491 research outputs found

    Changes in the cell shape and actin organization accompanying primary ciliogenesis in Xenopus epithelial cells

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    Xenopus epithelial A6 cells produce primary cilia most readily when the confluent culture is serumdeprived, in contrast with various mammalian epithelial cells, which usually produce cilia in confluent cultures without serum starvation. Here, we observed A6 cells under the conditions that promote ciliogenesis, and found a few unusual features accompanying ciliogenesis including changes in cell shape and actin re-organization. Upon serum starvation, cells tended to reduce the area of attachment to the substratum and increase the height before ciliogenesis. Cells in highly ciliated areas formed thick actin bundles in their periphery. In addition, cells transiently formed a unique cone-shaped assembly of stress fibers, specifically in the basal region in the early phase of ciliogenesis. Although involvement of actin filaments in ciliogenesis has been widely recognized in recent studies, these actin structures have not been reported. Thus, ciliogenesis in A6 cells appears to reveal novel ciliogenesis-accompanying cellular changes that have been overlooked in studies using other cell lines

    Ectopic Expression of Human Herpesvirus 1 Thymidine Kinase Induces Male Infertility

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    The herpesvirus family comprises several widespread infectious pathogens. They infect a variety of animal hosts, including humans and cause complex clinical outcomes. Recently, the possible correlation between genital infection by human herpesviruses (HHVs) and male infertility has attracted considerable attention. In this chaper, we investigated the mechanism of HHV‐1‐induced infertility in transgenic (Tg) rats and its possible correlation with infertility in human males. Ectopic expression of HHV‐1 thymidine kinase (TK) in the testis of Tg rats increased male infertility. In addition, truncated TK proteins were found in postmeiotic spermatids of Tg rat testis, leading to progressive degeneration of germ cells and vacuolization of the seminiferous epithelium. These findings suggest the possibility that a similar process occurs within HHV‐infected human germ cells

    X-ray spectral diagnostics for satellite lines of H-like Mg ions measured by a high resolution spectrometer

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    X-ray spectra of H-like Mg ions produced in a laser plasma have been measured by space-resolved high-resolution spectroscopy. We identified satellite lines near Ly[alpha] lines, 2lnl′ ? 1snl′ + h[nu] for n = 2, 3, and 4. We construct a collisional radiative model including the doubly excited states for the intensity ratios of satellite lines. We use atomic data calculated by different methods for satellite lines and compare the results. We derive the electron temperature and density of the laser-produced plasma by a new technique using intensity ratios of only satellite lines. This technique is useful because the Ly[alpha] lines are often affected by opacity

    Properties of OV Spectral Lines in Ionizing and Recombining Plasmas

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    A collisional-radiative model for Be-like oxygen ions has been constructed for OV plasmaspectroscopy. The model takes into account recombination processes as well as collisional ionization, radiative transitions, and collisional excitation/deexcitation. Two sets of atomic data are used for comparison. We obtain OV line intensities as functions of electron temperature and density. The line intensity ratios of 2s3s 35 - 2s3p \u27Pr=o.r., are measured in LHD plasmas and are consistent with our models. The line intensity ratio of 2s2p 3P - 2p"P and 2s2 tS - 2s2p rP in recombining plasma is an increasing function of temperature and one measured in the LHD plasma indicates electron temperature less than 7eV. The ratios measured in steady-state phase are larger than I and difficult to explain with the current model

    Impact of carotid atherosclerosis on long-term mortality in chronic hemodialysis patients

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    Impact of carotid atherosclerosis on long-term mortality in chronic hemodialysis patients.BackgroundCardiovascular event is the major cause of mortality in patients on maintenance hemodialysis. We prospectively tested the predictive values of atherosclerotic parameters for all-cause and cardiovascular outcomes in 219 hemodialysis patients (age, 58 ± 13 years; time on hemodialysis, 13 ± 7 years; male/female, 144/75).MethodsWe measured blood homocysteine (Hcy), ultrasound carotid artery intima media thickness (IMT) and % aortic wall calcification at L2/3 region [% of calcification index in the abdominal aortic wall (%ACI)] by computed tomography (CT) scan, and followed all patients for 5 years.ResultsDuring the follow-up periods, 54 patients (25%) died, 40 (74%) of them of cardiovascular causes. IMT was significantly higher in patients who expired (0.75 ± 0.02mm) than in those who survived (0.62 ± 0.01mm). IMT was significantly correlated with age (r = 0.47, P < 0.01) and %ACI (r = 0.27, P < 0.01). The survival rate during the observation was significantly lower in the final IMT third (58%) than in the first (90%) and the middle IMT third (80%) (P < 0.01). Multivariate Cox proportional hazards analysis revealed that diabetes and IMT became independent determinants of all-cause and cardiovascular death. Adjusted hazards ratios of all-cause and cardiovascular mortality for an increase of 0.1mm in IMT were 1.31 (95% CI, 1.07 to 1.59) and 1.41 (95% CI, 1.12 to 1.76). In contrast, %ACI at abdominal aorta and blood Hcy did not affect their 5-year mortality.ConclusionThese findings suggested that measurement of carotid artery IMT is useful for predicting long-term mortality in patients receiving maintenance hemodialysis

    ラット大脳皮質における電位オシレーターを駆動するための状況に応じた戦略

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    Information integration in the brain requires functional connectivity between local neural networks. Here, we investigated the interregional coupling mechanism from the viewpoint of oscillations using optical recording methods. Low-frequency electrical stimulation of rat neocortical slices in a caffeine-containing medium induced oscillatory activity between the primary visual cortex (Oc1) and medial secondary visual cortex (Oc2M), in which the oscillation generator was located in the Oc2M and was triggered by a feedforward signal. During to-and-fro oscillatory activity, neural excitation was marked in layer II/III. When the upper layer was disrupted between Oc1 and Oc2M, feedforward signals could propagate through the deep layer and switch on the oscillator in the Oc2M. When the lower layer was disrupted between Oc1 and Oc2M, feedforward signals could propagate through the upper layer and switch on the oscillator in the Oc2M. In the backward direction, neither the upper layer cut nor the lower layer cut disrupted the propagation of the oscillations. In all cases, the horizontal and vertical pathways were used as needed. Fluctuations in the oscillatory waveforms of the local field potential at the upper and lower layers in the Oc2M were reversed, suggesting that the oscillation originated between the two layers. Thus, the neocortex may work as a safety device for interregional communications in an alternative way to drive voltage oscillators in the neocortex

    雌ラットにおいて生殖腺の状態とエストロゲン環境が視床下部オキシトシン遺伝子発現および血清オキシトシンレベルに及ぼす影響

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    Oxytocin (OT) and its receptor (OTR) play various roles in the central and peripheral regulation of appetite and body weight. Previously, we have shown that the administration of OT markedly decreased appetite and body weight gain in ovariectomized (OVX) obese rats. In addition, recent studies have shown that the endogenous OT system is also affected by endogenous or exogenous estrogen. In this study, we showed that ovariectomy decreased rats' hypothalamic OT/OTR mRNA and serum OT levels, but did not affect their visceral fat OTR mRNA levels. The chronic administration of estradiol (E2) abrogated these ovariectomy-induced changes; i.e., it increased the rats' hypothalamic OT/OTR mRNA and serum OT levels, and may be associated with reductions in food intake and body weight gain. In addition, acute E2 administration increased the rats' hypothalamic OTR mRNA and serum OT levels, but did not affect their hypothalamic OT mRNA levels. Taken together, these results suggest that endogenous OT and/or OTR expression might be positively regulated by E2 and that the suppressive effects of E2 on appetite and body weight gain might be mediated, at least in part, by the OT system. Thus, we consider that OT might be a target hormone to pursue subsequent interventions of menopause for menopause-induced metabolic disorders
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