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: 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: Observational studies suggest that dietary isoflavones reduce breast cancer risk, and this may be caused in part by effects on endogenous hormone concentrations. Because intestinal bacteria metabolize isoflavones, it was hypothesized that consumption of probiotic bacteria would enhance the biologic effects of isoflavones, including effects on endogenous hormones.', 'Twenty (20) postmenopausal breast cancer survivors and 20 healthy postmenopausal women completed four 42-day diet periods in a randomized, crossover design. They received one of the following: isolated soy protein; isolated milk protein; soy + probiotic capsules; or milk + probiotic capsules. Each protein supplement provided 0.38 g protein/(kg body weight/day) (26.6 +/- 4.5 g protein/day) and soy protein provided 0.64 mg isoflavones/(kg body weight/day) (44.4 +/- 7.5 mg isoflavones/day). Probiotic capsules provided 10(9) colony-forming units Lactobacillus acidophilus (strain DDS-1), Bifidobacterium longum, and 15-20 mg fructo-oligosaccharide.', 'Plasma samples were collected at baseline and after each diet for analysis of estrogens, follicle-stimulating hormone (FSH), androgens, and sex hormone?binding globulin (SHBG).', 'Hormone levels were not affected by soy, probiotic supplements, or equol producer status, and neither cancer status nor equol producer status altered the effects of soy or probiotics. Furthermore probiotics did not alter the effects of soy consumption. Soy protein tended to decrease SHBG compared to milk protein diets (p = 0.05), although both proteins significantly decreased SHBG relative to baseline (p = 0.0001 and p = 0.03).\Question: Does short-term soy and probiotic supplementation markedly affect concentrations of reproductive hormones in postmenopausal women with and without histories of breast cancer?

A: These data suggest that short-term, moderate consumption of isoflavone-containing soy protein and consumption of these particular probiotic capsules do not significantly alter reproductive hormone concentrations in breast cancer survivors or controls, regardless of equol producer status.
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Q: Context: We questioned whether infection with murine gammaherpesvirus 68 (HV-68) might exacerbate inflammatory bowel disease using mice deficient in IL-10 (IL-10-/-) as a model of developing colitis.', 'Groups of C57BL/6 mice and IL-10-/- mice were mock-treated or infected with HV-68. Two months following infection, mice were euthanized and a variety of parameters were measured to quantify the extent of inflammation and the presence of virus. Measurements included survival, body weight, splenomegaly, colonic disease scores, liver histopathology, viable bacteria in the liver, and splenic viral burden.', 'IL-10-/- mice infected with HV-68 displayed reduced survival, lower body weights, increased splenomegaly, exacerbated colonic disease scores, increased numbers of viable bacteria in the liver, and increased leukocyte liver infiltration when compared to mock-treated IL-10-/- mice or HV-68 infected C57BL/6 mice. Surprisingly, levels of infectious or latent virus were not significantly different between the groups of mice exposed to HV-68.\Question: Does infection with murine gammaherpesvirus 68 exacerbate inflammatory bowel disease in IL-10-deficient mice?

A:
The presence of HV-68 in IL-10-/- mice exacerbates the developing clinical disease in this animal model of colitis.
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