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  • 1
    In: Human Brain Mapping, Wiley, Vol. 42, No. 18 ( 2021-12-15), p. 6000-6013
    Kurzfassung: Children's learning capabilities change while growing up. One framework that describes the cognitive and neural development of children's growing learning abilities is the two‐component model. It distinguishes processes that integrate separate features into a coherent memory representation (associative component) and executive abilities, such as elaboration, evaluation, and monitoring, that support memory processing (strategic component). In an fMRI study using an object‐location association paradigm, we investigated how the two components influence memory performance across development. We tested children (10–12 years, n  = 31), late adolescents (18 years, n  = 29), and adults (25+ years, n  = 30). For studying the associative component, we also probed how the utilisation of prior knowledge (schemas) facilitates memory across age groups. Children had overall lower retrieval performance, while adolescents and adults did not differ from each other. All groups benefitted from schemas, but this effect did not differ between groups. Performance differences between groups were associated with deactivation of the dorsal medial prefrontal cortex (dmPFC), which in turn was linked to executive functioning. These patterns were stronger in adolescents and adults and seemed absent in children. Thus, the children's executive system, the strategic component, is not as mature and thus cannot facilitate memory performance in the same way as in adolescents/adults. In contrast, we did not find age‐related differences in the associative component; with activity in the angular gyrus predicting memory performance systematically across groups. Overall, our results suggest that differences of executive rather than associative abilities explain memory differences between children, adolescents, and adults.
    Materialart: Online-Ressource
    ISSN: 1065-9471 , 1097-0193
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2021
    ZDB Id: 1492703-2
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    Online-Ressource
    Online-Ressource
    Wiley ; 2021
    In:  Human Brain Mapping Vol. 42, No. 18 ( 2021-12-15)
    In: Human Brain Mapping, Wiley, Vol. 42, No. 18 ( 2021-12-15)
    Materialart: Online-Ressource
    ISSN: 1065-9471 , 1097-0193
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2021
    ZDB Id: 1492703-2
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    Online-Ressource
    Online-Ressource
    Springer Science and Business Media LLC ; 2015
    In:  Bioprocess and Biosystems Engineering Vol. 38, No. 9 ( 2015-9), p. 1685-1692
    In: Bioprocess and Biosystems Engineering, Springer Science and Business Media LLC, Vol. 38, No. 9 ( 2015-9), p. 1685-1692
    Materialart: Online-Ressource
    ISSN: 1615-7591 , 1615-7605
    Sprache: Englisch
    Verlag: Springer Science and Business Media LLC
    Publikationsdatum: 2015
    ZDB Id: 1476357-6
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    In: Animals, MDPI AG, Vol. 13, No. 15 ( 2023-07-26), p. 2410-
    Kurzfassung: Equine atypical myopathy is caused by hypoglycin A (HGA) and methylenecyclopropylglycine (MCPrG), the known protoxins of sycamore maple (Acer pseudoplatanus). Various tissues from five atypical myopathy cases were analyzed but only HGA was found. Whether deamination of MCPrG has already occurred in the intestine as the first stage of metabolization has not been investigated. Activation of the protoxins to methylenecyclopropylacetyl (MCPA)-CoA and methylenecyclopropylformyl (MCPF)-CoA, respectively, occurred mainly in the skeletal muscles, as evidenced by very high concentrations of MCPA-carnitine and MCPF-carnitine in this tissue. Inhibition of the acyl-CoA dehydrogenases of short- and medium-chain as well as branched-chain fatty acids by the toxins led to a strong increase in the corresponding acylcarnitines, again preferentially in skeletal muscles. An accumulation of the long-chain acylcarnitines beyond the level of the control samples could not be detected in the tissues. As a high amount of HGA was always found unmetabolized in the organs, we speculate that targeting the interruption of further metabolization might be a way to stop the progression of intoxication. Inhibition of the mitochondrial branched-chain amino acid aminotransferase, i.e., the first enzyme responsible for the activation of sycamore maple protoxins, could be a therapeutic approach.
    Materialart: Online-Ressource
    ISSN: 2076-2615
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2023
    ZDB Id: 2606558-7
    SSG: 23
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Online-Ressource
    Online-Ressource
    Frontiers Media SA ; 2021
    In:  Frontiers in Veterinary Science Vol. 8 ( 2021-10-26)
    In: Frontiers in Veterinary Science, Frontiers Media SA, Vol. 8 ( 2021-10-26)
    Kurzfassung: In horses, congenital defects of energy production from long-chain fatty acids have not been described so far. In contrast, inhibition of fatty acid degradation caused by the toxins hypoglycin A and methylenecyclopropylglycine from various maple species are observed frequently. These non-proteinogenic aminoacids are passed on placentally to fetuses or with collostrum or milk to newborn foals. Nevertheless, newborn foals become very rarely symptomatic. Vertical transmission apparently is not sufficient to induce clinical disease without a particular genetic constellation being present. One of these rare cases was investigated here using samples from a mare and her foal. Intoxication by hypoglycin A and methylenecyclopropylglycine is also of interest to human pathology, because these toxins have caused fatal poisonings after consumption of certain fruits many times, especially in children. Maple toxins, their metabolites and some short-chain acyl compounds were quantified by ultrahigh-pressure liquid chromatography/tandem mass spectrometry. An comprehensive spectrum of long-chain acylcarnitines was prepared using electrospray ionization tandem mass spectrometry. Organic acids and acylglycines were determined by gas chromatography mass spectrometry. For evaluation, results of other horses poisoned by maple material as well as unaffected control animals were used. In the serum of the foal, hypoglycin A was detected at a low concentration only. Toxin metabolites reached & lt;3.5% of the mean of a comparison group of horses suffering from atypical myopathy. The spectrum of acylcarnitines indicated enzyme inhibition in short-chain and medium-chain regions typical of acer poisoning, but the measured concentrations did not exceed those previously found in clinically healthy animals after maple consumption. The values were not sufficient to explain the clinical symptoms. In contrast, a remarkably strong enrichment of tetradecenoylcarnitine and hexadecenoylcarnitine was observed. This proves a blockade of the long-chain enoyl-CoA hydratase (EC 4.2.1.74). Vertical transfer of maple toxins to a newborn foal is sufficient for induction of clinical disease only if there is an additional specific reactivity to the active toxins. This was found here in an inhibition of long-chain enoyl-CoA hydratase. Isolated dysfunction of this enzyme has not yet been reported in any species. Further studies are necessary to prove a specific genetic defect.
    Materialart: Online-Ressource
    ISSN: 2297-1769
    Sprache: Unbekannt
    Verlag: Frontiers Media SA
    Publikationsdatum: 2021
    ZDB Id: 2834243-4
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    Online-Ressource
    Online-Ressource
    MDPI AG ; 2017
    In:  International Journal of Neonatal Screening Vol. 3, No. 1 ( 2017-02-04), p. 1-
    In: International Journal of Neonatal Screening, MDPI AG, Vol. 3, No. 1 ( 2017-02-04), p. 1-
    Materialart: Online-Ressource
    ISSN: 2409-515X
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2017
    ZDB Id: 2840820-2
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    Online-Ressource
    Online-Ressource
    Springer Science and Business Media LLC ; 2012
    In:  BMC Gastroenterology Vol. 12, No. 1 ( 2012-12)
    In: BMC Gastroenterology, Springer Science and Business Media LLC, Vol. 12, No. 1 ( 2012-12)
    Materialart: Online-Ressource
    ISSN: 1471-230X
    Sprache: Englisch
    Verlag: Springer Science and Business Media LLC
    Publikationsdatum: 2012
    ZDB Id: 2041351-8
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    Online-Ressource
    Online-Ressource
    Wiley ; 2021
    In:  Journal of Veterinary Internal Medicine Vol. 35, No. 1 ( 2021-01), p. 606-609
    In: Journal of Veterinary Internal Medicine, Wiley, Vol. 35, No. 1 ( 2021-01), p. 606-609
    Kurzfassung: Plants from the Sapindaceae family that are consumed by horses (maple) and humans (ackee and litchi) are known to contain the toxins hypoglycin A and methylenecyclopropylglycine which cause seasonally occurring myopathy in horses and entero‐encephalopathic sickness in humans. Vertical transmission of these toxins from a mare to her foal has been described once. However the mare's milk was not available for analysis in this case. We investigated mare's milk in a similar case. Objective We hypothesized that hypoglycin A and methylenecyclopropylglycine, like other amino acids' are secreted into the milk. Animals Mare with atypical myopathy. Methods A sample of the mare's milk and 6 commercial horse milk samples were extracted with a methanolic standard solution and analyzed for hypoglycin A, methylenecyclopropylglycine, and metabolites using tandem mass spectrometry after column chromatographic separation. Results There were hypoglycin A (0.4 μg/L) and the associated metabolites methylenecyclopropylacetyl glycine and carnitine (18.5 and 24.6 μg/L) plus increased concentrations of several acylcarnitines in the milk. The milk also contained methylenecyclopropylformyl glycine and carnitine (0.8 and 60 μg/L). The latter substances were also detected in 1 of 6 commercial horse milk samples. Conclusions and Clinical Importance Transmission of the maple toxins can occur through mare's milk. Vertical transmission of Sapindacea toxins might also have importance for human medicine, for example, after consumption of ackee or litchi.
    Materialart: Online-Ressource
    ISSN: 0891-6640 , 1939-1676
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2021
    ZDB Id: 2177690-8
    SSG: 22
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 9
    Online-Ressource
    Online-Ressource
    SAGE Publications ; 2016
    In:  Journal of Veterinary Diagnostic Investigation Vol. 28, No. 2 ( 2016-03), p. 98-104
    In: Journal of Veterinary Diagnostic Investigation, SAGE Publications, Vol. 28, No. 2 ( 2016-03), p. 98-104
    Kurzfassung: Hypoglycin A (2-amino-3-(2-methylidenecyclopropyl)propanoic acid) is the plant toxin shown to cause atypical myopathy in horses. It is converted in vivo to methylenecyclopropyl acetic acid, which is transformed to a coenzyme A ester that subsequently blocks beta oxidation of fatty acids. Methylenecyclopropyl acetic acid is also conjugated with carnitine and glycine. Acute atypical myopathy may be diagnosed by quantifying the conjugates of methylenecyclopropyl acetic acid plus a selection of acyl conjugates in urine and serum. We describe a new mass spectrometric method for sample volumes of 〈 0.5 mL. Samples were extracted with methanol containing 5 different internal standards. Extracts were analyzed by ultra–high-performance liquid chromatography–tandem mass spectrometry focusing on 11 metabolites. The total preparation time for a series of 20 samples was 100 min. Instrument run time was 14 min per sample. For the quantification of carnitine and glycine conjugates of methylenecyclopropyl acetic acid in urine, the coefficients of variation for intraday quantification were 2.9% and 3.0%, respectively. The respective values for interday were 9.3% and 8.0%. Methylenecyclopropyl acetyl carnitine was detected as high as 1.18 µmol/L in serum (median: 0.46 µmol/L) and 1.98 mmol/mol creatinine in urine (median: 0.79 mmol/mol creatinine) of diseased horses, while the glycine derivative accumulated up to 1.97 mmol/mol creatinine in urine but was undetectable in most serum samples. In serum samples from horses with atypical myopathy, the intraday coefficients of variation for C4–C8 carnitines and glycines were ≤4.5%. Measured concentrations exceeded those in healthy horses by ~10 to 1,400 times.
    Materialart: Online-Ressource
    ISSN: 1040-6387 , 1943-4936
    Sprache: Englisch
    Verlag: SAGE Publications
    Publikationsdatum: 2016
    ZDB Id: 2265211-5
    SSG: 22
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    Online-Ressource
    Online-Ressource
    International Scientific Information, Inc. ; 2011
    In:  Annals of Transplantation Vol. 16, No. 2 ( 2011), p. 68-75
    In: Annals of Transplantation, International Scientific Information, Inc., Vol. 16, No. 2 ( 2011), p. 68-75
    Materialart: Online-Ressource
    ISSN: 1425-9524
    Sprache: Englisch
    Verlag: International Scientific Information, Inc.
    Publikationsdatum: 2011
    ZDB Id: 2393116-4
    Standort Signatur Einschränkungen Verfügbarkeit
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