instruction:
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.
question:
Context: Radiation induces an important apoptosis response in irradiated organs. The objective of this study was to investigate the radioprotective effect of tetramethylpyrazine (TMP) on irradiated lymphocytes and discover the possible mechanism of protection.', 'Lymphocytes were pretreated for 12 h with TMP (25-200 molL(-1)) and then exposed to 4 Gy radiation. Cell apoptosis and the signaling pathway were analyzed.', 'Irradiation increased cell death, DNA fragmentation, activated caspase activation and cytochrome c translocation, downregulated B-cell lymphoma 2 (Bcl-2) and up-regulated Bcl-2-associated X protein (Bax). Pretreated with TMP significantly reversed this tendency. Several anti-apoptotic characteristics of TMP, including the ability to increase cell viability, inhibit caspase-9 activation, and upregulate Bcl-2 and down-regulate Bax in 4Gy-irradiated lymphocytes were determined. Signal pathway analysis showed TMP could translate nuclear factor-B (NF-B) from cytosol into the nucleus.\Question: Does tetramethylpyrazine protect lymphocytes from radiation-induced apoptosis through nuclear factor-B?
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The results suggest that TMP had a radioprotective effect through the NF-B pathway to inhibit apoptosis, and it may be an effective candidate for treating radiation diseases associated with cell apoptosis.

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Context: Human breast tumors are heterogeneous and consist of phenotypically diverse cells. Breast cancer cells with a CD44+/CD24- phenotype have been suggested to have tumor-initiating properties with stem cell-like and invasive features, although it is unclear whether their presence within a tumor has clinical implications. There is also a large heterogeneity between tumors, illustrated by reproducible stratification into various subtypes based on gene expression profiles or histopathological features. We have explored the prevalence of cells with different CD44/CD24 phenotypes within breast cancer subtypes.', 'Double-staining immunohistochemistry was used to quantify CD44 and CD24 expression in 240 human breast tumors for which information on other tumor markers and clinical characteristics was available. Gene expression data were also accessible for a cohort of the material.', 'A considerable heterogeneity in CD44 and CD24 expression was seen both between and within tumors. A complete lack of both proteins was evident in 35% of the tumors, while 13% contained cells of more than one of the CD44+/CD24-, CD44-/CD24+ and CD44+/CD24+ phenotypes. CD44+/CD24- cells were detected in 31% of the tumors, ranging in proportion from only a few to close to 100% of tumor cells. The CD44+/CD24- phenotype was most common in the basal-like subgroup--characterized as negative for the estrogen and progesterone receptors as well as for HER2, and as positive for cytokeratin 5/14 and/or epidermal growth factor receptor, and particularly common in BRCA1 hereditary tumors, of which 94% contained CD44+/CD24- cells. The CD44+/CD24- phenotype was surprisingly scarce in HER2+ tumors, which had a predominantly CD24+ status. A CD44+/CD24- gene expression signature was generated, which included CD44 and alpha6-integrin (CD49f) among the top-ranked overexpressed genes.\Question: Does the CD44+/CD24- phenotype is enriched in basal-like breast tumors?
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We demonstrate an association between basal-like and particularly BRCA1 hereditary breast cancer and the presence of CD44+/CD24- cells. Not all basal-like tumors and very few HER2+ tumors, however, contain CD44+/CD24- cells, emphasizing that a putative tumorigenic ability may not be confined to cells of this phenotype and that other breast cancer stem cell markers remain to be identified.

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Context: Total blood homocysteine (Hcys) and folate levels have been investigated in association with cognitive dysfunction in healthy but not in multimorbid elderly patients. We hypothesized that total serum Hcys is an adequate marker to identify multimorbid elderly patients with cognitive dysfunction assessed by the Short Cognitive Performance Test (SKT) and Mini-Mental State Examination (MMSE).', 'Cross-sectional study.', 'The study center was an acute geriatric hospital.', 'A total of 189 multimorbid elderly patients were recruited.', 'Cognitive dysfunction was determined according to the SKT and MMSE. Biochemical parameters (Hcys, folate, vitamin B12, hemoglobin), nutritional status (BMI, Mini Nutritional Assessment, nutritional intake), and activities of daily living were assessed.', 'According to the SKT, 25.4% of patients showed no cerebral cognitive dysfunction, 21.2% had suspected incipient cognitive dysfunction, 12.7% showed mild cognitive dysfunction, 9.0% had moderate cognitive dysfunction, and 31.7% of patients were demented. The median plasma Hcys value was elevated by approximately 20% in multimorbid elderly patients, independent of cognitive dysfunction. Serum folate and vitamin B12 concentrations were within normal ranges. We did not find significant differences in nutritional status, activities of daily living, numbers of diseases or medications, or selected biochemical parameters between the SKT groups.\Question: Do total serum homocysteine levels identify cognitive dysfunction in multimorbid elderly patients?
answer:
Elevated serum Hcys levels with normal plasma folate and vitamin B12 concentrations were observed in multimorbid elderly patients. The plasma Hcys level did not appear to be an important biological risk factor for cognitive dysfunction in multimorbid geriatric patients.