Stelleninhaber geht – Wissen bleibt!

In Deutschland nimmt der Anteil älterer Arbeitnehmerinnen und Arbeitnehmer tendenziell zu. Deshalb muss sich die Bibliotheksleitung verstärkt auf das altersbedingte Ausscheiden älterer Arbeitnehmer einstellen. Eine langjährige Fachkraft verfügt über spezielles Erfahrungswissen im direkten Aufgabenfeld. Die Bibliotheksleitung muss den Transfer allen relevanten Wissens, dazu gehört das Erfahrungswissen, vom Stelleninhaber auf seinen Nachfolger ermöglichen und unterstützen. Am Beispiel der Universitätsbibliothek der Bergakademie Freiberg wird untersucht, wie das Wissensmanagement im Rahmen eines Stellenwechsels derzeit geregelt ist. Das geschieht mit Hilfe von Tiefeninterviews in verschiedenen Abteilungen. Die Auswertung der Interviews bildet die Basis für ein Konzept für das Wissensmanagement beim Stellenwechsel an der UB Freiberg. Das Konzept benennt u. a. Maßnahmen zur Identifikation des stellenbezogenen Wissens, Maßnahmen zur Dokumentation des relevanten Wissens und Instrumente zur Wissensweitergabe beim Stellenwechsel

Effect of acute and chronic CSC treatment in HIV-infected U1 cells.

<p>a) CSC treatment (50 μg/ml) for 6H resulted in significantly enhanced level of ROS in U1 cells, compared to control cells. b) Chronic (4-day) daily treatment with CSC (25 μg/ml) resulted in significantly higher ROS levels in U1 cells. c) PMA stimulation following 4-day CSC treatment was associated with statistically significant increase in HIV replication, as measured by HIV-1 p24 antigen level in cell supernatant, in CSC treated U1 cells compared to vehicle-treated control group. *p≤0.05; **p≤0.01.</p

Caspase-3 activation in CSC treated U937 cells.

<p>a) Treatment with CSC was associated with a time-dependent increase in caspase-3 activity. The increase in caspase-3 activity, compared to vehicle-treated cells, was found to be significant 24H and 48H after CSC treatment. b) The CSC-mediated induction of caspase-3 activity was completely blocked following pretreatment with vitamin C in U937 cells. *p≤0.05; **p≤0.01.</p

Effects of Cigarette Smoke Condensate on Oxidative Stress, Apoptotic Cell Death, and HIV Replication in Human Monocytic Cells - Fig 1

<p>a) Dose-response of cigarette smoke condensate (CSC) treatment on reactive oxygen species (ROS) production in human U937 monocytic cells. CSC treatment at 3H was found to enhance ROS production in a dose-dependent manner. b) Time-kinetic of ROS induction following CSC treatment in U937 cells. CSC treatment (50 μg/ml) in U937 cells resulted in a time-dependent significant enhancement in ROS production as measured using a flow cytometer. Compared to the respective vehicle-treated cells, CSC-treated U937 cells were marked by significantly higher levels of ROS at 1H, 3H, 6H, 9H and 12H post-treatment. The peak for enhanced ROS production was 6H following CSC treatment. c) Effects of vitamin C pretreatment on induction of ROS production by CSC. Pretreatment with vitamin C significantly inhibited the CSC-mediated induction in ROS levels in U937 cells. *p≤0.05; **p≤0.01.</p

Effect of CSC treatment on CYP1A1 gene transcription in monocytic cells.

<p>a) mRNA levels of CYP1A1 were found to be significantly higher in CSC treated monocytic cells compared to control cells. Acute (6H) treatment of U937 and U1 cells with CSC resulted in ~25 and ~15 fold higher CYP1A1 mRNA level respectively, as compared to DMSO-treated cells. Chronic treatment (4-day) of U1 cells with CSC was also associated with statistically significant upregulation in CYP1A1 mRNA level (~40 fold). b) The CSC-mediated upregulation in CYP1A1 gene transcription was found to be mediated via the aromatic hydrocarbon receptor (AHR). Pretreatment of U937 cells with the AHR antagonist, CH223191, significantly blocked the CSC-mediated induction of CYP1A1 mRNA level. *p≤0.05; **p≤0.01.</p

CSC treatment in U937 cells is associated with increased apoptosis.

<p>a) Representative dot plot shows that, compared to vehicle-treated control cells, a significantly higher proportion of U937 cells were positively stained with annexin dye following CSC treatment. b) Bar graph summarizing the percent apoptotic cells in Q2 from CSC treated U937 cells. c) Effect of CSC treatment on cell viability in U937 cells as measured by MTT assay. Results from MTT assay confirm a loss of cell viability in CSC treated U937 cells compared to vehicle-treated control cells. *p≤0.05; **p≤0.01.</p

CSC-mediated changes in expression of CYP1 enzymes in HIV-infected human primary macrophages.

<p>a) Compared to the vehicle-treated control cells, CSC-treatment (4-day) was associated with an enhanced transcription of CYP1A1 gene in HIV-infected primary macrophages (upper panel). However, the expression of CYP1A1 protein was not upregulated following chronic treatment with CSC (lower panel). b) CSC-treatment (4-day) was associated with an enhanced transcription of CYP1B1 gene in HIV-infected primary macrophages (upper panel). CYP1B1 protein was also found to be significantly upregulated in CSC treated macrophages compared to vehicle treated HIV-infected human primary macrophages (lower panel). **p≤0.01.</p

Presentation_1_Utility of a Novel Three-Dimensional and Dynamic (3DD) Cell Culture System for PK/PD Studies: Evaluation of a Triple Combination Therapy at Overcoming Anti-HER2 Treatment Resistance in Breast Cancer.PDF

<p>Background: Emergence of Human epidermal growth factor receptor 2 (HER2) therapy resistance in HER2-positive (HER2+) breast cancer (BC) poses a major clinical challenge. Mechanisms of resistance include the over-activation of the PI3K/mTOR and Src pathways. This work aims to investigate a novel combination therapy that employs paclitaxel (PAC), a mitotic inhibitor, with everolimus (EVE), an mTOR inhibitor, and dasatinib (DAS), an Src kinase inhibitor, as a modality to overcome resistance.</p><p>Methods: Static (two dimensional, 2D) and three-dimensional dynamic (3DD) cell culture studies were conducted using JIMT-1 cells, a HER2+ BC cell line refractory to HER2 therapies. Cell viability and caspase-3 expression were examined after JIMT-1 cell exposure to agents as monotherapy or in combination using a 2D setting. A pharmacokinetic/pharmacodynamic (PK/PD) combination study with PAC+DAS+EVE was conducted over 3 weeks in a 3DD setting. PAC was administered into the system via a 3 h infusion followed by the addition of a continuous infusion of EVE+DAS 24 h post-PAC dosing. Cell counts and caspase-3 expression were quantified every 2 days. A semi-mechanistic PK/PD model was developed using the 2D data and scaled up to capture the 3DD data. The final model integrated active caspase-3 as a biomarker to bridge between drug exposures and cancer cell dynamics. Model fittings were performed using Monolix software.</p><p>Results: The triple combination significantly induced caspase-3 activity in the 2D cell culture setting. In the 3DD cell culture setting, sequential dosing of PAC then EVE+DAS showed a 5-fold increase in caspase-3 activity and 8.5-fold decrease in the total cell number compared to the control. The semi-mechanistic PK/PD models fit the data well, capturing the time-course profiles of drug concentrations, caspase-3 expression, and cell counts in the 2D and 3DD settings.</p><p>Conclusion: A novel, sequential triple combination therapeutic regimen was successfully evaluated in both 2D and 3DD in vitro cell culture systems. The efficacy of this combination at inhibiting the cellular proliferation and re-growth of HER2/mTOR resistant cell line, JIMT-1, is demonstrated. A biomarker-linked PK/PD model successfully captured all time-course data. The latter can be used as a modeling platform for a direct translation from 3DD in vitro settings to the clinic.</p

Effect of Methamphetamine on Spectral Binding, Ligand Docking and Metabolism of Anti-HIV Drugs with CYP3A4

<div><p>Cytochrome P450 3A4 (CYP3A4) is the major drug metabolic enzyme, and is involved in the metabolism of antiretroviral drugs, especially protease inhibitors (PIs). This study was undertaken to examine the effect of methamphetamine on the binding and metabolism of PIs with CYP3A4. We showed that methamphetamine exhibits a type I spectral change upon binding to CYP3A4 with δA_max and K_D of 0.016±0.001 and 204±18 μM, respectively. Methamphetamine-CYP3A4 docking showed that methamphetamine binds to the heme of CYP3A4 in two modes, both leading to N-demethylation. We then studied the effect of methamphetamine binding on PIs with CYP3A4. Our results showed that methamphetamine alters spectral binding of nelfinavir but not the other type I PIs (lopinavir, atazanavir, tipranavir). The change in spectral binding for nelfinavir was observed at both δA_max (0.004±0.0003 vs. 0.0068±0.0001) and K_D (1.42±0.36 vs.2.93±0.08 μM) levels. We further tested effect of methamphetamine on binding of 2 type II PIs; ritonavir and indinavir. Our results showed that methamphetamine alters the ritonavir binding to CYP3A4 by decreasing both the δA_max (0.0038±0.0003 vs. 0.0055±0.0003) and K_D (0.043±0.0001 vs. 0.065±0.001 nM), while indinavir showed only reduced K_D in presence of methamphetamine (0.086±0.01 vs. 0.174±0.03 nM). Furthermore, LC-MS/MS studies in high CYP3A4 human liver microsomes showed a decrease in the formation of hydroxy ritonavir in the presence of methamphetamine. Finally, CYP3A4 docking with lopinavir and ritonavir in the absence and presence of methamphetamine showed that methamphetamine alters the docking of ritonavir, which is consistent with the results obtained from spectral binding and metabolism studies. Overall, our results demonstrated differential effects of methamphetamine on the binding and metabolism of PIs with CYP3A4. These findings have clinical implication in terms of drug dose adjustment of antiretroviral medication, especially with ritonavir-boosted antiretroviral therapy, in HIV-1-infected individuals who abuse methamphetamine.</p></div

Spectral binding of methamphetamine with CYP3A4.

<p>(A) The spectral binding was performed at varying concentrations of methamphetamine from 1 μM to 2 mM. The graph was plotted using difference in absorbance at 390 and 416 nm vs. concentration of methamphetamine. The graph was fitted with hyperbolic equation using non-linear regression analysis in sigma plot 11. (B) Docking simulation of methamphetamine binding with CYP3A4 in two different binding modes. The heme, methamphetamine, and interacting amino acid residues of CYP3A4 are represented in red, green, and blue, respectively.</p