130 research outputs found

    Antidepressant Efficacy and Behavioral Comparisons of Two Animal Models of Depression

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    The current study examined the validity of the chronic mild stress and learned helplessness models of depression in addition to testing the efficacy of the tricyclic antidepressant imipramine. Thirty-six male albino rats were randomly assigned to three experimental conditions: control, chronic mild stress (CMS), and learned helplessness (LH). Half of the animals in each condition received IP injections of imipramine at 10 mg/kg/day, and the other half received equal volumes of isotonic saline. All animals were weighed daily throughout experimentation. The CMS animals were chronically stressed for a period of five weeks after which learned helplessness was induced in the LH group through one two hour shock session. All groups were tested weekly for sucrose consumption and following the initiation of learned helplessness behavioral tests were conducted. A Morris Water Maze and open field test were used to evaluate the spatial memory and anxiety behavior respectively of the rats. The results of this study indicate that the CMS model of depression is not very reliable in that sucrose consumption did not decrease even after 6 weeks of testing. The animals given imipramine showed significant growth delays which is indicated by their delayed weight gain in comparison to saline animals. LH rats showed more hyperactivity in the open field test on days 2, 3, and 7 of testing and deficits in spatial memory on the first day of Morris Water Maze testing

    Prolonged High Fat Diet Reduces Dopamine Reuptake without Altering DAT Gene Expression

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    The development of diet-induced obesity (DIO) can potently alter multiple aspects of dopamine signaling, including dopamine transporter (DAT) expression and dopamine reuptake. However, the time-course of diet-induced changes in DAT expression and function and whether such changes are dependent upon the development of DIO remains unresolved. Here, we fed rats a high (HFD) or low (LFD) fat diet for 2 or 6 weeks. Following diet exposure, rats were anesthetized with urethane and striatal DAT function was assessed by electrically stimulating the dopamine cell bodies in the ventral tegmental area (VTA) and recording resultant changes in dopamine concentration in the ventral striatum using fast-scan cyclic voltammetry. We also quantified the effect of HFD on membrane associated DAT in striatal cell fractions from a separate group of rats following exposure to the same diet protocol. Notably, none of our treatment groups differed in body weight. We found a deficit in the rate of dopamine reuptake in HFD rats relative to LFD rats after 6 but not 2 weeks of diet exposure. Additionally, the increase in evoked dopamine following a pharmacological challenge of cocaine was significantly attenuated in HFD relative to LFD rats. Western blot analysis revealed that there was no effect of diet on total DAT protein. However, 6 weeks of HFD exposure significantly reduced the 50 kDa DAT isoform in a synaptosomal membrane-associated fraction, but not in a fraction associated with recycling endosomes. Our data provide further evidence for diet-induced alterations in dopamine reuptake independent of changes in DAT production and demonstrates that such changes can manifest without the development of DIO

    "Sie müssen die Welt auf eine neue Weise betrachten!". Eine von \u27Tenet\u27 inspirierte Reflexion über die Zeitlichkeit pädagogischer Zukunft

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    2020 wurde der Science-Fiction-Spionage-Thriller Tenet des Regisseurs Christopher Nolan veröffentlicht. Der Film traktiert nicht nur kulturell eingewöhnte Sehgewohnheiten, sondern auch Annahmen über chronologische Zeitflüsse, indem er ein komplexes temporales Tableau inszeniert und die Zeiten Gegenwart, Zukunft und Vergangenheit in eine konfrontative Begegnung miteinander bringt. Im vorliegenden Beitrag lassen sich die Autorinnen und der Autor von diesem medialen Zeitzeugnis inspirieren und fragen, ob eine Verkomplizierung des Beziehungsgefüges der Zeiten bzw. der Zeiten-Ordnung auch von pädagogischer Relevanz sein kann: Was passiert mit Pädagogik, wenn man die Chrono-Logik der Zukunft einer kulturtheoretischen Revision unterzieht? Dabei folgen die Autorinnen und der Autor einer Spur, die bei Tenet ihren Ausgang nimmt, den temporaltheoretischen Überlegungen Michael Wimmers und Achim Landwehrs folgt und am Spurende sich der Frage Wie müss(t)en wir die Welt auf eine neue Weise betrachten? anzunehmen beabsichtigt. Dabei schlagen sie vor, Abschied von dem normativ-zielbegründenden Gehalt der Figur einer offenen Zukunft zu nehmen und ihn fruchtbar für einen temporalen Neueinsatz zu machen. (DIPF/Orig.)In 2020, director Christopher Nolan\u27s science fiction spy thriller Tenet was released. The film not only traces culturally accustomed viewing habits but also assumptions about chrono-logical time flows by staging a complex temporal tableau and bringing the present, future and past into a confrontational encounter with each other. In this article, the authors are inspired by this medial testimony of time and its representations of temporality and ask whether a complication of the relational structure of times (or the order of times) can also be of pedagogical relevance: What happens to pedagogy when the chrono-logic of the future is subjected to a cultural-theoretical revision? In doing so, the authors pursue a track that starts with Tenet, follows the temporal-theoretical considerations of Michael Wimmer and Achim Landwehr, and at its end intends to address the question How do/ would we have to look at the world in a new way? In doing so, the authors propose to take leave of the normative-goal-justifying content of the figure of an open future to make it fruitful for a temporal new use of pedagogy. (DIPF/Orig.

    A p38MAPK/MK2 signaling pathway leading to redox stress, cell death and ischemia/reperfusion injury

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    Background Many diseases and pathological conditions are characterized by transient or constitutive overproduction of reactive oxygen species (ROS). ROS are causal for ischemia/reperfusion (IR)-associated tissue injury (IRI), a major contributor to organ dysfunction or failure. Preventing IRI with antioxidants failed in the clinic, most likely due to the difficulty to timely and efficiently target them to the site of ROS production and action. IR is also characterized by changes in the activity of intracellular signaling molecules including the stress kinase p38MAPK. While ROS can cause the activation of p38MAPK, we recently obtained in vitro evidence that p38MAPK activation is responsible for elevated mitochondrial ROS levels, thus suggesting a role for p38MAPK upstream of ROS and their damaging effects.<p></p> Results Here we identified p38MAPKα as the predominantly expressed isoform in HL-1 cardiomyocytes and siRNA-mediated knockdown demonstrated the pro-oxidant role of p38MAPKα signaling. Moreover, the knockout of the p38MAPK effector MAPKAP kinase 2 (MK2) reproduced the effect of inhibiting or knocking down p38MAPK. To translate these findings into a setting closer to the clinic a stringent kidney clamping model was used. p38MAPK activity increased upon reperfusion and p38MAPK inhibition by the inhibitor BIRB796 almost completely prevented severe functional impairment caused by IR. Histological and molecular analyses showed that protection resulted from decreased redox stress and apoptotic cell death.<p></p> Conclusions These data highlight a novel and important mechanism for p38MAPK to cause IRI and suggest it as a potential therapeutic target for prevention of tissue injury.<p></p&gt

    Differential effects of HIF2α antagonist and HIF2α silencing in renal cancer and sensitivity to repurposed drugs

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    Background In clear cell renal cell carcinoma, 80% of cases have biallelic inactivation of the VHL gene, leading to constitutive activation of both HIF1α and HIF2α. As HIF2α is the driver of the disease promoting tumour growth and metastasis, drugs targeting HIF2α have been developed. However, resistance is common, therefore new therapies are needed. Methods We assessed the effect of the HIF2α antagonist PT2385 in several steps of tumour development and performed RNAseq to identify genes differentially expressed upon treatment. A drug screening was used to identify drugs with antiproliferative effects on VHL-mutated HIF2α-expressing cells and could increase effectiveness of PT2385. Results PT2385 did not reduce cell proliferation or clonogenicity but, in contrast to the genetic silencing of HIF2α, it reduced in vitro cell invasion. Many HIF-inducible genes were down-regulated upon PT2385 treatment, whereas some genes involved in cell migration or extracellular matrix were up-regulated. HIF2α was associated with resistance to statins, addition to PT2385 did not increase the sensitivity. Conclusions: this study shows key differences between inhibiting a target versus knockdown, which are potentially targetable

    Pharmacokinetics of intramuscular maropitant in pigs (Sus scrofa domesticus)

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    Pigs are at risk of vomiting from medical conditions as well as the emetic side effects of drugs administered for peri-operative manipulations, but there is a lack of pharmacokinetic data for potential anti-emetic therapies, such as maropitant, in this species. The main objective of this study was to estimate plasma pharmacokinetic parameters for maropitant in pigs after a single intramuscular (IM) administration dosed at 1.0 mg/ kg. A secondary objective was to estimate pilot pharmacokinetic parameters in pigs after oral (PO) administration at 2.0 mg/kg. Maropitant was administered to six commercial pigs at a dose of 1.0 mg/kg IM. Plasma samples were collected over 72 h. After a 7-day washout period, two pigs were administered maropitant at a dose of 2.0 mg/ kg PO. Maropitant concentrations were measured via liquid chromatography/mass spectrometry (LC–MS/ MS). A non-compartmental analysis was used to derive pharmacokinetics parameters. No adverse events were noted in any of the study pigs after administration. Following single IM administration, maximum plasma concentration was estimated at 412.7 ± 132.0 ng/mL and time to maximum concentration ranged from 0.083 to 1.0 h. Elimination half-life was estimated at 6.7 ± 1.28 h, and mean residence time was 6.1 ± 1.2 h. Volume of distribution after IM administration was 15.9 L/ kg. Area under the curve was 1336 ± 132.0 h*ng/mL. The relative bioavailability of PO administration was noted to be 15.5% and 27.2% in the two pilot pigs. The maximum systemic concentration observed in the study pigs after IM administration was higher than what was observed after subcutaneous administration in dogs, cats, or rabbits. The achieved maximum concentration exceeded the concentrations for anti-emetic purposes in dogs and cats; however, a specific anti-emetic concentration is currently not known for pigs. Further research is needed into the pharmacodynam

    Imaging-Based Screen Identifies Laminin 411 as a Physiologically Relevant Niche Factor with Importance for i-Hep Applications.

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    Use of hepatocytes derived from induced pluripotent stem cells (i-Heps) is limited by their functional differences in comparison with primary cells. Extracellular niche factors likely play a critical role in bridging this gap. Using image-based characterization (high content analysis; HCA) of freshly isolated hepatocytes from 17 human donors, we devised and validated an algorithm (Hepatocyte Likeness Index; HLI) for comparing the hepatic properties of cells against a physiological gold standard. The HLI was then applied in a targeted screen of extracellular niche factors to identify substrates driving i-Heps closer to the standard. Laminin 411, the top hit, was validated in two additional induced pluripotent stem cell (iPSC) lines, primary tissue, and an in vitro model of α1-antitrypsin deficiency. Cumulatively, these data provide a reference method to control and screen for i-Hep differentiation, identify Laminin 411 as a key niche protein, and underscore the importance of combining substrates, soluble factors, and HCA when developing iPSC applications

    Dynamics of urinary and respiratory shedding of Severe acute respiratory syndrome virus 2 (SARS-CoV-2) RNA excludes urine as a relevant source of viral transmission

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    PURPOSE To investigate the expression of the receptor protein ACE-2 alongside the urinary tract, urinary shedding and urinary stability of SARS-CoV-2 RNA. METHODS Immunohistochemical staining was performed on tissue from urological surgery of 10 patients. Further, patients treated for coronavirus disease (COVID-19) at specialized care-units of a university hospital were assessed for detection of SARS-CoV-2 RNA in urinary samples via PCR, disease severity (WHO score), inflammatory response of patients. Finally, the stability of SARS-CoV-2 RNA in urine was analyzed. RESULTS High ACE-2 expression (3/3) was observed in the tubules of the kidney and prostate glands, moderate expression in urothelial cells of the bladder (0-2/3) and no expression in kidney glomeruli, muscularis of the bladder and stroma of the prostate (0/3). SARS-CoV-2 RNA was detected in 5/199 urine samples from 64 patients. Viral RNA was detected in the first urinary sample of sequential samples. Viral RNA load from other specimen as nasopharyngeal swabs (NPS) or endotracheal aspirates revealed higher levels than from urine. Detection of SARS-CoV-2 RNA in urine was not associated with impaired WHO score (median 5, range 3-8 vs median 4, range 1-8, p = 0.314), peak white blood cell count (median 24.1 Ă— 1000/ml, range 5.19-48.1 versus median 11.9 Ă— 1000/ml, range 2.9-60.3, p = 0.307), peak CRP (median 20.7~mg/dl, 4.2-40.2 versus median 11.9~mg/dl, range 0.1-51.9, p = 0.316) or peak IL-6 levels (median: 1442~ng/ml, range 26.7-3918 versus median 140~ng/ml, range 3.0-11,041, p = 0.099). SARS-CoV-2 RNA was stable under different storage conditions and after freeze-thaw cycles. CONCLUSIONS SARS-CoV-2 RNA in the urine of COVID-19 patients occurs infrequently. The viral RNA load and dynamics of SARS-CoV-2 RNA shedding suggest no relevant route of transmission through the urinary tract
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