123 research outputs found

    Exercise is a potent stimulus for enhancing circulating DNase activity

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    AbstractObjectivesTo elucidate cell free DNA (cfDNA) clearance kinetics following an acute bout of high intensity exercise by measuring circulating DNase activity reduction (AR).Design and methodsSerum cfDNA concentration and DNase-AR were measured prior to and post (immediately post, 7 and 30min post) an acute bout of rowing exercise until exhaustion.ResultsSerum cfDNA concentration was significantly (P≤.001) elevated immediately post (2.5-fold) and 7min post exercise (2.3-fold) with a return close to baseline at 30min post exercise (1.5-fold). The rise in cfDNA was accompanied by a concomitant, significant (P≤.001) decrease in serum DNase-AR from 15.1% prior to exercise to 3.1% AR at cessation of the exercise test and 7min post exercise (3.9% AR). DNase-AR returned close to baseline at 30min post exercise (5.2% AR).ConclusionsA single bout of high intensity exercise is a potent stimulus for enhancing circulating DNase activity in healthy people. Acute exercise may therefore be considered as a non-pharmacological stimulus to trigger DNase activity.This finding may be relevant for pathological conditions associated with increased cfDNA concentrations like cystic fibrosis, where pharmacological recombinant human DNase (rhDNase) treatment has been successfully used to improve patients' health and physical function

    The origin and maintenance of mammalian peroxisomes involves a de novo PEX16-dependent pathway from the ER

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    Peroxisomes are ubiquitous organelles that proliferate under different physiological conditions and can form de novo in cells that lack them. The endoplasmic reticulum (ER) has been shown to be the source of peroxisomes in yeast and plant cells. It remains unclear, however, whether the ER has a similar role in mammalian cells and whether peroxisome division or outgrowth from the ER maintains peroxisomes in growing cells. We use a new in cellula pulse-chase imaging protocol with photoactivatable GFP to investigate the mechanism underlying the biogenesis of mammalian peroxisomes. We provide direct evidence that peroxisomes can arise de novo from the ER in both normal and peroxisome-less mutant cells. We further show that PEX16 regulates this process by being cotranslationally inserted into the ER and serving to recruit other peroxisomal membrane proteins to membranes. Finally, we demonstrate that the increase in peroxisome number in growing wild-type cells results primarily from new peroxisomes derived from the ER rather than by division of preexisting peroxisomes

    Sympathetic nervous system activity and anti-lipolytic response to iv-glucose load in subcutaneous adipose tissue of obese and obese type 2 diabetic subjects

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    The study aim was to investigate the effect of endogenous insulin release on lipolysis in subcutaneous adipose tissue after adrenergic stimulation in obese subjects diagnosed with type 2 diabetes (T2D). In 14 obese female T2D subjects, or 14 obese non-T2D controls, glycerol concentration was measured in response to the α1,2,ß-agonist norepinephrine, the α1-agonist norfenefrine and the ß2-agonist terbutaline (each 10-4 M), using the microdialysis technique. After 60 minutes of stimulation, an intravenous glucose load (0.5 g/kg lean body mass) was given. Local blood flow was monitored by means of the ethanol technique. Norepinephrine and norfenefrine induced a four and three fold rise in glycerol dialysate concentration (p\u3c0.001, each), with a similar pattern in adipose tissue. Following agonist stimulation and glucose infusion, endogenous insulin release inhibited lipolysis in the presence of norepinephrine, which was more rapid and pronounced in healthy obese controls than in T2D subjects (p = 0.024 obese vs T2D subjects). Insulin-induced inhibition of lipolysis in the presence of norfenefrine was similar in all study participants. In the presence of terbutaline the lipolysis rate increased two fold until the effect of endogenous insulin (p\u3c0.001). A similar insulin-induced decrease in lipolysis was observed for each of the norfenefrine groups and the terbutaline groups, respectively. Adipose tissue blood flow remained unchanged after the iv-glucose load. Both norepinephrine and norfenefrine diminished blood flow slightly, but insulin reversed this response (p\u3c0.001 over the entire time). Terbutaline alone and terbutaline plus increased endogenous insulin augmented local blood flow (p\u3c0.001 over the entire time). In conclusion, a difference in insulin-induced inhibition of lipolysis was observed in obese T2D subjects compared to obese healthy controls following modulation of sympathetic nervous system activity and is assumed to be due to ß1-adrenoceptor mediated stimulation by norepinephrine

    Lowering the sintering temperature of barium strontium titanate bulk ceramics by barium strontium titanate-gel and BaCu(B₂O₅)

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    In this paper the influence of barium strontium titanate (BST) xerogel as a sinter additive and BaCu(B2_{2}O5_{5}) (BCB) as a liquid phase sintering aid on the sintering behavior of BST bulk ceramics is investigated. BST as well as BCB powders were synthesized via a mixed oxide route and BST gel via a sol-gel process. Compared to pure BST bulk ceramics, BST gel reduces the sintering start (onset temperature) by up to 174°C and increases the density for a sintering temperature of 1200°C. By adding BCB to the BST powder the sintering was completed much faster and the onset temperatures were reduced by 281°C and 312°C for 1 mol. % and 2.5 mol. %, respectively. With 2.5 mol. % BCB, the highest density of 96 % (5.41 g∙cm3^{-3}) was achieved at 950°C

    Carbohydrate Intake in Form of Gel Is Associated With Increased Gastrointestinal Distress but Not With Performance Differences Compared With Liquid Carbohydrate Ingestion During Simulated Long-Distance Triathlon

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    The ingestion of exogenous carbohydrates (CHO) during prolonged endurance exercise, such as long-distance triathlon, is considered beneficial with regard to performance. However, little is known about whether this performance benefit differs among different forms of CHO administration. To this end, the purpose of our study was to determine the impact of CHO ingestion from a semisolid source (GEL) on measures of performance and gastrointestinal (GI) comfort compared with CHO ingestion from a liquid source (LIQ). Nine well-trained triathletes participated in this randomized crossover study. Each participant completed a 60-min swim, 180-min bike exercise, and a 60-min all-out run in a laboratory environment under 2 conditions, once while receiving 67.2 ± 7.2 g · h–1 (M ± SD) of CHO from GEL and once while receiving 67.8 ± 4.2 g · h–1 of CHO from LIQ. The amount of fluid provided was matched among conditions. Respiratory exchange ratio (RER), blood glucose, and lactate as well as GI discomfort were assessed at regular intervals during the experiment. The distance covered during the final all-out run was not significantly different among participants ingesting GEL (11.81 ± 1.38 km) and LIQ (11.91 ± 1.53 km; p = .89). RER, blood glucose, and lactate did not differ significantly at any time during the experiment. Seven participants reported GI discomfort with GEL, and no athlete reported GI discomfort with LIQ (p = .016). This study suggests that administration of GEL does not alter long-distance triathlon performance when compared with LIQ, but GEL seems to be associated with reduced GI tolerance. Athletes should consider this a potential disadvantage of GEL administration during long-distance triathlon

    Carbohydrate Intake in Form of Gel Is Associated With Increased Gastrointestinal Distress but Not With Performance Differences Compared With Liquid Carbohydrate Ingestion During Simulated Long-Distance Triathlon

    Get PDF
    The ingestion of exogenous carbohydrates (CHO) during prolonged endurance exercise, such as long-distance triathlon, is considered beneficial with regard to performance. However, little is known about whether this performance benefit differs among different forms of CHO administration. To this end, the purpose of our study was to determine the impact of CHO ingestion from a semisolid source (GEL) on measures of performance and gastrointestinal (GI) comfort compared with CHO ingestion from a liquid source (LIQ). Nine well-trained triathletes participated in this randomized crossover study. Each participant completed a 60-min swim, 180-min bike exercise, and a 60-min all-out run in a laboratory environment under 2 conditions, once while receiving 67.2 ± 7.2 g · h–1 (M ± SD) of CHO from GEL and once while receiving 67.8 ± 4.2 g · h–1 of CHO from LIQ. The amount of fluid provided was matched among conditions. Respiratory exchange ratio (RER), blood glucose, and lactate as well as GI discomfort were assessed at regular intervals during the experiment. The distance covered during the final all-out run was not significantly different among participants ingesting GEL (11.81 ± 1.38 km) and LIQ (11.91 ± 1.53 km; p = .89). RER, blood glucose, and lactate did not differ significantly at any time during the experiment. Seven participants reported GI discomfort with GEL, and no athlete reported GI discomfort with LIQ (p = .016). This study suggests that administration of GEL does not alter long-distance triathlon performance when compared with LIQ, but GEL seems to be associated with reduced GI tolerance. Athletes should consider this a potential disadvantage of GEL administration during long-distance triathlon

    Gigantism in unique biogenic magnetite at the Paleocene-Eocene Thermal Maximum

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    We report the discovery of exceptionally large biogenic magnetite crystals in clay-rich sediments spanning the Paleocene-Eocene Thermal Maximum (PETM) in a borehole at Ancora, New Jersey. Aside from previously-described abundant bacterial magnetofossils, electron microscopy reveals novel spearhead-like and spindle-like magnetite up to 4 μm long and hexaoctahedral prisms up to 1.4 μm long. Similar to magnetite produced by magnetotactic bacteria, these single-crystal particles exhibit chemical composition, lattice perfection, and oxygen isotopes consistent with an aquatic origin. Electron holography indicates single-domain magnetization despite their large crystal size. We suggest that the development of a thick suboxic zone with high iron bioavailability – a product of dramatic changes in weathering and sedimentation patterns driven by severe global warming – drove diversification of magnetite-forming organisms, likely including eukaryotes

    Sun stanshe

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    Розглянута структура фотоелектричної станції середньої потужності з можливістю передачі енергії в промислову мережу. Запропоновані рішення для спрощення схемотехніки перетворювальної частини сонячної станції, спрямовані на зниження її собівартості. Проведено експериментальні дослідження особливостей функціонування сонячної станції. Розглянуто можливі аварійні режими роботи сонячної станції та надано рекомендації щодо їх усунення. Проведено аналіз експериментальних досліджень і на їх основі запропоновано шляхи підвищення ККД станції.The structure of a small-scale photovoltaic station, which can be used on single structures, is considered. At the same time, it is desirable to have a backup the battery on accumulators for reliable power supply and to be connected to the industrial network. Thus, the structure of the photovoltaic station, which has the ability to accumulate energy in the battery on accumulators and transfer the remnants to the industrial network, using it as a reservoir of infinite capacity, is proposed. The influence on the production of electricity from the photovoltaic station is shown due to the unevenness of the illumination of the surface of the solar panels

    Komplexchemie perhalogenierter Cyclopentadiene und Alkine

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    (1,2,3,4,5)Pentachlorferrocen reagiert mit Butyllithium und anschließend mit MeSSMe zu [C5Cl4(SMe)]FeCP (Cp = η5-C5H5) (1). Durch Wiederholung dieser Prozedur lassen sich [C5Cl3(SMe)2]FeCp (2) und [C5Cl2(SMe)3]FeCp (3) erhalten. Eine Kristallstrukturanalyse von 2 zeigt eine 1,3-Anordnung der beiden SMe-Gruppen. Eine Anzahl unsymmetrischer Cymantrenbis- und tristhioether (4–6) wurde auf ähnliche Weise aus [C5Cl4(SR)]Mn(CO)3 bzw. [C5Cl3(SR)2]Mn(CO)3 (R = Me, Ph) dargestellt. Auch Cymantrenyl-Selenoether [C5Cl5−n(SeR)n]Mn(CO)3 (7–10) (R = Me, n = 1, 2, 3; R = Ph, n = 2) konnten erhalten werden
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