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: Prognosis and treatment of patients with breast carcinoma of no special type (NST) is dependent on a few established parameters, such as tumor size, histological grade, lymph node stage, expression of estrogen receptor, progesterone receptor, and HER-2/neu, and proliferation index. The original Nottingham Prognostic Index (NPI) employs a three-tiered classification system that stratifies patients with breast cancer into good, moderate, and poor prognostic groups. The aim of our study was to use robust immunohistochemical methodology for determination of ER, PR, HER-2/neu, Ki-67, p53, and Bcl-2, and to observe differences in the expression of these markers when patients are stratified according to the original, three-tiered Nottingham Prognostic Index.', 'Paraffin blocks from 120 patients diagnosed with breast carcinoma, NST, were retrieved from our archive. Cases included in the study were female patients previously treated with modified radical mastectomy and axillary dissection.', 'Our study demonstrates that expression of markers of good prognosis, such as ER, PR, and Bcl-2, is seen with higher frequency in good and moderate NPI groups. In contrast, overexpression of HER-2/neu, a marker of adverse prognosis, is more frequent in moderate and poor NPI groups. High proliferation index, as measured by Ki-67, is seen in moderate and poor NPI groups, whereas low proliferation index is seen in good NPI groups.\Question: Does classification of patients with breast cancer according to Nottingham prognostic index highlight significant differences in immunohistochemical marker expression?

A: These data confirm that the original, three-tiered NPI statistically correlates with the expression of prognostic immunohistochemical markers in breast carcinoma NST.
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Q: Context: The measurement of affective symptoms in older persons who decline cognitively is uncertain. The authors investigated whether mood variability predicts dementia in patients with age-related macular degeneration (AMD).', 'Three-year observational study after a clinical trial.', 'Community follow-up of outpatients ascertained from retina clinics.', 'One hundred sixty patients with AMD.', "Geriatric Depression Scale (GDS) administered every 2 weeks for 6 months to subjects; Informant Questionnaire for Cognitive Decline in the Elderly (IQCODE) administered to subjects' knowledgeable informants.", 'Twenty-three subjects (14.4%) declined cognitively. Age, education, baseline GDS score > or =5, and variability in GDS scores (i.e., fluctuations between adjacent time points) were associated with cognitive decline. For GDS variability, each 1 unit increase in the residual standard deviation (SD) of the GDS increased the risk for cognitive decline by 93% (IDR = 1.92; 95% CI [1.27-2.91]). Thus, subjects with a residual SD of 1 were nearly twice as likely to become demented as subjects with no variability in GDS scores. The risk for subjects with SDs of 2 increased more than threefold (IDR = 3.68; 95% CI [1.61-8.47]). A multiple regression analysis showed that GDS variability was a significant risk factor for dementia after controlling for significant covariates.\Question: Does variability in depressive symptoms predict cognitive decline in age-related macular degeneration?

A: These data suggest a useful approach to conceptualizing and measuring depressive symptoms in older persons. Variability in self-reported mood may be an early sign of dementia and may offer new insights into the neurobiological mechanisms linking depression and cognition
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Q: Context: Oxidative stress is central to the pathogenesis of Parkinson's disease (PD), but the mechanisms involved in the control of this stress in dopaminergic cells are not fully understood. There is increasing evidence that selenoproteins play a central role in the control of redox homeostasis and cell defense, but the precise contribution of members of this family of proteins during the course of neurodegenerative diseases is still elusive.", 'We demonstrated first that selenoprotein T (SelT) whose gene disruption is lethal during embryogenesis, exerts a potent oxidoreductase activity. In the SH-SY5Y cell model of dopaminergic neurons, both silencing and overexpression of SelT affected oxidative stress and cell survival. Treatment with PD-inducing neurotoxins such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or rotenone triggered SelT expression in the nigrostriatal pathway of wild-type mice, but provoked rapid and severe parkinsonian-like motor defects in conditional brain SelT-deficient mice. This motor impairment was associated with marked oxidative stress and neurodegeneration and decreased tyrosine hydroxylase activity and dopamine levels in the nigrostriatal system. Finally, in PD patients, we report that SelT is tremendously increased in the caudate putamen tissue.', 'These results reveal the activity of a novel selenoprotein enzyme that protects dopaminergic neurons against oxidative stress and prevents early and severe movement impairment in animal models of PD.\Question: Does selenoprotein T exert an Essential Oxidoreductase Activity That Protects Dopaminergic Neurons in Mouse Models of Parkinson 's Disease?

A:
Our findings indicate that selenoproteins such as SelT play a crucial role in the protection of dopaminergic neurons against oxidative stress and cell death, providing insight into the molecular underpinnings of this stress in PD.
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