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: 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: Thus far, live attenuated SIV has been the most successful method for vaccinating macaques against pathogenic SIV challenge; however, it is not clear what mechanisms are responsible for this protection. Adoptive transfer studies in mice have been integral to understanding live attenuated vaccine protection in models like Friend virus. Previous adoptive transfers in primates have failed as transferred cells are typically cleared within hours after transfer.', 'Here we describe adoptive transfer studies in Mauritian origin cynomolgus macaques (MCM), a non-human primate model with limited MHC diversity. Cells transferred between unrelated MHC-matched macaques persist for at least fourteen days but are rejected within 36 hours in MHC-mismatched macaques. Cells trafficked from the blood to peripheral lymphoid tissues within 12 hours of transfer.\Question: Do allogeneic lymphocytes persist and traffic in feral MHC-matched mauritian cynomolgus macaques?
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MHC-matched MCM provide the first viable primate model for adoptive transfer studies. Because macaques infected with SIV are the best model for HIV/AIDS pathogenesis, we can now directly study the correlates of protective immune responses to AIDS viruses. For example, plasma viral loads following pathogenic SIV challenge are reduced by several orders of magnitude in macaques previously immunized with attenuated SIV. Adoptive transfer of lymphocyte subpopulations from vaccinated donors into SIV-naïve animals may define the immune mechanisms responsible for protection and guide future vaccine development.


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Context: Proper selection of patients for carotid artery stenting (CAS) remains controversial despite multiple controlled trials. This relates in part to differences in interpretation of the relative importance of myocardial vs stroke complications after the procedure by different specialties and a lack of granular clinical data to analyze outcomes outside the large clinical trials. The objective of this study was to assess the effect of preoperative medications, procedure parameters, and patient characteristics on outcomes of CAS performed in a multispecialty national database.', 'We analyzed all patients who underwent CAS between 2005 and 2014 in the Vascular Quality Initiative. A multivariate logistic regression model was built to assess the effects of age, gender, comorbidities, smoking, preprocedure medications, procedure details, and hypotension or hypertension that required intravenous medication on 30-day death or stroke rates.', 'A total of 5263 patients underwent CAS (mean age, 70 years; 63% male). The 30-day stroke/death rate was 3.4% (1.5% minor stroke, 0.9% major stroke, and 1.2% death; 40% of patients who had major strokes died within 30 days), and the myocardial infarction rate was 0.8%. Postprocedural hypertension requiring treatment occurred in 519 cases (9.9%), and it was associated with a 3.4-fold increase in stroke/death (odds ratio, 3.39; 95% confidence interval, 2.30-5.00; P < .0001). Preprocedural beta-blocker use for >30 days was associated with a 34% reduction in the stroke/death risk (odds ratio, 0.66; 95% confidence interval, 0.46-0.95; P = .025) compared with nonuse. Beta-blocker use was not associated with postprocedural hypotension. Other predictors of postoperative stroke and death included age, symptomatic status, diabetes (type 1 or type 2), and postprocedural hypotension, whereas prior carotid endarterectomy and distal embolic protection use were protective.\Question: Is beta-blocker use associated with lower stroke and death after carotid artery stenting?
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Postprocedural hypertension and hypotension that require treatment are both strongly associated with periprocedural stroke/death after CAS. Beta blockers significantly reduce the stroke/death risk associated with carotid stenting and should be investigated prospectively for potential use during CAS.