Wells, P. G., Bhuller, Y., Chen, C. S., Jeng, W., Kasapinovic, S., Kennedy, J. C., et al. (2005). Molecular and biochemical mechanisms in teratogenesis involving reactive oxygen species. Toxicol Appl Pharmacol, 207(2 Suppl), 354–366.
Abstract: Developmental pathologies may result from endogenous or xenobiotic-enhanced formation of reactive oxygen species (ROS), which oxidatively damage cellular macromolecules and/or alter signal transduction. This minireview focuses upon several model drugs (phenytoin, thalidomide, methamphetamine), environmental chemicals (benzo[a]pyrene) and gamma irradiation to examine this hypothesis in vivo and in embryo culture using mouse, rat and rabbit models. Embryonic prostaglandin H synthases (PHSs) and lipoxygenases bioactivate xenobiotics to free radical intermediates that initiate ROS formation, resulting in oxidation of proteins, lipids and DNA. Oxidative DNA damage and embryopathies are reduced in PHS knockout mice, and in mice treated with PHS inhibitors, antioxidative enzymes, antioxidants and free radical trapping agents. Thalidomide causes embryonic DNA oxidation in susceptible (rabbit) but not resistant (mouse) species. Embryopathies are increased in mutant mice deficient in the antioxidative enzyme glucose-6-phosphate dehydrogenase (G6PD), or by glutathione (GSH) depletion, or inhibition of GSH peroxidase or GSH reductase. Inducible nitric oxide synthase knockout mice are partially protected. Inhibition of Ras or NF-kB pathways reduces embryopathies, implicating ROS-mediated signal transduction. Atm and p53 knockout mice deficient in DNA damage response/repair are more susceptible to xenobiotic or radiation embryopathies, suggesting a teratological role for DNA damage, consistent with enhanced susceptibility to methamphetamine in ogg1 knockout mice with deficient repair of oxidative DNA damage. Even endogenous embryonic oxidative stress carries a risk, since untreated G6PD- or ATM-deficient mice have increased embryopathies. Thus, embryonic processes regulating the balance of ROS formation, oxidative DNA damage and repair, and ROS-mediated signal transduction may be important determinants of teratological risk.
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Guo, G. L., Moffit, J. S., Nicol, C. J., Ward, J. M., Aleksunes, L. A., Slitt, A. L., et al. (2004). Enhanced acetaminophen toxicity by activation of the pregnane X receptor. Toxicol Sci, 82(2), 374–380.
Abstract: The pregnane X receptor (PXR) is a ligand-activated transcription factor and member of the nuclear receptor superfamily. Activation of PXR represents an important mechanism for the induction of cytochrome P450 3A (CYP3A) enzymes that can convert acetaminophen (APAP) to its toxic intermediate metabolite, N-acetyl-p-benzoquinone imine (NAPQI). Therefore, it was hypothesized that activation of PXR plays a major role in APAP-induced hepatotoxicity. Pretreatment with the PXR activator, pregnenolone 16alpha-carbonitrile (PCN), markedly enhanced APAP-induced hepatic injury, as revealed by increased serum ALT levels and hepatic centrilobular necrosis, in wild-type but not in PXR-null mice. Further analysis showed that following PCN treatment, PXR-null mice had lower CYP3A11 expression, decreased NAPQI formation, and increased maintenance of hepatic glutathione content compared to wild-type mice. Thus, these results suggest that PXR plays a critical role in APAP-induced hepatic toxicity, probably by inducing CYP3A11 expression and hence increasing bioactivation.
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Hunt, G. R., Gray R.D., & Taylor, A. H. (2013). Why is tool use rare in animals? (Boesch C C. J. anz C, Ed.). Cambridge, MA.: Cambridge University Press.
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Westerduin, F. E., Lankveld, D. P. K., van der Velden, M. A., Back, W., & Sloet van Oldruitenborgh-Oosterbaan, M. M. (2003). [Splenectomy in a dressage pony: end of sports career?]. Tijdschr Diergeneeskd, 128(13), 406–411.
Abstract: A 14-year-old Arabian cross-bred gelding was referred to the University Clinic because of mild, recurrent signs of colic for 5 days. The pony showed icteric mucous membranes, haemolytic blood, and dark coloured urine. Internal examination did not give a clear diagnosis. Unidentified intra-abdominal strands were found and haemorrhagic abdominocentesis led to the decision to perform an exploratory laparatomy. An extremely enlarged spleen was the sole finding. A splenal biopsy sample was taken and surgery was completed. The pony remained colicky, so the spleen was examined by ultrasonography. After this examination, the tentative diagnosis 'tumour of the spleen' was made and splenectomy was performed. Pathological examination of the spleen revealed splenomegaly caused by infarctions of unknown origin. Eight weeks after surgery, the pony started again in dressage competition. Six months after splenectomy, the pony won the provincial dressage competition.
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Boissevain, I. (2007). [Animal and human rights in installments] (Vol. 132).
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Sloet van Oldruitenborgh-Oosterbaan, M. M., Blok, M. B., Begeman, L., Kamphuis, M. C. D., Lameris, M. C., Spierenburg, A. J., et al. (2006). Workload and stress in horses: comparison in horses ridden deep and round ('rollkur') with a draw rein and horses ridden in a natural frame with only light rein contact. Tijdschr Diergeneeskd, 131(5), 152–157.
Abstract: 'Rollkur' or 'overbending' is the low and deep riding of a dressage horse during training or warming up. Lately, this technique has been criticized, and not necessarily objectively, on welfare grounds. To be able to evaluate these criticisms, more needs to be known about the workload and stress of horses being ridden 'rollkur'. The aim of the present study was to compare the workload of eight riding-school horses when being ridden deep and round with a draw rein ('rollkur') and when being ridden in a natural frame with only light rein contact ('free'). Workload (as measured by heart rate and blood lactate concentration) was slightly higher when horses were ridden 'rollkur' than when they were ridden 'free'. There were no differences in packed cell volume, or glucose and cortisol concentrations. No signs of uneasiness or stress could be determined when the horses were ridden 'rollkur'. Subjectively, all horses improved their way of moving during 'rollkur' and were more responsive to their rider.
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Huebener, E. (2004). Die Bewegungen von Pferderumpf und -rücken aus der Sicht des Reiters. Tierärztl. Umschau, 6, 327–334.
Abstract: Die Bewegungen von Rumpf und Rücken des Pferdes in der Fortbewegung bestimmen Sitz und Schenkelhilfen – Grundlagen pferdgerechten und kultivierten, feinfühligen Reitens. In ihrer Tendenz ließen sich diese Bewegungen jetzt aus den Fußfolgen der Grundgangarten ableiten. Die Erkenntnisse sind per Video verifiziert. Mit ihrer Übersetzung in Diagramme wurde versucht, den gegenwärtigen Wissensstand für nicht-reitende Wissenschaftler und denkende Reiter gleichermaßen verständlich darzustellen. Die Akzeptanz des aufbereiteten Wissens in der Reiterei würde verbessert, wenn man zu gemessenen Werten für die Bewegungen des Pferderückens und des Pferderumpfes käme. Plädoyer eines “Nur-Reiters” für einschlägige, universitäre Forschung.
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Huebener, E. (2005). Der Natur abgelauschte Erkenntnisse: Der Weg zum Balancesitz und zum Begreifen des Timers für Signale an das Pferd;. Tierärztl. Umschau, 2, 90–99.
Abstract: Zusammenfassung
Mit dem Beitrag “Die Bewegungen von Pferderumpf und -rücken aus der Sicht des Reiters” (TU 59, 327-334, 2004) wurde um universitäre Forschung zur Ermittlung gemessener Werte für diese Begleiter der Fortbewegung geworben.
Die Entdeckung des Ranges der Rumpf-Rücken-Bewegungen für pferdgerechtes und kultiviertes, feinfühliges Reiten ist mit der Entwicklung des Balancesitzes und der Technik des vom Pferd Zeitvorgaben Empfangens und ihm Signale Sendens (Reiter sagen: des Fühlens und Einwirkens) eng verbunden. Ihre Geschichte läßt sich über viereinhalb Jahrhunderte verfolgen. Ein kurzer Abriß wird hier nachgeliefert.
Er mündet erneut in ein Plädoyer für interdisziplinäres universitäres Forschen, weil auch bei Sitz und Hilfengebung, weiteren Grundlagen des Reitens – im Interesse effektiveren Unterrichts an der Basis unseres “Sports” – dringender Klärungsbedarf besteht.
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Huebener, E. (2004). Movements of Trunk and Back of the Horse from a Rider's View. Tierärztl. Umschau, 6, 327.
Abstract: The trunk and back movements of the horse during locomotion determine seat position and leg aids of the rider, this is the basis for horse-oriented and cultivated, sensitive riding. In their tendency these movements could now be derived from the foot sequences of the basic paces. The realizations are verified by video. By translating these movements into diagrams, the author is making an attempt to present the current state of knowledge for non-riding scholars and academically oriented riders alike. The acceptance of the prepared riding knowledge would be improved if one could produce measured values of the horse's back and trunk movements. An appeal of a rider for relevant, scholarly research.
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Huebener, E. (2005). Listening to Nature: Ways to A Balanced Seat and Understanding the Correct Timing for the Rider's Aids. Tierärztl. Umschau, 2, 90–99.
Abstract: In the publication “Movements of trunk and back of the horse from a riders view” in the TU 59, 327-334, 2004 the author suggested that academic research is necessary to determine measurable parameters for these agents of the horse's movement.
The discovery of the importance of the trunk-back-movements for a sensitive and horse-oriented riding style is closely connected to the development of the balanced seat and the technique of receiving signals from and sending signals to the horse at the right time (riders would say: “the feel and the impact”). The history of this interaction between horse and rider can be traced for four and a half centuries. A short digest will be published here later. Again the studies result in a demand for interdisciplinary academic research.
There is an urgent need to clarify the impact of the riders's seat and aids (two more pillars in the art of riding) in the interest teaching riding correctly and more efficiently at the so-called 'basis' of our sport.
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