In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Q: Context: Alternative splicing is important for increasing the complexity of the human proteome from a limited genome. Previous studies have shown that for some autoantigens, there is differential immunogenicity among alternatively spliced isoforms.', 'Herein, we tested the hypothesis that alternative splicing is a common feature for transcripts of autologous proteins that are autoantigens. The corollary hypothesis tested was that nonautoantigen transcripts have a lower frequency of alternative splicing.', 'The extent of alternative splicing within 45 randomly selected self-proteins associated with autoimmune diseases was compared with 9554 randomly selected proteins in the human genome by using bioinformatics analyses. Isoform-specific regions that resulted from alternative splicing were studied for their potential to be epitopes for antibodies or T-cell receptors.', 'Alternative splicing occurred in 100% of the autoantigen transcripts. This was significantly higher than the approximately 42% rate of alternative splicing observed in the 9554 randomly selected human gene transcripts ( P < .001). Within the isoform-specific regions of the autoantigens, 92% and 88% encoded MHC class I and class II-restricted T-cell antigen epitopes, respectively, and 70% encoded antibody binding domains. Furthermore, 80% of the autoantigen transcripts underwent noncanonical alternative splicing, which is also significantly higher than the less than 1% rate in randomly selected gene transcripts ( P < .001).\Question: Does increased noncanonical splicing of autoantigen transcripts provide the structural basis for expression of untolerized epitopes?

A: These studies suggest that noncanonical alternative splicing may be an important mechanism for the generation of untolerized epitopes that may lead to autoimmunity. Furthermore, the product of a transcript that does not undergo alternative splicing is unlikely to be a target antigen in autoimmunity.
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Q: Context: Nonviral vectors based on polyethylenimine (PEI) usually contain an excess of PEI that is not complexed to DNA. Since unbound PEI contributes to cellular and systemic toxicity, purification of polyplexes from unbound PEI is desirable.', 'Size exclusion chromatography (SEC) was used to purify PEI polyplexes of free PEI. Transfection properties of purified polyplexes and the effect of free PEI on gene delivery were studied in vitro and in vivo after systemic application into mice.', 'SEC did not change the size and zeta-potential of polyplexes. Independent of the amount of PEI used for complex formation, purified PEI polyplexes had the same final PEI nitrogen/DNA phosphate ratio of 2.5. Notably, purified PEI polyplexes demonstrated low cellular and systemic toxicity. High transfection efficiency was achieved with purified polyplexes at high DNA concentrations (8-15 microg/ml). At low DNA concentrations (2-4 microg/ml) gene transfer with purified particles was less efficient than with polyplexes containing free PEI both in vitro and in vivo. Mechanistic studies showed that free PEI partly blocked cellular association of DNA complexes but was essential for the following intracellular gene delivery. Adding free PEI to cells treated with purified particles with a delay of up to 4 h resulted in significantly enhanced transfection efficiency compared with non-purified particles or purified particles without free PEI.\Question: Does purification of polyethylenimine polyplexes highlight the role of free polycations in gene transfer?

A: This study presents an efficient method to remove free PEI from PEI polyplexes by SEC. Our results from transfection experiments demonstrate that free PEI substantially contributes to efficient gene expression but also mediates toxic effects in a dose-dependent manner. Purified polyplexes without free PEI have to be applied at increased concentrations to achieve high transfection levels, but exhibit a greatly improved toxicity profile.
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Q: Context: Accumulating evidence has indicated that inflammation may act as a potential mechanism underlying post-operative cognitive dysfunction (POCD). High-mobility group box 1 (HMGB1), as a known late mediator of inflammation, is involved in the development of post-operative complications. Thus, we sought to determine the role of HMGB1 in reflecting POCD following major gastrointestinal surgery.', 'Fifty-three elderly patients undergoing gastrointestinal surgery were recruited, and 50 patients completed the study. Serum HMGB1 and interleukin (IL)-6 levels were measured pre-operatively and at 6 h, day 1 and day 3 post-operatively. Neuropsychological tests were administered before and 1 week after surgery. POCD was determined using a Z score ≥ 1.96.', 'Seventeen (34%, 17/50) patients developed POCD at 1 week. The POCD group had higher serum HMGB1 levels at day 1 (12.15 ± 3.12 vs. 9.91 ± 3.15 ng/ml, P = 0.021) and day 3 (11.04 ± 2.88 vs. 8.52 ± 3.31 ng/ml, P = 0.011). IL-6 levels at 6 h (51.18 ± 15.22 vs. 39.20 ± 14.32 pg/ml, P = 0.009) and day 1 (41.59 ± 11.08 vs. 33.81 ± 11.42 pg/ml, P = 0.026) were significantly higher in POCD patients. Serum values of IL-6 at 6 h, HMGB1 at day 1 and levels of education showed positive correlations with Z scores. HMGB1 at day 3 and IL-6 at 6 h were independent risk factors.\Question: Does serum high-mobility group box 1 protein correlate with cognitive decline after gastrointestinal surgery?

A:
Serum HMGB1 and IL-6 levels increase significantly after major gastrointestinal surgery in elderly patients and such elevations are associated with the occurrence of cognitive decline after surgery.
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