Agrin-induced acetylcholine receptor clustering in mammalian muscle requires tyrosine phosphorylation.

Agrin is thought to be the nerve-derived factor that initiates acetylcholine receptor (AChR) clustering at the developing neuromuscularjunction. We have investigated the signaling pathway in mouse C2 myotubes and report that agrin induces a rapid but transient tyrosine phosphorylation of the AChR beta subunit. As the beta-subunit tyrosine phosphorylation occurs before the formation of AChR clusters, it may serve as a precursor step in the clustering mechanism. Consistent with this, we observed that tyrosine phosphorylation of the beta subunit correlated precisely with the presence or absence of clustering under several experimental conditions. Moreover, two tyrosine kinase inhibitors, herbimycin and staurosporine, that blocked beta-subunit phosphorylation also blocked agrin-induced clustering. Surprisingly, the inhibitors also dispersed preformed AChR clusters, suggesting that the tyrosine phosphorylation of other proteins may be required for the maintenance of receptor clusters. These findings indicate that in mammalian muscle, agrin-induced AChR clustering occurs through a mechanism that requires tyrosine phosphorylation and may involve tyrosine phosphorylation of the AChR itself

Adventitial VEGF165 gene transfer induces positive remodeling and prevents luminal loss after experimental balloon angioplasty in porcine coronary arteries

Deckblatt-Impressum persönlicher Dank Inhaltsverzeichnis Einleitung Stand der Forschung Zielsetzung Material und Methoden Ergebnisse Diskussion Zusammenfassung Summary Literaturverzeichnis Abbildungs- und Tabellenverzeichnis Abkürzungsverzeichnis Publikationen Anhang Danksagung SelbständigkeitserklärungHintergrund: Negatives arterielles Remodeling spielt eine wichtige Rolle in der Pathogenese der Restenose nach PTCA. Eine experimentelle Studie konnte zeigen, dass die Ballonangioplastie von Koronarien die Angiogenese von Mikrogefäßen (Vasa vasorum) in der Adventitia induziert. Die Regression dieser adventitiellen Mikrogefäße fällt zeitlich zusammen mit dem negativen arteriellen Remodeling, das zum Lumenverlust der Arterie führt. Diese Beobachtungen lassen vermuten, dass verstärkte Angiogenese und verzögerte bzw. verhinderte Regression der verletzungsinduzierten Mikrogefäße das negative Remodeling reduzieren oder sogar verhindern kann. Experimentelle Studien haben gezeigt, dass die Bildung von Mikrogefäßen innerhalb eines arteriosklerotischen Plaques möglicherweise das Plaquewachstum verstärken. Daher sollten sich experimentelle Ansätze der therapeutischen Angiogenese eher auf die Adventitia als auf die Tunica Intima oder Media einer Arterie fokussieren. Zielsetzung: Diese Studie untersuchte erstmalig den Effekt eines lokalen (peri)adventitiellen Gentransfers mit VEGF165 (vascular endothelial growth factor) auf die Verdickung der Gefäßwand, die Angiogenese bzw. Regression von Mikrogefäßen in der Adventitia, und das arterielle Remodeling nach Induktion einer Gefäßwandläsion in Schweinekoronarien durch Ballondilatation. Des weiteren wurden die ballondilatierten Abschnitte auf ihren Kollagen-, Elastin-, -Aktin-, Makrophagen- und T-Lymphozyten-Gehalt untersucht. Methoden: Bei 22 Hausschweinen wurden jeweils 2 Koronararterien dilatiert und anschließend ein Plasmid/Liposomen-basierter Gentransfer vorgenommen (jeweils 50 µg Plasmid wurden mit 50 µg Lipofectin komplexiert). Eine Koronarie erhielt dabei VEGF165, die jeweils andere das funktionslose Kontrollgen LacZ. Unter Verwendung eines Nadelinjektions-Katheters wurden die Plasmid-Liposomen-Komplexe direkt in den (peri)adventitiellen Raum der dilatierten Gefäßabschnitte injiziert. Einen, 7, 14 und 28 Tage (n = 5 je Zeitpunkt) später wurden die Koronarien mittels morphometrischer Untersuchungen an digitalisierten Bildern, Immunhistochemie, Histochemie, RT- PCR und in Situ Hybridisierung analysiert. Ergebnisse: Die durchschnittliche Intima+Media (I+M)-Fläche nach Angioplastie nahm in beiden Behandlungsgruppen gleichermaßen zu, und es wurden auch sonst keine signifikanten Unterschiede in der Intima+Media festgestellt, weder für die Fläche, noch für die Mikrogefäß- Dichte, noch für die Entzündungszell-Dichte oder die Matrix-Zusammensetzung. Am Tag 14 und 28 nach Intervention zeigten die VEGF-behandelten Gefäße eine signifikante Zunahme der Lamina elastica externa-Fläche (positives Remodeling), und dementsprechend auch weniger Lumenverlust als die LacZ-Gruppe (Lumenverlust Tag 14 - VEGF: 5,09 % ± 7,5; LacZ: 40,13 % ± 2,93. Lumenverlust Tag 28 - VEGF: 5,35 % ± 18,33; LacZ: 49,04 % ± 1,64. P < 0,05). Das positive Remodeling und die Erhaltung der Lumenfläche in der VEGF-Gruppe war assoziiert mit einer signifikant höheren adventitiellen Mikrogefäß-Dichte, Endothelzell- und T-Lymphozyten-Dichte, einem signifikant höheren Elastingehalt, und signifikant weniger kontraktilen Myofibroblasten zu den Zeitpunkten 14 und 28 Tage. Keine statistisch signifikanten Unterschiede wurden hingegen hinsichtlich der Adventitia-Fläche und der Makrophagen-Dichte beobachtet. Der adventitielle Kollagengehalt war nur am Tag 14 signifikant unterschiedlich, am Tag 28 war nur ein Trend zu mehr Kollagen in der VEGF-Gruppe erkennbar. Schlussfolgerung: Im vorliegenden Tierexperiment mit verletzungsinduzierter Koronarläsion erwies sich der Nadelinjektions-Katheter-vermittelte VEGF165-Gentransfer in die äußeren Kompartimente der Arterie als sicher hinsichtlich des unerwünschten Voranschreitens des Plaquewachstums, da weder die I+M-Fläche, noch ihre Vaskularisation, noch die I+M-Komposition im Vergleich zur LacZ-Gruppe verändert waren. Der lokal begrenzte, (peri)adventitielle VEGF165-Gentransfer bewirkte eine verstärkte Vaskularsisation in der Adventitia und Reduktion der Mikrogefäß-Regression, und der Lumenverlust konnte durch ein ausgeprägtes positives Remodeling der Arterie verhindert werden. Die Vergrößerung des Gefäßquerschnitts ging einher mit einer signifikant höheren adventitiellen Mikrogefäßdichte und Endothelzell-Zahl, was die Hypothese unterstützt, dass eine verbesserte Sauerstoff-Versorgung des Gewebes und eine möglicherweise erhöhte Bioverfügbarkeit von endothelialem Stickstoffmonoxid (NO) das arterielle Remodeling beeinflussen. Die Erhöhung des adventitiellen Elastingehalts bei gleichzeitiger Reduktion der kontraktilen Zellen in der Adventitia scheint eine funktionelle Rolle in der Entstehung von positivem arteriellem Remodeling zu spielenBackground: Negative arterial remodeling is known to play an important role in the pathogenesis of restenosis after PTCA. Previous studies have shown that coronary balloon angioplasty induces adventitial microvessel (Vasa vasorum) angiogenesis, and that the regression of these adventitial microvessels coincides with negative arterial remodeling leading to arterial lumen loss. These findings suggest that increased angiogenesis and delayed/inhibited regression of injury-induced microvessels may reduce (or even prevent) negative remodeling. As experimental studies have provided evidence that neovascularization within the atherosclerotic plaque may enhance plaque progression, trials on therapeutical angiogenesis should address rather the adventitia than the tunica intima or media of the artery. Objective: This study examined the effect of local (peri)adventitial vascular endothelial growth factor (VEGF165) gene transfer on vascular thickening, adventitial microvessel angiogenesis/regression, and arterial remodeling after balloon injury-induced lesion formation in porcine coronary arteries. Moreover, lesions were examined for total collagen, elastin, and -actin content and macrophages/T cell density. Methods: 20 pigs underwent balloon injury in two major coronary arteries, followed by plasmid liposome gene transfer with either VEGF165 or control gene LacZ (50 µg of DNA with 50 µg of Lipofectine) into the (peri)adventitial space using a needle injection catheter. Coronary arteries were examined at days 1, 7, 14, and 28 (n = 5 per group) after dilation/gene transfer using morphometrical analysis of digitized images, immunohistochemistry, histochemistry, RT-PCR, and in situ hybridization. Results: The mean Intima+Media (I+M) area increased after angioplasty in both treatment groups equally and showed no significant difference neither in dimension nor in I+M microvessel density, I+M inflammatory cell density, or I+M matrix composition. At days 14 and 28, VEGF treated arteries showed significant positive remodeling and accordingly less lumen area loss compared to LacZ treated arteries (lumen loss day 14 - VEGF: 5.09 % ± 7.5; LacZ: 40.13 % ± 2.93. lumen loss day 28 - VEGF: 5.35 % ± 18.33; LacZ: 49.04 % ± 1.64. P < 0,05). The lumen area preservation in the VEGF group was associated with significant higher densities of adventitial microvessels, endothelial cells, T cells and elastin, and less contractile myofibroblasts at days 14 and 28 after intervention. No statistcally significant differences were observed regarding the adventitial area and the macrophage density. Collagen content differed significantly only at day 14, at day 28 there was only a trend towards increased adventitial collagen in the VEGF treated group. Conclusions: In this porcine model of coronary artery injury, needle injection catheter mediated VEGF165 gene transfer into the outer compartment of the artery was safe in terms of unwanted lesion progression as the procedure neither enhanced I+M growth or vascularization nor caused any changes in I+M matrix composition. The locally restricted, (peri)adventitial delivery of VEGF165 gene induced neovascularization in the adventitia, prevented the anticipated adventitial microvessel regression, and reduced lumen area loss due to distinct positive remodeling. The enlargement of the artery was associated with a significantly elevated adventitial microvessel and endothelial cell density, suggesting improved tissue oxygenation and conceivably increased local nitric oxide (NO) availability as modulators of arterial remodeling. Adventitial elastin accumulation associated with a reduced amount of contractile cells in the adventitia might play a functional role in the development of positive arterial remodeling

Jim Jones: A popular figure amongst many

Don’t drink the Kool-Aid! Ever heard this term? Where it’s a term that is based off the worst mass suicide ever to happen in the history of the world. Jim Jones a popular preacher in the 1950s to 1970s who taught about social justice. He was breaking ground in race relations, when it was still shady during that time period and he also introduced the idea of a “Utopian Society”. Struggling with economic, physical and emotional circumstances in his early life, made him realize what his mission was for later in life. It was through these circumstances that led him to form the Peoples Temple and gain such popularity amongst his congregation, and political figures. In summary, this paper focuses on my theme which is “What made Jim Jones such a popular figure in society”. It explores his background, his teachings, the links of several different counter-culture movements that were happening throughout that time period to his movement, the definition of a cult and examples, and lastly a brief summary of the fateful day, November 1978

NuzzleBug: Debugging Block-Based Programs in Scratch

While professional integrated programming environments support developers with advanced debugging functionality, block-based programming environments for young learners often provide no support for debugging at all, thus inhibiting debugging and preventing debugging education. In this paper we introduce NuzzleBug, an extension of the popular block-based programming environment Scratch that provides the missing debugging support. NuzzleBug allows controlling the executions of Scratch programs with classical debugging functionality such as stepping and breakpoints, and it is an omniscient debugger that also allows reverse stepping. To support learners in deriving hypotheses that guide debugging, NuzzleBug is an interrogative debugger that enables to ask questions about executions and provides answers explaining the behavior in question. In order to evaluate NuzzleBug, we survey the opinions of teachers, and study the effects on learners in terms of debugging effectiveness and efficiency. We find that teachers consider NuzzleBug to be useful, and children can use it to debug faulty programs effectively. However, systematic debugging requires dedicated training, and even when NuzzleBug can provide correct answers learners may require further help to comprehend faults and necessary fixes, thus calling for further research on improving debugging techniques and the information they provide.Comment: To appear at the 2024 IEEE/ACM 46th International Conference on Software Engineering (ICSE '24), April 14--20, 2024, Lisbon, Portuga

Scale and scope matter when explaining varying patterns ofcommunity diversity in riverine metacommunities

Large-scale species and genetic metacommunity patterns are influenced by variation in environmental factors and distancebetween communities, according to previous studies. However, these studies often used different measures to assess patternsof metacommunity diversity, distances between communities and grain sizes at which environmental variables are measured.This hinders interpretations and generalizations of the underlying process that drive metacommunity diversity. We applied asynthetic and multi-analytical approach to identify general factors structuring the diversity of a large riverine metacommunity.Using complementing approaches we analyzed how distance, measured as Euclidean or topological distance, and environmentalfactors, assessed at different grain sizes, influenced different measures of metacommunity diversity (species richness, functionalrichness and phylogenetic diversity) of mayfly, stonefly and caddisfly species in a large river network (river Rhine, Switzerland).We found the amount of explained variation in species diversity was generally unaffected by grain size, but improved with the useof topological distance, compared to Euclidean distance. Variation in functional diversity was best explained by environmentalfactors at small grain sizes and topological distance. Variation in phylogenetic diversity was best explained when environmentalvariables were assessed at larger grain sizes and Euclidean distance was used. Overall, our results indicate that processesstructuring metacommunity diversity may differ at the species, functional or phylogenetic level of the community, as recentlypostulated in the metacommunity–phylogenetics approach. While such differences may hinder comparisons across studiesusing different methodologies, it offers opportunities to disentangle the structuring factors within metacommunities by applyingmultiple analytical approaches to the same dataset

RA-based Didactic Games for Biology Teaching

Concurrent Session

Identifying a sufficient core group for trachoma transmission.

BackgroundIn many infectious diseases, a core group of individuals plays a disproportionate role in transmission. If these individuals were effectively prevented from transmitting infection, for example with a perfect vaccine, then the disease would disappear in the remainder of the community. No vaccine has yet proven effective against the ocular strains of chlamydia that cause trachoma. However, repeated treatment with oral azithromycin may be able to prevent individuals from effectively transmitting trachoma.Methodology/principal findingsHere we assess several methods for identifying a core group for trachoma, assuming varying degrees of knowledge about the transmission process. We determine the minimal core group from a completely specified model, fitted to results from a large Ethiopian trial. We compare this benchmark to a core group that could actually be identified from information available to trachoma programs. For example, determined from the rate of return of infection in a community after mass treatments, or from the equilibrium prevalence of infection.Conclusions/significanceSufficient groups are relatively easy for programs to identify, but will likely be larger than the theoretical minimum

Diseño e implementación de mejoras a la plataforma para la gestión de pruebas de proyectos de software - mantest

El desarrollo de software es un proceso que generalmente involucra confusión y conjeturas entre los integrantes del equipo. Los cambios prematuros, la adición de nuevos requerimientos por parte del cliente o simplemente la solución de una falla en el aplicativo son ítems que se reflejan en el desgate del equipo, lo cual puede a conducir a nuevos fallos del mismo. El Testing (prueba) de software tiene como objetivo minimizar el impacto de estos fallos en la funcionalidad del aplicativo y maximizar el porcentaje de obtención de los resultados esperados de la misma

Adsorbentes de residuos lignocelulósicos en la remoción de Pb y Zn en aguas de río Parcoy-La Libertad, 2023

La contaminación del agua superficial por metales pesados a causa de la minería es una problemática vigente en algunos países, por lo cual se han desarrollado técnicas para su descontaminación alcanzando diversos grados de eficiencia. Sin embargo, es necesario contar con alternativas eco amigables y de bajo costo. Es por ello, que se propuso evaluar el efecto que producen los adsorbentes de residuos lignocelulósicos en la remoción de Pb y Zn presente en las aguas del río Parcoy en la región la Libertad. La metodología desarrollada fue experimental, los residuos se acondicionaron a una temperatura de 400 ºC y 300 ºC y a tiempos de pirolisis de 1 y 2 h respectivamente, para obtener biocarbón el cual fue aplicado por cada muestra de 500 mL usando dosis de 2,5 y 5 g y a tiempos de 1, 3 y 12 horas. Los resultados muestran que las mejores condiciones para remover Pb y Zn en las aguas del rio Parcoy utilizando el biocarbón de fibra de coco y pajilla de arroz es a un tiempo de 12 horas y con dosis de 2.5 g. Se concluye que los adsorbentes bajo la forma de biocarbón obtenido de residuos lignocelulósicos tienen efecto favorable en la remoción de Pb y Zn en aguas de río Parcoy-La Libertad, 2023