Tapering for marathon and cardiac autonomic function.

The purpose of this study was to investigate changes in post-exercise heart rate recovery (HRR) and heart rate variability (HRV) during an overload-tapering paradigm in marathon runners and examine their relationship with running performance. 9 male runners followed a training program composed of 3 weeks of overload followed by 3 weeks of tapering (-33±7%). Before and after overload and during tapering they performed an exhaustive running test (Tlim). At the end of this test, HRR variables (e.g. HRR during the first 60 s; HRR60 s) and vagal-related HRV indices (e.g. RMSSD5-10 min) were examined. Tlim did not change during the overload training phase (603±105 vs. 614±132 s; P=0.992), but increased (727±185 s; P=0.035) during the second week of tapering. Compared with overload, RMSSD5-10 min (7.6±3.3 vs. 8.6±2.9 ms; P=0.045) was reduced after the 2(nd) week of tapering. During tapering, the improvements in Tlim were negatively correlated with the change in HRR60 s (r=-0.84; P=0.005) but not RMSSD5-10 min (r=-0.21; P=0.59). A slower HRR during marathon tapering may be indicative of improved performance. In contrast, the monitoring of changes in HRV as measured in the present study (i.e. after exercise on a single day), may have little or no additive value.

Stable isotope compositions of mammoth teeth from Niederweningen, Switzerland: Implications for the Late Pleistocene climate, environment, and diet

Oxygen and carbon isotope compositions of well-preserved mammoth teeth from the Middle Wurmian (40-70 ka) peat layer of Niederweningen, the most important mammoth site in Switzerland, were analysed to reconstruct Late Pleistocene palaeoclimatic and palaeoenvironmental conditions. Drinking water (delta(18)O values of approximately -12.3 +/- 0.9 parts per thousand were calculated front oxygen isotope compositions of mammoth tooth enamel apatite using a species-specific calibration for modern elephants. These delta(18)O(H2O) values reflect the mean oxygen isotope composition of the palaeo-precipitation and are similar to those directly measured for fate Pleistocene groundwater from aquifers in northern Switzerland and southern Germany. Using a present-day delta(18)O(H2)o-precipitation-air temperature relation for Switzerland, a mean annual air temperature (MAT) of around 4.3 +/- 2.1 degrees C can be calculated for the Middle Wurmian at this site. This MAT is in good agreement with palaeotemperature estimates on the basis of Middle Wurmian groundwater recharge temperatures and beetle assemblages. Hence, the climatic conditions in this region were around 4 degrees C cooler during the Middle Wurmian interstadial phase, around 45-50ka BP, than they are today. During this period the mammoths from Niederweningen lived in an open tundra-like, C(3) plant-dominated environment as indicated by enamel (delta(13)C values of -11.5 +/- 0.3 parts per thousand and pollen and macroplant fossils found in the embedding peat. The low variability of enamel delta(13)C and delta(18)O values from different mammoth teeth reflects similar environmental conditions and supports a relatively small time frame for the fossil assemblage. (C) 2006 Elsevier Ltd and INQUA. All rights reserved.

The population genetics of clonal and partially clonal diploids.

The consequences of variable rates of clonal reproduction on the population genetics of neutral markers are explored in diploid organisms within a subdivided population (island model). We use both analytical and stochastic simulation approaches. High rates of clonal reproduction will positively affect heterozygosity. As a consequence, nearly twice as many alleles per locus can be maintained and population differentiation estimated as F(ST) value is strongly decreased in purely clonal populations as compared to purely sexual ones. With increasing clonal reproduction, effective population size first slowly increases and then points toward extreme values when the reproductive system tends toward strict clonality. This reflects the fact that polymorphism is protected within individuals due to fixed heterozygosity. Contrarily, genotypic diversity smoothly decreases with increasing rates of clonal reproduction. Asexual populations thus maintain higher genetic diversity at each single locus but a lower number of different genotypes. Mixed clonal/sexual reproduction is nearly indistinguishable from strict sexual reproduction as long as the proportion of clonal reproduction is not strongly predominant for all quantities investigated, except for genotypic diversities (both at individual loci and over multiple loci).

Exposure of highway maintenance workers to fine particulate matter and noise

In this study, we assessed the mixed exposure of highway maintenance workers to airborne particles, noise, and gaseous co-pollutants. The aim was to provide a better understanding of the workers' exposure to facilitate the evaluation of short-term effects on cardiovascular health endpoints. To quantify the workers' exposure, we monitored 18 subjects during 50 non-consecutive work shifts. Exposure assessment was based on personal and work site measurements and included fine particulate matter (PM2.5), particle number concentration (PNC), noise (Leq), and the gaseous co-pollutants: carbon monoxide, nitrogen dioxide, and ozone. Mean work shift PM2.5 concentrations (gravimetric measurements) ranged from 20.3 to 321 μg m(-3) (mean 62 μg m(-3)) and PNC were between 1.6×10(4) and 4.1×10(5) particles cm(-3) (8.9×10(4) particles cm(-3)). Noise levels were generally high with Leq over work shifts from 73.3 to 96.0 dB(A); the averaged Leq over all work shifts was 87.2 dB(A). The highest exposure to fine and ultrafine particles was measured during grass mowing and lumbering when motorized brush cutters and chain saws were used. Highest noise levels, caused by pneumatic hammers, were measured during paving and guardrail repair. We found moderate Spearman correlations between PNC and PM2.5 (r = 0.56); PNC, PM2.5, and CO (r = 0.60 and r = 0.50) as well as PNC and noise (r = 0.50). Variability and correlation of parameters were influenced by work activities that included equipment causing combined air pollutant and noise emissions (e.g. brush cutters and chain saws). We conclude that highway maintenance workers are frequently exposed to elevated airborne particle and noise levels compared with the average population. This elevated exposure is a consequence of the permanent proximity to highway traffic with additional peak exposures caused by emissions of the work-related equipment.

Comparison of organ doses and image quality between CT and flat panel XperCT scans in wrist and inner ear examinations.

The aim of this study was to evaluate and compare organ doses delivered to patients in wrist and petrous bone examinations using a multislice spiral computed tomography (CT) and a C-arm cone-beam CT equipped with a flat-panel detector (XperCT). For this purpose, doses to the target organ, i.e. wrist or petrous bone, together with those to the most radiosensitive nearby organs, i.e. thyroid and eye lens, were measured and compared. Furthermore, image quality was compared for both imaging systems and different acquisition modes using a Catphan phantom. Results show that both systems guarantee adequate accuracy for diagnostic purposes for wrist and petrous bone examinations. Compared with the CT scanner, the XperCT system slightly reduces the dose to target organs and shortens the overall duration of the wrist examination. In addition, using the XperCT enables a reduction of the dose to the eye lens during head scans (skull base and ear examinations).

Expression of killer cell immunoglobulin-like receptors (KIRs) by natural killer cells during acute CMV infection after kidney transplantation.

Human cytomegalovirus (CMV) infection may be a serious complication related to immunosuppression after solid organ transplantation. Due to their cytotoxicity, T-cells and natural killer (NK) cells target and clear the virus from CMV-infected cells. Although immunosuppressive drugs suppress T-cell proliferation and activation, they do not affect NK cells that are crucial for controlling the infection. The regulation of NK cells depends on a wide range of activating and inhibitory receptors such as the family of killer-cell immunoglobulin-like receptors (KIRs). Several human genetic studies have demonstrated the association of KIR genes with the clearance of infections. Since the respective activities of the different KIR proteins expressed by NK cells during CMV infection have not been extensively studied, we analyzed the expression of KIRs in a cohort of 22 CMV-IgG(+) renal transplant patients at the time of CMV reactivation, after antiviral therapy and 6 months later. Our data revealed a marked expression of KIR3DL1 during the acute phase of the reactivation. We set up an in vitro model in which NK cells, derived either from healthy donors or from transplanted patients, target allogeneic fibroblasts, CMV-infected or uninfected. Our results demonstrate a significant correlation between the lysis of CMV-infected fibroblasts and the expression of KIR3DL1. Blocking experiments with antibodies to MHC-I, to NKG2D and to NKG2C confirmed the importance of KIR3DL1. Consequently, our results suggest that KIR proteins and especially KIR3DL1 could play an important role during CMV-infection or CMV reactivation in immunosuppressed patients.

1st datings of ammonite-bearing Bajocian suites from Caucasus (Georgia) - K-Ar ages of volcanic hornblendes

Volcanic flows and tuffs interbedded with ammonite-bearing sediments directly correlatable with the stratotype section of the Bajocian stage have been dated for the first time within the Caucasus area. Three samples, each from a different section, allowed separation of well-preserved brown hornblende; these are considered reliable geochronometers in a region where subsequent volcanic activity occurred. The dated separates are V139: a volcanic layer probably near the base, V142 another layer near the top of the Lower Bajocian substage; V141 a boulder from a latest Bajocian volcanic conglomerate. From bottom to top, apparent ages at 173.5 +/- 2.6, 164.8 +/- 2.5 and 167.1 +/- 1.9 Ma (analytical uncertainty, 95% confidence level) respectively, can be calculated. The consistency of the results is obtained if the dated boulder is interpreted as derived from an underlying layer, The Bajocian-Bathonian boundary is much younger than commonly accepted and younger than 164 Ma.

Induction of potent antitumor CTL responses by recombinant vaccinia encoding a melan-A peptide analogue.

There is considerable interest in the development of vaccination strategies that would elicit strong tumor-specific CTL responses in cancer patients. One strategy consists of using recombinant viruses encoding amino acid sequences corresponding to natural CTL-defined peptide from tumor Ags as immunogens. However, studies with synthetic tumor antigenic peptides have demonstrated that introduction of single amino acid substitutions may dramatically increase their immunogenicity. In this study we have used a well-defined human melanoma tumor Ag system to test the possibility of translating the immunological potency of synthetic tumor antigenic peptide analogues into recombinant vaccinia viruses carrying constructs with the appropriate nucleotide substitutions. Our results indicate that the use of a mutated minigene construct directing the expression of a modified melanoma tumor Ag leads to improved Ag recognition and, more importantly, to enhanced immunogenicity. Thus, recombinant vaccinia viruses containing mutated minigene sequences may lead to new strategies for the induction of strong tumor-specific CTL responses in cancer patients.

A qui administrer le vaccin anti-pneumococcique? [We should received and pneumococcal immunization?]

Alors que l'immunisation active contre l'influenza semble être actuellement largement entrée dans la pratique médicale, force est de constater que c'est loin d'être le cas pour les infections à pneumocoque. La vaccination anti-pneumocoque. La vaccination anti-pneumococcique, qui est incluse dans les schémas d'immunisation de nombreux pays, ne fait actuellement pas l'objet de recommendations particulières en Suisse et son utilisation y reste marginale. Compte tenu du nombre élevé d'infections sévères et de décès potentiellement évitables, sa généralisation à tous les groupes à risque doit être encouragée. De plus, cette stratégie pourrait se révéler utile face à la progression inexorable de la proportion de souches résistantes à la pénicilline et aux autres microbes.

Mechanisms of spindle positioning during "Caenorhabditis elgans" asymmetric cell division

Résumé : Le positionnement correct du fuseau mitotique est crucial pour les divisions cellulaires asymétriques, car il gouverne le contrôle spatial de la division cellulaire et assure la ségrégation adéquate des déterminants cellulaires. Malgré leur importance, les mécanismes contrôlant le positionnement du fuseau mitotique sont encore mal compris. Chez l'embryon au stade une-cellule du nématode Caenorhabditis elegans, le fuseau mitotique est positionné de manière asymétrique durant l'anaphase grâce à l'action de générateurs de force situés au cortex cellulaire, et dont la nature était jusqu'alors indéterminée. Ces générateurs de force corticaux exercent une traction sur les microtubules astraux et sont dépendants de deux protéines Gα et de leurs protéines associées. Cette thèse traite de la nature de la machinerie responsable pour la génération des forces de tractions, ainsi que de son lien avec les protéines Gα et associées. Nous avons combiné des expériences de coupure par faisceau laser du fuseau mitotique avec le contrôle temporel de l'inactivation de gènes ou de l'exposition à des produits pharmacologiques. De cette manière, nous avons établi que la dynéine, un moteur se déplaçant vers l'extrémité négative des microtubules, ainsi que la dynamique des microtubules, sont toutes deux requises pour la génération efficace des forces de tractions. Nous avons démontré que les protéines Gα et leurs protéines associées GPR-1/2 et LIN-5 interagissent in vivo avec LIS-1, un composant du complexe de la dynéine. De plus, nous avons découvert que les protéines Gα, GPR-1/2 et LIN-5 promeuvent la présence du complexe de la dynéine au cortex cellulaire. Nos résultats suggèrent un mécanisme par lequel les protéines Gα permettent le recrutement cortical de GPR-1/2 et LIN-5, assurant ainsi la présence de la dynéine au cortex. Conjointement avec la dynamique des microtubules, ce mécanisme permet la génération des forces de tractions afin d'obtenir une division cellulaire correcte. Comme les mécanismes contrôlant le positionnement du fuseau mitotique et les divisions cellulaires asymétriques sont conservés au cours de l'évolution, nous espérons que les mécanismes élucidés par ce travail sont d'importance générale pour la génération de la diversité cellulaire durant le développement. De plus, ces mécanismes pourraient être applicables à d'autres divisions asymétriques, comme celle des cellules souches, dont le disfonctionnement peut entraîner la génération de cellules cancéreuses. Abstract : Proper spindle positioning is crucial for asymmetric cell division, because it controls spatial aspects of cell division and the correct inheritance of cell-fate determinants. However, the mechanisms governing spindle positioning remain incompletely understood. In the Caenorhabditis elegans one-cell stage embryo, the spindle becomes asymmetrically positioned during anaphase through the action of as-yet unidentified cortical force generators that pull on astral microtubules and that depend on two Gα proteins and associated proteins. This thesis addresses the nature of the force generation machinery and the link with the Gα and associated proteins. By performing spindle-severing experiments following temporally restricted gene inactivation and drug exposure, we established that microtubule dynamics and the minus-end directed motor dynein are both required for generating efficient pulling forces. We discovered that the Gα proteins and their associated proteins GPR-1/2 and LIN-5 interact in vivo with LIS-1, a component of the dynein complex. Moreover, we uncovered that LIN-5, GPR-1/2 and the Gα proteins promote the presence of the dynein complex at the cell cortex. Our findings suggest a mechanism by which the Gα proteins enable GPR-1/2 and LIN-5 recruitment to the cortex, thus ensuring the presence of cortical dynein. Together with microtubule dynamics, this allows pulling forces to be exerted and proper cell division to be achieved. Because the mechanisms of spindle positioning and asymmetric cell division are conserved across evolution, we expect the underlying mechanism uncovered here to be of broad significance for the generation of cell diversity during development. Moreover, this mechanism could be relevant for other asymmetric cell divisions, such as stem cell divisions, whose dysfunction may lead to the generation of cancer cells.

Le marché des footballeurs. Réseaux et circuits dans l'économie globale

Fin assemblage entre démarches théoriques et empiriques, l'ouvrage illustre les logiques sous-jacentes à la mondialisation du marché des footballeurs. Il présente des informations de première main sur le fonctionnement des réseaux de transfert, collectées par l'auteur au cours de dix années de recherches menées en Europe et en Afrique. Des données statistiques inédites, élaborées par l'Observatoire des footballeurs professionnels, et de nombreuses illustrations cartographiques rendent la lecture particulièrement agréable. L'analyse des réseaux et circuits migratoires des footballeurs permet de saisir le rôle décisif joué par de nombreux intermédiaires dans le développement d'un marché global de talents. L'ouvrage dévoile la manière dont agents, dirigeants de clubs et spéculateurs privés investissent sur des joueurs dans l'optique de mettre en place des chaînes de transferts à valeur ajoutée. Ce processus est exemplifié à travers l'étude du cas des footballeurs africains