An investigation into the aggregation of therapeutic peptides through adsorption to primary containers

Therapeutic peptides are highly functional drugs currently being investigated for a number of diseases, due to their naturally occurrence in the body, their targeted mechanism and efficacy and tolerability. The four therapeutic peptides under investigation in this thesis; glucagon, liraglutide, g797 and exendin-4 are all used or on trial for mediating blood glucose levels as a safe and effective treatment for type 2 diabetes. One of the largest drawbacks of peptides is their ability to aggregate and adsorb to surfaces that they come into contact with during their lifecycle; vials and syringes, causing loss of function, drug and toxicity. A large, underexplored area of drug related research is investigation into the interface; in part due to its complexity. A plethora of different methods were used in order to investigate the peptide solutions ability to aggregate and adsorb to surfaces. The initial step was to investigate the stability of the four therapeutic peptides in solution, providing information on the aggregation of the peptides in bulk, investigated by the Atomic Force Microscope and Zeta Potential. Images of secondary structures formed in solution by each peptide were produced, as well as providing information on the charges of the solution and the colloidal stability, showing the need for an added lipidated chain for peptide stability. Surface induced aggregation was then investigated through studying a variety of surfaces using the Quartz Crystal Microbalance with dissipation, giving both the wet mass adsorbed, as well as indications of the rigidity of the layer formed. The two most common surfaces used in the pharmaceutical industry; borosilicate glass and polystyrene, were amongst the surfaces investigated and were shown to cause the highest adsorption of peptide, ranking as the least effective surfaces at preventing aggregation. Another factor determining peptide adsorption to surfaces is roughness. Surfaces of different roughness were created through addition of gold nanoparticles, and using the QCM-D, adsorption was compared to that of flat gold surfaces. An increase of adsorption on flat surfaces compared to rougher surfaces was found, indicating a more intricate relationship than previously thought. E- beam lithography was then used to create different nanostructures on the gold surface. Ultimately, the thesis aimed at tackling a large problem within the pharmaceutical industry, by providing alternative pathways to challenge the problem of aggregation through adsorption to primary containers

Pharmacological LRRK2 kinase inhibition induces LRRK2 protein destabilization and proteasomal degradation

Leucine-rich repeat kinase 2 (LRRK2) kinase activity is increased in several pathogenic mutations, including the most common mutation, G2019S, and is known to play a role in Parkinson’s disease (PD) pathobiology. This has stimulated the development of potent, selective LRRK2 kinase inhibitors as one of the most prevailing disease-modifying therapeutic PD strategies. Although several lines of evidence support beneficial effects of LRRK2 kinase inhibitors, many questions need to be answered before clinical applications can be envisaged. Using six different LRRK2 kinase inhibitors, we show that LRRK2 kinase inhibition induces LRRK2 dephosphorylation and can reduce LRRK2 protein levels of overexpressed wild type and G2019S, but not A2016T or K1906M, LRRK2 as well as endogenous LRRK2 in mouse brain, lung and kidney. The inhibitor-induced reduction in LRRK2 levels could be reversed by proteasomal inhibition, but not by lysosomal inhibition, while mRNA levels remained unaffected. In addition, using LRRK2 S910A and S935A phosphorylation mutants, we show that dephosphorylation of these sites is not required for LRRK2 degradation. Increasing our insight in the molecular and cellular consequences of LRRK2 kinase inhibition will be crucial in the further development of LRRK2-based PD therapies

BiCMOS variable gain transimpedance amplifier for automotive applications

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Spontaneous midgestation abortion associated with Bacteroides fragilis: a case report.

A midtrimester pregnancy loss, due to B. fragilis is described. We hypothesize that in early pregnancy anaerobic bacterial vaginosis has the greatest pathogenicity, while an intermediate (mixed) flora is most dangerous in midtrimester miscarriages, and that aerobic vaginitis is more dangerous than anaerobes towards the second half of the pregnancy. Unfortunately, no screen and treat policy has yet been proven to be sufficiently powerful to prevent the vast majority of infection-related prematurity. © 2005 Taylor & Francis.status: publishe

Molecular networks regulating cell division during Arabidopsis leaf growth

Leaves are the primary organs for photosynthesis and as such have a pivotal role for plant growth and development. Leaf development is a multi-factorial and dynamic process involving many genes that regulate size, shape, and differentiation. The processes that mainly drive leaf development are cell proliferation and cell expansion, and numerous genes have been identified that, when ectopically expressed or down-regulated, increase cell number and/or cell size during leaf growth. Many of the genes regulating cell proliferation are functionally interconnected and can be grouped in regulatory modules. Here, we review our current understanding of six important gene regulatory modules affecting cell proliferation during Arabidopsis leaf growth: DA1-EOD1, GRF-GIF, SWI/SNF, GA-DELLA, KLU, and PEAPOD. Furthermore, we discuss how post-mitotic cell expansion and these six modules regulating cell proliferation make up final leaf size