Climate change and global responsibility - the role of energy consumption, GDP and CO2 emissions

Climate change is one of the biggest challenges faced by this generation. Despite being the single most important environmental challenge facing the planet and despite over two decades of international climate negotiations, global greenhouse gas (GHG) emissions continue to rise. By the middle of this century, GHGs must be reduced by as much as 40-70% if dangerous climate change is to be avoided. In the Kyoto Protocol no quantitative emission limitation and reduction commitments were placed on the developing countries. For the planning of the future commitments period and possible participation of developing countries, information of the functioning of the energy systems, CO2 emissions development in different sectors, energy use and technological development in developing countries is essential. In addition to the per capita emissions, the efficiency of the energy system in relation to GHG emissions is crucial for the decision of future long-term burden sharing between countries. Country’s future development of CO2 emissions can be defined by the estimated CO2 intensity of the future and the estimated GDP growth. The changes in CO2 intensity depend on several factors, but generally developed countries’ intensity has been increasing in the industrialization phase and decreasing when their economy shifts more towards the system dominated by the service sector. The level of the CO2 intensity depends by a large extent on the production structure and the energy sources that are used. Currently one of the most urgent issues regarding global climate change is to decide the future of the Kyoto Protocol. Negotiations on this topic have already been initiated, with the aim of being finalised by the 2015. This thesis provides insights into the various approaches that can be used to characterise the concept of comparable efforts for developing countries in a future international climate agreement. The thesis examines the post-Kyoto burden sharing questions for developing countries using the contraction and convergence model, which is one approach that has been proposed to allocate commitments regarding future GHG emissions mitigation. This new approach is a practical tool for the evaluation of the Kyoto climate policy process and global climate change negotiations from the perspective of the developing countries.

Construction de l'Est et de l'Ouest : vers des compétences interculturelles. Un exemple de recherche à Hong-Kong en situation de mobilité académique

Numerous scholars have already stressed the need to prepare students prior to academic mobility (Abdallah-Pretceille, 2003; Jackson, 2013, for example) in order to face hypermodernity (Aubert, 2004). As per the new mobilities paradigm (Urry, 2007), this implies considering individuals at the centre of political and institutional issues. Furthermore, the multiplicity of terminology of references towards academic mobility, and intercultural competences, justifies this research. The theory, for this doctoral dissertation, applies “renewed interculturality” (Dervin, 2012), a move away from a culturalist approach. Intercultural competences are therefore defined as a stepping back from discourses on the Other that may emerge during encounters. In order to collect the data, six focus groups have been organised with two batches of students from a Higher Education Institution in Hong-Kong, an “education hub” (Dervin & Machart, 2014) that is striving to be competitive particularly in increasing the number of incomingand outcoming students. Training and education to interculturality have been implemented prior to academic mobility in order to observe the impact on participants’ discourses before and after the mobility. Theories of enunciation and dialogism represent the methodology allowing us to compare and analyse the reported voices in the participants’ discourse and their prosodic realisation (Martin & White, 2005) before and after the experience of academic mobility. I have attempted to observe the dialogic space available to welcome the Other during encounters in the participants’ discourse. The results seem to underline the increased number of reported voices in participants’ discourse after study abroad, but as the space opened for negotiation is instable and depends on the interlocutors and the voices addressed, consequently, further research appears necessary to study the influences of a preparation prior to mobility on the contraction or expansion of heteroglossia. All in all, this doctoral dissertation aimed to renew preparation

The effects of fiscal policy after the global recession: assessing the evidences

This paper offers a commented review of the most recent empirical studies of the effects of fiscal contraction on economic growth, which have helped underpin the prescription that fiscal policy should be expansionary in coming years in order to contain economic semi-stagnation in the developed countries. The paper shows that there is ample literature showing that fiscal expansion helps the economy grow, and that fiscal contraction tends to reduce output and employment in the short term.

Atestación y respuesta: reflexión a partir de una fenomenologia hermenéutica de las capacidades

El siguiente ensayo busca explorar la tesis según la cual en la atestación o reconocimiento de sí, el sí-mismo que está en juego está atestiguado primeramente de modo prospectivo. Atestiguarse es reconocerse no en sí, sino en un envío, en una conminación que resulta del encuentro con lo otro; de este modo, se puede afirmar que la identidad personal es ante todo una identidad de éxodo, es decir enviada. Para el análisis de estas tesis quisiéramos centrarnos en la fenomenología hermenéutica del hombre capaz que desarrolla Ricœur de modo explícito en Soi-même comme un autre, y que ya ha bosquejado desde Le volontaire et l'involontaire. Con ello interrogaremos en qué sentido las capacidades son un modo de ser respondiente del sí-mismo ante lo otro que lo envía, y luego interrogaremos, en los márgenes de la hermenéutica bíblica del autor, el alcance de lo que significa responder para el sí-mismo.

Recueil de copies et de pièces imprimées concernant principalement la juridiction de la connetablie et maréchaussée de France. Ce recueil s'arrête à 1782.

Contient : 1 « Charta pro consulibus et habitatoribus villae de Florentia. Charte en faveur des habitants de la ville de Florence en la senechaussée de Toulouze. Trésor des chartes, pièce 630 du registre 80, page 396 ». Acte, en latin, du roi JEAN. Novembre 1350 ; 2 « Edit du roy HENRY IV, concernant les duels, donné à Blois, au mois d'avril 1602, registré au parlement le 7e juin suivant » ; 3 « Observations sommaires sur la jurisdiction des connetable et maréchaux de France » (fol. 19-31), suivies de reflexions sur ces observations (fol. 33-38) ; d'un relevé des édits et déclarations concernant la connétablie et la juridiction des maréchaux (fol. 39) ; d'une pièce imprimée intitulée : « Articles extraits des edits, ordonnances, declarations du roi et arrêts du conseil d'Etat, concernant les offices du point d'honneur », de 1693 à 1771 (fol. 41-44) ; d'une autre pièce imprimée, portant pour titre : « Articles extraits des ordonnances, edits et declarations, ou les Douze anciens articles fondamentaux enregistrés en la cour et publiés en la communauté des avocats et procureurs, dits vulgairement l'Ordonnance de 1356, pour la justice militaire et jurisdiction royale, civile, de police et criminelle du siege general de la connestablie et mareschaussée de France, à la table de marbre du Palais à Paris, universelle pour tout le royaume » ; 4 « Observations au sujet de l'arrêt de la cour, du 9 may 1767 », concernant les « soy-disants jésuites » ; 5 « Projet de requisitoire et de jugement de la connetablie » concernant les jésuites ; 6 « Arrest de la chambre des comptes, qui, en execution de l'ordonnance du 15 janvier 1573 et de la declaration du roi du 6 janvier 1574, enregistrées les 3 avril 1573 et 12 fevrier 1574, ordonne que les commissaires des guerres, controleurs, tresoriers, payeurs, de la gendarmerie, feront enregistrer leurs provisions au siege de la connétablie, avec déclaration de leur residence et domicile, et en outre les payeurs, les actes de leurs cautions, et fait defenses aux tresoriers, payeurs de leur payer à l'avenir leurs gages qu'en rapportant copie collationnée, pour une fois seulement, desdits enregistrements faute de quoi lesdits gages ne seront passés au jugement de leurs comptes. Du 23 août 1746 ». Pièce imprimée ; 7 « Articles extraits des anciennes ordonnances, edits et declarations, arrests et reglemens, pour etablir la necessité où sont les commissaires, controlleurs, tresoriers et payeurs generaux ou particuliers, ordinaires ou extraordinaires des guerres, de la maison du roy, de la cavalerie legère, des regimens et garnisons, et autres, de faire enregistrer au siège général de la connétablie et marechaussée de France, à la table de marbre du Palais à Paris, leurs lettres de provisions, actes de reception de caution et departement, y envoyer les roles des montres, et y declarer le lieu de leur residence et le nom de leurs cautions, sous peine de ne pouvoir être payés de leurs gages, qui ne pourront être alloués sans cette formalité, dans les comptes des tresoriers et payeurs, comme aussi l'obligation où ces officiers sont de proceder sur les actions qui leur sont intentées au sujet des fonctions dépendantes de leurs charges et maniement, de même que pour les contestations qui leur surviennent pour raison de leurs ventes d'offices, vente volontaire ou forcée par saisie reelle et adjudication en justice dans ce tribunal, où ils ont leurs causes commises exclusivement à toutes autres cours et juges, sans que le committimus ni l'evocation puisse avoir lieu, dont ils sont conseillers nés par la seance et voix deliberative qu'il a plu à Sa Majesté leur y accorder en certain cas, et dans lequel, par cette raison, leurs informations de vie et moeurs et leurs assemblées doivent se faire ». Paris, 1746. Pièce imprimée ; 8 « Arrest du conseil d'Estat du roi, qui, sans s'arrêter à l'arrêt du parlement de Besançon, du 20 novembre 1731, ni à tout ce qui s'en était ensuivi, ordonne que le procès encommencé contre les nommés Antoine Le Noir et François-Marie de La Croix, cavaliers de marechaussée, à la résidence d'Orgelet, pour raison de sommes par eux induement exigées d'un prisonnier par eux conduit dans les prisons de la conciergerie dudit parlement de Besançon, sera fait et jugé par les officiers du siège de la connétablie, conformement à la sentence dudit siège, du 13 decembre 1731, fait défense aux officiers du parlement de Besançon de prendre aucune connoissance des abus, excès et malversations commis par les officiers et archers de marechaussée dans l'exercice de leurs charges et commissions. Du 16 fevrier 1732 » ; Autre « arrêt du conseil d'Estat du roi, qui renvoye au siége de la connetablie la connoissance des accusations intentées contre le nommé Jean-Baptiste Lambert, cavalier de la marechaussée du département d'Arras, pour raison d'excès pretendus par lui commis en la personne d'un habitant de la ville de Lille en Flandre, qu'il avoit arrêté en vertu de l'ordre verbal de son lieutenant ; casse et annulle le decret de prise de corps decerné à ce sujet par les maieur et echevins de Lille, contre ledit Lambert, et leur fait défenses de rendre de pareils jugemens à l'avenir, et de connoître des fautes, abus et malversations qui pourroient être commis par les officiers de la marechaussée dans l'exercice de leurs fonctions, à peine de nullité, et de repondre en leurs propres et privés noms des dommages et intérêts desdits officiers ; ordonne que ledit arrêt sera enregistré au greffe de l'hôtel de ville. Du 12 juillet 1737 » ; 9 « Discussion elevée entre la connetablie et le parlement de Besançon, au sujet de la competence de la connetablie » ; a « Remontrance du parlement de Besançon » ; b « Observations sur les remontrances du parlement de Besançon » ; c « Projet de reponse » par JOLY DE FLEURY, procureur général au parlement de Paris, « à une consultation de M. le garde des sceaux » au sujet des remontrances susenoncées, 16 juin 1782 ; Double des pièces qui font l'objet des articles ci-dessus, cotés a, b, c ; 10 « Memoire pour le sieur Joly prévôt de la connetablie et marechaussée de France, à la suite et près la personne de feu monsieur le marechal de La Feuillade, qui traite de l'origine, des pouvoirs, fonctions, privileges et exemptions, ensemble des juges des privileges, des prevôts, officiers et archers, gardes de la prevôtés à la suite, et près la personne de chacun de messieurs les maréchaux de France, pourvus par le roi sur leur nomination » le tout rédigé par « Noirot, procureur » et publié « à Paris au Palais » en 1744. Pièce imprimée de 28 pages ; 11 « Autorités qui établissent le droit au siége de la connétablie de connoître et juger, souverainement et sans appel, les cas prévôtaux, en appellant audit siége les anciens avocats de la cour au nombre porté par l'ordonnance, et faisant juger la compétence à la Tournelle du parlement ». Les autorités citées sont comprises entre les années 1549-1647. Pièce de 8 pages in-4° imprimée « à Paris, chez P. G. Simon, imprimeur du parlement, rue Mignon Saint André des Arts, 1782 » ; 12 « Arrest de la cour du parlement, qui maintient le siège de la connetablie et marechaussée de France à la table de marbre du Palais à Paris, dans le droit de connoitre de tous cas et délits, dont la connoissance lui appartient, et dont il est en possession de connoitre, aux termes et conformément aux edits, ordonnances, declarations du roi, arrêts et reglemens concernant la jurisdiction dudit siége... Donné en notre dite cour de parlement le 2 septembre... 1767 ». Pièce de 8 pages in-4°, imprimée « à Paris, chez P.-G. Simon, imprimeur du parlement, rue de La Harpe, à l'Hercule, 1768 » ; 13 Extrait de l'« Encyclopedie », tome X, page 94, au mot Maréchal de France ; 14 « Declaration du roi... LOUIS » XIV, « donnée à Arles, au mois de janvier 1660, verifiée en parlement, le 5e fevrier, enregistrée au siège de la connestablie, le 10e du même mois de ladite année, confirmée par autre declaration du 20e août 1663, par laquelle S. M. ordonne qu'en reiterant et confirmant les edits et declarations cy devant données, concernant la jurisdiction de la connestablie et marechaussée de France à la table de marbre du Palais, à Paris, notamment celles de 1356, 1573 et 1617, portant que le privilège de committimus aux requestes du Palais et de l'Hostel, et l'attribution du scel du Chastelet ne peuvent avoir lieu contre ledit siège, et toutes saisies faites entre les mains des tresoriers de l'ordinaire et extraordinaire des guerres et cavalerie legère, et autres payeurs des gages des officiers et archers de marechaussée, sont nulles, si elles ne sont faites de l'ordonnance du lieutenant general de la connestablie »

Recueil de pièces sur l'histoire de France, provenant des frères DE SAINTE-MARTHE. II.

Catalogue des évêques de Mayence (fol. 4), — Besançon (fol. 32), — Metz (fol. 51), — Chiemsee (fol. 68), — Trèves (fol. 72). — Souscriptions d'archevêques et évêques à divers conciles (fol. 99). — Liste de relations diplomatiques et géographiques du XVIe siècle, en italien (fol. 137). — Quartiers du duc de Bourgogne, petit-fils de Louis XIV, 1684 (fol. 141, 306). — « Discours de ce qui s'est passé en la ville de Poictiers ès années 1588 et 1589 » (fol. 153) ; armorial des maires de Poitiers (fol. 165), suivi d'autres pièces sur le Poitou. — « Mémoires de la ville de Loudun et du pays de Loudunois, par M. Louis Trincant, procureur du Roy au siège de Loudun » (fol. 192), suivi de pièces justificatives et de deux lettres de Trincant aux frères de Sainte-Marthe (fol. 262, 263). — « Discours concernant l'usurpation de la Navarre, dresséz par Arnaud d'Oihénart, avocat en la Cour de parlement de Navarre » (fol. 272). — Généalogies de la maison de Prunelay (fol. 302), — et des Borgia (fol. 346). — Extraits d'une histoire de Suède (fol. 308). — Épitaphes de l'abbaye du Val au diocèse de Paris (fol. 328), et inscriptions ou épitaphes diverses, entre autres des Villequier, des ducs de Lorraine, de Marguerite de Valois (fol. 368). — Catalogue des auteurs cités dans l'Histoire généalogique des Sainte-Marthe (fol. 386). — Voyages à travers la France (fol. 406 et 491), la Hollande et l'Angleterre (fol. 436). — Liste des personnes auxquelles les Sainte-Marthe ont fait présent de leurs ouvrages (fol. 470). — Note sur la reine Christine de Suède (fol. 484). — Conquête de la Hollande, 1672 (fol. 496). — Évêques de Pologne (fol. 519). — Discours de la Servitude volontaire, de La Boétie (fol. 551).

Expression and function of endothelin and its receptors in vascular adventitial fibroblasts

Objective: The adventitia has been recognized to play important roles in vascular oxidative stress, remodelling and contraction. We recently demonstrated that adventitial fibroblasts are able to express endothelin-1 (ET-1) in response to angiotensin II (ANG II). However, the mechanisms by which ANG II induces ET-1 expression are unknown. It is also unclear whether the ET-1 receptors are expressed in the adventitia. We therefore examined the role of oxidative stress in the regulation of ET-1. We also investigated the expression of both the ETA and ETB receptors and the roles of these two types of receptors in collagen synthesis and ET-1 clearance in adventitial fibroblasts. Methods and Results: Adventitial fibroblasts were isolated and cultured from the thoracic mouse aorta. Cells were treated with ANG II (lOOnM), ET-1 (lOpM), NADPH oxidase inhibitor apocynin (lOOfiM), the superoxide anion scavenger tempol (lOOfiM), the ANG II receptor antagonists (100[aM), losartan (AT| receptor) and PD 1233 19 (AT2 receptor), the ET-1 receptor antagonists (lOOuM), BQ123 (ETA receptor) and BQ788 (ETB receptor), and the ETB receptor agonist (lOOnM) Sarafotoxin 6C. ET-1 peptide levels were determined by ELISA, while ETA ,ETB and collagen levels were determined by Western blot. ANG II increased ET-1 peptide levels in a time-dependent manner reaching significance when incubated for 24 hours. NAD(P)H oxidase inhibitor, apocynin, as well as the superoxide scanverger, tempol, significantly reduced ANG Il-induced ET-1 peptide levels while over-expression of SOD1 (endogenous antioxidant enzyme) significantly decreased ANG Il-induced collagen I expression, therefore implicating reactive oxygen species in the mediation of ET-1. ANG II increased ETA receptor protein as well as collagen in a similar fashion, reaching significance after 4, 6, and 24 hours treatment. ANG II induced collagen was reduced while in the presence of the ETA receptor antagonist suggesting the role of the ETa receptor in the regulation of the extracellular matrix. ANG II treatment also increased ETB receptor protein levels in a time-dependent manner. ANG II treatment in the presence of the ETB receptor antagonist significantly increased ET-1 peptide levels. On another hand, the ETB receptor agonist, Sarafotoxin 6C, significantly decreased ET-1 peptide levels. These data implicate the role of the ETb receptor in the clearance of the ET-1 peptide. Conclusion: ANG II-induced increases of ET-1 peptide appears to be mediated by reactive oxygen species derived from NAD(P)H oxidase. Both the ETA and ETB receptors are expressed in adventitial fibroblasts. The ETA receptor subtype mediates collagen I expression, while the ETB receptor may play a protective role through increasing the clearance of the ET- 1 peptide.

The capillary supply of human skeletal muscle in health and disease

BACKGROUND: Capillaries function to provide a surface area for nutrient and waste exchange with cells. The capillary supply of skeletal muscle is highly organized, and therefore, represents an excellent choice to study factors regulating diffusion. Muscle is comprised of three specific fibre types, each with specific contractile and metabolic characteristics, which influence the capillary supply of a given muscle; in addition, both environmental and genetic factors influence the capillary supply, including aging, physical training, and various disease processes. OBJECTIVE: The present study was undertaken to develop and assess the functionality of a data base, from which virtual experiments can be conducted on the capillary supply of human muscle, and the adaptations of the capillary bed in muscle to various perturbations. METHODS: To create the database, an extensive search of the literature was conducted using various search engines, and the three key words - "capillary, muscle, and human". This search yielded 169 papers from which the data for the 46 variables on the capillary supply and fibre characteristics of muscle were extracted for inclusion in the database. A series of statistical analyses (ANOVA) were done on the capillary database to examine differences in skeletal muscle capillarization and fibre characteristics between young and old individuals, between healthy and diseased individuals, and between untrained, endurance trained, endurance welltrained, and resistance trained individuals, using SAS. RESULTS: There was a significantly higher capillarization in the young compared to the old individuals, in the healthy compared to the diseased individuals, and in the endurance-trained and endurance well-trained compared to the untrained individuals. CONCLUSIONS: The results of this study support the conclusion that the capillary supply of skeletal muscle is closely regulated by factors aimed at optimizing oxygen and nutrient supply and/or waste removal in response to changes in muscle mass and/or metabolic activity.

Effects of isometric elbow flexion on electromyographic spike analysis

The main objective of this research was to examine the relationship between surface electromyographic (SEMG) spike activity and force. The secondary objective was to determine to what extent subcutaneous tissue impacts the high frequency component of the signal, as well as, examining the relationship between measures of SEMG spike shape and their traditional time and frequency analogues. A total of96 participants (46 males and 50 females) ranging in age (18-35 years), generated three 5-second isometric step contractions at each force level of 40, 60, 80, and 100 percent of maximal voluntary contraction (MVC). The presentation of the contractions was balanced across subjects. The right arm of the subject was positioned in the sagittal plane, with the shoulder and elbow flexed to 90 degrees. The elbow rested on a support in a neutral position (mid pronation/mid supination) and placed within a wrist cuff, fastened below the styloid process. The wrist cuff was attached to a load cell (JR3 Inc., Woodland, CA) recording the force produced. Biceps brachii activity was monitored with a pair of Ag/AgCI recording electrodes (Grass F-E9, Astro-Med Inc., West Warwick, RI) placed in a bipolar configuration, with an interelectrode distance (lED) of 2cm distal to the motor point. Data analysis was performed on a I second window of data in the middle of the 5-second contraction. The results indicated that all spike shape measures exhibited significant (p < 0.01) differences as force increase~ from 40 to 100% MVC. The spike shape measures suggest that increased motor unit (MU) recruitment was responsible for increasing force up to 80% MVC. The results suggested that further increases in force relied on MU III synchronization. The results also revealed that the subcutaneous tissue (skin fold thickness) had no relationship (r = 0.02; P > 0.05) with the mean number of peaks per spike (MNPPS), which was the high frequency component of the signal. Mean spike amplitude (MSA) and mean spike frequency (MSF) were highly correlated with their traditional measures root mean square (RMS) and mean power frequency (MPF), respectively (r = 0.99; r = 0.97; P < 0.01).

The surface electromyography-force relationship during isometric dorsiflexion in males and females

This study evaluated sex-related differences in the tibialis anterior (TA) surface electromyography (EMG) to force relationship. One-hundred participants (50 males and 50 females) performed three isometric contractions at 20, 40, 60, 80, and 100% of maximal voluntary contraction (MVC) in an apparatus designed to isolate the action of the dorsiflexors. The surface EMG signal was amplified (lOOOx), band-pass filtered (10-500Hz), and sampled at 2048 Hz. The load cell signal was low-passed filtered at 100 Hz and sampled at the same rate. Males were stronger than females {P <0.05). However, there was no significant difference in root-mean-square (RMS) values between sexes {P <0.05). Both sexes exhibited a quadratic increase in RMS across force levels (P <0.05). The mean power frequency (MNF) for males was greater than for females {P <0.05). Males and females exhibited a linear increase in both frequency measures up to 80% of MVC (P <0.05). Between 80 and 100% MVC, the frequency values for the females plateaued while males showed a decrease {P <0.05). The magnitude of the difference in MNF between males and females was consistent with sex-specific TA physiology. In general, the pattern of means for RMS and MNF between males and females revealed no sex-related differences in the surface EMG/force relationship. We therefore conclude that there are no sex-related differences in the gradation of muscle force.

The roles of ERK1/2 and PI3K in abnormal vascular functions in angiotensin II-infused hypertensive rats

Background: Ang II plays a major role in cardiovascular regulation. Recently, it has become apparent that vascular superoxide anion may play an important role in hypertension development. Treatment with antisense NAD(P)H oxidase or SOD decreased BP in Ang II-infused rats. Wang et al recently reported mice which lack one of the subunits of NAD(P)H oxidase developed hypertension at a much lower extent when compared to the wild type animals infused with Ang II, indicating that superoxide anion contributes to elevation in BP in the Ang II-infused hypertensive model. In the Ang II-infused hypertensive model, altered reactivity of blood vessels is often associated with the elevation of systolic blood pressure. We have observed abnormal tension development and impaired endothelium-dependent relaxation in the isolated aorta of Ang II-infused and DOCA-salt hypertensive rats. Recently, several other cellular signal molecules, including ERK1I2 and PI3K, have been determined to play important roles in the regulation of smooth muscle contraction and relaxation. ERKl/2 and PI3K pathways are also reported to contribute to Ang II induced cell growth, hypertrophy, remodeling and contraction. Moreover, these signaling pathways have shown ROS-sensitive properties. Therefore, the aim of the present study is to investigate the roles of ERKl12 and PI3K in vascular oxidative stress, spontaneous tone and impaired endothelium relaxation in Ang II-infused hypertensive model. Hypothesis: We hypothesize that the activation of ERKl12 and PI3K are elevated in response to an Ang II infusion for 6 days. The elevated activation of phospho-ERKl/2 and PI3K mediated the increased level of vascular superoxide anion, the abnormal vascular contraction and impaired endothelium-dependent vascular relaxation in Ang II-infused hypertensive rats. Methods: Vascular superoxide anion level is measured by lucigenin chemiluminescence. Spontaneous tone and ACh-induced endothelium-dependent relaxation was measured by isometric tension recording in organ chamber. The activity of ERK pathway will be measured by its Western blot of phosphorylation of ERK. PI3K activity was evaluated indirectly by Western blot of the phosphorylation of PDKl, a downstream protein of PI3K signaling pathway. The role of each pathway was also addressed via comparing the responses to the specific inhibitors. Results: Superoxide anion was markedly increased in the isolated thoracic aorta from Ang II-infused rats. There was spontaneous tone developed in rings from Ang II-induced hypertensive but not sham-operated normotensive rats. ACh-induced endothelium-dependent relaxation function is impaired in Ang II-infused hypertensive rats. Superoxide dismutase and NAD(P)H oxidase inhibitor, apocynin, inhibited the abnormal spontaneous tone and ameliorated impaired endothelium-dependent relaxation. The expression of phopho-ERKII2 was enhanced in Ang II-infused rats, indicating the activity of ERK1I2 could be increased. MEK1I2 inhibitors, PD98059 and U126, but not their inactive analogues, SB203580 and U124, significantly reduced the vascular superoxide anion in aortas from Ang II-infused rats. The MEK1I2 inhibitors reduced the spontaneous tone and improved the impaired endothelium-dependent relaxation in aorta of hypertension. These findings supported the role of ERKII2 signaling pathway in vascular oxidative stress, spontaneous tone and impaired endothelium-dependent relaxation in Ang II-infused hypertensive rats. The amount of phospho-PDK, a downstream protein of PI3K was increased in Ang II rats indicating the activity of PI3K activity was elevated. Strikingly, PI3K significantly inhibited the increase of superoxide anion level, abnormal spontaneous tone and restored endothelium-dependent relaxation in Ang II-infused hypertensive rats. These findings indicated the important role of PI3K in Ang II-infused hypertensive rats. Conclusion: ERKII2 and PI3K signaling pathways are sustained activated in Ang II-infused hypertensive rats. The activated ERKII2 and PI3K mediate the increase of vascular superoxide anion level, vascular abnormal spontaneous tone and impaired endothelium-dependent relaxation.

The influence of skeletal muscle cell volume on carbohydrate metabolism in contracting skeletal muscle

This study investigated the regulation of carbohydrate metabolism through changes in skeletal muscle cell volume immediately post contraction and during recovery. Using an established in vitro isolated muscle strip model, soleus (SOL) and extensor digitorum longus (EDL) were dissected from male rats and incubated in an organ bath (perfused with 95% O2; 5% CO2, pH 7.4, temperature 25°C) containing medium- 199 altered to a target osmotic condition (iso-, hypo- or hyper-osmotic; 290, 1 80, 400 mmol/kg). Muscles were stimulated for 10 minutes (40 Hz SOL; 30 Hz EDL) and then either immediately flash frozen or allowed to recover for 20 minutes before subsequent metabolite and enzyme analysis. Results demonstrated a relative water decrease in HYPER vs. HYPOosmotic condition (n=8/group; p<0.05) regardless of muscle type. Specifically, the SOL HYPER condition had elevated metabolite concentrations after 10 minutes of stimulation in comparison to both HYPO and ISO (p<0.05), while EDL muscle did not show any significant difTerences between the HYPER or HYPO conditions. After 20 minutes of recovery, metabolic changes occurred in both SOL and EDL with the SOL HYPER condition showing greater relative changes in metabolite concentrations versus HYPO. The results of the current study have demonstrated that osmotic imbalance induces metabolic change within the skeletal muscle cell and muscle type may influence the mechanisms utilized for cell volume regulation.

Decreased motor unit firing rate in the potentiated tibialis anterior in humans

With repeated activity, force production, rate of force production, and relaxation time are impaired. These are characteristics ofa fatigued muscle (Vandenboom, 2004). However, brief bouts of near maximal to maximal activity results in the increased ability of the muscle to generate force, termed post activation potentiation (P AP)(V andervoort et aI., 1983). The purpose of the present study was to characterize motor unit firing rate (MUFR) in the unfatigued, potentiated tibialis anterior (TA). Using a quadrifilar needle electrode, MUFR was measured during a 5s 50% MVC in which the TA was either potentiated or unpotentiated; monopolar electrodes measured surface parameters. A lOs MVC was used to potentiate the muscle. Firing rate decreased significantly from 20.15±2.9Opps to 18.27±2.99pps, while mean power frequency decreased significantly from 60. 13±7.75 Hz to 53.62±8.56 Hz. No change in root mean square (RMS) was observed. Therefore, in the present study, MUFR decreases in response to a potentiated TA.

The influence of myosin regulatory light chain phosphorylation on the contractile performance of fatigued mammalian skeletal muscle

ABSTRACT The myosm regulatory light chain (RLC) of type II fibres is phosphorylated by Ca2+ -calmodulin dependent myosin light chain kinase (skMLCK) during muscular activation. The purpose of this study was to explore the effect of skMLCK gene ablation on the fatigability of mouse skeletal muscles during repetitive stimulation. The absence of myosin RLC phosphorylation in skMLCK knockout muscles attenuated contractile performance without a significant metabolic cost. Twitch force was potentiated to a greater extent in wildtype muscles until peak force had diminished to ~60% of baseline (37.2 ± 0.05% vs. 14.3 ± 0.02%). Despite no difference in peak force (Po) and shortening velocity (Vo), rate of force development (+dP/dt) and shortening-induced deactivation (SID) were almost two-fold greater in WT muscles. The present results demonstrate that myosin RLC phosphorylation may improve contractile performance during fatigue; providing a contractile advantage to working muscles and protecting against progressive fatigue.

The reliability of an isometric test based on constant perception of effort

To date there is no documented procedure to extrapolate findings of an isometric nature to a whole body performance setting. The purpose of this study was to quantify the reliability of perceived exertion to control neuromuscular output during an isometric contraction. 21 varsity athletes completed a maximal voluntary contraction and a 2 min constant force contraction at both the start and end of the study. Between pre and post testing all participants completed a 2 min constant perceived exertion contraction once a day for 4 days. Intra-class correlation coefficient (R=O.949) and standard error of measurement (SEM=5.12 Nm) concluded that the isometric contraction was reliable. Limits of agreement demonstrated only moderate initial reliability, yet with smaller limits towards the end of 4 training sessions. In conclusion, athlete's na"ive to a constant effort isometric contraction will produce reliable and acceptably stable results after 1 familiarization sessions has been completed.