227 research outputs found

    Iron deficiency induces changes in riboflavin secretion and the mitochondrial electron transport chain in hairy roots of Hyoscyamus albus.

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    Hyoscyamus albus hairy roots secrete riboflavin under Fe-deficient conditions. To determine whether this secretion was linked to an enhancement of respiration, both riboflavin secretion and the reduction of 2,3,5-triphenyltetrazolium chloride (TTC), as a measure of respiration activity, were determined in hairy roots cultured under Fe-deficient and Fe-replete conditions, with or without aeration. Appreciable TTC-reducing activity was detected at the root tips, at the bases of lateral roots and in internal tissues, notably the vascular system. TTC-reducing activity increased under Fe deficiency and this increase occurred in concert with riboflavin secretion and was more apparent under aeration. Riboflavin secretion was not apparent under Fe-replete conditions. In order to examine which elements of the mitochondrial electron transport chain might be involved, the effects of the respiratory inhibitors, barbiturate, dicoumarol, malonic acid, antimycin, KCN and salicylhydroxamic acid (SHAM) were investigated. Under Fe-deficient conditions, malonic acid affected neither root growth, TTC-reducing activity nor riboflavin secretion, whereas barbiturate and SHAM inhibited only root growth and TTC-reducing activity, respectively, and the other compounds variously inhibited growth and TTC-reducing activity. Riboflavin secretion was decreased, in concert with TTC-reducing activity, by dicoumarol, antimycin and KCN, but not by SHAM. In Fe-replete roots, all inhibitors which reduced riboflavin secretion in Fe-deficient roots showed somewhat different effects: notably, antimycin and KCN did not significantly inhibit TTC-reducing activity and the inhibition by dicoumarol was much weaker in Fe-replete roots. Combined treatment with KCN and SHAM also revealed that Fe-deficient and Fe-replete roots reduced TTC in different ways. A decrease in the Fe content of mitochondria in Fe-deficient roots was confirmed. Overall, the results suggest that, under conditions of Fe deficiency in H. albus hairy roots, the alternative NAD(P)H dehydrogenases, complex III and complex IV, but not the alternative oxidase, are actively involved both in respiration and in riboflavin secretion

    Selective activation of STAT5 unveils its role in stem cell self-renewal in normal and leukemic hematopoiesis

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    Although the concept of a leukemic stem cell system has recently been well accepted, its nature and the underlying molecular mechanisms remain obscure. Constitutive activation of signal transducers and activators of transcription 3 (STAT3) and STAT5 is frequently detected in various hematopoietic tumors. To evaluate their role in normal and leukemic stem cells, we took advantage of constitutively active STAT mutants to activate STAT signaling selectively in hematopoietic stem cells (HSCs). Activation of STAT5 in CD34–c-Kit+Sca-1+ lineage marker– (CD34–KSL) HSCs led to a drastic expansion of multipotential progenitors and promoted HSC self-renewal ex vivo. In sharp contrast, STAT3 was demonstrated to be dispensable for the HSC maintenance in vivo, and its activation facilitated lineage commitment of HSCs in vitro. In a mouse model of myeloproliferative disease (MPD), sustained STAT5 activation in CD34–KSL HSCs but not in CD34+KSL multipotential progenitors induced fatal MPD, indicating that the capacity of STAT5 to promote self-renewal of hematopoietic stem cells is crucial to MPD development. Our findings collectively establish a specific role for STAT5 in self-renewal of normal as well as leukemic stem cells

    Increased de novo riboflavin synthesis and hydrolysis of FMN are involved in riboflavin secretion from Hyoscyamus albus hairy roots under iron deficiency

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    Riboflavin secretion by Hyoscyamus albus hairy roots under Fe deficiency was examined to determine where riboflavin is produced and whether production occurs via an enhancement of riboflavin biosynthesis or a stimulation of flavin mononucleotide (FMN) hydrolysis. Confocal fluorescent microscopy showed that riboflavin was mainly localized in the epidermis and cortex of the root tip and, at the cellular level, in the apoplast. The expressions of three genes involved in the de novo biosynthesis of riboflavin (GTP cyclohydrolase II/3,4-dihydroxy-2-butanone 4-phosphate synthase; 6,7-dimethyl-8-ribityllumazine synthase; riboflavin synthase) were compared between Fe-starved and Fe-replete roots over a time-course of 7 days, using RT-PCR. All three genes were found to be highly expressed over the period 1–7 days in the roots cultured under Fe deficiency. Since riboflavin secretion began to be detected only from 3 days, there was a lag phase observed between the increased transcript accumulations and riboflavin secretion. To determine whether FMN hydrolysis might contribute to the riboflavin secretion in Fe-deficient root cultures, FMN hydrolase activity was determined and was found to be substantially increased after 3 days, when riboflavin secretion became detectable. These results suggested that not only de novo riboflavin synthesis but also the hydrolysis of FMN contributes to riboflavin secretion under conditions of Fe deficiency. Respiration activity was assayed during the time-course, and was also found to be enhanced after 3 days under Fe deficiency, suggesting a possible link with riboflavin secretion. On the other hand, several respiratory inhibitors were found not to affect riboflavin synthase transcript accumulation

    Effects of Assisted Reproduction Technology on Placental Imprinted Gene Expression

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    We used placental tissue to compare the imprinted gene expression of IGF2, H19, KCNQ1OT1, and CDKN1C of singletons conceived via assisted reproduction technology (ART) with that of spontaneously conceived (SC) singletons. Of 989 singletons examined (ART n = 65; SC n = 924), neonatal weight was significantly lower (P < .001) in the ART group than in the SC group, but placental weight showed no significant difference. Gene expression analyzed by real-time PCR was similar for both groups with appropriate-for-date (AFD) birth weight. H19 expression was suppressed in fetal growth retardation (FGR) cases in the ART and SC groups compared with AFD cases (P < .02 and P < .05, resp.). In contrast, CDKN1C expression was suppressed in FGR cases in the ART group (P < .01), while KCNQ1OT1 expression was hyperexpressed in FGR cases in the SC group (P < .05). As imprinted gene expression patterns differed between the ART and SC groups, we speculate that ART modifies epigenetic status even though the possibilities always exist

    Anti-stress effects of the hydroalcoholic extract of Rosa gallica officinalis in mice

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    Rosa gallica, a plant of the Rosa genus, has been used widely since the 13th century and is cultivated in many areas as a medicinal plant for the preparation of herbal medicines. However, details of the neuropsychological effects of R. gallica remain unclear; therefore we aimed to investigate the neuropsychological effects of a water-soluble extract of R. gallica in male C57BL/6N mice under normal conditions and under chronic stress. We administered a water-soluble extract of R. gallica to mice and performed a series of behavioral experiments to compare the treated animals with the untreated controls. No significant differences in activity level, anxiety-like behavior, depression-like behavior, body weight, and body temperature were observed between R. gallica-treated mice and control mice. However, in mice subjected to chronic stress, the observed decrease in activity was smaller in the R. gallica-treated mice than in the control mice. The oral administration of R. gallica did not affect the normal behavior of mice. However, when the mice were subjected to stress, R. gallica exerted an anti-stress effect. Therefore, R. gallica has potential as a medicinal plant for the purpose of stress prevention

    Comprehensive behavioral study of the effects of vanillin inhalation in mice

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    Vanillin is widely used in food and cosmetics, among other substances, for its sweet smell. However, the neuropsychological effects of vanillin inhalation have not been elucidated. In this study, we investigated the effect of vanillin inhalation on mouse behavior. First, we investigated whether the aroma of vanillin was attractive or repulsive for mice. Thereafter, the mice inhaled vanillin for 20 min before each test in a series of behavioral tests (elevated plus maze, open field, Y-maze, tail suspension, cotton bud biting, and Porsolt forced swim tests). In these tests, the mice showed a neutral response to vanillin. Mice that inhaled vanillin had a suppressed pain response in the hot plate test. In addition, the grip strength of the forelimbs of mice that inhaled vanillin was decreased. No significant differences were found between the mice inhaling vanillin and control mice in the open field, Y-maze, tail suspension, forced swimming, and aggression tests. These results show that vanillin inhalation has anti-nociceptive effects, similar to other routes of administration. The results also show that vanillin inhalation does not cause significant behavioral effects

    Delay of computed tomography is associated with poor outcome in patients with blunt traumatic aortic injury a nationwide observational study in Japan

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    Katayama, Yusuke MD, PhD; Kitamura, Tetsuhisa MD, DrPHb; Hirose, Tomoya MD, PhDa,c; Kiguchi, Takeyuki MD, PhD; Matsuyama, Tasuku MD, PhDe; Sado, Junya PhDb; Kiyohara, Kosuke DrPH; Izawa, Junichi MD, DrPH; Tachino, Jotaro MD; Ebihara, Takeshi MD; Yoshiya, Kazuhisa MD, PhD; Nakagawa, Yuko MD, PhD; Shimazu, Takeshi MD, PhDa Delay of computed tomography is associated with poor outcome in patients with blunt traumatic aortic injury, Medicine: August 2018 - Volume 97 - Issue 35 - p e12112 doi: 10.1097/MD.000000000001211

    Improvement of acquisition and analysis methods in multi-electrode array experiments with iPS cell-derived cardiomyocytes

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    AbstractIntroductionMulti-electrode array (MEA) systems and human induced pluripotent stem (iPS) cell-derived cardiomyocytes are frequently used to characterize the electrophysiological effects of drug candidates for the prediction of QT prolongation and proarrhythmic potential. However, the optimal experimental conditions for obtaining reliable experimental data, such as high-pass filter (HPF) frequency and cell plating density, remain to be determined.MethodsExtracellular field potentials (FPs) were recorded from iPS cell-derived cardiomyocyte sheets by using the MED64 and MEA2100 multi-electrode array systems. Effects of HPF frequency (0.1 or 1Hz) on FP duration (FPD) were assessed in the presence and absence of moxifloxacin, terfenadine, and aspirin. The influence of cell density on FP characteristics recorded through a 0.1-Hz HPF was examined. The relationship between FP and action potential (AP) was elucidated by simultaneous recording of FP and AP using a membrane potential dye.ResultsMany of the FP waveforms recorded through a 1-Hz HPF were markedly deformed and appeared differentiated compared with those recorded through a 0.1-Hz HPF. The concentration–response curves for FPD in the presence of terfenadine reached a steady state at concentrations of 0.1 and 0.3μM when a 0.1-Hz HPF was used. In contrast, FPD decreased at a concentration of 0.3μM with a characteristic bell-shaped concentration–response curve when a 1-Hz HPF was used. The amplitude of the first and second peaks in the FP waveform increased with increasing cell plating density. The second peak of the FP waveform roughly coincided with AP signal at 50% repolarization, and the negative deflection at the second peak of the FP waveform in the presence of E-4031 corresponded to early afterdepolarization and triggered activity.DiscussionFP can be used to assess the QT prolongation and proarrhythmic potential of drug candidates; however, experimental conditions such as HPF frequency are important for obtaining reliable data

    Telephone triage service use is associated with better outcomes among patients with cerebrovascular diseases: a propensity score analysis using population-based data

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    IntroductionThe telephone triage service is an emergency medical system through which citizens consult telephone triage nurses regarding illness, and the nurses determine the urgency and need for an ambulance. Despite being introduced in several countries, its impact on emergency patients has not been reported. We aimed to determine the effect of the telephone triage service on the outcomes of hospitalized patients diagnosed with cerebrovascular disease upon arrival after being transported by an ambulance.MethodsThis retrospective study included patients with cerebrovascular disease who were transported by ambulance between January 2016 and December 2019. The primary outcome was discharge to home by day 21 of hospitalization. A total of 344 patients who used the telephone triage service were propensity score-matched to 344 patients who directly called for an ambulance.ResultsTelephone triage service use was associated with discharge to home by hospital day 21 (crude odd ratio: 1.8; 95% confidence interval: 1.3–2.4) and was not significantly associated with survival on hospital day 21 in multivariate regression analysis.ConclusionThe prognoses of cerebral infarction, intracerebral hemorrhage, and subarachnoid hemorrhage depend on the time from symptom onset to treatment. Telephone triage services may allow patients to receive treatment more rapidly than traditional ambulance requests, resulting in improved patient outcomes. The findings of this study suggest that the use of telephone triage services is associated with improved outcomes in patients with cerebrovascular disease and indicate that the costs for medical expenses and disability may be greatly reduced in an aging society
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