Neck Muscle Function and Adolescent Headache

Muscular function of the neck region may be of importance for the etiology of headache, especially of tension-type headache. However, very few data exist on the association of neck muscle function with different types of headache in adolescents. The main aim of the study was to examine the association of neck muscle function with adolescent headache. The associations between leisure time activities, endurance strength of the upper extremities (UE endurance) and mobility of the neck-shoulder region and adolescent headache were studied. In addition, the associations of force production, EMG/force ratio, co-activation and fatigue characteristics, and cross-sectional area (CSA) of neck muscles with adolescent headache were studied. The study is part of a population-based cohort study of 12-year-old children with and without headache. The study had five phases (years 1998-2003). At the age of 13 years, a sample of 183 adolescents (183/311) participated in endurance strength and mobility measurements of the neck-shoulder region. In addition, the type and level of physical and other leisure activity were elicited with open and structured questions. At the age of 17 years, a random sample of 89 adolescents (89/202) participated in force and EMG measurements of the neck-shoulder muscles. In addition, at the age of 17 years, a sample of 65 adolescents (65/89) participated in CSA measurements of the neck muscles. At the age of 13 years, intensive participation in overall sports activity was associated with migraine. Frequent computer use was associated both with migraine and tension-type headache. The type of sports or other leisure activity classified them on the basis of body loading was not associated with headache type. In girls, low UE endurance of both sides, and low cervical rotation of the dominant side, were associated with tension-type headache, and low UE endurance of non-dominant side with migraine. In boys, no associations occurred between UE endurance and mobility variables and headache types. At the age of 17 years, in girls, high EMG/force ratios between the EMG of the left agonist sternocleidomastoid muscle (SCM) and maximal neck flexion and neck rotation force to the right side as well as high co-activation of right antagonist cervical erector spinae (CES) muscles during maximal neck flexion force were associated with migraine-type headache. In girls, neck force production was not associated with headache types but low left shoulder flexion force was associated with tension-type headache. In boys, no associations were found between EMG and force variables and headache. Increased SCM muscles fatigue of both sides was associated with tension-type headache. In boys, the small CSA of the right SCM muscle and, in girls, of combined right SCM and scalenus muscles was associated with tension-type headache. Similarly, in boys, the large CSA of the right SCM muscle, of the combined right SCM and scalenus muscles, of the left semispinalis capitis muscle, of the combined left semispinalis and splenius muscles was associated with migraine. No other differences in the CSA of neck flexion or extension muscles were found. Differences in the neuromucular function of the neck-shoulder muscles were associated with adolescent headache, especially in girls. Differences in the cross-sectional area of unilateral neck muscles were associated with headache, especially in boys. Differences in the neuromuscular function and in the cross-sectional area of the neck muscles also occurred between different types of headache. It remains to be established whether the findings are primary or secondary to adolescent migraine and tension headache. Keywords: adolescent, cross-sectional area, electromyography, endurance strength, fatigue, force, headache, leisure time activity, migraine, mobility, neck muscles, tension-type headache

Capillarity and fibre types in locomotory muscles of wild yellow-legged gulls (Larus cachinnans)

This study analyzes the capillarity and fibre-type distribution of six locomotory muscles of gulls. The morphological basis and the oxygen supply characteristics of the skeletal muscle of a species with a marked pattern of gliding flight are established, thus contributing to a better understanding of the physiology of a kind of flight with low energetic requirements. The four wing muscles studied (scapulotriceps, pectoralis, scapulohumeralis, and extensor metacarpi) exhibited higher percentages of fast oxidative glycolytic fibres (>70%) and lower percentages of slow oxidative fibres (<16%) than the muscles involved in nonflight locomotion (gastrocnemius and iliotibialis). Capillary densities ranged from 816 to 1,233 capillaries mm(-2), having the highest value in the pectoralis. In this muscle, the fast oxidative glycolytic fibres had moderate staining for succinate dehydrogenase and relatively large fibre sizes, as deduced from the low fibre densities (589-665 fibres mm(-2)). All these findings are seen as an adaptive response for gliding, when the wing is held outstretched by isometric contractions. The leg muscles studied included a considerable population of slow oxidative fibres (>14% in many regions), which suggests that they are adapted to postural activities. Regional variations in the relative distributions of fibre types in muscle gastrocnemius may reflect different functional demands placed on this muscle during terrestrial and aquatic locomotion. The predominance of oxidative fibres and capillary densities under 1,000 capillaries mm(-2) in leg muscles is probably a consequence of an adaptation for slow swimming and maintenance of the posture on land rather than for other locomotory capabilities, such as endurance or sprint activities.

Reactive Recruitment of Attentional Control in Math Anxiety: An ERP Study of Numeric Conflict Monitoring and Adaptation

This study uses event-related brain potentials (ERPs) to investigate the electrophysiological correlates of numeric conflict monitoring in math-anxious individuals, by analyzing whether math anxiety is related to abnormal processing in early conflict detection (as shown by the N450 component) and/or in a later, response-related stage of processing (as shown by the conflict sustained potential; Conflict-SP). Conflict adaptation effects were also studied by analyzing the effect of the previous trial"s congruence in current interference. To this end, 17 low math-anxious (LMA)and 17 high math-anxious (HMA) individuals were presented with a numerical Stroop task. Groups were extreme in math anxiety but did not differ in trait or state anxiety or in simple math ability. The interference effect of the current trial (incongruent-congruent) and the interference effect preceded by congruence and by incongruity were analyzed both for behavioral measures and for ERPs. A greater interference effect was found for response times in the HMA group than in the LMA one. Regarding ERPs, the LMA group showed a greater N450 component for the interference effect preceded by congruence than when preceded by incongruity, while the HMA group showed greater Conflict-SP amplitude for the interference effect preceded by congruence than when preceded by incongruity. Our study showed that the electrophysiological correlates of numeric interference in HMA individuals comprise the absence of a conflict adaptation effect in the first stage of conflict processing (N450) and an abnormal subsequent up-regulation of cognitive control in order to overcome the conflict (Conflict-SP). More concretely, our study shows that math anxiety is related to a reactive and compensatory recruitment of control resources that is implemented only when previously exposed to a stimuli presenting conflicting information

The nitric oxide pathway in pig isolated calyceal smooth muscle.

In pig and humans, whose kidneys have a multi-calyceal collecting system, the initiation of ureteral peristalsis takes place in the renal calyces. In the pig and human ureter, recent evidence suggests that nitric oxide (NO) is an inhibitory mediator that may be involved in the regulation of peristalsis. This study was designed to assess whether the NO synthase/NO/cyclic GMP pathway modulates the motility of pig isolated calyceal smooth muscle. Immunohistochemistry revealed a moderate overall innervation of the smooth muscle layer, and no neuronal or inducible NO synthase (NOS) immunoreactivities. Endothelial NOS immunoreactivities were observed in the urothelium and vascular endothelium, and numerous cyclic GMP-immunoreactive (-IR) calyceal smooth muscle cells were found. As measured by monitoring the conversion of L-arginine to L-citrulline, Ca(2+)-dependent NOS activity was moderate. Assessment of functional effects was performed in tissue baths and showed that NO and SIN-1 decreased spontaneous and induced contractions of isolated preparations in a concentration-dependent manner. In strips exposed to NO, there was a 10-fold increase of the cyclic GMP levels compared with control preparations (P < 0.01). It is concluded that a non-neuronal NOS/NO/cyclic GMP pathway is present in pig calyces, where it may influence motility. The demonstration of cyclic GMP-IR smooth muscle cells suggests that NO acts directly on these cells. This NOS/NO/cyclic GMP pathway may be a target for drugs inhibiting peristalsis of mammalian upper urinary tract. Neurourol. Urodynam. 18:673-685, 1999.

Formoterol treatment downregulates the myostatin system in skeletal muscle of cachectic tumour-bearing rats

Cachexia is a common systemic manifestation. Additionally, myostatin is known to be a negative regulator of skeletal muscle development. The present study aimed to investigate whether formoterol down-regulates the myostatin system in skeletal muscle of tumour-bearing rats. Real-time PCR and Western blotting were used for the analysis. Results showed that rats bearing the Yoshida AH-130 ascites hepatoma, a cachexia-inducing tumour, exhibited marked muscle wasting that affected the mass of the muscles studied. The cachectic animals exhibited a significant increase in the mRNA levels of the myostatin receptor (ActIIB) in gastrocnemius muscles. Notably, the expression of the various forms of follistatin, a protein with the opposite effects to those of myostatin, was significantly reduced as a result of the implantation of the tumour. When the animals were treated with formoterol, a β-agonist with anti-cachectic potential, increases in skeletal muscle weights were observed. The β-agonist significantly increased levels of various follistatin isoforms and significantly decreased the expression levels of the myostatin receptor. In addition, formoterol treatment resulted in a significant decrease of the myostatin protein content of the gastrocnemius muscle. In conclusion, the results presented indicate that certain anabolic actions of formoterol on the skeletal muscle of cachectic animals may be mediated via the myostatin system.

Les critères STOPP/START.v2 : adaptation en langue française. [STOPP/START.v2 criteria: Adaptation into French language]

Objectif STOPP/START est un outil de détection de la prescription médicamenteuse potentiellement inappropriée chez la personne de 65 ans ou plus. La version initiale de 2008 vient d'être mise à jour et améliorée par ses auteurs. Nous en présentons l'adaptation et la validation en langue française. Méthodes L'adaptation en français de l'outil STOPP/START.v2 a été réalisée par deux experts, confirmée par la méthode de traduction-inverse, et finalisée d'après les commentaires de neufs évaluateurs francophones, gériatres, pharmaciens cliniciens, et médecin généraliste de quatre pays (France, Belgique, Suisse, Canada). La validation a été complétée par une analyse de concordance inter-juge (CCI) des critères STOPP/START.v2 appliqués à dix vignettes cliniques standardisées. Résultats Les 115 critères de STOPP/START.v2 en français sont, par rapport à la version originale anglaise, identiques par leur classification mais adaptés en termes de présentation (critères START.v2 commençant par la condition clinique, et accompagnés par une justification du caractère inapproprié de l'omission) voire de formulation de certains critères. Cette adaptation en français est validée par (i) la traduction-inverse montrant le respect du sens clinique de la version originale, (ii) l'identification semblable des critères lorsque appliqués à dix vignettes cliniques par les neuf évaluateurs, et (iii) le haut niveau de concordance de ces neuf évaluations tant pour STOPP.v2 (CCI 0,849) que pour START.v2 (CCI 0,921). Conclusion L'adaptation en langue française des critères STOPP/START.v2 fournit aux cliniciens un outil de détection de la prescription médicamenteuse potentiellement inappropriée chez les personnes de 65 ans et plus qui est logique, fiable et facile à utiliser. Objective STOPP/START is a screening tool to detect potentially inappropriate prescribing in persons aged 65 or older. Its Irish authors recently updated and improved the initially published version of 2008. We present the adaptation and validation into French language of this updated tool. Methods STOPP/START.v2 was adapted into French by two experts, then confirmed by a translation-back translation method and finalised according to the comments of nine French-speaking assessors - geriatricians, pharmacologists and a general physician - from four countries (France, Belgium, Switzerland, and Canada). The validation was completed by an inter-rater reliability (IRR) analysis of the STOPP/START.v2 criteria applied to 10 standardized clinical vignettes. Results In comparison to the original English version, the 115 STOPP/START.v2 criteria in French language classify in identical manner, but the presentation has been adjusted (START.v2 first specifies the clinical condition followed by an explanation of the inappropriateness of the prescription or omission). This adaptation into French language was validated by means of (i) the translation/back-translation, which showed that the French version complied with the clinical meaning of the original criteria; (ii) the similar screening results when applied by the nine specialists to the 10 cases; and (iii) the high level of inter-rater reliability of these 9 evaluations, for both STOPP (IRR 0.849) and START.v2 (IRR 0.921). Conclusion The adaptation into French of the STOPP/START.v2 criteria provides clinicians with a screening tool to detect potentially inappropriate prescribing in patients aged 65 and older that is more logical, more reliable and easier to use.

Expression of Glycogen Phosphorylase Isoforms in Cultured Muscle from Patients with McArdle´s Disease Carrying the p.R771PfsX33 PYGM Mutation

Mutations in the PYGM gene encoding skeletal muscle glycogen phosphorylase (GP) cause a metabolic disorder known as McArdle's disease. Previous studies in muscle biopsies and cultured muscle cells from McArdle patients have shown that PYGM mutations abolish GP activity in skeletal muscle, but that the enzyme activity reappears when muscle cells are in culture. The identification of the GP isoenzyme that accounts for this activity remains controversial.

Adaptation of a Gaussia princeps Luciferase reporter system in Candida albicans for in vivo detection in the Galleria mellonella infection model.

For the past 10 years, mini-host models and in particular the greater wax moth Galleria mellonella have tended to become a surrogate for murine models of fungal infection mainly due to cost, ethical constraints and ease of use. Thus, methods to better assess the fungal pathogenesis in G. mellonella need to be developed. In this study, we implemented the detection of Candida albicans cells expressing the Gaussia princeps luciferase in its cell wall in infected larvae of G. mellonella. We demonstrated that detection and quantification of luminescence in the pulp of infected larvae is a reliable method to perform drug efficacy and C. albicans virulence assays as compared to fungal burden assay. Since the linearity of the bioluminescent signal, as compared to the CFU counts, has a correlation of R(2) = 0.62 and that this method is twice faster and less labor intensive than classical fungal burden assays, it could be applied to large scale studies. We next visualized and followed C. albicans infection in living G. mellonella larvae using a non-toxic and water-soluble coelenterazine formulation and a CCD camera that is commonly used for chemoluminescence signal detection. This work allowed us to follow for the first time C. albicans course of infection in G. mellonella during 4 days.

AMP-activated protein kinase plays an important evolutionary conserved role in the regulation of glucose metabolism in fish skeletal muscle cells

AMPK, a master metabolic switch, mediates the observed increase of glucose uptake in locomotory muscle of mammals during exercise. AMPK is activated by changes in the intracellular AMP:ATP ratio when ATP consumption is stimulated by contractile activity but also by AICAR and metformin, compounds that increase glucose transport in mammalian muscle cells. However, the possible role of AMPK in the regulation of glucose metabolism in skeletal muscle has not been investigated in other vertebrates, including fish. In this study, we investigated the effects of AMPK activators on glucose uptake, AMPK activity, cell surface levels of trout GLUT4 and expression of GLUT1 and GLUT4 as well as the expression of enzymes regulating glucose disposal and PGC1α in trout myotubes derived from a primary muscle cell culture. We show that AICAR and metformin significantly stimulated glucose uptake (1.6 and 1.3 fold, respectively) and that Compound C completely abrogated the stimulatory effects of the AMPK activators on glucose uptake. The combination of insulin and AMPK activators did not result in additive nor synergistic effects on glucose uptake. Moreover, exposure of trout myotubes to AICAR and metformin resulted in an increase in AMPK activity (3.8 and 3 fold, respectively). We also provide evidence suggesting that stimulation of glucose uptake by AMPK activators in trout myotubes may take place, at least in part, by increasing the cell surface and mRNA levels of trout GLUT4. Finally, AICAR increased the mRNA levels of genes involved in glucose disposal (hexokinase, 6-phosphofructokinase, pyruvate kinase and citrate synthase) and mitochondrial biogenesis (PGC-1α) and did not affect glycogen content or glycogen synthase mRNA levels in trout myotubes. Therefore, we provide evidence, for the first time in non-mammalian vertebrates, suggesting a potentially important role of AMPK in stimulating glucose uptake and utilization in the skeletal muscle of fish.

Effect of short-duration lipid supplementation on fat oxidation during exercise and cycling performance.

The effect of intramyocellular lipids (IMCLs) on endurance performance with high skeletal muscle glycogen availability remains unclear. Previous work has shown that a lipid-supplemented high-carbohydrate (CHO) diet increases IMCLs while permitting normal glycogen loading. The aim of this study was to assess the effect of fat supplementation on fat oxidation (Fox) and endurance performance. Twenty-two trained male cyclists performed 2 simulated time trials (TT) in a randomized crossover design. Subjects cycled at ∼53% maximal voluntary external power for 2 h and then followed 1 of 2 diets for 2.5 days: a high-CHO low-fat (HC) diet, consisting of CHO 7.4 g·kg(-1)·day(-1) and fat 0.5 g·kg(-1)·day(-1); or a high-CHO fat-supplemented (HCF) diet, which was a replication of the HC diet with ∼240 g surplus fat (30% saturation) distributed over the last 4 meals of the diet period. On trial morning, fasting blood was sampled and Fox was measured during an incremental exercise; a ∼1-h TT followed. Breath volatile compounds (VOCs) were measured at 3 time points. Mental fatigue, measured as reaction time, was evaluated during the TT. Plasma free fatty acid concentration was 50% lower after the HCF diet (p < 0.0001), and breath acetone was reduced (p < 0.05) "at rest". Fox peaked (∼0.35 g·kg(-1)) at ∼42% peak oxygen consumption, and was not influenced by diet. Performance was not significantly different between the HCF and HC diets (3369 ± 46 s vs 3398 ± 48 s; p = 0.39), nor were reaction times to the attention task and VOCs (p = NS for both). In conclusion, the short-term intake of a lipid supplement in combination with a glycogen-loading diet designed to boost intramyocellular lipids while avoiding fat adaptation did not alter substrate oxidation during exercise or 1-hour cycling performance.

The genetic basis of color-related local adaptation in a ring-like colonization around the Mediterranean.

Uncovering the genetic basis of phenotypic variation and the population history under which it established is key to understand the trajectories along which local adaptation evolves. Here, we investigated the genetic basis and evolutionary history of a clinal plumage color polymorphism in European barn owls (Tyto alba). Our results suggest that barn owls colonized the Western Palearctic in a ring-like manner around the Mediterranean and meet in secondary contact in Greece. Rufous coloration appears to be linked to a recently evolved nonsynonymous-derived variant of the melanocortin 1 receptor (MC1R) gene, which according to quantitative genetic analyses evolved under local adaptation during or following the colonization of Central Europe. Admixture patterns and linkage disequilibrium between the neutral genetic background and color found exclusively within the secondary contact zone suggest limited introgression at secondary contact. These results from a system reminiscent of ring species provide a striking example of how local adaptation can evolve from derived genetic variation.

Adaptation of Root Function by Nutrient-Induced Plasticity of Endodermal Differentiation.

Plant roots forage the soil for minerals whose concentrations can be orders of magnitude away from those required for plant cell function. Selective uptake in multicellular organisms critically requires epithelia with extracellular diffusion barriers. In plants, such a barrier is provided by the endodermis and its Casparian strips-cell wall impregnations analogous to animal tight and adherens junctions. Interestingly, the endodermis undergoes secondary differentiation, becoming coated with hydrophobic suberin, presumably switching from an actively absorbing to a protective epithelium. Here, we show that suberization responds to a wide range of nutrient stresses, mediated by the stress hormones abscisic acid and ethylene. We reveal a striking ability of the root to not only regulate synthesis of suberin, but also selectively degrade it in response to ethylene. Finally, we demonstrate that changes in suberization constitute physiologically relevant, adaptive responses, pointing to a pivotal role of the endodermal membrane in nutrient homeostasis.