Effects of parabolic flight and spaceflight on the endocannabinoid system in humans

The endocannabinoid system (ECS) plays an important role in the regulation of physiological functions, from stress and memory regulation to vegetative control and immunity. The ECS is considered a central and peripheral stress response system to emotional or physical challenges and acts through endocannabinoids (ECs), which bind to their receptors inducing subsequent effecting mechanisms. In our studies, the ECS responses have been assessed through blood concentrations of the ECs anandamide and 2-arachidonoylglycerol. In parallel, saliva cortisol was determined and the degree of perceived stress was quantified by questionnaires. This report summarizes the reactivity of the ECS in humans subjected to brief periods of kinetic stress and weightlessness during parabolic flights and to prolonged stress exposure during life onboard the International Space Station (ISS). Both conditions resulted in a significant increase in circulating ECs. Under the acute stress during parabolic flights, individuals who showed no evidence of motion sickness were in low-stress conditions and had a significant increase of plasma ECs. In contrast, highly stressed individuals with severe motion sickness had an absent EC response and a massive increase in hypothalamic-pituitary-adrenal axis activity. Likewise, chronic but well-tolerated exposure to weightlessness and emotional and environmental stressors on the ISS for 6 months resulted in a sustained increase in EC blood concentrations, which returned to baseline values after the cosmonauts' return. These preliminary results suggest that complex environmental stressors result in an increase of circulating ECs and that enhanced EC signaling is probably required for adaptation and tolerance under stressful conditions

Thermophile-specific proteins: the gene product of aq_1292 from Aquifex aeolicus is an NTPase

BACKGROUND: To identify thermophile-specific proteins, we performed phylogenetic patterns searches of 66 completely sequenced microbial genomes. This analysis revealed a cluster of orthologous groups (COG1618) which contains a protein from every thermophile and no sequence from 52 out of 53 mesophilic genomes. Thus, COG1618 proteins belong to the group of thermophile-specific proteins (THEPs) and therefore we here designate COG1618 proteins as THEP1s. Since no THEP1 had been analyzed biochemically thus far, we characterized the gene product of aq_1292 which is THEP1 from the hyperthermophilic bacterium Aquifex aeolicus (aaTHEP1). RESULTS: aaTHEP1 was cloned in E. coli, expressed and purified to homogeneity. At a temperature optimum between 70 and 80°C, aaTHEP1 shows enzymatic activity in hydrolyzing ATP to ADP + P(i )with k(cat )= 5 × 10(-3 )s(-1 )and K(m )= 5.5 × 10(-6 )M. In addition, the enzyme exhibits GTPase activity (k(cat )= 9 × 10(-3 )s(-1 )and K(m)= 45 × 10(-6 )M). aaTHEP1 is inhibited competitively by CTP, UTP, dATP, dGTP, dCTP, and dTTP. As shown by gel filtration, aaTHEP1 in its purified state appears as a monomer. The enzyme is resistant to limited proteolysis suggesting that it consists of a single domain. Although THEP1s are annotated as "predicted nucleotide kinases" we could not confirm such an activity experimentally. CONCLUSION: Since aaTHEP1 is the first member of COG1618 that is characterized biochemically and functional information about one member of a COG may be transferred to the entire COG, we conclude that COG1618 proteins are a family of thermophilic NTPases

Crystal structure of THEP1 from the hyperthermophile Aquifex aeolicus: a variation of the RecA fold

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.Abstract Background aaTHEP1, the gene product of aq_1292 from Aquifex aeolicus, shows sequence homology to proteins from most thermophiles, hyperthermophiles, and higher organisms such as man, mouse, and fly. In contrast, there are almost no homologous proteins in mesophilic unicellular microorganisms. aaTHEP1 is a thermophilic enzyme exhibiting both ATPase and GTPase activity in vitro. Although annotated as a nucleotide kinase, such an activity could not be confirmed for aaTHEP1 experimentally and the in vivo function of aaTHEP1 is still unknown. Results Here we report the crystal structure of selenomethionine substituted nucleotide-free aaTHEP1 at 1.4 Å resolution using a multiple anomalous dispersion phasing protocol. The protein is composed of a single domain that belongs to the family of 3-layer (α/β/α)-structures consisting of nine central strands flanked by six helices. The closest structural homologue as determined by DALI is the RecA family. In contrast to the latter proteins, aaTHEP1 possesses an extension of the β-sheet consisting of four additional β-strands. Conclusion We conclude that the structure of aaTHEP1 represents a variation of the RecA fold. Although the catalytic function of aaTHEP1 remains unclear, structural details indicate that it does not belong to the group of GTPases, kinases or adenosyltransferases. A mainly positive electrostatic surface indicates that aaTHEP1 might be a DNA/RNA modifying enzyme. The resolved structure of aaTHEP1 can serve as paradigm for the complete THEP1 family.Published versio

On the cytotoxicity of HCR-NTPase in the neuroblastoma cell line SH-SY5Y

Pasdziernik M, Kaltschmidt B, Kaltschmidt C, Klinger C, Kaufmann M. On the cytotoxicity of HCR-NTPase in the neuroblastoma cell line SH-SY5Y. BMC Research Notes. 2009;2(1):102.Background: The human cancer-related nucleoside triphosphatase (HCR-NTPase) is overexpressed in several tumour tissues including neuroblastoma. HCR-NTPase is an enzyme exhibiting a slow in vitro activity in hydrolysing nucleosidetriphosphates. However, its in vivo function is still unknown. To learn more about the physiological role of HCR-NTPase, we both overexpressed and silenced it in the neuroblastoma cell line SH-SY5Y. Findings: No effect was observed when the expression of endogenously expressed HCR-NTPase in the cells was silenced by RNA interference. On the other hand, overexpression of HCR-NTPase led to cytotoxicity of the protein in SH-SY5Y cells. Even if the catalytic essential amino acid glutamate 114 was replaced by alanine (E114A-HCR-NTPase), the protein remained cytotoxic. The results could be confirmed by successfully rescuing the cells via RNA interference. Conclusion: Although expressed in several tumours, at least in SH-SY5Y, HCR-NTPase is not essential for the cells to survive. Increased levels of the protein lead to cytotoxicity due to physical intracellular interactions rather than hydrolysis of nucleosidetriphosphates by its intrinsic residual enzymatic activity

Short-scar facelift without temporal flap: a 10-year experience.

BACKGROUND: The understanding of facial anatomy and its changes through aging has led to the development of several different facelift techniques that focus on being less invasive and traumatic and, at the same time, providing natural long-lasting results. In this article we describe step by step our facelift technique as it has been done over the past 10 years by the senior author. METHODS: This is a retrospective, descriptive, transversal study in which all patients who underwent a rhytidectomy using our technique from January 2002 to September 2012 were included. All patients were operated on under local anesthesia and superficial conscious sedation. All surgeries were performed by the same surgeon. A complete step-by-step description of the surgical technique can be found in the main article. RESULTS: Between January 2002 and September 2012, a total of 113 patients underwent facelift surgery. Of these, 88.9 % were women and 11.1 % were men. The mean age was 55.3 (± 8.66) years. Primary surgeries represented 80.3 % (n = 94), secondary 18.8 % (n = 22), and tertiary 0.85 % (n = 1). Only one major complication, representing 0.8 %, consisting of a right-sided temporal paresis with 2 months complete recovery was seen. The minor complications rate was 23.1 %. The most common minor complication was hypertrophic/keloid scars which made up 77.8 % of all minor complications. CONCLUSIONS: The technique described provides good and long-lasting aesthetic results with shorter scars, smaller areas of dissection (without temporal and postauricular flaps), and a shorter recovery period. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .Revisión por pare

Validity and responsiveness of the EQ-5D in assessing and valuing health status in patients with somatoform disorders

Background: The EQ-5D is a generic questionnaire providing a preference-based index score applicable to cost-utility analysis. This is the first study to validate the EQ-5D in patients with somatoform disorders. Methods: Data of the EQ-5D descriptive system, the British and the German EQ-5D index and the EQ Visual Analogue Scale, the Patient Health Questionnaire 15, the Patient Health Questionnaire 9, the Whiteley Index 7 and the Short Form 36 were collected from 294 patients at baseline, 244 at 6 months and 256 at 12 months after baseline. The discriminative ability of the EQ-5D was evaluated by comparison with a general population sample and by the ability to distinguish between different symptom severities. Convergent validity was analysed by assessing associations between the EQ-5D and the other instruments. Responsiveness was evaluated by analysing the effects on scores between two measurements in groups of patients reporting worse, same or better health. The Bonferroni correction was employed. Results: For all items of the EQ-5D except ‘self-care’, patients with somatoform disorders reported more problems than the general population. The EQ-5D showed discriminative ability in patients with different symptom severities. For nearly all reference instruments there were significant differences in mean scores between respondents with and without problems in the various EQ-5D items and strong correlations with the EQ Visual Analogue Scale and the EQ-5D index scores. Evidence for the responsiveness of the EQ-5D could only be found for patients with better health; effects were medium at the utmost. Conclusions: The EQ-5D showed a considerable validity and a limited responsiveness in patients with somatoform disorders. Trial registration: Current Controlled Trials ISRCTN5528079

Ice nucleation efficiency of natural dust samples in the immersion mode

A total of 12 natural surface dust samples, which were surface-collected on four continents, most of them in dust source regions, were investigated with respect to their ice nucleation activity. Dust collection sites were distributed across Africa, South America, the Middle East, and Antarctica. Mineralogical composition has been determined by means of X-ray diffraction. All samples proved to be mixtures of minerals, with major contributions from quartz, calcite, clay minerals, K-feldspars, and (Na, Ca)-feldspars. Reference samples of these minerals were investigated with the same methods as the natural dust samples. Furthermore, Arizona test dust (ATD) was re-evaluated as a benchmark. Immersion freezing of emulsion and bulk samples was investigated by differential scanning calorimetry. For emulsion measurements, water droplets with a size distribution peaking at about 2 µm, containing different amounts of dust between 0.5 and 50 wt % were cooled until all droplets were frozen. These measurements characterize the average freezing behaviour of particles, as they are sensitive to the average active sites present in a dust sample. In addition, bulk measurements were conducted with one single 2 mg droplet consisting of a 5 wt % aqueous suspension of the dusts/minerals. These measurements allow the investigation of the best ice-nucleating particles/sites available in a dust sample. All natural dusts, except for the Antarctica and ATD samples, froze in a remarkably narrow temperature range with the heterogeneously frozen fraction reaching 10 % between 244 and 250 K, 25 % between 242 and 246 K, and 50 % between 239 and 244 K. Bulk freezing occurred between 255 and 265 K. In contrast to the natural dusts, the reference minerals revealed ice nucleation temperatures with 2–3 times larger scatter. Calcite, dolomite, dolostone, and muscovite can be considered ice nucleation inactive. For microcline samples, a 50 % heterogeneously frozen fraction occurred above 245 K for all tested suspension concentrations, and a microcline mineral showed bulk freezing temperatures even above 270 K. This makes microcline (KAlSi3O8) an exceptionally good ice-nucleating mineral, superior to all other analysed K-feldspars, (Na, Ca)-feldspars, and the clay minerals. In summary, the mineralogical composition can explain the observed freezing behaviour of 5 of the investigated 12 natural dust samples, and partly for 6 samples, leaving the freezing efficiency of only 1 sample not easily explained in terms of its mineral reference components. While this suggests that mineralogical composition is a major determinant of ice-nucleating ability, in practice, most natural samples consist of a mixture of minerals, and this mixture seems to lead to remarkably similar ice nucleation abilities, regardless of their exact composition, so that global models, in a first approximation, may represent mineral dust as a single species with respect to ice nucleation activity. However, more sophisticated representations of ice nucleation by mineral dusts should rely on the mineralogical composition based on a source scheme of dust emissions