Aging in vitro and D-glucose uptake kinetics of diploid human fibroblasts

By use of a rapid technique, initial rates of D-glucose transport were obtained during the lifespan in vitro of a commercially available strain of human embryo lung fibroblasts (Flow 2000). The apparent Km of the D-glucose carrier did not change during senescence in vitro: = 1.8 mM (range 1.3-2.3) in phase II, = 1.8 mM (range 1.5-2.2) in phase III. Transport rates remained constant in stationary phase II cultures, which had completed between 30% and 80% of their replicative lifespan. A wide variation, however, was observed in terminally differentiated cells (phase III), which showed a two- to threefold increase in average cell size and protein content. In some senescent cultures, glucose transport calculated on a per cell basis was also two-to threefold increased, while it was strongly decreased (-75%) in others. When calculated per unit of cell water, protein, and surface area, respectively, transport rates in phase III cultures ranged from values established for stationary phase II cultures down to very low values. Detaching cells flushed off from senescent cultures did not show measurable rates of glucose transport into the inulin impermeable cell space. Present evidence argues against the idea that an impairment of D-glucose transport might precede loss of replicative potential in aging human fibroblasts. Instead our data indicate that the transport capacity of cell membrane finally decreases during postreplicative senescence in terminally differentiated cells

Altered expression of transforming growth factor-βs in chronic renal rejection

Altered expression of transforming growth factor-βs in chronic renal rejection. We examined the altered expression of transforming growth factor-βs in chronic renal rejection in humans, including transforming growth factor beta-1 (TGF-β1), TGF-β2, TGF-β3 and their receptors, transforming growth factor beta receptor type I (TβR-I) and TβR-II. Using Northern blot analysis and immunohistochemistry, 10 specimens of chronically rejected and 8 normal kidney samples were analyzed. By Northern blot analysis the expression of mRNA encoding TGF-β1, TGF-β2, TGF-β3 (P < 0.02), TβR-I and TβR-II (P < 0.02) was decreased in chronically rejected renal cortex samples, compared to normal controls. Immunohistochemical analysis of the normal renal cortex showed strong immunostaining for TGF-β1 and TGF-β3, and mild immunostaining for TGF-β2 in the proximal and distal tubulointerstitium, but no signal for any of the TGF-β isoforms in the glomeruli or in the cortical vessels. In sharp contrast, the glomeruli and the cortical vessels of the rejected kidney specimens exhibited strong immunostaining for TGF-β1 and TGF-β3, whereas the tubules revealed a decrease in immunoreactivity. TβRI and TβRII immunostaining showed similar changes as observed with TGF-β1 and TGF-β3 antibodies. There was a concomitant increase in B-cell accumulation in the glomeruli, while T-cells and macrophages were diffusely abundant in the rejected samples. Since TGF-βs are potent inducers of extracellular matrix proteins and have been shown to be involved in fibrotic disease, the increase in TGF-β1 and TGF-β3 immunoreactivity in the glomeruli suggests that there is a redistribution in TGF-β expression in chronic renal allograft rejection. Together with changes affected by B-cell mediated immunity, the above alterations might contribute to the histopathological changes that occur in this disorder, such as intimal fibrosis, arteriosclerosis and glomerular and tubular sclerosis

Near-infrared spectroscopy of EX Lupi in outburst

EX Lup is the prototype of the EXor class of young eruptive stars: objects showing repetitive brightenings due to increased accretion from the circumstellar disk to the star. In this paper, we report on medium-resolution near-infrared spectroscopy of EX\,Lup taken during its extreme outburst in 2008, as well as numerical modeling with the aim of determining the physical conditions around the star. We detect emission lines from atomic hydrogen, helium, and metals, as well as first overtone bandhead emission from carbon monoxide. Our results indicate that the emission lines are originating from gas located in a dust-free region within ~ 0.2 AU of the star. The profile of the CO bandhead indicates that the CO gas has a temperature of 2500 K, and is located in the inner edge of the disk or in the outer parts of funnel flows. The atomic metals are probably co-located with the CO. Some metallic lines are fluorescently excited, suggesting direct exposure to ultraviolet photons. The Brackett series indicates emission from hot (10000 K) and optically thin gas. The hydrogen lines display a strong spectro-astrometric signal, suggesting that the hydrogen emission is probably not coming from an equatorial boundary layer; a funnel flow or disk wind origin is more likely. This picture is broadly consistent with the standard magnetospheric accretion model usually assumed for normally accreting T Tauri stars. Our results also set constraints on the eruption mechanism, supporting a model where material piles up around the corotation radius and episodically falls onto the star.Comment: 12 pages, 8 figures, 1 table, accepted for publication in Ap

Effects of a single aerobic exercise session on body image

Background and Objectives Most research on the effects of exercise on body image has concentrated on the benefits of regular exercise. However, some research has indicated that exercise has an immediate impact on body image. The aims of this study were to investigate the immediate effects of aerobic exercise in a fitness class and the at-home environment on body image, and to examine the impact of nutritional status (i.e., normal weight vs. overweight/obesity) and exercise addiction on these changes. Method 322 Hungarian women participated in the study with two different environmental conditions, fitness class condition (N = 155) and at-home video condition (N = 167). They completed the Body Appreciation Scale and Exercise Addiction Inventory before and after a one-hour aerobic exercise session. Self-report data on weight, height and exercise frequency were also collected. Results There were no significant differences between the fitness class and video groups in terms of age, educational level, BMI, body appreciation, exercise frequency and exercise addiction. We found that 7.5% (N = 24) of the participants were at risk for exercise addiction. Aerobic exercise had a significant positive effect on body appreciation (t(321) = 7.564, p < .001) independently from environment and nutritional status. Exercise addiction moderated the relationship between exercise and body image, the at risk for exercise addiction group showed the greatest improvement (F(1) = 3.252, p = .040). Conclusion The results indicate that even a one-hour aerobic exercise session has a positive effect on body image; this has important practical implications for intervention strategies and weight-loss treatments. | Elméleti háttér és célkitűzés Bár a legtöbb kutatás a rendszeres testedzés testképre gyakorolt pozitív hatására fókuszál, néhány vizsgálat eredménye a testedzés testképre tett azonnali hatására hívja fel a figyelmet. Jelen tanulmány célja az aerobik edzés testképre gyakorolt azonnali hatásának vizsgálata fitnesztermi és otthoni edzési körülmények között, továbbá a tápláltsági állapot (normális testsúly vs. túlsúly/elhízás) és a testedzésfüggőség potenciális moderátor szerepének vizsgálata az edzés és a testkép alakulása közötti kapcsolatban. Módszer A vizsgálatba aerobikedzést folytató nőket vontunk be (n = 322). A résztvevők egyik része edzőteremben folytatta a testgyakorlást (n = 155), másik része otthon végzett aerobik testedzést, video vagy DVD segítségével (n = 167). Mérőeszközök önbeszámolóval nyert testtömeg és testmagasság, a testedzés gyakoriságára vonatkozó kérdés, Testértékelési Skála, Testedzés Addikció Kérdőív. Az adatfelvétel az egyórás testgyakorlást megelőzően és azt követően történt. Eredmények Nem találtunk szignifikáns különbséget az edzőteremben és az otthonukban aerobik edzést folytató nők között az életkor, az iskolai végzettség, a BMI, a testértékelés, a testedzés gyakorisága és a testedzésfüggőség tekintetében. A válaszadók 7,5%-a (n = 24) esetében jelenik meg a testedzésfüggőség kockázata. Az egyórás testedzés szignifikáns, kedvező hatást gyakorolt a testképre (t(321) = 7,564; p < 0,001), amely hatás a testgyakorlás helyszínétől (edzőterem vs. otthon) és a tápláltsági állapottól függetlennek bizonyult. A testedzésfüggőség azonban moderálta a testgyakorlás és a testkép változásának kapcsolatát: a testedzést követően a testedzésfüggőség szempontjából veszélyeztetett csoportban mutatkozott meg a legnagyobb mértékű, pozitív irányú változás a testkép tekintetében (F(1) = 3,252; p = 0,040). Következtetés Eredményeink arra utalnak, hogy akár egy egyórás testgyakorlásnak is pozitív hatása lehet a testképre, amelynek jelentős gyakorlati implikációi vannak a testsúlycsökkentő kezelések szempontjából

Genome wide mapping reveals PDE4B as an IL-2 induced STAT5 target gene in activated human PBMCs and lymphoid cancer cells

IL-2 is the primary growth factor for promoting survival and proliferation of activated T cells that occurs following engagement of the Janus Kinase (JAK)1-3/and Signal Transducer and Activator of Transcription (STAT) 5 signaling pathway. STAT5 has two isoforms: STAT5A and STAT5B ( commonly referred to as STAT5) which, in T cells, play redundant roles transcribing cell cycle and survival genes. As such, inhibition of STAT5 by a variety of mechanisms can rapidly induce apoptosis in certain lymphoid tumor cells, suggesting that it and its target genes represent therapeutic targets to control certain lymphoid diseases. To search for these molecules we aligned IL-2 regulated genes detected by Affymetrix gene expression microarrays with the STAT5 cistrome identified by chip-on-ChIP analysis in an IL-2-dependent human leukemia cell line, Kit225. Select overlapping genes were then validated using qRT(2)PCR medium-throughput arrays in human PHA-activated PBMCs. Of 19 putative genes, one key regulator of T cell receptor signaling, PDE4B, was identified as a novel target, which was readily up-regulated at the protein level (3 h) in IL-2 stimulated, activated human PBMCs. Surprisingly, only purified CD8+ primary T-cells expressed PDE4B, but not CD4+ cells. Moreover, PDE4B was found to be highly expressed in CD4+ lymphoid cancer cells, which suggests that it may represent a physiological role unique to the CD8+ and lymphoid cancer cells and thus might represent a target for pharmaceutical intervention for certain lymphoid diseases

Geometric phase outside a Schwarzschild black hole and the Hawking effect

We study the Hawking effect in terms of the geometric phase acquired by a two-level atom as a result of coupling to vacuum fluctuations outside a Schwarzschild black hole in a gedanken experiment. We treat the atom in interaction with a bath of fluctuating quantized massless scalar fields as an open quantum system, whose dynamics is governed by a master equation obtained by tracing over the field degrees of freedom. The nonunitary effects of this system are examined by analyzing the geometric phase for the Boulware, Unruh and Hartle-Hawking vacua respectively. We find, for all the three cases, that the geometric phase of the atom turns out to be affected by the space-time curvature which backscatters the vacuum field modes. In both the Unruh and Hartle-Hawking vacua, the geometric phase exhibits similar behaviors as if there were thermal radiation at the Hawking temperature from the black hole. So, a measurement of the change of the geometric phase as opposed to that in a flat space-time can in principle reveal the existence of the Hawking radiation.Comment: 14 pages, no figures, a typo in the References corrected, version to appear in JHEP. arXiv admin note: text overlap with arXiv:1109.033

Cytogerontology since 1881: A reappraisal of August Weismann and a review of modern progress

Cytogerontology, the science of cellular ageing, originated in 1881 with the prediction by August Weismann that the somatic cells of higher animals have limited division potential. Weismann's prediction was derived by considering the role of natural selection in regulating the duration of an organism's life. For various reasons, Weismann's ideas on ageing fell into neglect following his death in 1914, and cytogerontology has only reappeared as a major research area following the demonstration by Hayflick and Moorhead in the early 1960s that diploid human fibroblasts are restricted to a finite number of divisions in vitro. In this review we give a detailed account of Weismann's theory, and we reveal that his ideas were both more extensive in their scope and more pertinent to current research than is generally recognised. We also appraise the progress which has been made over the past hundred years in investigating the causes of ageing, with particular emphasis being given to (i) the evolution of ageing, and (ii) ageing at the cellular level. We critically assess the current state of knowledge in these areas and recommend a series of points as primary targets for future research

Gate-tunable black phosphorus spin valve with nanosecond spin lifetimes

Two-dimensional materials offer new opportunities for both fundamental science and technological applications, by exploiting the electron spin. While graphene is very promising for spin communication due to its extraordinary electron mobility, the lack of a band gap restricts its prospects for semiconducting spin devices such as spin diodes and bipolar spin transistors. The recent emergence of 2D semiconductors could help overcome this basic challenge. In this letter we report the first important step towards making 2D semiconductor spin devices. We have fabricated a spin valve based on ultra-thin (5 nm) semiconducting black phosphorus (bP), and established fundamental spin properties of this spin channel material which supports all electrical spin injection, transport, precession and detection up to room temperature (RT). Inserting a few layers of boron nitride between the ferromagnetic electrodes and bP alleviates the notorious conductivity mismatch problem and allows efficient electrical spin injection into an n-type bP. In the non-local spin valve geometry we measure Hanle spin precession and observe spin relaxation times as high as 4 ns, with spin relaxation lengths exceeding 6 um. Our experimental results are in a very good agreement with first-principles calculations and demonstrate that Elliott-Yafet spin relaxation mechanism is dominant. We also demonstrate that spin transport in ultra-thin bP depends strongly on the charge carrier concentration, and can be manipulated by the electric field effect

Total and Methyl Mercury Contents and Distribution Characteristics in Cicada, Cryptotympana atrata (Fabricius)

Total and methyl mercury concentrations of cicada bodies, wings, and exuviae were investigated to study the mercury distribution characteristics. Results indicated that total and methyl mercury concentrations of cicada bodies were 2.64 mg/kg and 123.93 ng/g on average, respectively. In cicada tissues, total mercury concentrations were found to increase in the order of exuviae (0.50 mg/kg on average) < wings (0.98 mg/kg on average) < cicada bodies (2.64 mg/kg on average) and methyl mercury concentrations of cicada bodies were 123.93 ng/g on average and were the highest. Methyl mercury concentrations accounted for about 4.69% of total mercury in cicada bodies and most mercury was in inorganic forms in cicada. Sex differences of total mercury concentrations were significantly great (F = 8.433, p < 0.01) and total mercury concentrations of the males, which were 3.38 mg/kg on average, were much higher. Correlation analysis showed that neither total nor methyl mercury concentrations of cicada bodies was significantly related to the corresponding contents of soil (r = 0.0598, p > 0.05)