1,127 research outputs found

    Low estrogen levels and obesity are associated with shorter telomere lengths in pre-and postmenopausal women

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    The aim of this study was to determine whether there is an association between leukocyte telomere length (LTL), and estrogen level, oxidative stress, cardiovascular disease (CVD) risk factors, and cardiorespiratory fitness (CRF) in pre-and postmenopausal obese women. Fifty-four obese women (premenopausal, n= 25; postmenopausal, n= 29) were selected to participate in this study. The outcome measurements in the pre-and postmenopausal groups were compared using independent t-tests and Pearson correlation analysis. The estrogen level (P< 0.001), LTL (P< 0.05), high-density lipoprotein level (P< 0.05), and CRF (P< 0.001) were higher in premenopausal women than in postmenopausal women. The body fat percentage (P< 0.05) and triglyceride concentration (P< 0.05) were lower in premenopausal women than in postmenopausal women. There were no significant associations between LTL, CVD risk, CRF, and oxidative stress and antioxidant enzyme activity in premenopausal women. The body mass index (BMI) and body fat percentage in postmenopausal women were negatively associated with LTL (P< 0.05). When all women were considered (i.e., both pre-and postmenopause), the BMI, percentage of fat, and waist circumference had a negative association with LTL (P < 0.05), and estrogen levels were positively associated with LTL (P< 0.05). Decreased estrogen levels after menopause, a pivotal factor in the biology of aging, and obesity were more associated with shorter telomere lengths in pre-and postmenopausal women than aerobic capacity and other CVD risk factors

    Potential redox-sensitive Akt activation by dopamine activates Bad and promotes cell death in melanocytes

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    Dopamine (DA) is a well known oxidative neurotoxin. In addition, Akt has been reported to deliver a survival signal that inhibits apoptosis. However, it has also been reported that chronic Akt activation leads to apoptosis in response to oxidative stress. The objective of the present study was to investigate the possible role of the Akt pathway in vitiligo and its possible relationship with DA-induced cell death using Mel-Ab cells. Cultured Mel-Ab cells were treated with DA with and without N-Acetyl-L-cysteine (NAC), which is known to have antioxidative properties. Cell viability was then assessed by a crystal violet assay and Annexin staining was performed. The changes in the expression of Akt were analyzed by western blot analysis. The cell viability was reduced by approximately 60% in response to treatment with 500 µM DA, and NAC effectively prevented this cytotoxic effect. Likewise, treatment with DA produced numerous Annexin positive cells, while treatment with NAC prevented this apoptotic cell death. Akt was slowly phosphorylated after treatment with DA, while NAC clearly inhibited the DA-induced Akt activation. Western blot analysis also showed that treatment with DA induced the activation of Bad. Finally, LY294002 exerted a protective effect against DA-induced apoptotic cell death. DA may induce redox-sensitive Akt activation and increase the level of Bad, which can promote cell death by heterodimerization with survival proteins. Moreover, NAC effectively protects against DA-induced melanocyte death via inhibition of DA-induced Akt activation

    Meteorin regulates mesendoderm development by enhancing nodal expression

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    During gastrulation, distinct lineage specification into three germ layers, the mesoderm, endoderm and ectoderm, occurs through an elaborate harmony between signaling molecules along the embryonic proximo-distal and anterior-posterior axes, and Nodal signaling plays a key role in the early embryonic development governing embryonic axis formation, mesoderm and endoderm specification, and left-right asymmetry determination. However, the mechanism by which Nodal expression is regulated is largely unknown. Here, we show that Meteorin regulates Nodal expression and is required for mesendoderm development. It is highly expressed in the inner cell mass of blastocysts and further in the epiblast and extra-embryonic ectoderm during gastrulation. Genetic ablation of the Meteorin gene resulted in early embryonic lethality, presumably due to impaired lineage allocation and subsequent cell accumulation. Embryoid body culture using Meteorin-null embryonic stem (ES) cells showed reduced Nodal expression and concomitant impairment of mesendoderm specification. Meteorin-null embryos displayed reduced levels of Nodal transcripts before the gastrulation stage, and impaired expression of Goosecoid, a definitive endoderm marker, during gastrulation, while the proximo-distal and anterior-posterior axes and primitive streak formation were preserved. Our results show that Meteorin is a novel regulator of Nodal transcription and is required to maintain sufficient Nodal levels for endoderm formation, thereby providing new insights in the regulation of mesendoderm allocation.open1113sciescopu

    Implicative Int-Soft Filters of R

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    The notion of implicative int-soft filters is introduced, and related properties are investigated. A relation between an int-soft filter and an implicative int-soft filter is discussed, and conditions for an int-soft filter to be an implicative int-soft filter are provided. Characterizations of an implicative int-soft filter are considered, and a new implicative int-soft filter from an old one is displayed. The extension property of an implicative int-soft filter is established

    mtDNAmanager: a Web-based tool for the management and quality analysis of mitochondrial DNA control-region sequences

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    BACKGROUND: For the past few years, scientific controversy has surrounded the large number of errors in forensic and literature mitochondrial DNA (mtDNA) data. However, recent research has shown that using mtDNA phylogeny and referring to known mtDNA haplotypes can be useful for checking the quality of sequence data. RESULTS: We developed a Web-based bioinformatics resource "mtDNAmanager" that offers a convenient interface supporting the management and quality analysis of mtDNA sequence data. The mtDNAmanager performs computations on mtDNA control-region sequences to estimate the most-probable mtDNA haplogroups and retrieves similar sequences from a selected database. By the phased designation of the most-probable haplogroups (both expected and estimated haplogroups), mtDNAmanager enables users to systematically detect errors whilst allowing for confirmation of the presence of clear key diagnostic mutations and accompanying mutations. The query tools of mtDNAmanager also facilitate database screening with two options of "match" and "include the queried nucleotide polymorphism". In addition, mtDNAmanager provides Web interfaces for users to manage and analyse their own data in batch mode. CONCLUSION: The mtDNAmanager will provide systematic routines for mtDNA sequence data management and analysis via easily accessible Web interfaces, and thus should be very useful for population, medical and forensic studies that employ mtDNA analysis. mtDNAmanager can be accessed at http://mtmanager.yonsei.ac.krope

    Angelicae Dahuricae Radix Inhibits Dust Mite Extract-Induced Atopic Dermatitis-Like Skin Lesions in NC/Nga Mice

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    We examined whether Angelicae Dahuricae Radix (AR) suppresses the development of atopic dermatitis (AD)-like skin lesions induced by Dermatophagoides farinae in NC/Nga mice. To investigate the effect of AR, we measured the AD severity score, measured plasma levels of IgE and histamine, and performed histological analysis in NC/Nga mice. We also confirmed the anti-inflammatory effects of AR by measuring TARC/CCL17 production from LPS-treated RAW 264.7 cells and mRNA levels of TARC and MDC/CCL22 in TNF-α/IFN-γ-treated HaCaT cells. 10 mg/day of AR extract was applied for 4 weeks to NC/Nga mice. Both the AR extract and 0.1% tacrolimus suppressed the development of AD-like skin lesions and reduced dermatitis scores of the back and ear skin. AR extracts caused an inhibition of histological changes induced by repeated application of D. farinae and a reduction of IgE and histamine levels in plasma (P < 0.05). Furthermore, NO production in LPS-treated RAW 264.7 cells was diminished in a dose-dependent manner, and hTARC production and TARC and MDC mRNA levels in TNF-α/IFN-γ-treated HaCaT cells were diminished by AR. The inhibitory effect of AR on NO, TARC and MDC production may be associated with the suppression of AD-like skin lesions in D. farinae-induced NC/Nga mice

    Safety Evaluation of Yukmijihwang-tang: Assessment of Acute and Subchronic Toxicity in Rats

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    Yukmijihwang-tang (YMJ; Liu wei di huang tang (China), Rokumigan (Japan)) has been used in the treatment of diseases including renal disorder, cognitive vitality, and diabetes mellitus. However, there is very little information regarding the toxicity of YMJ to give an assurance of safety for clinical treatment. To provide safety information for YMJ, we evaluated its acute and sub-chronic toxicity in rats. The single-dose toxicity of YMJ was examined using Sprague-Dawley rats. Rats were treated with YMJ extract orally at 0, 500, 1000, or 2000 mg/kg body weight. After a single administration, clinical signs were observed every day for two weeks, and body weights were measured five times, including an initial measurement on day 1 (the day of administration). In the sub-chronic oral toxicity study, YMJ was administered to rats at 0, 500, 1000, or 2000 mg/kg/day for 13 weeks. Mortalities, clinical signs, body weight changes, food and water consumption, ophthalmologic findings, urinalysis, hematological and biochemical parameters, gross findings, organ weights, and histological examination were monitored during the study period. We found no mortality and no abnormalities in clinical signs, body weights, and necropsy findings for any of the animals in the acute and sub-chronic studies following oral administration in the rat at up to 2000 mg/kg/day YMJ. YMJ may not have any single-dose toxicity; the LD50 of YMJ was over 2000 mg/kg, and it is safe for rats. The no-observed-adverse-effect-level (NOAEL) was considered to be 2000 mg/kg/day
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