Monitoring Insulin Aggregation via Capillary Electrophoresis

Early stages of insulin aggregation, which involve the transient formation of oligomeric aggregates, are an important aspect in the progression of Type II diabetes and in the quality control of pharmaceutical insulin production. This study is the first to utilize capillary electrophoresis (CE) with ultraviolet (UV) detection to monitor insulin oligomer formation at pH 8.0 and physiological ionic strength. The lag time to formation of the first detected species in the aggregation process was evaluated by UV-CE and thioflavin T (ThT) binding for salt concentrations from 100 mM to 250 mM. UV-CE had a significantly shorter (5–8 h) lag time than ThT binding (15–19 h). In addition, the lag time to detection of the first aggregated species via UV-CE was unaffected by salt concentration, while a trend toward an increased lag time with increased salt concentration was observed with ThT binding. This result indicates that solution ionic strength impacts early stages of aggregation and β-sheet aggregate formation differently. To observe whether CE may be applied for the analysis of biological samples containing low insulin concentrations, the limit of detection using UV and laser induced fluorescence (LIF) detection modes was determined. The limit of detection using LIF-CE, 48.4 pM, was lower than the physiological insulin concentration, verifying the utility of this technique for monitoring biological samples. LIF-CE was subsequently used to analyze the time course for fluorescein isothiocyanate (FITC)-labeled insulin oligomer formation. This study is the first to report that the FITC label prevented incorporation of insulin into oligomers, cautioning against the use of this fluorescent label as a tag for following early stages of insulin aggregation

Unraveling the Early Events of Amyloid-β Protein (Aβ) Aggregation: Techniques for the Determination of Aβ Aggregate Size

The aggregation of proteins into insoluble amyloid fibrils coincides with the onset of numerous diseases. An array of techniques is available to study the different stages of the amyloid aggregation process. Recently, emphasis has been placed upon the analysis of oligomeric amyloid species, which have been hypothesized to play a key role in disease progression. This paper reviews techniques utilized to study aggregation of the amyloid-β protein (Aβ) associated with Alzheimer’s disease. In particular, the review focuses on techniques that provide information about the size or quantity of oligomeric Aβ species formed during the early stages of aggregation, including native-PAGE, SDS-PAGE, Western blotting, capillary electrophoresis, mass spectrometry, fluorescence correlation spectroscopy, light scattering, size exclusion chromatography, centrifugation, enzyme-linked immunosorbent assay, and dot blotting

Life after the death of the letter: German post -epistolary cultures, 1832–1910

The condition of German epistolary culture in the nineteenth century is commonly perceived by literary critics in the light of the ‘end of the Briefroman.’ On the other hand, recent investigations have shown that the media of communication and their technological basis were profoundly discussed in the period. Bridging the gap between technology and literature, this dissertation investigates some of the most current cultural attitudes towards letter-writing and epistolarity from the perspective of nineteenth- and turn-of-the-century fiction-writers (from Karl Gutzkow to Ricarda Huch), as well as cultural historians and journalists to argue that, especially after 1850, definitions of Kommunikation begin to be divided into a dichotomy between ‘culture’ and ‘technology,’ a logic that continues to affect the way in which critical theory understands the decay of epistolary literature in the Industrial Age

The Relationship between Deaf and Hard-of-Hearing Students' Japanese Sign Language and Japanese Language Proficiency

The present study represents an attempt at investigating the relationship between the Japanese Sign Language proficiency and the Japanese literacy skills of high school students who are deaf and hard-of-hearing (D/HH). A pilot test of Japanese Sign Language was designed and administered to 138 D/HH students. A validation analysis was carried out employing classical test theory methods, and test scores were compared to scores obtained by the same participants on a Japanese language and literacy test. Although the small number and heterogeneity of the items in the Japanese Sign Language Test lowered the test's reliability estimate, the comparison with the Japanese language and literacy test provided useful insights into the relationship between the two languages. In particular, students who performed well on the general narrative comprehension task of the Japanese Sign Language Test, and those who were good at processing sequential information in Japanese Sign Language, also had good overall command of written Japanese. Moreover, there seemed to be a positive correlation between students' metalinguistic awareness of Japanese Sign Language and their knowledge of Japanese grammar

Mass spectrometric methods for characterization of protein aggregation and antigen recognition structures

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The Evaluation of Unincorporated Areas – Particularities and Perspectives on the Real Estate Market

The real estate market in Romania occupies an important position within the national economy, with the results in the real estate field having a significant impact on the determination of the macroeconomic indicators� values. We can consider that within each economy, the real estate market represents a complex sector, due to the high volume of carried out transactions and to the high number of individuals that take part in the carrying out of the transactions. The importance of area evaluation is guaranteed by the high number of its practical applications. The information provided by the evaluator is used by judicial institutions as a basis for various decision making processes