Citrulline malate supplementation does not improve German Volume Training performance or reduce muscle soreness in moderately trained males and females

Background Use of supplements to aid performance is common practice amongst recreationally active individuals, including those without a sufficient evidence base. This investigation sought to assess whether acute supplementation with 8 g of citrulline malate (CM) (1.11: 1 ratio) would improve anaerobic performance. Methods A randomised double blind placebo control trial was employed, using a counterbalanced design. We recruited recreationally active men and women to take part in an isokinetic chair protocol, based on German Volume Training (GVT) whereby participants attempted to perform 10 sets of 10 repetitions against a force representing 70% of their peak concentric force. Results The number of repetitions achieved over the course of the GVT was 94.0 ± 7.9 and 90.9 ± 13.9 for placebo and CM respectively. There was no significant difference between the placebo and CM treatment for number of repetitions (P = 0.33), isometric (P = 0.60), concentric (P = 0.38), or eccentric (P = 0.65) peak force following the GVT. Total muscle soreness was significantly higher in the CM compared to the placebo treatment following the GVT protocol over 72 h (P = 0.01); although this was not accompanied by a greater workload/number of repetitions in the CM group. Conclusions We conclude that an acute dose of CM does not significantly affect anaerobic performance using an isokinetic chair in recreational active participants. Practical implications include precaution in recommending CM supplementation. Coaches and athletes should be aware of the disparity between the chemical analyses of the products reviewed in the present investigation versus the manufacturers’ claims

Transcriptional Regulation of Ribosome Components Are Determined by Stress According to Cellular Compartments in Arabidopsis thaliana

Plants have to coordinate eukaryotic ribosomes (cytoribosomes) and prokaryotic ribosomes (plastoribosomes and mitoribosomes) production to balance cellular protein synthesis in response to environmental variations. We identified 429 genes encoding potential ribosomal proteins (RP) in Arabidopsis thaliana. Because cytoribosome proteins are encoded by small nuclear gene families, plastid RP by nuclear and plastid genes and mitochondrial RP by nuclear and mitochondrial genes, several transcriptional pathways were attempted to control ribosome amounts. Examining two independent genomic expression datasets, we found two groups of RP genes showing very different and specific expression patterns in response to environmental stress. The first group represents the nuclear genes coding for plastid RP whereas the second group is composed of a subset of cytoribosome genes coding for RP isoforms. By contrast, the other cytoribosome genes and mitochondrial RP genes show less constraint in their response to stress conditions. The two subsets of cytoribosome genes code for different RP isoforms. During stress, the response of the intensively regulated subset leads to dramatic variation in ribosome diversity. Most of RP genes have same promoter structure with two motifs at conserved positions. The stress-response of the nuclear genes coding plastid RP is related with the absence of an interstitial telomere motif known as telo box in their promoters. We proposed a model for the “ribosome code” that influences the ribosome biogenesis by three main transcriptional pathways. The first pathway controls the basal program of cytoribosome and mitoribosome biogenesis. The second pathway involves a subset of cytoRP genes that are co-regulated under stress condition. The third independent pathway is devoted to the control of plastoribosome biosynthesis by regulating both nuclear and plastid genes

Returning to work by thyroid cancer survivors 5 years after diagnosis: the VICAN survey

International audiencePurpose: Return to work (RTW) following cancer diagnosis is a challenge for both the patient and society. As thyroid cancer (TC) incidence is increasing, this study aims to assess difficulties in returning to work and income changes in TC survivors 5 years post-diagnosis.Methods: This study belongs to the national VICAN survey conducted in France among TC patients diagnosed between January and June 2010. Data were collected through phone interviews, medical surveys and from the national medico-administrative register in 2012 and 2015. We used multivariate logistic regressions to investigate TC impact on employment and income changes.Results: Of 146 patients, 121(82.9%) were women; the mean age was 42 years (SD = 8.34), 119 (81.3%) were diagnosed at an early stage, and 142(97.6%) underwent thyroidectomy. At 5 years post-diagnosis, 116 (79.7%) of the TC survivors were professionally active, 22 (15.4%) were unemployed and 8 (4.90%) were receiving disability. Among the patients employed at the time of diagnosis (n = 122), 15 (12.3%) had not returned to work 5 years post-diagnosis. Between 2 and 5 years post-diagnosis, there was no significant improvement in rates of RTW. At 5 years post-diagnosis, 90 (61.6%) reported an income decline. All TC survivors who have not returned to work were women and declared higher fatigue. Moreover, in multivariate analyses, not returning to work was associated with weight gain (OR = 8.41 (1.21; 58.23)) and working arrangements (6.90 (1.18-38.48)), while income decline was associated with comorbidities (OR = 2.28 (1.07; 4.86)) and to be engaged in manual work (OR = 2.28 (1.07; 4.88)).Conclusion: This study highlights that, despite a good prognostic, up to 12.3% of TC survivors had not returned to work and 61.6% reported an income decline, 5 years post-diagnosis. Weight gain, fatigue, to be a woman and working-type arrangement were associated with higher probability of not returning to work.Implications for cancer survivors: TC affects a young working population. Our study identified potentially vulnerable TC survivors and important modifiable factors which may help TC survivors to be professionally active and, therefore, increase their overall quality of life

Mechanisms of uranium and thorium accumulation in the bone matrix

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Temperature evolution of infrared- and Raman-active phonons in graphite

International audienceWe perform a comparative experimental and theoretical study of the temperature dependence up to 700 K of the frequency and linewidths of the graphite E1u and E2g optical phonons (∼1590 and 1580 cm−1) by infrared (IR) and Raman spectroscopy. Despite their similar character, the temperature dependence of the two modes is quite different, e.g., the frequency shift of the IR-active E1u mode is almost twice as big as that of the Raman-active E2g mode. Ab initio calculations of the anharmonic properties are in remarkable agreement with measurements and explain the observed behavior

Low-temperature FIR and submillimetre mass absorption coefficient of interstellar silicate dust analogues

Context. Cold dust grains are responsible for the far-infrared and submillimetre (FIR/submm) emission observed by Herschel and Planck. Their thermal emission is usually expressed as a modified black body law in which the FIR/submm dust opacity, or mass absorption coefficient (MAC), is described by the MAC at a given wavelength κλ0 and the temperature- and wavelength-independent emissivity spectral index β. However, numerous data from previous space and balloon-borne missions and recently from Herschel and Planck show that the dust emission is not well understood, as revealed for example by the observed anti-correlation of β with the grain temperature. Aims. The aim of this work is to measure the optical properties of interstellar dust analogues at low temperatures to give astronomers the necessary data for interpreting FIR/submm observations such as those from the Herschel and Planck satellites. Methods. We synthesised, via sol-gel methods, analogues of interstellar amorphous silicate grains, rich in Mg and Ca, and having stoichiometry of olivine and pyroxene. The samples are characterised by various techniques to determine their composition, size, amorphisation degree. All the amorphous samples are annealed at 1100 °C to study the crystallised materials for comparison. We measured the MAC of all the samples in the 2–25 μm range at room temperature and in the 100–1000/1500 μm range for grain temperatures varying from 300 to 10 K. Results. The experimental results show that, for all the amorphous samples, the grain MAC decreases when the grain temperature decreases and that the local spectral index, β, defined as the slope of the MAC curve, is anti-correlated with the grain temperature. These variations, which are not observed in the crystallised samples, are related to the amorphous nature of the samples. In addition, the spectral shape of the MAC is complex and cannot be described by a single spectral index over the 100–1500 μm range. At short wavelengths (λ ≤ 500/700 μm), β is in the range 1.6–2.1 for all grain temperature and grain composition. However, at longer wavelengths (λ ≥ 500/700 μm), β ≤ 2 for samples with a pyroxene stoichiometry and β ≥ 2 for samples with an olivine stoichiometry. Conclusions. The dust properties in the FIR/submm domain and at low temperature are more complicated than expected. The simplifying asymptotic expression based on a single temperature- and wavelength-independent spectral index used by astronomers is not appropriate to describe the dust MAC, hence the dust emission, and may induce significant errors on the derived parameters, such as the dust mass and the dust physical and chemical properties. Instead, dust emission models should use the dust MAC as a function of wavelength and temperature

Thermodynamic and Structural Investigation of Synthetic Actinide–Peptide Scaffolds

International audienceThe complexation of uranium and europium, in oxidation states +VI and +III, respectively, was investigated with pertinent bio-inorganic systems. Three aspartate-rich pentapeptides with different structural properties were selected for study to rationalize the structure–affinity relationships. Thermodynamic results, crosschecked by both isothermal titration calorimetry and time-resolved laser fluorescence spectroscopy, showed different affinity depending on the peptide for both Eu(III) and U(VI). The thermodynamic aspects were correlated to structural predictions, which were acquired by density functional theory quantum chemical calculations and from IR and extended X-ray absorption fine structure experiments. The combination of these microscopic properties revealed that carbonyl–metal interactions affected the entropy in the case of europium, while the larger uranyl cation was mostly affected by preorganization and steric effects, so that the affinity was enhanced through enthalpy. The approach described here revealed various microscopic aspects governing peptide actinide affinity. Highlighting these mechanisms should certainly contribute to the rational synthesis of higher affinity biomimetic aspartic ligands

Actinide(IV) Deposits on Bone: Potential Role of the Osteopontin–Thorium Complex

International audienceIn case of a nuclear event, contamination (broad or limited) of the population or of specific workers might occur. In such a senario, the fate of actinide contaminants may be of first concern, in particular with regard to human target organs like the skeleton. To improve our understanding of the toxicological processes that might take place, a mechanistic approach is necessary. For instance, ∼50% of Pu(IV) is known from biokinetic data to accumulate in bone, but the underlining mechanisms are almost unknown. In this context, and to obtain a better description of the toxicological mechanisms associated with actinides(IV), we have undertaken the investigation, on a molecular scale, of the interaction of thorium(IV) with osteopontin (OPN) a hyperphosphorylated protein involved in bone turnover. Thorium is taken here as a simple model for actinide(IV) chemistry. In addition, we have selected a phosphorylated hexapeptide (His-pSer-Asp-Glu-pSer-Asp-Glu-Val) that is representative of the peptidic sequence involved in the bone interaction. For both the protein and the biomimetic peptide, we have determined the local environment of Th(IV) within the bioactinidic complex, combining isothermal titration calorimetry, attenuated total reflectance Fourier transform infrared spectroscopy, theoretical calculations with density functional theory, and extended X-ray absorption fine structure spectroscopy at the Th LIII edge. The results demonstrate a predominance of interaction of metal with the phosphate groups and confirmed the previous physiological studies that have highlighted a high affinity of Th(IV) for the bone matrix. Data are further compared with those of the uranyl case, representing the actinyl(V) and actinyl(VI) species. Last, our approach shows the importance of developing simplified systems [Th(IV)–peptide] that can serve as models for more biologically relevant systems

Actinide Complexation with Biomimetic Phosphorylated Molecules

International audienceMost data available on the interaction of actinides with biological systems are based on physiological or biokinetic measurements, with scarce information on the structure of the actinide coordination site. This proceeding article describes an approach for structural elucidation of actinide biological complexes. Indeed most of c.a. actinide circulation pathways are unknown, as they accumulate mostly in bones, kidney and liver. In case of accidental release of radionuclide in the environment, internal contamination under either acute or chronic conditions has the potential to induce both radiological and chemical toxicity through significant interaction with the metabolome or proteome followed by possible functional modifications. For instance, the metalloproteins present primary, secondary and tertiary structures, and also different post-translational modifications, all playing a crucial role in interacting with their partners, which can be altered by actinide bonding. When tightly bound, metal ions are critical to the function, structure, and stability of the proteins, by disabling specific interactions through significant local or global conformational modifications. In order to overcome the intricacy of actinide chemistry combined with that of metalloproteins, a simplified study toward better understanding the interaction of actinides and biological systems using simple biomolecules such as amino acids has therefore been considered. Focus is made on the cation coordination site itself, given that conformational effects are not taken into account in this approach. In a first step, we have selected simple phosphorylated building blocks that may be considered as chemical representatives of some ubiquitous target metalloproteins or some important phosphorylated peptides or proteins