Boye , Graven-Nielsen Thomas , Hirata Rogerio Pessoto , Boudreau Shellie A.
Published: August 2017

Aims

Muscle pain affects corticomotor areas representing the affected muscle, by changing the size of representation and reduces the corticospinal output as assessed by transcranial magnetic stimulation (TMS). Less work has been done to understand how pain in one muscle group may affect synergistic ipsilateral muscles distal to the pain. This study aimed to explore the effects of acute extensor carpi radialis (ECR) muscle pain on TMS motor-evoked potentials (MEPs) of the ECR and the first dorsal interosseus (FDI) muscle, which are known to strongly overlap within the corticomotor area.

Methods

Eight healthy volunteers (1 woman) were injected with hypertonic saline (5.8%, 0.5 mL) into the ECR muscle. Pain intensity was assessed by the visual analogue scale (VAS) every minute for 10 min. TMS was applied at 120% of ECR resting motor threshold, and MEPs were acquired from the ECR and the FDI muscles. At baseline, 10 TMS pulses were delivered. Temporal mapping of ECR and FDI MEPs over 10 min duration was performed by delivering 100 single-pulses of TMS, at 6 s interstimulus-interval. The MEPs for each muscle were averaged at baseline, peak-pain (1 –2 min epoch), and 10 min post-injection

Results

Pain intensity reduced significantly at 10 min postinjection as compared to peak-pain (P = 0.011). Further, one-way repeated measures analysis of variance revealed that ECR MEPs were altered at peak-pain compared to baseline (P > 0.05), but not 10 min post-injection (P > 0.05). Baseline and 10 min post-injection of ECR MEPs did not differ significantly (P = 0.67). The MEPs of the FDI muscle did not show a similar alteration over time (P = 0.1).

Conclusions

Despite the overlap between ECR and FDI representations, acute muscle pain of the ECR only significantly altered cortical excitability of the ECR muscle representation.
The size of pain referral patterns from a tonic painful mechanical stimulus is increased in women
Authors: Liu Q.G. , Palsson T.S. , Sørensen L.B. , Graven-Nielsen T.
Published: August 2017

Aims

The purpose of this study was to investigate potential gender differences in pain referral patterns induced by a tonic painful mechanical stimulus.

Methods

Forty-five healthy adults (22 women) participated in this study. Pressure pain thresholds (PPTs) were assessed at the infraspinatus, the brachioradialis and the gastrocnemius muscles on the dominant side, using handheld algometry. Following this, painful pressure at the infraspinatus muscle was induced using the algometer by rapidly increasing the pressure until it reached the level of 7 cm on VAS (PVAS7). This pressure was kept constant for 60s. Upon release, the subject was asked to indicate the area of the pressure-induced pain on a digital body chart. PPT values, PVAS7 and the pain area (number of pixels) were extracted for data analysis.

Results

No gender differences were found in PPT values (P >0.05). The pressure needed to reach 7 cm on the VAS was significantly lower in the female group (687.4±50.5 kPa) compared with males (971.0 ± 49.6 kPa; unpaired t-test: P < 0.05). The size of the pain area following PVAS7 stimulation for 60 s was significantly larger in the female group (12,578.5 ± 17,280.3 pixels) compared with the male group (6175.0 ± 9518.5 pixels; Mann–Whitney-U; P < 0.05).

Conclusions

Despite comparable PPT values, women demonstrated larger pain areas compared with men although the standardized painful stimulus which intensity was perceived similarly as 7 cm on the VAS scale in both groups. These findings suggest that there are gender-specific differences in pain distribution and referred pain but it is unclear through which mechanism they are mediated.
Topical allyl-isothiocyanate (mustard oil) as a TRPA1-dependent human surrogate model of pain, hyperalgesia, and neurogenic inflammation – A dose response study
Authors: Andersen H.H. , Lo Vecchio S. , Gazerani P. , Arendt-Nielsen L.
Published: August 2017

Aims

Transient receptor potential ion channel A1 (TRPA1) has been shown to play a pathoetiological role in several painful and inflammatory conditions and therefore several new drug candidates, targeting TRPA1 are currently being developed [1]. While the natural TRPA1-agonist allyl-isothiocyanate (AITC, known as “mustard oil”) is an exceedingly common animal pain model, it has only been sparsely investigated as a potential human surrogate model of pain and neurogenic inflammation. This study aimed to evaluate dose-response features of AITC as a sensitizing, algogenic irritant in human skin.

Methods

Three concentrations of AITC (10%, 50%, 90%) and vehicle (100% paraffin) were applied for 5 min to 3 cm × 3 cm areas on the volar forearms in 14 healthy volunteers, and evoked pain (visual analog scale 0–100 mm) and pain quality were assessed. Following the application, a battery of quantitative sensory tests was conducted including assessment of mechanical and thermal sensitivity. Neurogenic inflammation was evaluated using Laser Perfusion Imaging (FLPI). Erythema and pigmentation were assessed before, immediately after and≈64 h after AITC exposure.

Results

Topical application of AITC induced significant dose-dependent, moderate-to-severe spontaneous pain mostly described as burning as well as mechanical and heat hyperalgesia (p < 0.05). The model also produced robust dynamic mechanical allodynia (p < 0.05). Only modest increases in pain hypersensitivity were observed between the 50% and 90% concentrations. Neurogenic inflammation was evoked by all concentrations and assessments by FLPI demonstrated a significant dose dependent increase from 10% to 50% ATIC, with a ceiling effect from 50% to 90%.

Conclusions

Topical AITC-application evokes dose-dependent rapid pain and somatosensory sensitization with optimal concentrations recommended to be above 10% and equal to or below 50%. The model is translatable and could be useful in pharmacological proof-of-concept studies of TRPA1-antagonists, analgesics and anti-inflammatory compounds or for exploratory clinical purposes (e.g. loss- or gain-of-function in peripheral neuropathies).
Combined electric and pressure cuff pain stimuli for assessing conditioning pain modulation (CPM)
Authors: Tsukamoto M. , Petersen K.K. , Mørch C.D. , Arendt-Nielsen L.
Published: August 2017

Aims

Traditionally, conditioning pain modulation (CPM) can be assessed by applying a test stimulus (TS) before and after application of a conditioning stimulus (CS), which is normally applied extra-segmental. Currently, no studies have attempted to apply the TS and CS to the same site using different stimuli modalities. The aim of this study was to evaluate electrical TS and cuff pressure CS applied to the same experimental site for studying CPM.

Methods

20 male volunteers participated in this study, which consisted of stimulations applied by a cuff-algometer (NociTech and Aalborg University, Denmark) and current stimulator (Digitimer DS5, UK), through two Ag/AgCl electrodes (Ambu® Neuroline 700, Denmark). The cuff was wrapped around the lower leg and stimulation electrodes were placed under the cuff and to the same location on the contralateral leg. Electrical TS were applied to the non-dominant leg with or without cuff pressure CS on the dominant (CS1) or the same (non-dominant) leg (CS2, electrode under cuff). The subjects were instructed to rate the electrical evoked pain intensity on a 10-cm continuous visual analog scale (VAS, “0” represented “no pain”, and “10” represented “maximal pain”). The pain detection threshold (PDT) was defined as “1” on the VAS scale.

Results

There was no significant deference in PDT for neither CS1 nor CS2. A median split subanalysis on CPM-responders versus CPM-nonresponders to the TS + CS1 combination. Using this grouping, there was significant increase in PDT when comparing TS to TS + CS1 or TS + CS2 (4.0 mA vs 5.6 mA; P < 0.05, 4.0 mA vs 5.1 mA; P < 0.05).

Conclusions

The study indicates that CPM can be evoked in a subgroup of subjects by applying the electrical test stimulus and cuff pressure conditioning stimuli to the same experimental site.
The effect of facilitated temporal summation of pain, widespread pressure hyperalgesia and pain intensity in patients with knee osteoarthritis on the responds to Non-Steroidal Anti-Inflammatory Drugs – A preliminary analysis
Authors: Petersen K.K. , Simonsen O. , Andersen M.M. , Olesen A.E. , Arendt-Nielsen L.
Published: August 2017

Background

Non-Steroidal Anti-Inflammatory Drug (NSAID) treatment is recommended as the first step in the treatment of knee osteoarthritis (KOA). Due to the risk of side-effects of NSIADs and low responds rate, methods for selection of NSAID responders are highly warranted. Recent studies suggest that pain sensitization in KOA might be predictive for the effect of surgical treatment, why the purpose of the present study was to evaluated whether quantitative sensory testing (QST) could be predictive for the effect of NSAID treatment in KOA.

Material and methods

100 patients were enrolled and assessed using temporal summation of pain (TSP), pressure pain thresholds (PPT) and pain intensity (visual analog scale, VAS; 0: no pain and 10: worst imaginable pain) before and 8 weeks after daily treatment of Ibuprofen 400 mg × 3, Paracetamol 1 g × 3 and Pantoprazole 20 mg × 1. TSP was assessed by the difference in pain scores to one PinPrick stimulus followed by 10 PinPrick stimuli. PPT was assessed at the extensor carpi radialis longus muscle. Responders were categorized as decrease in pain intensity of at least three VAS-points.

Results

80 patients had complete data at follow-up. 28 patients were categorized as responders and 52 patients as non-responders. Pre-treatment pain intensity (responders: 7.5 (SD: 1.6) vs. nonresponders: 6.5 (SD: 2.3), P < 0.03) and TSP (responders: 1.9 (SD: 2.5) vs. non-responders: 1.0 (SD: 1.5), P < 0.05) were significantly higher in responders compared with non-responders. Pre-treatment PPT at the arm trended towards significantly lower in responders (293 kPa (SD: 85)) compared with no responders (339 kPa (SD: 124), P < 0.06).

Conclusions

This preliminary analysis indicate that KOA patients with high pain intensities, facilitated TSP and widespread pressure hyperalgesia respond to NSAIDs.
How to obtain the biopsychosocial record in multidisciplinary pain clinic? An action research study
Authors: Sejling L.B. , Svensson L. , Jensen P.F. , Pawlak W.Z.
Published: August 2017

Background

Patients with complicated chronic non-malignant pain (CCNMP) should be referred to the multidisciplinary treatment based on the biopsychosocial pain model. This is not a trivial task to obtain the biopsychosocial record (BPSR) during the first visit in multidisciplinary pain center – some important data can be missing, but it is difficult to choose the right questions.

Purpose

To find the optimal method for obtaining of BPSR in patients with CCNMP.

Methods

The action research methodology is used. First, the literature search was done. Second, the meetings between therapists were hold. Third, the patients are asked about their experiences with obtaining of BPSR.

Results

The following area of interest were identified: (1) patient’s demographic data, (2) lifestyle factors, (3) previous diseases, (4) concurrent diseases, (5) previous pain treatments, (6) pain intensity and effect of the actual pain treatment, (7) general activity, (8) mood, (9) walking activity, (10) work ability, (11) home activities, (12) relations with other people, (13) sleep, (14) enjoyment of life, (15) patients expectations from treatment, and (16) treatment goals. Patients are asked about those variables. Either Visual Analogue Scale or Numeric Rating Scale is used for assessment of pain intensity and pain influence on variables (7) to (14). First, data about variables (1) to (6) are collected by the physician. Next, data about variables (7) to (15) are gathered under interview with the nurse. Last, the physician and the nurse keep the meeting on treatment goals and treatment course. Up to date (February 2017), 8 patients were asked about their experience with obtaining of BPSR. All but one patient were very satisfied.

Conclusions

The method presented above seems to be promising approach to obtaining of BPSJ in patients with CCNMP. The study is ongoing and updated results will be presented at the conference.
Prevalence and pattern of helmet-induced headache among Danish military personnel
Authors: Rahmani Z. , Kochanek A. , Astrup J.J. , Poulsen J.N. , Gazerani P.
Published: August 2017

Aims

Headache is a leading reason to seek medical care. Several subtypes of headaches have been defined, one of which is external compression headache. This headache is due to an external physical compression applied on the head. It affects approximately 4% of the general population; however, certain populations for example construction workers and military personnel with particular needs of headwear or helmet are at higher risk for development of this type of headache. Generally, external compression headache is poorly studied and there is no report on helmet-induced headache among Danish military personnel. This survey-based study was designed to investigate prevalence and pattern of helmet-induced external compression headache among these personnel.

Methods

Questionnaires were carefully developed and delivered to a total of 279 participants who use helmets in the Danish military service. The military of the Northern Jutland region of Denmark facilitated recruitment of study participants. Questionnaires were delivered on paper and anonymous answers were collected and used for further analysis. Data were handled using descriptive statistics.

Results

Up to 30% of the participants reported headache in relation to wearing the military helmet. Headache was defined as moderate intensity with pressing pain quality mostly located in front of the head. Two types of helmets in this study were different in the weight and padding of the inner part and delivered different pattern of pressure; while one evenly delivered pressure on multiple head regions, the other delivered pressure mostly on the sides and top of the head. This suggests that helmet pressure and headache location might be associated.

Conclusions

This study was first to demonstrate prevalence and pattern of helmet-induced headache among military personnel in North Jutland, Denmark. Findings of this study call for further attention to helmet-induced headache and strategies to minimize the burden, for example by design of appropriate helmets.