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1
MATKOVSKA, Ivanna. „Zenoviy Flinta’s artistic ceramics of 1960-80s: Stages of development of the author’s creative manner and influence of artist’s painting on his artistic ceramicsand Ukrainization“. Contemporary Art, Nr. 17 (30.11.2021): 69–84. http://dx.doi.org/10.31500/2309-8813.17.2021.248429.
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The works of Zenovia Flint, an outstanding artist, teacher and nonconformist ceramist, who embodied in his ceramic works of the 1960s and 1980s his own picturesque informal searches and philosophical images-allegories in the author’s manner, are analyzed. For the first time, the systematization of directions and stages of formation of Z. Flint’s authorial style in the field of artistic ceramics was performed, as well as an art analysis of the influence of the artist’s painting on his ceramics.
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Cheng, Zhao Gang, Xin Hua Ni und Xie Quan Liu. „The Mechanical-Stress-Field of Matrix in Eutectic Ceramic Composite“. Applied Mechanics and Materials 121-126 (Oktober 2011): 3607–11. http://dx.doi.org/10.4028/www.scientific.net/amm.121-126.3607.
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Based on the interaction between nano-fiber and eutectic interphase, forth-phase mode is used to get the mechanical stress field of matrix in eutectic composite ceramics. The effective flexibility increment tensor of eutectic ceramic composite is obtained by the volumetric average strain. The remote stress boundary condition of the eutectic composite ceramis is accounted for getting the mechanical stress field in matrix. The results show the mechanical stress field of the matrix is associated with the stiffness and the volume fractions of each component in eutectic composite ceramic , the shape of interphase and nano-fiber. The stresses in matrix will decrease due to the strong constraining effects of the eutectic interphase. The eutectic interphase make the eutectic composite ceramics strengthen.
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Uchasova, E. G., O. V. Gruzdeva und Yu A. Dyleva. „CERAMIDS AND THEIR ROLE IN THE DEVELOPMENT OF CARDIOVASCULAR DISEASES (REVIEW OF LITERATURE)“. Russian Clinical Laboratory Diagnostics 65, Nr. 6 (15.05.2020): 341–46. http://dx.doi.org/10.18821/0869-2084-2020-65-6-341-346.
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Almost all known stress stimuli, including inflammatory agonists, chemotherapeutic agents and saturated fatty acids, cause the synthesis of ceramide and its metabolites. In recent studies, it has been shown that excessive synthesis of ceramides causes the development of various metabolic diseases, such as obesity, diabetes and cardiovascular diseases. Currently, the role of ceramids in the development of obesity and diabetes has been studied quite well. At the same time, studies devoted to the study of lipid data in the development of cardiovascular disease are not large. In this review, we generalize the data on this new class of bioactive lipids for understanding their role in the development of cardiovascular diseases.
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Kawana, Momoko, Masatoshi Miyamoto, Yusuke Ohno und Akio Kihara. „Comparative profiling and comprehensive quantification of stratum corneum ceramides in humans and mice by LC/MS/MS“. Journal of Lipid Research 61, Nr. 6 (07.04.2020): 884–95. http://dx.doi.org/10.1194/jlr.ra120000671.
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Ceramides are the predominant lipids in the stratum corneum (SC) and are crucial components for normal skin barrier function. Although the composition of various ceramide classes in the human SC has been reported, that in mice is still unknown, despite mice being widely used as animal models of skin barrier function. Here, we performed LC/MS/MS analyses using recently available ceramide class standards to measure 25 classes of free ceramides and 5 classes of protein-bound ceramides from human and mouse SC. Phytosphingosine- and 6-hydroxy sphingosine-type ceramides, which both contain an additional hydroxyl group, were abundant in the human SC (35% and 45% of total ceramides, respectively). In contrast, in mice, phytosphingosine- and 6-hydroxy sphingosine-type ceramides were present at ∼1% and undetectable levels, respectively, and sphingosine-type ceramides accounted for ∼90%. In humans, ceramides containing α-hydroxy FA were abundant, whereas ceramides containing β-hydroxy or ω-hydroxy FA were abundant in mice. The hydroxylated β-carbon in β-hydroxy ceramides was in the (R) configuration. Genetic knockout of β-hydroxy acyl-CoA dehydratases in HAP1 cells increased β-hydroxy ceramide levels, suggesting that β-hydroxy acyl-CoA, an FA-elongation cycle intermediate in the ER, is a substrate for β-hydroxy ceramide synthesis. We anticipate that our methods and findings will help to elucidate the role of each ceramide class in skin barrier formation and in the pathogenesis of skin disorders.
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Liu, Li-Ka, Vineet Choudhary, Alexandre Toulmay und William A. Prinz. „An inducible ER–Golgi tether facilitates ceramide transport to alleviate lipotoxicity“. Journal of Cell Biology 216, Nr. 1 (23.12.2016): 131–47. http://dx.doi.org/10.1083/jcb.201606059.
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Ceramides are key intermediates in sphingolipid biosynthesis and potent signaling molecules. However, excess ceramide is toxic, causing growth arrest and apoptosis. In this study, we identify a novel mechanism by which cells prevent the toxic accumulation of ceramides; they facilitate nonvesicular ceramide transfer from the endoplasmic reticulum (ER) to the Golgi complex, where ceramides are converted to complex sphingolipids. We find that the yeast protein Nvj2p promotes the nonvesicular transfer of ceramides from the ER to the Golgi complex. The protein is a tether that generates close contacts between these compartments and may directly transport ceramide. Nvj2p normally resides at contacts between the ER and other organelles, but during ER stress, it relocalizes to and increases ER–Golgi contacts. ER–Golgi contacts fail to form during ER stress in cells lacking Nvj2p. Our findings demonstrate that cells regulate ER–Golgi contacts in response to stress and reveal that nonvesicular ceramide transfer out of the ER prevents the buildup of toxic amounts of ceramides.
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Suchard, Suzanne J., Vania Hinkovska-Galcheva, Pamela J. Mansfield, Laurence A. Boxer und James A. Shayman. „Ceramide Inhibits IgG-Dependent Phagocytosis in Human Polymorphonuclear Leukocytes“. Blood 89, Nr. 6 (15.03.1997): 2139–47. http://dx.doi.org/10.1182/blood.v89.6.2139.
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Abstract Ceramide is a product of agonist-induced sphingolipid metabolism in several cell types, including polymorphonuclear leukocytes (PMNs). In adherent PMNs, the kinetics of ceramide production correspond with the termination of fMLP-stimulated H2O2 release. Furthermore, short chain ceramides inhibit fMLP-mediated H2O2 release in adherent PMNs. In the present study, we investigated the effects of short chain ceramides and sphingoid bases on phagocytosis of IgG-opsonized erythrocytes (EIgG) by suspended PMNs activated with fMLP. N-Acetylsphingosine, N-acetylphytosphingosine, phytosphingosine, sphingosine, and dihydrosphingosine, but not N-acetyldihydrosphingosine, inhibited phagocytosis of EIgG. In contrast, these same lipids did not inhibit fMLP-mediated chemotaxis. Endogenous ceramide levels increased within the first few minutes of phagocytosis, with a significant (P < .05) accumulation by 30 minutes, the time by which phagocytosis was terminated. Neutral sphingomyelinase activity paralleled the increase in ceramide, consistent with the generation of ceramide by the hydrolysis of sphingomyelin. The N-acetyl-conjugated sphingols (C2 ceramides) blocked phosphatidylethanol formation indicating that phospholipase D (PLD) is an intracellular target of ceramide action. These data suggest that ceramides, generated through activation of the sphingomyelin cycle, act as negative regulators of FcγR-mediated phagocytosis.
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Kalhorn, Thomas, und Richard A. Zager. „Renal cortical ceramide patterns during ischemic and toxic injury: assessments by HPLC-mass spectrometry“. American Journal of Physiology-Renal Physiology 277, Nr. 5 (01.11.1999): F723—F733. http://dx.doi.org/10.1152/ajprenal.1999.277.5.f723.
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Ceramides are a class of signaling molecules that can acutely accumulate in tissues as part of a “stress response.” They are classically measured by the diacylglycerol kinase assay, which, in general, measures total ceramide rather than individual moieties within the diverse ceramide family. The present study was undertaken to 1) adapt current HPLC-mass spectrometry technology for measuring individual renal ceramides, and 2) use this technique to more fully characterize the nature of the renal ceramide “stress” reaction. Renal cortical tissues were obtained from CD-1 mice under control conditions and 2 or 18 h after renal injury (ischemia-reperfusion and glycerol-mediated myohemoglobinuria). C24, C22, and C16 ceramides were identified in normal renal cortex, constituting 70, 10, and 20% of the total ceramide pool, respectively. Within each of these families, heterogeneity was apparent because of differing degrees of unsaturation (0–3 double bonds) in the constituent fatty acid of ceramide. Renal injury dramatically changed ceramide profiles: 1) total ceramide increased by ∼300%; 2) although all ceramides participated in this reaction, they did so to differing degrees; 3) this caused pronounced changes in ceramide distribution patterns; 4) injury induced a striking shift toward unsaturated (vs. saturated) fatty acids within the C22 and C24 (but not the C16) ceramide pools; and 5) the extent of these qualitative changes differed according to the etiology of the initiating renal damage. Thus we conclude that ceramide stress response involves major qualitative (and not simply quantitative) changes in ceramide expression that are partially disease dependent. These findings underscore the fact that simply measuring total renal ceramide content (e.g., by diacylglycerol kinase assay) substantially oversimplifies the nature and, hence, the potential implications of the ceramide stress reaction.
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Drazba, Margaret A., Ida Holásková, Nadine R. Sahyoun und Melissa Ventura Marra. „Associations of Adiposity and Diet Quality with Serum Ceramides in Middle-Aged Adults with Cardiovascular Risk Factors“. Journal of Clinical Medicine 8, Nr. 4 (17.04.2019): 527. http://dx.doi.org/10.3390/jcm8040527.
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Rates of adverse cardiovascular events have increased among middle-aged adults. Elevated ceramides have been proposed as a risk factor for cardiovascular events. Diet quality and weight status are inversely associated with several traditional risk factors; however, the relationship to ceramides is less clear. This study aimed to determine associations of adiposity and diet quality with circulating ceramides in middle-aged adults (n = 96). Diet quality was estimated using the Healthy Eating Index 2015 (HEI-2015). Serum ceramide concentrations were determined by liquid chromatography–mass spectrometry. A ceramide risk score was determined based on ceramides C16:0, C18:0, and C24:1 and their ratios to C24:0. Participants who were classified as at ‘moderate risk’ compared to ‘lower-risk’ based on a ceramide risk score had significantly higher body mass index (BMI) values, as well as higher rates of elevated fibrinogen levels, metabolic syndrome, and former smoking status. BMI was positively associated with the ceramide C18:0 (R2 = 0.31, p < 0.0001), the ratio between C18:0/C24:0 ceramides (R2 = 0.30, p < 0.0001), and the ceramide risk score (R2 = 0.11, p < 0.009). Total HEI-2015 scores (R2 = 0.42, p = 0.02), higher intakes of vegetables (R2 = 0.44, p = 0.02) and whole grains (R2 = 0.43, p = 0.03), and lower intakes of saturated fats (R2 = 0.43, p = 0.04) and added sugar (R2 = 0.44, p = 0.01) were associated with lower C22:0 values. These findings suggest that circulating ceramides are more strongly related to adiposity than overall diet quality. Studies are needed to determine if improvements in weight status result in lower ceramides and ceramide risk scores.
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Spassieva, Stefka D., Thomas D. Mullen, Danyelle M. Townsend und Lina M. Obeid. „Disruption of ceramide synthesis by CerS2 down-regulation leads to autophagy and the unfolded protein response“. Biochemical Journal 424, Nr. 2 (11.11.2009): 273–83. http://dx.doi.org/10.1042/bj20090699.
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Ceramide metabolism has come under recent scrutiny because of its role in cellular stress responses. CerS2 (ceramide synthase 2) is one of the six mammalian isoforms of ceramide synthase and is responsible for the synthesis of VLC (very-long-chain) ceramides, e.g. C24, C24:1. To study the role of CerS2 in ceramide metabolism and cellular homoeostasis, we down-regulated CerS2 using siRNA (small interfering RNA) and examined several aspects of sphingolipid metabolism and cell stress responses. CerS2 down-regulation had a broad effect on ceramide homoeostasis, not just on VLC ceramides. Surprisingly, CerS2 down-regulation resulted in significantly increased LC (long-chain) ceramides, e.g. C14, C16, and our results suggested that the increase was due to a ceramide synthase-independent mechanism. CerS2-down-regulation-induced LC ceramide accumulation resulted in growth arrest which was not accompanied by apoptotic cell death. Instead, cells remained viable, showing induction of autophagy and activation of PERK [PKR (double-stranded-RNA-dependent protein kinase)-like endoplasmic reticulum kinase] and IRE1 (inositol-requiring 1) pathways [the latter indicating activation of the UPR (unfolded protein response)].
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Unanyan, K. G., I. P. Balmasova, V. N. Tsarev, A. M. Mkrtumyan, K. S. Elbekyan, K. G. Karakov und S. D. Arutyunov. „Ceramids as biomarkers of chronic periodontitis associated with type 2 diabetes“. RUDN Journal of Medicine 24, Nr. 4 (15.12.2020): 325–37. http://dx.doi.org/10.22363/2313-0245-2020-24-4-325-337.
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Relevance . The association of chronic periodontitis with type 2 diabetes mellitus is one of the most frequent manifestations of systemic effects that are etiologically associated with periodontopathogenic bacteria in the biofilm of the gingival sulcus. In this regard, the study of the metabolic mechanisms leading to such systemic effects and serving their markers is an urgent problem. Aim . Study of the features of sphingolipid/ceramide metabolism, both produced by etiologically significant microflora, and present in periodontal tissues of patients on the example of the association of chronic periodontitis with type 2 diabetes. Materials and methods . The observation groups included 58 patients with chronic periodontitis in association with type 2 diabetes, 39 patients with chronic periodontitis without concomitant systemic pathology, and 27 conditionally healthy people. All the examined patients underwent molecular genetic studies of the taxonomic and metabolic profiles of the dental sulcus/ periodontal pockets microbiota using 16S sequencing and evaluation of phosphorylated ceramides in saliva by the activity of the ceramid kinase enzyme. Results . It was found that in the Association of chronic periodontitis with type 2 diabetes mellitus, there are features of the taxonomic composition of the dental sulcus/periodontal pockets microbiota, which are combined with a decrease in sphingolipid metabolism. In addition, in these patients, depending on the duration of diabetes mellitus, there was an increasing drop in the saliva of ceramide kinase, which determines the phosphorylation of sphingolipids/ceramides. Conclusion . In the Association of chronic periodontitis with type 2 diabetes mellitus, the systemic effects of the dental sulcus/ periodontal pockets microbiota are manifested by a decrease in sphingolipid metabolism, including a decrease in ceramide kinase in periodontal tissues, which can serve as a marker of the combined pathological process.
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Minamino, Miki, Ikuyo Sakaguchi, Takashi Naka, Norikazu Ikeda, Yoshiko Kato, Ikuko Tomiyasu, Ikuya Yano und Kazuo Kobayashi. „Bacterial ceramides and sphingophospholipids induce apoptosis of human leukaemic cells“. Microbiology 149, Nr. 8 (01.08.2003): 2071–81. http://dx.doi.org/10.1099/mic.0.25922-0.
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The genus Sphingobacterium, whose members are Gram-negative non-fermentative rods, possesses ceramides and related sphingophospholipids (SPLs) with isoheptadecasphinganine and 2-hydroxy or non-hydroxy isopentadecanoic acid. This paper reports evidence that ceramides isolated from Sphingobacterium spiritivorum ATCC 33861 induce endonucleolytic DNA cleavage in human myeloid leukaemia HL-60 cells in vitro, which is the primary characteristic biochemical marker for apoptosis or programmed cell death. Ceramides and SPLs also induced DNA fragmentation and caspase-3 activation, followed by changes in morphology, such as alterations in the size of nuclei and cells, and cell cycle shortening. Apoptotic activity correlated with the ceramide structure. Ceramide with a 2-hydroxy fatty acid showed stronger apoptotic activity than ceramide with a non-hydroxy fatty acid. Furthermore, the major five SPLs (ceramide phosphorylethanolamine-1 and -2, ceramide phosphorylinositol-1 and -2, and ceramide phosphorylmannose-1) showed apoptosis-inducing activity in HL-60 cells, indicating that the ceramide moiety of the SPLs plays a crucial role as the intracellular second messenger but that their hydrophilicity is less important in this regard. The hydrophilic part of SPLs may play a role in other cellular response systems. The involvement of Fas antigen was implicated in the apoptotic event since Fas antigen expression was observed after 3 or 4 h stimulation of HL-60 cells with bacterial ceramides. However, a time-course study for caspase-3 activation indicated maximal activity at 1 h after stimulation with bacterial ceramides, suggesting that two (or possibly more) mechanisms of signal transduction, Fas-dependent and Fas-independent, may be involved. Fas antigen expression and caspase-3 activation by five kinds of SPLs were observed after 3 or 4 h. These results indicate that there is a difference in the response of HL-60 cells to bacterial ceramides and SPLs.
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Véret, Julien, Nicolas Coant, Evgeny V. Berdyshev, Anastasia Skobeleva, Nicole Therville, Danielle Bailbé, Irina Gorshkova, Viswanathan Natarajan, Bernard Portha und Hervé Le Stunff. „Ceramide synthase 4 and de novo production of ceramides with specific N-acyl chain lengths are involved in glucolipotoxicity-induced apoptosis of INS-1 β-cells“. Biochemical Journal 438, Nr. 1 (27.07.2011): 177–89. http://dx.doi.org/10.1042/bj20101386.
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Pancreatic β-cell apoptosis induced by palmitate requires high glucose concentrations. Ceramides have been suggested to be important mediators of glucolipotoxicity-induced β-cell apoptosis. In INS-1 β-cells, 0.4 mM palmitate with 5 mM glucose increased the levels of dihydrosphingosine and dihydroceramides, two lipid intermediates in the de novo biosynthesis of ceramides, without inducing apoptosis. Increasing glucose concentrations to 30 mM amplified palmitate-induced accumulation of dihydrosphingosine and the formation of (dihydro)ceramides. Of note, glucolipotoxicity specifically induced the formation of C18:0, C22:0 and C24:1 (dihydro)ceramide molecular species, which was associated with the up-regulation of CerS4 (ceramide synthase 4) levels. Fumonisin-B1, a ceramide synthase inhibitor, partially blocked apoptosis induced by glucolipotoxicity. In contrast, apoptosis was potentiated in the presence of D,L-threo-1-phenyl-2-palmitoylamino-3-morpholinopropan-1-ol, an inhibitor of glucosylceramide synthase. Moreover, overexpression of CerS4 amplified ceramide production and apoptosis induced by palmitate with 30 mM glucose, whereas down-regulation of CerS4 by siRNA (short interfering RNA) reduced apoptosis. CerS4 also potentiates ceramide accumulation and apoptosis induced by another saturated fatty acid: stearate. Collectively, our results suggest that glucolipotoxicity induces β-cell apoptosis through a dual mechanism involving de novo ceramide biosynthesis and the formation of ceramides with specific N-acyl chain lengths rather than an overall increase in ceramide content.
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Shin, Kyong-Oh, Sungeun Kim, Byeong Deog Park, Yoshikazu Uchida und Kyungho Park. „N-Palmitoyl Serinol Stimulates Ceramide Production through a CB1-Dependent Mechanism in In Vitro Model of Skin Inflammation“. International Journal of Molecular Sciences 22, Nr. 15 (02.08.2021): 8302. http://dx.doi.org/10.3390/ijms22158302.
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Ceramides, a class of sphingolipids containing a backbone of sphingoid base, are the most important and effective structural component for the formation of the epidermal permeability barrier. While ceramides comprise approximately 50% of the epidermal lipid content by mass, the content is substantially decreased in certain inflammatory skin diseases, such as atopic dermatitis (AD), causing improper barrier function. It is widely accepted that the endocannabinoid system (ECS) can modulate a number of biological responses in the central nerve system, prior studies revealed that activation of endocannabinoid receptor CB1, a key component of ECS, triggers the generation of ceramides that mediate neuronal cell fate. However, as the impact of ECS on the production of epidermal ceramide has not been studied, we here investigated whether the ECS stimulates the generation of epidermal ceramides in an IL-4-treated in vitro model of skin inflammation using N-palmitoyl serinol (PS), an analog of the endocannabinoid N-palmitoyl ethanolamine. Accordingly, an IL-4-mediated decrease in cellular ceramide levels was significantly stimulated in human epidermal keratinocytes (KC) following PS treatment through both de novo ceramide synthesis- and sphingomyelin hydrolysis-pathways. Importantly, PS selectively increases ceramides with long-chain fatty acids (FAs) (C22–C24), which mainly account for the formation of the epidermal barrier, through activation of ceramide synthase (CerS) 2 and Cer3 in IL-4-mediated inflamed KC. Furthermore, blockade of cannabinoid receptor CB1 activation by AM-251 failed to stimulate the production of total ceramide as well as long-chain ceramides in response to PS. These studies demonstrate that an analog of endocannabinoid, PS, stimulates the generation of specific ceramide species as well as the total amount of ceramides via the endocannabinoid receptor CB1-dependent mechanism, thereby resulting in the enhancement of epidermal permeability barrier function.
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Tessema, E. N., R. H. H. Neubert und J. Wohlrab. „Pflanzliche Ceramide zur kosmetischen Anwendung“. Aktuelle Dermatologie 45, Nr. 07 (Juli 2019): 336–42. http://dx.doi.org/10.1055/a-0881-6924.
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ZusammenfassungDie Bedeutung von Ceramiden als aktive Inhaltstoffe in kosmetischen Präparaten hat in den letzten Jahren erheblich an Bedeutung gewonnen. Im dermatologischen Kontext werden Ceramide meist in Kombination mit anderen Lipiden sowie weiteren kosmetischen Wirkstoffen in Präparaten zur Barriereprotektion und -regeneration bei chronisch-entzündlichen Hauterkrankungen bzw. bei Diabetes mellitus oder Altershaut eingesetzt. Da die Herstellung von synthetischen Ceramiden sehr kostenintensiv ist, kann die Verwendung von pflanzlichen Ceramiden mit vergleichbaren physikochemischen Eigenschaften eine Alternative darstellen. Neuere Verfahren ermöglichen die Glykosylierung dieser aus Pflanzenextrakten isolierten Ceramide und deren Einsatz in kosmetischen Zubereitungen. Weitere Untersuchungen müssen klären, ob sich glykosylierte pflanzliche Ceramide in die natürlichen Lipidmembranen im Stratum corneum integrieren und welche funktionellen Auswirkungen sie auf die Barrierefunktion haben. Die bisherigen Daten begründen ein großes Potenzial pflanzlicher Ceramide für die Barriere-protektive Anwendung in kosmetischen Präparaten.
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Ighodaro, Eseosa T., Jonathan Graff-Radford, Jeremy A. Syrjanen, Hai H. Bui, Ronald C. Petersen, David S. Knopman, Clifford R. Jack, Samantha M. Zuk, Prashanthi Vemuri und Michelle M. Mielke. „Associations Between Plasma Ceramides and Cerebral Microbleeds or Lacunes“. Arteriosclerosis, Thrombosis, and Vascular Biology 40, Nr. 11 (November 2020): 2785–93. http://dx.doi.org/10.1161/atvbaha.120.314796.
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Objective: High plasma ceramide levels and ratios are associated with poor outcomes in individuals with cardiovascular disease; less is known about their relation to cerebral small vessel disease. We examined whether high plasma ceramide levels or ratios were associated with cerebral microbleeds (CMBs) and lacunes and whether associations differ by sex. Approach and Results: We included 548 participants enrolled in the MCSA (Mayo Clinic Study of Aging) with concurrent plasma ceramide assays and magnetic resonance imaging. CMBs were quantified on T2* magnetic resonance imaging and lacunes on T2 fluid-attenuated inversion recovery magnetic resonance imaging. Fasting plasma ceramides were assayed using liquid chromatography-electrospray ionization tandem mass spectrometry. We used logistic regression models adjusting for age, sex, hypertension, and diabetes mellitus to examine the relationship between ceramides and presence of a lacune; hurdle models were used for presence and number of CMBs. Each SD increase in the log ceramide C16:0/24:0 ratio was associated with greater odds of a CMB (odds ratio, 1.28 [95% CI, 1.01–1.64]). There was an interaction between sex and the ceramide C16:0/24:0 ratio ( P =0.049). The association between this ratio and presence of a CMB was stronger for women (odds ratio, 1.87 [95% CI, 1.20–3.00]) than men (odds ratio, 1.09 [95% CI, 0.80–1.46]). Several ceramides and all ceramide ratios were associated with number of CMBs. We did not find associations between plasma ceramides and lacunes. Conclusions: In a population-based sample, the plasma ceramide C16:0/24:0 ratio was associated with CMBs and was stronger for women. Plasma ceramides are differentially associated with cerebral small vessel pathologies.
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Al Moaleem, Mohammed M., Hafiz A. Adawi, Khalaf F. Alsharif, Hassan A. Alhazmi, Faris A. Alshahrani, Ramzi M. Abu Hadi, Recep Kara et al. „Impact of Smokeless Tobacco on the Color Stability of Zirconia, Zirconia-Reinforced Lithium Silicate and Feldspathic CAD/CAM Restorative Materials: An In Vitro Study“. Coatings 12, Nr. 2 (05.02.2022): 207. http://dx.doi.org/10.3390/coatings12020207.
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WHO estimates that the global number of tobacco users exceeds 1.3 billion people. Few studies have examined the effect of locally made smokeless tobacco (ST) products on the color changes of material used in dental prosthetics. Bearing the recent advances in CAD/CAM ceramic restorations material in mind, this study aimed to assess ST influence on mean color change (∆E*) values among selected CAD/CAM ceramic types: multilayer zirconia (Ceramill Zolid PS), zirconia-reinforced lithium silicate ceramic (Vita Suprinity), and feldspathic (Vita TriLuxe) restorative materials. The color changes of the ceramics were compared to VITA classical and VITA 3D-MASTER shade guides. Sixty CAD/CAM ceramic specimens (20 samples each) were fabricated from Ceramill Zolid PS, Vita TriLuxe Forte, and VITA Suprinity. Specimens were prepared and divided into two groups according to the ST type and immersed for two weeks. Basic VITA classical and VITA 3D-MASTER colors were recorded at a baseline of one week and two weeks. The highest ∆E* values were recorded in the black ST for Vita Suprinity (4.77) in the first week, followed by Vita TriLuxe (4.07) in the second week. For white ST, Vita TriLuxe (4.87), and Vita Suprinity (4.42) showed extensive color change after two weeks and one week, respectively. The color change was least in zirconia for black and white ST after one week. CAD/CAM ceramic materials showed no significant difference after 1 and 2 weeks for the tested ST types. The effects of ST on CAD/CAM ceramic material (∆E* values) were high but did not reach clinically unacceptable values. Zirconia showed the least amount of color change among all the tested materials.
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Safronova, Elena Mikhailovna. „Saint Petersburg period of creativity of P. K. Vaulin (1906-1914)“. Человек и культура, Nr. 2 (Februar 2021): 1–11. http://dx.doi.org/10.25136/2409-8744.2021.2.35221.
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The subject of this research is the stylistic peculiarities and means of artistic expression of the architectural majolica by Peter Kuzmich Vaulin. The object of this research is the architectural ceramics of Vaulin in facades of the buildings of St. Petersburg in the early XX century. The application of inclusive approach allows tracing correlations between the historical facts and the cultural characteristics of this period. The compositional-artistic analysis, comparative-descriptive method, and imagery-stylistic analysis were used for consideration of the means of artistic expression of architectural ceramics, compositional interaction of the materials and space, and examination of the style and formative peculiarities of ceramics. Detailed analysis is conducted on the Saint Petersburg period of the ceramist P. K. Vaulin, opening of his own ceramic workshop, and active participation in the development of decorative image of St. Petersburg in the early XX century. Special attention is given to the most remarkable works of the master for architectural decoration of the city. Emphasis is placed on his works for the Insurance Company Building “Russia”, which is brilliant example of the harmonious synthesis of majolica and architecture. The conclusion is made that the architectural ceramics of the master made in many ways determined the majolica decoration of St. Petersburg – compositional, textured, color, imagery-stylistic, and plastic peculiarities of the ceramic works of P. K. Vaulin contributed to aesthetic transformation of the environment. The scientific novelty of consists in the thesis that the ceramic workshop of P. K. Vaulin was one of the leading manufacturers of artistic majolica of the indicated period. It is also proven that the Heldwein-Vaulin workshop was able to organically synthesize the heritage of the best traditions of the past with the courage and ambiguity of the Art Nouveau.
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Allan-Yorke, Justine, Michel Record, Claude de Préval, Christian Davrinche und Jean-Luc Davignon. „Distinct Pathways for Tumor Necrosis Factor Alpha and Ceramides in Human Cytomegalovirus Infection“. Journal of Virology 72, Nr. 3 (01.03.1998): 2316–22. http://dx.doi.org/10.1128/jvi.72.3.2316-2322.1998.
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ABSTRACT Human cytomegalovirus (HCMV) infection can be fatal to immunocompromised individuals. We have previously reported that gamma interferon and tumor necrosis factor alpha (TNF-α) synergistically inhibit HCMV replication in vitro. Ceramides have been described as second messengers induced by TNF-α. To investigate the mechanisms involved in the inhibition of HCMV by TNF-α, in the present study we have analyzed ceramide production by U373 MG astrocytoma cells and the effects of TNF-α versus ceramides on HCMV replication. Our results show that U373 MG cells did not produce ceramides upon incubation with TNF-α. Moreover, long-chain ceramides induced by treatment with exogenous bacterial sphingomyelinase inhibited HCMV replication in synergy with TNF-α. Surprisingly, short-chain permeant C6-ceramide increased viral replication. Our results show that the anti-HCMV activity of TNF-α is independent of ceramides. In addition, our results suggest that TNF-α and endogenous long-chain ceramides use separate pathways of cell signalling to inhibit HCMV replication, while permeant C6-ceramide appears to activate a third pathway leading to an opposite effect.
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Maldonado-Hernández, Jorge, Gabriela E. Saldaña-Dávila, Mónica I. Piña-Aguero, Benjamín A. Núñez-García und Mardia G. López-Alarcón. „Association between Plasmatic Ceramides Profile and AST/ALT Ratio: C14:0 Ceramide as Predictor of Hepatic Steatosis in Adolescents Independently of Obesity“. Canadian Journal of Gastroenterology and Hepatology 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/3689375.
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Objective. To assess the association between plasma ceramides and hepatic steatosis (HS) in adolescents, independently of obesity. Materials and Methods. Ninety-four adolescents from two previous studies conducted and published by our crew were included. Study subjects were stratified in three groups: normal weight (n=18), obesity (n=34), and obesity + HS (n=42). The presence of HS was defined when ALT/AST ratio was <1. Ceramides subspecies (C14:0, C16:0, C18:0, C24:0, and C24:1) were determined by LC/MS. Results. All ceramides correlated directly with ALT levels and inversely with ALT/AST ratio; the strongest correlation was observed among C14:0 ceramide (r=0.41 and r=-0.54, resp.; P<0.001). Furthermore, significant correlations were observed between cholesterol and all ceramides except for C24:1 ceramide. Interestingly ceramides C14:0, C18:0, and C24:1 correlated directly with both fasting insulin and HOMA-IR index. For assessing HS, a cut-off point of 10.3 nmol/L for C14:0 ceramide reported a sensitivity of 92.7% and a specificity of 73.5% when normal weight and obesity groups (n=52) were compared against obesity + HS group (n=42). Positive and negative predictive values were 77.5% and 90.2%, respectively. Conclusions. Plasma ceramides are closely associated with hepatic steatosis in adolescents. C14:0 ceramide could be a novel biomarker of HS independently of obesity.
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Yura, Yoshiaki, Atsushi Masui und Masakazu Hamada. „Inhibitors of Ceramide- and Sphingosine-Metabolizing Enzymes as Sensitizers in Radiotherapy and Chemotherapy for Head and Neck Squamous Cell Carcinoma“. Cancers 12, Nr. 8 (26.07.2020): 2062. http://dx.doi.org/10.3390/cancers12082062.
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In the treatment of advanced head and neck squamous cell carcinoma (HNSCC), including oral SCC, radiotherapy is a commonly performed therapeutic modality. The combined use of radiotherapy with chemotherapy improves therapeutic effects, but it also increases adverse events. Ceramide, a central molecule in sphingolipid metabolism and signaling pathways, mediates antiproliferative responses, and its level increases in response to radiotherapy and chemotherapy. However, when ceramide is metabolized, prosurvival factors, such as sphingosine-1-phosphate (S1P), ceramide-1-phosphate (C1P), and glucosylceramide, are produced, reducing the antitumor effects of ceramide. The activities of ceramide- and sphingosine-metabolizing enzymes are also associated with radio- and chemo-resistance. Ceramide analogs and low molecular-weight compounds targeting these enzymes exert anticancer effects. Synthetic ceramides and a therapeutic approach using ultrasound have also been developed. Inhibitors of ceramide- and sphingosine-metabolizing enzymes and synthetic ceramides can function as sensitizers of radiotherapy and chemotherapy for HNSCC.
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Petrache, Irina, Terry R. Medler, Amy T. Richter, Krzysztof Kamocki, Ugonma Chukwueke, Lijie Zhen, Yuan Gu et al. „Superoxide dismutase protects against apoptosis and alveolar enlargement induced by ceramide“. American Journal of Physiology-Lung Cellular and Molecular Physiology 295, Nr. 1 (Juli 2008): L44—L53. http://dx.doi.org/10.1152/ajplung.00448.2007.
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The molecular events leading to emphysema development include generation of oxidative stress and alveolar cell apoptosis. Oxidative stress upregulates ceramides, proapoptotic signaling sphingolipids that trigger further oxidative stress and alveolar space enlargement, as shown in an experimental model of emphysema due to VEGF blockade. As alveolar cell apoptosis and oxidative stress mutually interact to mediate alveolar destruction, we hypothesized that the oxidative stress generated by ceramide is required for its pathogenic effect on lung alveoli. To model the direct lung effects of ceramide, mice received ceramide intratracheally (Cer12:0 or Cer8:0; 1 mg/kg) or vehicle. Apoptosis was inhibited with a general caspase inhibitor. Ceramide augmentation shown to mimic levels found in human emphysema lungs increased oxidative stress, and decreased, independently of caspase activation, the lung superoxide dismutase activity at 48 h. In contrast to their wild-type littermates, transgenic mice overexpressing human Cu/Zn SOD were significantly protected from ceramide-induced superoxide production, apoptosis, and air space enlargement. Activation of lung acid sphingomyelinase in response to ceramide treatment was abolished in the Cu/Zn SOD transgenic mice. Since cigarette smoke-induced emphysema in mice is similarly ameliorated by the Cu/Zn SOD overexpression, we hypothesized that cigarette smoke may induce ceramides in the mouse lung. Utilizing tandem mass spectrometry, we documented increased lung ceramides in adult mice exposed to cigarette smoke for 4 wk. In conclusion, ceramide-induced superoxide accumulation in the lung may be a critical step in ceramide's proapoptotic effect in the lung. This work implicates excessive lung ceramides as amplifiers of lung injury through redox-dependent mechanisms.
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Kagotani, Kazuhiro, Hiroko Nakayama, Liqing Zang, Yuki Fujimoto, Akihito Hayashi, Ryoji Sono, Norihiro Nishimura und Yasuhito Shimada. „Lecithin-Based Dermal Drug Delivery for Anti-Pigmentation Maize Ceramide“. Molecules 25, Nr. 7 (31.03.2020): 1595. http://dx.doi.org/10.3390/molecules25071595.
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Ceramides have several well-known biological properties, including anti-pigmentation and anti-melanogenesis, which make them applicable for use in skincare products in cosmetics. However, the efficacy of ceramides is still limited. Dermal or transdermal drug delivery systems can enhance the anti-pigmentation properties of ceramides, although there is currently no systemic evaluation method for the efficacy of these systems. Here we prepared several types of lecithin-based emulsion of maize-derived glucosylceramide, determining PC70-ceramide (phosphatidylcholine-base) to be the safest and most effective anti-pigmentation agent using zebrafish larvae. We also demonstrated the efficacy of PC70 as a drug delivery system by showing that PC70-Nile Red (red fluorescence) promoted Nile Red accumulation in the larval bodies. In addition, PC70-ceramide suppressed melanin in mouse B16 melanoma cells compared to ceramide alone. In conclusion, we developed a lecithin-based dermal delivery method for ceramide using zebrafish larvae with implications for human clinical use.
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Reidy, Paul T., Ziad S. Mahmassani, Alec I. McKenzie, Jonathan J. Petrocelli, Scott A. Summers und Micah J. Drummond. „Influence of Exercise Training on Skeletal Muscle Insulin Resistance in Aging: Spotlight on Muscle Ceramides“. International Journal of Molecular Sciences 21, Nr. 4 (22.02.2020): 1514. http://dx.doi.org/10.3390/ijms21041514.
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Intramuscular lipid accumulation has been associated with insulin resistance (IR), aging, diabetes, dyslipidemia, and obesity. A substantial body of evidence has implicated ceramides, a sphingolipid intermediate, as potent antagonists of insulin action that drive insulin resistance. Indeed, genetic mouse studies that lower ceramides are potently insulin sensitizing. Surprisingly less is known about how physical activity (skeletal muscle contraction) regulates ceramides, especially in light that muscle contraction regulates insulin sensitivity. The purpose of this review is to critically evaluate studies (rodent and human) concerning the relationship between skeletal muscle ceramides and IR in response to increased physical activity. Our review of the literature indicates that chronic exercise reduces ceramide levels in individuals with obesity, diabetes, or hyperlipidemia. However, metabolically healthy individuals engaged in increased physical activity can improve insulin sensitivity independent of changes in skeletal muscle ceramide content. Herein we discuss these studies and provide context regarding the technical limitations (e.g., difficulty assessing the myriad ceramide species, the challenge of obtaining information on subcellular compartmentalization, and the paucity of flux measurements) and a lack of mechanistic studies that prevent a more sophisticated assessment of the ceramide pathway during increased contractile activity that lead to divergences in skeletal muscle insulin sensitivity.
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Novgorodov, Sergei A., Zdzislaw M. Szulc, Chiara Luberto, Jeffrey A. Jones, Jacek Bielawski, Alicja Bielawska, Yusuf A. Hannun und Lina M. Obeid. „Positively Charged Ceramide Is a Potent Inducer of Mitochondrial Permeabilization“. Journal of Biological Chemistry 280, Nr. 16 (18.02.2005): 16096–105. http://dx.doi.org/10.1074/jbc.m411707200.
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Ceramide-induced cell death is thought to be mediated by change in mitochondrial function, although the precise mechanism is unclear. Proposed models suggest that ceramide induces cell death through interaction with latent binding sites on the outer or inner mitochondrial membranes, followed by an increase in membrane permeability, as an intermediate step in ceramide signal propagation. To investigate these models, we developed a new generation of positively charged ceramides that readily accumulate in isolated andin situmitochondria. Accumulated, positively charged ceramides increased inner membrane permeability and triggered release of mitochondrial cytochromec. Furthermore, the positively charged ceramide-induced permeability increase was suppressed by cyclosporin A (60%) and 1,3-dicyclohexylcarbodiimide (90%). These observations suggest that the inner membrane permeability increase is due to activation of specific ion transporters, not the generalized loss of lipid bilayer barrier functions. The difference in sensitivity of ceramide-induced ion fluxes to inhibitors of mitochondrial transporters suggests activation of at least two transport systems: the permeability transition pore and the electrogenic H+channel. Our results indicate the presence of specific ceramide targets in the mitochondrial matrix, the occupation of which triggers permeability alterations of the inner and outer mitochondrial membranes. These findings also suggest a novel therapeutic role for positively charged ceramides.
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Kretzschmar, Tom, Mohamed M. Bekhite, Jasmine M. F. Wu, Daniela Haase, Martin Förster, Tina Müller, Sandor Nietzsche et al. „Long-Chain and Very Long-Chain Ceramides Mediate Doxorubicin-Induced Toxicity and Fibrosis“. International Journal of Molecular Sciences 22, Nr. 21 (01.11.2021): 11852. http://dx.doi.org/10.3390/ijms222111852.
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Doxorubicin (Dox) is a chemotherapeutic agent with cardiotoxicity associated with profibrotic effects. Dox increases ceramide levels with pro-inflammatory effects, cell death, and fibrosis. The purpose of our study was to identify the underlying ceramide signaling pathways. We aimed to characterize the downstream effects on cell survival, metabolism, and fibrosis. Human fibroblasts (hFSF) were treated with 0.7 µM of Dox or transgenically overexpressed ceramide synthase 2 (FLAG-CerS2). Furthermore, cells were pre-treated with MitoTempo (MT) (2 h, 20 µM) or Fumonisin B1 (FuB) (4 h, 100 µM). Protein expression was measured by Western blot or immunofluorescence (IF). Ceramide levels were determined with mass spectroscopy (MS). Visualizations were conducted using laser scanning microscopy (LSM) or electron microscopy. Mitochondrial activity was measured using seahorse analysis. Dox and CerS2 overexpression increased CerS2 protein expression. Coherently, ceramides were elevated with the highest peak for C24:0. Ceramide- induced mitochondrial ROS production was reduced with MT or FuB preincubation. Mitochondrial homeostasis was reduced and accompanied by reduced ATP production. Our data show that the increase in pro-inflammatory ceramides is an essential contributor to Dox side-effects. The accumulation of ceramides resulted in a lipotoxic shift and subsequently mitochondrial structural and functional damage, which was partially reversible following inhibition of ceramide synthesis.
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Colomban, Ph. „Gel technology in ceramics, glass-ceramics and ceramic-ceramic composites“. Ceramics International 15, Nr. 1 (Januar 1989): 23–50. http://dx.doi.org/10.1016/0272-8842(89)90005-9.
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Walker, Maura E., Vanessa Xanthakis, Lynn L. Moore, Ramachandran S. Vasan und Paul F. Jacques. „Cumulative sugar-sweetened beverage consumption is associated with higher concentrations of circulating ceramides in the Framingham Offspring Cohort“. American Journal of Clinical Nutrition 111, Nr. 2 (11.12.2019): 420–28. http://dx.doi.org/10.1093/ajcn/nqz257.
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ABSTRACT Background Ceramides have been implicated in the pathogenesis of type 2 diabetes and cardiovascular disease. Limited data exist on how habitual dietary intake of foods that can alter hepatic lipid metabolism may influence circulating ceramide concentrations. Objectives We investigated the cross-sectional association of cumulative sugar-sweetened beverage (SSB) consumption with concentrations of 3 circulating ceramides and ceramide ratios. Methods We examined participants from the Framingham Heart Study's Offspring Cohort who had 3 ceramides measured (n = 1561, mean age 66 y, 59% women). SSB consumption was measured 4 times over ∼14 y. Participants were categorized by cumulative SSB intake as nonconsumers (0 to <1 SSB serving/mo) and occasional (1 SSB serving/mo to <1 serving/wk), frequent (1 SSB serving/wk to <1 serving/d), and daily (≥1 SSB serving/d) consumers. Multivariable linear regression models were used to relate cumulative SSB consumption (independent variable) to blood concentrations of ceramides (C16:0, C22:0, and C24:0) and ceramide ratios (C22:0/C16:0 and C24:0/C16:0). Results In adjusted models, more frequent cumulative SSB consumption was positively associated with concentrations of the C16:0 and C22:0 ceramides (Ptrend < 0.05). Compared with nonconsumers, daily consumers had 0.01 μg/mL (95% CI: 0.002, 0.017 µg/mL) and 0.06 µg/mL (95% CI: 0.018, 0.092 µg/mL) higher mean concentrations of the C16:0 and C22:0 ceramides, respectively. Results were consistent when modeling continuous cumulative SSB consumption per 1 serving/d. We observed effect modification by diabetes status in the relation between cumulative SSB consumption and concentrations of the C24:0 ceramide (Pinteraction = 0.014). In a stratified analysis, more frequent cumulative SSB consumption was positively associated with concentrations of the C24:0 ceramide only in individuals with prediabetes or diabetes (Ptrend = 0.001). Conclusions Our study raises the possibility that higher concentrations of distinct ceramide species, previously associated with adverse metabolic health, may be one mechanism by which SSB consumption contributes to higher risk of cardiometabolic diseases.
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Wojewodka, Gabriella, Juan B. De Sanctis und Danuta Radzioch. „Ceramide in Cystic Fibrosis: A Potential New Target for Therapeutic Intervention“. Journal of Lipids 2011 (2011): 1–13. http://dx.doi.org/10.1155/2011/674968.
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Patients with cystic fibrosis (CF) are afflicted with many symptoms but the greatest challenge is the fight against chronic bacterial infections, leading to decreased lung function and ultimately death. Our group has recently found reduced levels of ceramides in CF patients and mice. Ceramides are sphingolipids involved in the structure of cell membranes but also participate in the inflammatory response, in cell signalling through membrane microdomains (lipid rafts), and in apoptosis. These characteristics of ceramides make them strong candidates for therapeutic intervention in CF. As more studies have come to evaluate the role of ceramide in CF, conflicting results have been described. This paper discusses various views regarding the potential role of ceramide in CF, summarizes methods of ceramide detection and their role in the regulation of cellular and molecular processes.
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Perera, Meenu N., Shang H. Lin, Yuri K. Peterson, Alicja Bielawska, Zdzislaw M. Szulc, Robert Bittman und Marco Colombini. „Bax and Bcl-xL exert their regulation on different sites of the ceramide channel“. Biochemical Journal 445, Nr. 1 (15.06.2012): 81–91. http://dx.doi.org/10.1042/bj20112103.
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The present study demonstrates the important structural features of ceramide required for proper regulation, binding and identification by both pro-apoptotic and anti-apoptotic Bcl-2 family proteins. The C-4=C-5 trans-double bond has little influence on the ability of Bax and Bcl-xL to identify and bind to these channels. The stereochemistry of the headgroup and access to the amide group of ceramide is indispensible for Bax binding, indicating that Bax may interact with the polar portion of the ceramide channel facing the bulk phase. In contrast, Bcl-xL binding to ceramide channels is tolerant of stereochemical changes in the headgroup. The present study also revealed that Bcl-xL has an optimal interaction with long-chain ceramides that are elevated early in apoptosis, whereas short-chain ceramides are not well regulated. Inhibitors specific for the hydrophobic groove of Bcl-xL, including 2-methoxyantimycin A3, ABT-737 and ABT-263 provide insights into the region of Bcl-xL involved in binding to ceramide channels. Molecular docking simulations of the lowest-energy binding poses of ceramides and Bcl-xL inhibitors to Bcl-xL were consistent with the results of our functional studies and propose potential binding modes.
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Carrard, Justin, Hector Gallart-Ayala, Nadia Weber, Flora Colledge, Lukas Streese, Henner Hanssen, Christian Schmied, Julijana Ivanisevic und Arno Schmidt-Trucksäss. „How Ceramides Orchestrate Cardiometabolic Health—An Ode to Physically Active Living“. Metabolites 11, Nr. 10 (30.09.2021): 675. http://dx.doi.org/10.3390/metabo11100675.
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Cardiometabolic diseases (CMD) represent a growing socioeconomic burden and concern for healthcare systems worldwide. Improving patients’ metabolic phenotyping in clinical practice will enable clinicians to better tailor prevention and treatment strategy to individual needs. Recently, elevated levels of specific lipid species, known as ceramides, were shown to predict cardiometabolic outcomes beyond traditional biomarkers such as cholesterol. Preliminary data showed that physical activity, a potent, low-cost, and patient-empowering means to reduce CMD-related burden, influences ceramide levels. While a single bout of physical exercise increases circulating and muscular ceramide levels, regular exercise reduces ceramide content. Additionally, several ceramide species have been reported to be negatively associated with cardiorespiratory fitness, which is a potent health marker reflecting training level. Thus, regular exercise could optimize cardiometabolic health, partly by reversing altered ceramide profiles. This short review provides an overview of ceramide metabolism and its role in cardiometabolic health and diseases, before presenting the effects of exercise on ceramides in humans.
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Jiang, Hong. „Research on Applied-Information Technology in Online Compact System Based on Serial Communication“. Advanced Materials Research 1046 (Oktober 2014): 431–35. http://dx.doi.org/10.4028/www.scientific.net/amr.1046.431.
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The ceramic industry fall into two main categories: daily used ceramics and craft ceramic. With the demand for daily used ceramics is increasing in my country, ceramics enterprises are faced with intense market competition. Based on the investigation of ceramic industrial production, the traditional method for Ceramic production has some disadvantages, such as long periods of dies production, complicated production process, wasting human resource, high cost, short life, poor quality, easy to damage. According to the characteristics of daily used ceramics, this paper presents a rapid prototyping system based on RS-232C compacts. This system can cancel the long and complex development process of the dies, and can achieve rapid prototyping of ceramic body, thereby greatly reducing the cost of production of ceramic manufacturers.
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Søgaard, Ditte, Marcin Baranowski, Steen Larsen, Michael Taulo Lund, Cathrine Munk Scheuer, Carina Vestergaard Abildskov, Sofie Greve Dideriksen, Flemming Dela und Jørn Wulff Helge. „Muscle-Saturated Bioactive Lipids Are Increased with Aging and Influenced by High-Intensity Interval Training“. International Journal of Molecular Sciences 20, Nr. 5 (12.03.2019): 1240. http://dx.doi.org/10.3390/ijms20051240.
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Ceramide and diacylglycerol are linked to insulin resistance in rodents, but in humans the data are inconsistent. Insulin resistance is frequently observed with aging, but the role of ceramide and diacylglycerol is not clarified. Training improves metabolic health and, therefore, we aimed to elucidate the influence of age and high-intensity interval training (HIIT) on ceramide and diacylglycerol content in muscle. Fourteen young (33 ± 1) and 22 older (63 ± 1) overweight to obese subjects performed 6 weeks HIIT three times a week. Maximal oxygen uptake and body composition were measured and muscle biopsies and fasting blood samples were obtained. Muscle ceramide and diacylglycerol were measured by gas-liquid chromatography and proteins in insulin signaling, lipid and glucose metabolism were measured by Western blotting. Content of ceramide and diacylglycerol total, saturated, C16:0 and C18:0 fatty acids and C18:1 ceramide were higher in older compared to young. HIIT reduced saturated and C18:0 ceramides, while the content of the proteins involved in glucose (GLUT4, glycogen synthase, hexokinase II, AKT) and lipid metabolism (adipose triglyceride lipase, fatty acid binding protein) were increased after HIIT. We demonstrate a higher content of saturated ceramide and diacylglycerol fatty acids in the muscle of older subjects compared to young. Moreover, the content of saturated ceramides was reduced and muscle glucose metabolism improved at protein level after HIIT. This study highlights an increased content of saturated ceramides in aging which could be speculated to influence insulin sensitivity.
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Li, Bei, X. B. Liu, M. Chen und X. A. Mei. „Ferroelectric Properties of Bismuth Titanate Ceramics by Tm2O3/V2O5 Substitution“. Key Engineering Materials 633 (November 2014): 374–77. http://dx.doi.org/10.4028/www.scientific.net/kem.633.374.
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The ferroelectricity of Bi3.25Tm0.75Ti2.97V0.03O12 (BTTV) ceramic prepared at 1200°C by a conventional ceramic technique was investigated. The ceramic possess random-oriented polycrystalline structure. The remanent polarization (Pr) and coercive field (Ec) of the BTTV ceramics are 25 μC/cm2 and 70kV/cm, respectively. The Pr value of the BTTV ceramics up to 25 μC/cm2 is larger than that of the BTT ceramics. Therefore, co-sustitution of Tm and V in Bi4Ti3O12 (BIT) ceramics is effective for the improvement of the ferroelectricity of Bi4Ti3O12 ceramics.
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Yoon, Joonsik, Minjoo Noh, Jun Bae Lee und Jun Hyup Lee. „Highly Sustainable and Completely Amorphous Hierarchical Ceramide Microcapsules for Potential Epidermal Barrier“. Polymers 12, Nr. 9 (22.09.2020): 2166. http://dx.doi.org/10.3390/polym12092166.
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As a main component of the stratum corneum, ceramides can construct protective lamellae to provide an epidermal barrier against dehydration or external microorganisms. However, as ceramide molecules can easily form the isolated crystalline phase through self-assembly due to the amphipathic nature of bioactive lipids, the effective incorporation of ceramides into liquid media is the remaining issue for controlled release. Here, we report an unprecedented effective strategy to fabricate a completely amorphous and highly sustainable hierarchical ceramide polymer microcapsule for promising epidermal barrier by using the interpenetrating and cooperative self-construction of conical amphiphiles with a different critical packing parameter. The self-constructed amorphous architecture of ceramides in polymer microcapsule is achieved by the facile doping of conical amphiphiles and subsequent in situ polymerization of shell polymer in the core-shell geometry. It is experimentally revealed that an irregular cooperative packing structure formed by adaptive hydrophobic–hydrophilic interactions of cylindrical ceramides and conical amphiphiles in the confined microcapsule geometry enables a completely amorphous morphology of ceramides to be realized during the spontaneous encapsulation process. Furthermore, this elegant approach affords a highly dispersible and uniform hierarchical amorphous ceramide microcapsule with a greatly enhanced long-term stability compared to conventional crystalline ceramides.
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La Corte, Emanuele, Michele Dei Cas, Alberto Raggi, Monica Patanè, Morgan Broggi, Silvia Schiavolin, Chiara Calatozzolo et al. „Long and Very-Long-Chain Ceramides Correlate with A More Aggressive Behavior in Skull Base Chordoma Patients“. International Journal of Molecular Sciences 20, Nr. 18 (11.09.2019): 4480. http://dx.doi.org/10.3390/ijms20184480.
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Background: Skull base chordomas are rare tumors arising from notochord. Sphingolipids analysis is a promising approach in molecular oncology, and it has never been applied in chordomas. Our aim is to investigate chordoma behavior and the role of ceramides. Methods: Ceramides were extracted and evaluated by liquid chromatography and mass spectrometry in a cohort of patients with a skull base chordoma. Clinical data were also collected and correlated with ceramide levels. Linear regression and correlation analyses were conducted. Results: Analyzing the association between ceramides level and MIB-1, total ceramides and dihydroceramides showed a strong association (r = 0.7257 and r = 0.6733, respectively) with MIB-1 staining (p = 0.0033 and p = 0.0083, respectively). Among the single ceramide species, Cer C24:1 (r = 0.8814, p ≤ 0.0001), DHCer C24:1 (r = 0.8429, p = 0.0002) and DHCer C18:0 (r = 0.9426, p ≤ 0.0001) showed a significant correlation with MIB-1. Conclusion: Our lipid analysis showed ceramides to be promising tumoral biomarkers in skull base chordomas. Long- and very-long-chain ceramides, such as Cer C24:1 and DHCer C24:1, may be related to a prolonged tumor survival and aggressiveness, and the understanding of their effective biological role will hopefully shed light on the mechanisms of chordoma radio-resistance, tendency to recur, and use of agents targeting ceramide metabolism.
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TSERNG, Kou-Yi, und Ronda L. GRIFFIN. „Ceramide metabolite, not intact ceramide molecule, may be responsible for cellular toxicity“. Biochemical Journal 380, Nr. 3 (15.06.2004): 715–22. http://dx.doi.org/10.1042/bj20031733.
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Ceramides, which are produced from the hydrolysis of sphingomyelin or synthesized from serine and palmitate in a de novo pathway, are regarded as important cellular signals for inducing apoptosis. However, controversy over this proposed role of ceramides exists. Using stable isotope labelling coupled with GC (gas chromatography)-MS and mass isotopomer distribution analysis, we have studied the metabolism of exogenous long-chain ceramides in HL60 cells. Our results do not support the concept of enhanced ceramide transport into cells induced by solvent mixtures of ethanol and hydrocarbons. In addition, cell toxicity does not correlate with the amount of intact ceramide in the cells. Our results are more consistent with a disturbance of sphingomyelin metabolism induced by the solvent mixture. The characteristics of this disturbed sphingolipid disposition are the inhibition of dihydroceramide desaturation and an enhanced degradation of sphingomyelin. As a consequence, dihydroceramides accumulate and the cellular sphingomyelin content decreases. Inhibition of these pathways is most likely to be induced by the increased production of novel ceramide metabolites instead of by intact ceramides. Octadecane-1,2-diol is identified as a possible mediator. Treatments that divert ceramide degradation to the novel pathway are potential strategies in cancer therapy for inducing cell toxicity.
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Yan, Yan Yan, Bo Zhao und Jun Li Liu. „Research on the Fracture Phenomenon of Zirconia-Toughened Alumina Ceramics under Ultrasonic Vibration“. Key Engineering Materials 455 (Dezember 2010): 156–60. http://dx.doi.org/10.4028/www.scientific.net/kem.455.156.
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A study of the fracture phenomenon of zirconia-toughened alumina (ZTA) ceramics was carried. It analyzes the mechanisms of crack propagation of ZTA ceramics, and constructs fracture experiments of ZTA ceramics, so the propagation behavior on fracture in ZTA ceramics was investigated according to the experiment. By contrast, intercrystalline fracture happed in V-shaped groove of ceramic specimen under normal load without ultrasonic vibration during ceramic fracture, and transcrystalline fracture happed in V-shaped groove of ceramic specimen under normal load with ultrasonic vibration during ceramic fracture. Furthermore, the loading force of ceramic specimen under normal load with ultrasonic vibration is smaller than that under normal load without ultrasonic vibration all other conditions being equal. The results of fracture experiment prove that ultrasonic vibration assisted is good for the fracture of ceramic specimen, and it also proves that ultrasonic vibration assisted grinding may raise the working efficiency and improve surface integrity of ceramics from the standpoint of the fracture.
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Fujii, Masanori. „The Pathogenic and Therapeutic Implications of Ceramide Abnormalities in Atopic Dermatitis“. Cells 10, Nr. 9 (10.09.2021): 2386. http://dx.doi.org/10.3390/cells10092386.
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Ceramides play an essential role in forming a permeability barrier in the skin. Atopic dermatitis (AD) is a common chronic skin disease associated with skin barrier dysfunction and immunological abnormalities. In patients with AD, the amount and composition of ceramides in the stratum corneum are altered. This suggests that ceramide abnormalities are involved in the pathogenesis of AD. The mechanism underlying lipid abnormalities in AD has not yet been fully elucidated, but the involvement of Th2 and Th1 cytokines is implicated. Ceramide-dominant emollients have beneficial effects on skin barrier function; thus, they have been approved as an adjunctive barrier repair agent for AD. This review summarizes the current understanding of the mechanisms of ceramide abnormalities in AD. Furthermore, the potential therapeutic approaches for correcting ceramide abnormalities in AD are discussed.
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Richter, Christoph, und Pedram Ghafourifar. „Ceramide induces cytochrome c release from isolated mitochondria“. Biochemical Society Symposia 66 (01.09.1999): 27–31. http://dx.doi.org/10.1042/bss0660027.
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This chapter addresses the role of mitochondria in apoptosis. Emphasis is put on the recently observed influence of ceramides on mitochondrial functions. We report here that N-acetylsphingosine (C2-ceramide), N-hexanoylsphingosine (C6-ceramide) and, to a much lesser extent, C2-dihydroceramide, induce cytochrome c (cyt c) release from isolated rat liver mitochondria. Ceramide-induced cyt c release is prevented by a low concentration of Bcl-2. The release takes place when cyt c is oxidized, but not when it is reduced. Upon cyt c release mitochondrial oxygen consumption, mitochondrial transmembrane potential (ΔΨm) and Ca2+ retention are diminished. Bcl-2 prevents, and addition of cyt c reverses, the alteration of these mitochondrial functions. In ATP-energized mitochondria ceramides do not alter ΔΨm, neither when cyt c is oxidized nor when it is reduced. This rules out a non-specific disturbance by ceramides of mitochondrial-membrane integrity. It is concluded that some of the apoptogenic properties of ceramides are mediated via their interaction with mitochondrial cyt c followed by its release.
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Hansen, M. E., T. S. Tippetts, M. C. Anderson, Z. E. Holub, E. R. Moulton, A. C. Swensen, J. T. Prince und B. T. Bikman. „Insulin Increases Ceramide Synthesis in Skeletal Muscle“. Journal of Diabetes Research 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/765784.
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Aims. The purpose of this study was to determine the effect of insulin on ceramide metabolism in skeletal muscle.Methods. Skeletal muscle cells were treated with insulin with or without palmitate for various time periods. Lipids (ceramides and TAG) were isolated and gene expression of multiple biosynthetic enzymes were quantified. Additionally, adult male mice received daily insulin injections for 14 days, followed by muscle ceramide analysis.Results. In muscle cells, insulin elicited an increase in ceramides comparable to palmitate alone. This is likely partly due to an insulin-induced increase in expression of multiple enzymes, particularly SPT2, which, when knocked down, prevented the increase in ceramides. In mice, 14 days of insulin injection resulted in increased soleus ceramides, but not TAG. However, insulin injections did significantly increase hepatic TAG compared with vehicle-injected animals.Conclusions. This study suggests that insulin elicits an anabolic effect on sphingolipid metabolism in skeletal muscle, resulting in increased ceramide accumulation. These findings reveal a potential mechanism of the deleterious consequences of the hyperinsulinemia that accompanies insulin resistance and suggest a possible novel therapeutic target to mitigate its effects.
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Seitz, Aaron P., Heike Grassmé, Michael J. Edwards, Yael Pewzner-Jung und Erich Gulbins. „Ceramide and sphingosine in pulmonary infections“. Biological Chemistry 396, Nr. 6-7 (01.06.2015): 611–20. http://dx.doi.org/10.1515/hsz-2014-0285.
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Abstract Acid sphingomyelinase and ceramide have previously been shown to play a central role in infections with Neisseria gonorrhoeae, Staphylococcus aureus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli, and Mycobacterium avium. Recent studies have extended the role of sphingolipids in bacterial infections and have demonstrated that ceramide and sphingosine are central to the defense of lungs against bacterial pathogens. Ceramide accumulates in the airway epithelium of cystic fibrosis and ceramide synthase 2 (CerS2)-deficient mice, which respond to the lack of very long chain (C22-C24-) ceramides with a profound compensatory increase of long chain (mainly C16-) ceramides. In contrast, sphingosine is present in healthy airways and is almost completely absent from diseased or deficient epithelial cells. Both sphingolipids are crucially involved in the high susceptibility to infection of cystic fibrosis and CerS2-deficient mice, as indicated by findings showing that the normalization of ceramide and sphingosine levels rescue these mice from acute infection with P. aeruginosa.
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Vacaru, Ana M., Fikadu G. Tafesse, Philipp Ternes, Vangelis Kondylis, Martin Hermansson, Jos F. H. M. Brouwers, Pentti Somerharju, Catherine Rabouille und Joost C. M. Holthuis. „Sphingomyelin synthase-related protein SMSr controls ceramide homeostasis in the ER“. Journal of Cell Biology 185, Nr. 6 (08.06.2009): 1013–27. http://dx.doi.org/10.1083/jcb.200903152.
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Ceramides are central intermediates of sphingolipid metabolism with critical functions in cell organization and survival. They are synthesized on the cytosolic surface of the endoplasmic reticulum (ER) and transported by ceramide transfer protein to the Golgi for conversion to sphingomyelin (SM) by SM synthase SMS1. In this study, we report the identification of an SMS1-related (SMSr) enzyme, which catalyses the synthesis of the SM analogue ceramide phosphoethanolamine (CPE) in the ER lumen. Strikingly, SMSr produces only trace amounts of CPE, i.e., 300-fold less than SMS1-derived SM. Nevertheless, blocking its catalytic activity causes a substantial rise in ER ceramide levels and a structural collapse of the early secretory pathway. We find that the latter phenotype is not caused by depletion of CPE but rather a consequence of ceramide accumulation in the ER. Our results establish SMSr as a key regulator of ceramide homeostasis that seems to operate as a sensor rather than a converter of ceramides in the ER.
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Spassieva, Stefka D., Xiaojie Ji, Ye Liu, Kenneth Gable, Jacek Bielawski, Teresa M. Dunn, Erhard Bieberich und Lihong Zhao. „Ectopic expression of ceramide synthase 2 in neurons suppresses neurodegeneration induced by ceramide synthase 1 deficiency“. Proceedings of the National Academy of Sciences 113, Nr. 21 (09.05.2016): 5928–33. http://dx.doi.org/10.1073/pnas.1522071113.
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Sphingolipids exhibit extreme functional and chemical diversity that is in part determined by their hydrophobic moiety, ceramide. In mammals, the fatty acyl chain length variation of ceramides is determined by six (dihydro)ceramide synthase (CerS) isoforms. Previously, we and others showed that mutations in the major neuron-specific CerS1, which synthesizes 18-carbon fatty acyl (C18) ceramide, cause elevation of long-chain base (LCB) substrates and decrease in C18 ceramide and derivatives in the brain, leading to neurodegeneration in mice and myoclonus epilepsy with dementia in humans. Whether LCB elevation or C18 ceramide reduction leads to neurodegeneration is unclear. Here, we ectopically expressed CerS2, a nonneuronal CerS producing C22–C24 ceramides, in neurons of Cers1-deficient mice. Surprisingly, the Cers1 mutant pathology was almost completely suppressed. Because CerS2 cannot replenish C18 ceramide, the rescue is likely a result of LCB reduction. Consistent with this hypothesis, we found that only LCBs, the substrates common for all of the CerS isoforms, but not ceramides and complex sphingolipids, were restored to the wild-type levels in the Cers2-rescued Cers1 mutant mouse brains. Furthermore, LCBs induced neurite fragmentation in cultured neurons at concentrations corresponding to the elevated levels in the CerS1-deficient brain. The strong association of LCB levels with neuronal survival both in vivo and in vitro suggests high-level accumulation of LCBs is a possible underlying cause of the CerS1 deficiency-induced neuronal death.
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Bagautdinov, M. R. „Liver and skeletal muscle ceramides in alloxan-induced diabetes“. Kazan medical journal 95, Nr. 3 (15.06.2014): 402–4. http://dx.doi.org/10.17816/kmj1525.
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Aim. To study of liver and sceletal muscle ceramides in alloxan-induced diabetes at different periods after alloxan exposure. Methods. Repeated experiments were performed on white male rats. Diabetes was modeled by alloxan hydrochloride solution intraperitoneal injection. The disease development was monitored using clinical and laboratory parameters. Ceramides in tissues were determined in intact animals (control), at the 10, 20, 30, 45 and 60 day after the alloxan injection. Ceramides level in the plates was determined by thin layer chromatography using the external standard. Results. In intact animals, ceramides level in liver was twice as high as in muscle. At all terms after alloxan injection, ceramide level was significantly higher compared to controls, and was in muscle compared to liver, with similar change pattern. Up to the 20th day, a significant increase of ceramide level was observed compared to control (eightfold in liver and sevenfold in muscle). By 30th day, a partial recovery was registered, followed by subsequent increase of ceramide level. This indicates the influence of compensation mechanisms in the early stages of the experiment with further decompensation on late stages. Conclusion. In alloxan-induced type 1 diabetes, ceramide level in insulin-dependent tissues depends on the term after the alloxan injection; the findings are of great importance for the research of secondary insulin resistance, as well as other diabetes-associated pathological conditions, exact mechanisms.
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Cui, Fengdan, Guoqing Wu, Tian Ma und Weiping Li. „Effect of Ceramic Properties and Depth-of-penetration Test Parameters on the Ballistic Performance of Armour Ceramics“. Defence Science Journal 67, Nr. 3 (25.04.2017): 260. http://dx.doi.org/10.14429/dsj.67.10664.
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<p>Through an analysis on the relationship among ceramic properties, the depth of penetration (DOP) test parameters and the ballistic performance of armour ceramics based on literatures, the effects of ceramic type, tile thickness and projectile velocity on the ballistic performance of different kinds of ceramics were investigated systematically. The results show that the ballistic performance of different armour ceramics mainly depends on its density, and by using thin ceramic tiles or under high velocity impact, the ceramic composite armour could not provide effective ballistic protection. Furthermore, the differences in the ballistic performance of armour ceramic are found due to the different ballistic performance criteria and DOP test conditions. Additionally, the slope of the depth of penetration (not include tile thickness) (Pa) versus tile thickness has negative correlation with flexural strength of ceramics, indicating the flexural strength can be one of the criteria to evaluate the performance of armour ceramics.</p>
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Rudd, Andrew K., und Neal K. Devaraj. „Traceless synthesis of ceramides in living cells reveals saturation-dependent apoptotic effects“. Proceedings of the National Academy of Sciences 115, Nr. 29 (02.07.2018): 7485–90. http://dx.doi.org/10.1073/pnas.1804266115.
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Mammalian cells synthesize thousands of distinct lipids, yet the function of many of these lipid species is unknown. Ceramides, a class of sphingolipid, are implicated in several cell-signaling pathways but poor cell permeability and lack of selectivity in endogenous synthesis pathways have hampered direct study of their effects. Here we report a strategy that overcomes the inherent biological limitations of ceramide delivery by chemoselectively ligating lipid precursors in vivo to yield natural ceramides in a traceless manner. Using this method, we uncovered the apoptotic effects of several ceramide species and observed differences in their apoptotic activity based on acyl-chain saturation. Additionally, we demonstrate spatiotemporally controlled ceramide synthesis in live cells through photoinitiated lipid ligation. Our in situ lipid ligation approach addresses the long-standing problem of lipid-specific delivery and enables the direct study of unique ceramide species in live cells.
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Wu, Hongchang, und Yamin Ma. „Application of 3D Printing Reconstruction Algorithm in Ancient Ceramic Restoration“. Scientific Programming 2022 (29.01.2022): 1–10. http://dx.doi.org/10.1155/2022/8529229.
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The study of the ancient ceramic is of great significance to the identification of authenticity, value recognition, cultural types, and dissemination channels of the ceramic. In this study, a series of technical problems such as ceramic contour extraction, image distortion correction, and nonlinear contour modeling for 3D printing of rotating body under complex background were solved and a restoration algorithm for the shape of ancient ceramics was proposed. Then, an accurate contour model is established by using the two-dimensional images of the rotating ancient ceramics to reconstruct the three-dimensional model of the ceramic shape. The experimental results show that the modeling algorithm for three-dimensional printed ceramics can accurately obtain the three-dimensional model of rotating ancient ceramics, which is of certain significance to explore a new direction of the research and development of three-dimensional printed ancient ceramics.
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ALLAN, David. „Lipid metabolic changes caused by short-chain ceramides and the connection with apoptosis“. Biochemical Journal 345, Nr. 3 (25.01.2000): 603–10. http://dx.doi.org/10.1042/bj3450603.
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The effects of the short-chain ceramides D-erythro-N-acetylsphingosine (C2-ceramide), 6-[N-(7-nitrobenz-2-oxa-1,3-diazole-4-yl)amino]hexanoyl-D-erythro-sphingosine (NBD-ceramide) and N-[4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl]-D-erythro-sphingosine (DMB-ceramide) on the incorporation of [14C]acetate into baby-hamster kidney (BHK) fibroblasts have been examined. C2-ceramide at concentrations up to 20 μM caused an inhibition of synthesis of phosphatidylcholine (PtdCho), sphingolipids and cholesterol within 2 h. Similar effects in BHK cells were seen using other radioactive tracers ([3H]water, [3H]palmitate and [3H]choline) and using HL60 cells labelled with [14C]acetate. The inhibition of PtdCho synthesis corresponded to an accumulation of label in diacylglycerol and triacylglycerol, probably as a consequence of cytidylyltransferase blockade. With [3H]choline label, the decrease in sphingomyelin synthesis could be partly accounted for by accumulation of a slow-moving lipid, likely to be C2-sphingomyelin. NBD-ceramide also reduced sphingomyelin and cholesterol biosynthesis, but had much less effect on PtdCho and acylglycerols. In contrast, the only apparent effect of DMB-ceramide was to inhibit synthesis of sphingomyelin, with a reciprocal increase in DMB-sphingomyelin synthesis. However, all of these short-chain ceramides caused massive apoptosis after 18 h, whereas addition of N-acetyldihydrosphingosine or elevation of natural ceramide by treatment of cells with sphingomyelinase had little effect on lipid synthesis or apoptosis. The present findings suggest that the apoptotic effect of short-chain ceramides is sometimes associated with inhibition of cytidylyltransferase, but is more closely correlated with a competitive inhibition of normal sphingomyelin biosynthesis.
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Xie, Ru Hong, Jun Jie Feng und Shan Xin Feng. „Application Research of High Temperature Silver Plating in Products“. Materials Science Forum 980 (März 2020): 70–78. http://dx.doi.org/10.4028/www.scientific.net/msf.980.70.
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Silver has functional properties such as disinfection, sterilization, and anti-corrosion.The combination of silver and conventional ceramics by high-temperature silver plating can impart the functionality to ceramic products and increase the functionality of ceramic products.The traditional way of decorating ceramic products is mainly glazed decoration, which combines silver and ceramics, and its silver metallic luster can bring decorative effects to ceramic products. And it is produced by high-temperature silver plating, which saves costs in the production process compared to traditional silver plating.At the same time, compared with traditional ceramics, high-temperature silver-plated ceramics can take into account the properties of ceramics and can also play the role of disinfection, sterilization, anti-corrosion and other properties of silver. It is produced by high-temperature silver plating, which is more cost-effective than traditional silver plating in the production process. At the same time, compared with traditional ceramics, high-temperature silver-plated ceramics can achieve the disinfection and sterilization of silver in consideration of the properties of ceramics,anti-corrosion and other attributes, a reasonable combination of the two, fully demonstrate the functionality and decoration of both.
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Chung, Jin Ook, Christina Koutsari, Agnieszka Urszula Blachnio-Zablieska, Kazanna C. Hames und Michael D. Jensen. „Effects of meal ingestion on intramyocellular ceramide concentrations and fractional de novo synthesis in humans“. American Journal of Physiology-Endocrinology and Metabolism 314, Nr. 2 (01.02.2018): E105—E114. http://dx.doi.org/10.1152/ajpendo.00153.2017.
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We investigated the effects of meal ingestion on intramyofibrillar (IMF) and subsarcolemmal (SS) ceramide metabolism in volunteers ranging from lean to obese. Thirty-eight women and men underwent a steady-state meal ingestion protocol that included a 6.5-h infusion of [U-13C]palmitate and muscle biopsies 1.5 and 6.5 h after starting the tracer infusion. We measured IMF and SS sphingolipid concentrations and the contribution of plasma palmitate to intramyocellular C16:0 ceramide by use of LC-MS-MS. In response to meal ingestion SS C24 ceramide concentrations, but not C14-C20 concentrations, increased significantly. IMF ceramide concentrations did not change. The increases in SS C24 ceramides were negatively related to parameters of insulin resistance. The fractional contribution of plasma palmitate to intramyocellular C16:0 ceramides in both IMF and SS fractions was inversely related to overweight status (β = –0.432, P = 0.0095 and β = –0.443, P = 0.0058, respectively). These data indicate that meal ingestion has differing effects on SS ceramide subspecies and suggest that the fractional de novo synthesis of intramyocellular ceramide from plasma palmitate in the postprandial condition is reduced in those who are overweight.