Diplomats or Defendants? Defining the Future of Head-of-State Immunity

Fluorescence nanoscopy provides means to discernthe finer details of protein localization and interaction in cells by offeringan order of magnitude higher resolution than conventional optical imagingtechniques. However, these super resolution techniques put higher demands onthe optical system as well as on the fluorescent probes, making multicolorfluorescence nanoscopy a challenging task. Here we present a new and simpleprocedure which exploits the photostability and excitation spectra of dyes toincrease the number of simultaneous recordable targets in STED nanoscopy. Weuse this procedure to demonstrate four color STED imaging of platelets with ≤40 nm resolution and low crosstalk. Platelets can selectively store, sequesterand release a multitude of different proteins, and in a manner specific fordifferent physiological and disease states. By applying multicolor nanoscopy tostudy platelets, we can achieve spatial mapping of the protein organizationwith a high resolution, for multiple proteins at the same time and in the samecell. This provides a means to identify specific platelet activation states fordiagnostic purposes and to understand the underlying protein storage andrelease mechanisms. We studied the organization of the pro- and anti-angiogenicproteins VEGF and PF-4 together with fibrinogen and filamentous actin, andfound distinct features in their respective protein localization. Further,colocalization analysis revealed only minor overlap between the proteins VEGFand PF-4 indicating that they have separate storage and release mechanisms,corresponding well with their opposite rules as pro- and anti-angiogenicproteins, respectively.Updated from "Submitted" to "Published". QC 20140630</p

Microarray analysis using disiloxyl 70mer oligonucleotides

DNA microarray technology has evolved dramatically in recent years, and is now a common tool in researchers' portfolios. The scope of the technique has expanded from small-scale studies to extensive studies such as classification of disease states. Technical knowledge regarding solid phase microarrays has also increased, and the results acquired today are more reliable than those obtained just a few years ago. Nevertheless, there are various aspects of microarray analysis that could be improved. In this article we show that the proportions of full-length probes used significantly affects the results of global analyses of transcriptomes. In particular, measurements of transcripts in low abundance are more sensitive to truncated probes, which generally increase the degree of cross hybridization and loss of specific signals. In order to improve microarray analysis, we here introduce a disiloxyl purification step, which ensures that all the probes on the microarray are at full length. We demonstrate that when the features on microarrays consist of full-length probes the signal intensity is significantly increased. The overall increase in intensity enables the hybridization stringency to be increased, and thus enhance the robustness of the results

Возникновение первых аптек в восточной части территории Республики Беларусь в дореволюционный период (12-19 вв.)

АПТЕКИИСТОРИЯ МЕДИЦИН

Использование РДФ-топлива в качестве энергетического ресурса (опыт Европейского союза)

Материалы XI Междунар. науч. конф. студентов, аспирантов и молодых ученых, Гомель, 17-18 мая 2018 г

Comparative Evaluation of Anti-HER2 Affibody Molecules Labeled with Cu-64 Using NOTA and NODAGA

Imaging using affi body molecules enables discrimination between breast cancer metastases with high and low expression of HER2, making appropriate therapy selection possible. This study aimed to evaluate if the longer half-life of Cu-64 (T-1/2 = 12.7h) would make Cu-64 a superior nuclide compared to Ga-68 for PET imaging of HER2 expression using affibody molecules. The synthetic ZHER2: S1 affibody molecule was conjugated with the chelators NOTA or NODAGA and labeled with Cu-64. The tumor-targeting properties of Cu-64-NOTA-ZHER2: S1 and Cu-64-NODAGA-ZHER2: S1 were evaluated and compared with the targeting properties of Ga-68-NODAGA-ZHER2: S1 in mice. Both 64 Cu-NOTA-ZHER2: S1 and Cu-64-NODAGA-ZHER2: S1 demonstrated specific targeting of HER2-expressing xenografts. At 2 h after injection of Cu-64-NOTA-ZHER2: S1, Cu-64-NODAGA-ZHER2: S1, and Ga-68-NODAGAZHER2: S1, tumor uptakes did not differ significantly. Renal uptake of Cu-64-labeled conjugateswas dramatically reduced at 6 and 24 h after injection. Notably, radioactivity uptake concomitantly increased in blood, lung, liver, spleen, and intestines, which resulted in decreased tumor-to-organ ratios compared to 2 h postinjection. Organ uptake was lower for Cu-64-NODAGA-ZHER2: S1. The most probable explanation for this biodistribution pattern was the release and redistribution of renal radiometabolites. In conclusion, monoamide derivatives of NOTA and NODAGA may be suboptimal chelators for radiocopper labeling of anti-HER2 affibody molecules and, possibly, other scaffold proteins with high renal uptake

Stability Enhancement of a Dimeric HER2-Specific Affibody Molecule through Sortase A-Catalyzed Head-to-Tail Cyclization

Natural backbone-cyclized proteins have an increased thermostability and resistance towards proteases, characteristics that have sparked interest in head-to-tail cyclization as a method to stability-enhance proteins used in diagnostics and therapeutic applications, for example. In this proof-of principle study, we have produced and investigated a head-to-tail cyclized and HER2-specific ZHER2:342 Affibody dimer. The sortase A-mediated cyclization reaction is highly efficient (&gt;95%) under optimized conditions, and renders a cyclic ZHER3:342-dimer with an apparent melting temperature, Tm, of 68 °C, which is 3 °C higher than that of its linear counterpart. Circular dichroism spectra of the linear and cyclic dimers looked very similar in the far-UV range, both before and after thermal unfolding to 90 °C, which suggests that cyclization does not negatively impact the helicity or folding of the cyclic protein. The cyclic dimer had an apparent sub-nanomolar affinity (Kd ~750 pM) to the HER2-receptor, which is a ~150-fold reduction in affinity relative to the linear dimer (Kd ~5 pM), but the anti-HER2 Affibody dimer remained a high-affinity binder even after cyclization. No apparent difference in proteolytic stability was detected in an endopeptidase degradation assay for the cyclic and linear dimers. In contrast, in an exopeptidase degradation assay, the linear dimer was shown to be completely degraded after 5 min, while the cyclic dimer showed no detectable degradation even after 60 min. We further demonstrate that a site-specifically DyLight 594-labeled cyclic dimer shows specific binding to HER2-overexpressing cells. Taken together, the results presented here demonstrate that head-to-tail cyclization can be an effective strategy to increase the stability of an Affibody dimer

Surface Charge Sensitivity of Silicon Nanowires : Size Dependence

Silicon nanowires of different widths were fabricated in silicon on insulator (SOI) material using conventional process technology combined with electron-beam lithography. The aim was to analyze the size dependence of the sensitivity of such nanowires for biomolecule detection and for other sensor applications. Results from electrical characterization of the nanowires show a threshold voltage increasing with decreasing width. When immersed in an acidic buffer solution, smaller nanowires exhibit large conductance changes while larger wires remain unaffected. This behavior is also reflected in detected threshold shifts between buffer solutions of different pH, and we find that nanowires of width &gt; 150 nm are virtually insensitive to the buffer pH. The increased sensitivity for smaller sizes is ascribed to the larger surface/volume ratio for smaller wires exposing the channel to a more effective control by the local environment, similar to a surrounded gate transistor structure. Computer simulations confirm this behavior and show that sensing can be extended even down to the single charge level.QC 2010071