UV-excimer-laser ablation of polymethylmethacrylate at 248 nm: Characterization of incubation sites with Fourier transform IR- and UV-spectroscopy.

Ultraviolet and Fourier transform infrared (FTIR) spectroscopic experiments with thin films of polymethylmethacrylate (PMMA) are reported. During the incubation with 248 nm excimer laser light or continuous (cw) UV light sources PMMA exhibits a rapidly increasing, broad UV absorption. This is caused by the production of unsaturated species, which are detected in the infrared spectrum of irradiated PMMA films. The spectral data explain the incubation process preceding the ablation of PMMA at 248 nm. Taking advantage of the increased UV absorption, cw light incubated PMMA films can be selectively ablated by standard 308 nm excimer laser pulses

Ablation of polytetrafluoroethylene (Teflon) with femtosecond UV excimer laser pulses.

Experiments on the ablation of undoped polytetrafluoroethylene (Teflon) with 300 fs UV excimer laser pulses at 248 nm are reported for the first time. In contrast to standard excimer laser pulses, these ultrashort pulses ablate Teflon with good edge quality and no signs of thermal damage for fluences down to 0.5 J/cm2 with removal rates on the order of 1 μm per pulse

A Structural Equation Model

In recent years, the web has become a widely used source for health information. Pet owners seem to respond to the supply of medical information on the Internet by increasing their self-education. However, after more than a decade of the digital revolution, little is known about the Internet’s impact on the veterinarian-pet owner relationship. Recent research has raised concerns regarding the increase in self-education among pet owners. However, reasons suggest that the Internet might be a valuable source of pet-owner education for veterinarians. In particular, relationship-centered approaches of care might benefit from the information provided. Our study aimed to determine the perception of German veterinarians with regard to pet owners’ self-education on different aspects of veterinary care. An online survey was conducted for German veterinarians from November 2016 to June 2017. Data were analyzed using exploratory factor analysis and structural equation modeling. Within the structural equation model, we evaluated how the veterinarians’ attitude toward relationship-centered care might affect the evaluation of pet owners’ self-education. A total of 585 valid questionnaires were completed. The majority of veterinarians (83.6%) welcomed the principles of shared decision-making. Practically, all veterinarians reported a noticeable increase in pet owners’ self-education within the last few years. Perceptions on self-education’s impacts on veterinary practice varied among the participants. A beneficial impact of self-education was reported regarding the general quality of veterinary care and quality of follow-up care. Most concerns were related to a negative impact on the veterinarian-pet owner relationship and the pet owners’ demands on the veterinarians’ work after self-education. Moreover, many participants were afraid that unfiltered information may unsettle pet owners and, therefore, advised them against self-education. The structural equation model confirmed the hypothesis that a veterinarian’s positive attitude towards shared decision-making, empathic behavior, and his/her evaluation of self-education were associated. Therefore, we concluded that while there are beneficial potentials, there seem to be barriers that prevent the effective use of the Internet as a supportive medium in veterinary care. Further research and training are needed to enable the use of the Internet as an ancillary medium

Attitude of veterinarians toward self-informed animal owners affects shared decision making

The aims of this study were to investigate the role of the veterinarian characteristics (e.g., age, gender, self-estimation, use of the internet), and their attitudes concerning animal owners seeking self-information. A particular focus was laid on any association between shared decision making (SDM), age and gender. In an online survey, 527 German veterinarians were asked about their attitude regarding SDM principles and their experiences with self-informed animal owners. The factors associated with veterinarians’ perception of SDM were investigated in a multivariable linear regression model. A recently published structural equation model (1) consolidated the application of SDM, empathic behavior, and veterinarians’ evaluation of self-education as latent factors. Interconnected questionnaire items were processed using an exploratory factor analysis to 11 interpretable factors. Veterinarians who assumed therapy failure was associated with themselves had significantly higher rates of SDM (p=0.002). In contrast, SDM was significantly lower (p=0.002) if they assumed that therapy failure was due to the animal’s owners. SDM was negatively associated with the perceived quality of the pet owners’ self-information (p<0.001) and if skepticism was perceived as the reason for seeking the self-information (p=0.001). Veterinarians who advised against self-information (p=0.006) and those who assumed that self-information of animal owners goes along with uncertainty (p=0.001) had low SDM values (p=0.006). Asking the animal owner for self-information (p=0.001), and recommendations of good information sources (p=0.022) were positively associated with SDM. Looking at the influence of age and gender on the application of SDM, older people and males rated higher. However, the evaluation of the latent factor SDM was based on the self-estimation of the participants. Assuming that younger women were less self-confident, we cannot exclude that young female participants self-evaluated their SDM skills lower than older male participants, although both groups would objectively have the same SDM level. Practitioners who have a positive attitude toward animal owners, who enjoy contact with animal owners and welcome their interest in further (self-)information, show empathic behavior, and have a positive attitude toward SDM are more likely to have better veterinarian-animal owner-relationships

Dual effect of lithium on NFAT5 activity in kidney cells

Lithium salts are used widely for treatment of bipolar and other mental disorders. Lithium therapy is accompanied frequently by renal side effects, such as nephrogenic diabetes insipidus or chronic kidney disease (CKD),but the molecular mechanisms underlying these effects are still poorly understood. In the present study we examined the effect of lithium on the activity of the osmosensitive transcriptional activator nuclear factor of activated T cells 5 (NFAT5, also known as TonEBP),which plays a key role in renal cellular osmoprotection and urinary concentrating ability. Interestingly, we found different effects of lithium on NFAT5 activity, depending on medium osmolality and incubation time. When cells were exposed to lithium for a relative short period (24 h),NFAT5 activity was significantly increased, especially under isosmotic conditions, resulting in an enhanced expression of the NFAT5 target gene heat shock protein 70 (HSP70). Further analysis revealed that the increase of NFAT5 activity depended primarily on an enhanced activity of the c-terminal transactivation domain (TAD),while NFAT5 protein abundance was largely unaffected. Enhanced activity of the TAD is probably mediated by lithium-induced inhibitory phosphorylation of glycogen synthase kinase 3 beta (GSK-3 beta),which is in accordance with previous studies. When cells were exposed to lithium for a longer period (96 h),cellular NFAT5 activity and subsequently expression of HSP70 significantly decreased under hyperosmotic conditions, due to diminished NFAT5 protein abundance, also resulting from GSK-3 beta inhibition. Taken together, our results provide evidence that lithium has opposing effects on NFAT5 activity, depending on environmental osmolality and exposure duration. The potential impacts of these observations on the diverse effects of lithium on kidney function are discussed

NFAT5 Contributes to Osmolality-Induced MCP-1 Expression in Mesothelial Cells

Increased expression of the C-C chemokine monocyte chemoattractant protein-1 (MCP-1) in mesothelial cells in response to high glucose concentrations and/or high osmolality plays a crucial role in the development of peritoneal fibrosis during continuous ambulatory peritoneal dialysis (CAPD). Recent studies suggest that in kidney cells osmolality-induced MCP-1 upregulation is mediated by the osmosensitive transcription factor, nuclear factor of activated T cells 5 (NFAT5). The present study addressed the question of whether activation of NFAT5 by hyperosmolality, as present in PD fluids, contributes to MCP-1 expression in the mesothelial cell line Met5A. Hyperosmolality, induced by addition of glucose, NaCl, or mannitol to the growth medium, increased NFAT5 activity and stimulated MCP-1 expression in Met5A cells. siRNA-mediated knockdown of NFAT5 attenuated osmolality-induced MCP-1 upregulation substantially. Hyperosmolality also induced activation of nuclear factor-κB (NF-κB). Accordingly, pharmacological inhibition of NF-κB significantly decreased osmolality-induced MCP-1 expression. Taken together, these results indicate that high osmolalities activate the transcription factor NFAT5 in mesothelial cells. NFAT5 in turn upregulates MCP-1, likely in combination with NF-κB, and thus may participate in the development of peritoneal fibrosis during CAPD

Charakterisierung der transkriptionellen Aktivierung des cadBA-Operons durch den Transmembranregulator CadC aus Escherichia coli

Das Cad-System von Escherichia coli gehört zu den pH-induzierbaren Aminosäure-Decarboxylase- Systemen. Der Aktivator des Cad-Systems ist der membrangebundene Transkriptionsregulator CadC. CadC ist gleichzeitig Sensor für die Umweltreize pH und Lysin, und Effektorprotein, das die Expression des cadBA-Operons induziert. Im Rahmen dieser Arbeit wurden der molekulare Mechanismus der transkriptionellen Aktivierung des cadBA-Operons durch CadC und verschiedene Modelle für die Aktivierung eines membranintegrierten Transkriptionsaktivators untersucht. Im Rahmen dieser Arbeit konnten durch Footprint-Analysen innerhalb der regulatorischen Region des cadBA-Operons die zwei CadC-Bindestellen Cad1 (erstreckt sich von bp -150 bis -112, relativ zum Transkriptionsstart des cadBA-Operons) und Cad2 (bp -89 bis -59) identifiziert werden. DNA-Bindeexperimente in vitro zeigten, dass CadC mit einer höheren Affinität an Cad1 als an Cad2 bindet. Die Affinität von CadC zu Cad1 und Cad2 wurde durch unterschiedliche pH-Werte oder durch Lysin und Cadaverin nicht signifikant beeinflusst. Die Analyse der Bindestellen Cad1 und Cad2 in vivo ergab, dass das Vorhandensein beider Bindestellen für die Induktion der cadBA-Expression durch Lysin und einen niedrigen externen pH-Wert essentiell ist. Desweiteren wurde die Repression des cadBA-Operons unter nicht-induzierenden Bedingungen durch den globalen Repressor H-NS untersucht. Deletionsanalysen der regulatorischen Region des cadBA-Operons indizierten zwei H-NS-Bindestellen stromaufwärts der CadC-Bindestellen. Rechner-gestützte Sequenzanalysen legten die Existenz von zwei weiteren H-NS-Bindestellen nahe, die mit den CadC-Bindestellen und der -35/-10-Region von PCad überlappen. In hns- Deletionsstämmen war die cadBA-Expression sowohl unter induzierenden als auch unter nicht-induzierenden Bedingungen signifikant erhöht. Für die Aktivierung des cadBA-Operons war CadC essentiell. Biochemische und molekularbiologische Untersuchungen zum Oligomerisationszustand von CadC indizierten, dass CadC Tetramere ausbildet. Die periplasmatische Domäne war für die Oligomerisierung von CadC essentiell. Die Tetramere traten sowohl unter induzierenden als auch unter nicht-induzierenden Bedingungen auf. Daher scheint eine Aktivierung von CadC durch eine Oligomerisierung von CadC-Monomeren, die durch Umgebungsbedingungen wie den pH-Wert und die Lysin-Konzentration moduliert wird, unwahrscheinlich. Basierend auf den oben angeführten Daten wurde ein Modell für die transkriptionelle Aktivierung des cadBA-Operons entwickelt. Demzufolge bildet H-NS unter nicht-induzierenden Bedingungen innerhalb der regulatorischen Region des cadBA-Operons einen Repressionskomplex. Unter induzierenden Bedingungen bindet CadC als Tetramer zunächst an die Bindestelle Cad1, wodurch die anschließende Bindung an Cad2 erleichtert und stabilisiert wird. Durch die Bindung von CadC wird der H-NS vermittelte Repressionskomplex aufgelöst, wodurch eine Interaktion der RNA-Polymerase mit der -35/-10-Region von PCad und die cadBA-Transkription ermöglicht werden. Verschiedene membranintegrierte Transkriptionsfaktoren in eukaryontischen Zellen werden durch eine Regulierte Proteolyse (RP) aktiviert. Biochemische und molekularbiologische Untersuchungen zum molekularen Mechanismus des membran-integrierten Transkriptionsaktivators CadC ergaben bisher keine Hinweise darauf, dass CadC unter induzierenden Bedingungen durch einen Mechanismus ähnlich den der Regulierten Proteolyse aktiviert wird. Um die Funktion der Transmembrandomäne und der periplasmatischen Domäne für die Aktivierung von CadC genauer zu analysieren, wurden verschiedene C-terminal verkürzte CadC-Derivate hinsichtlich ihrer Funktionalität untersucht. Dabei zeigte sich, dass eine Membranassoziation oder -integration von CadC für die Induktion der cadBA-Expression notwendig war. Desweiteren war die periplasmatische Domäne für die CadC-Aktivierung essentiell. In Zusammenarbeit mit dem Department für Physik der LMU München wurde ein in silico Modell für die Regulation der cadBA-Expression erstellt. Zur Überprüfung des Modells wurde die Expression des Cad-Systems während einer simulierten Magen-Passage in vivo analysiert. Die experimentellen Daten stimmten mit dem Modell sehr gut überein. Das Modell ist also in der Lage, die in vivo-Daten zu abzubilden. Ein weiterer Aspekt dieser Arbeit war die Untersuchung der genauen physiologischen Funktion des Cad-Systems. Es konnte nachgewiesen werden, dass das Cad-System eine wichtige Funktion für die Säureresistenz von E. coli bei extremen Säurestress bei pH-Werten <3 hat. Dieser Effekt ist vor allem auf die pH-Wert steigernde Wirkung von ausgeschleustem Cadaverin zurückzuführen. Bei mildem Säurestress bis pH 5 erfüllt das Cad-System vermutlich keine wichtige Funktion