TASK DEFINITION: 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.
PROBLEM: Context: Chlorophyllin (CHL) was proved to have strong anti-inducement effect toward many mutagens and epicarcinogens. This study was to explore effect of CHL in preventing colon neoplasms in mice induced by dimethylhydrazine (DMH), and the selective inhibition on cyclooxygenase 2(COX-2).', 'The colorectal neoplasms were induced with DMH in mice and the different dose of CHL were administered in different phases, then the prevention of colorectal neoplasms by CHL was examined; The IC50 and growth curve of HT29 cells were measured with MTT method after treated with CHL; The effect of CHL on the expression of COX-1 mRNA and COX-2 mRNA in HT29 cells were measured with RT-PCR method; The effect of CHL on the expression of COX-2 protein and NF-kappaB protein were measured with western blot and immunohistochemistry methods.', 'The incidence of colon cancer, average tumor amount, and percentage of carcinoma in CHL group were significantly lower than those in DMH group (P< .05); CHL could inhibit the growth of HT29 cells. The effects were dose dependent; CHL could selectively inhibit the expression of COX-2mRNA in HT29 cells,the expression of COX-2 protein in colon neoplasms and HT29 cells, and the expression of NF-kappaB protein in colon neoplasms.\Question: Do [ CHL prevent colon neoplasms in mice and its selective inhibition on COX-2 ]?

SOLUTION: CHL could prevent colon neoplasms in mice induced by DMH and the preventive effect related to selective inhibition on COX-2, furthermore, the inhibition of CHL on COX-2 was realized by inhibiting NF-kappaB protein.

PROBLEM: Context: Cord blood (CB) hematopoietic stem cell transplantation has often been limited by the scarcity of stem cells. Therefore, the number of CB hematopoietic stem/progenitor cells (HSPCs) should be increased while maintaining the stem cell characteristics.', 'We designed an ex vivo culture system using endothelial progenitor cells (EPCs) as stroma to determine the capacity of expanding CB-HSPCs in a defined medium, the effect on engraftment of the expanded cells in a mouse model and the underlying mechanism.', "After 7 days of culture, compared with those cultured with cytokines alone (3.25 0.59), CD34+ cells under contact and non-contact co-culture with EPCs were expanded by 5.38 0.61 (P = 0.003) and 4.06 0.43 (P = 0.025)-fold, respectively. Direct cell-to-cell contact co-culture with EPCs resulted in more primitive CD34+ CD38- cells than stroma-free culture (156.17 21.32 versus 79.12 19.77-fold; P = 0.010). Comparable engraftment of day 7 co-cultured HSPCs with respect to HSPCs at day 0 in nonobese diabetic-severe combined immunodeficiency disease (NOD/SCID) mice was measured as a percentage of chimerism (13.3% 11.0% versus 16.0% 14.3%; P = 0.750). EPCs highly expressed interleukin 6 (IL6) and angiopoietin 1 (ANGPT1), the hematopoietic- related cytokines. A higher transcriptional level of WNT5A genes in EPCs and co-cultured HSPCs suggests that the activation of Wnt signaling pathway may play a role in HSPCs' expansion ex vivo.\Question: Do endothelial progenitor cells promote efficient ex vivo expansion of cord blood-derived hematopoietic stem/progenitor cells?

SOLUTION: These data demonstrated that EPCs improve the CD34+ population but do not compromise the repopulating efficacy of the amplified HSPCs, possibly via cytokine secretion and Wnt signaling pathway activation.

PROBLEM: Context: The polymorphism of the gene encoding methylenetetrahydrofolate reductase (MTHFR) and folic acid nutritional status play important roles in atherosclerosis. The present study investigated the total homocysteine-lowering effect of folic acid in response to the MTHFR genotype in patients who have cardiovascular disease.', 'Twenty-three patients who had cardiovascular disease (ages 44 to 88 y) were supplemented with 5 mg of folic acid/d for 8 wk. Blood samples were collected before and after supplementation for the measurement of folic acid. The presence of the 677C-->T mutation was assessed by polymerase chain reaction followed by restriction enzyme analysis.', 'After the 8 wk of folic acid supplementation, plasma total homocysteine decreased 40% in patients who had the TT genotype, 23% in those who had the CT genotype, 10% in those who had the CC genotype, and 27% in carriers of the T allele. The plasma total homocysteine-lowering effect of folic acid was significant only in patients who had the CT genotype and in carriers of the T allele.\Question: Does methylenetetrahydrofolate reductase polymorphism determine the plasma homocysteine-lowering effect of large-dose folic acid supplementation in patients with cardiovascular disease?

SOLUTION:
The MTHFR polymorphism may be involved in the total homocysteine-lowering effect of folic acid in patients who have cardiovascular disease.