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: Enterovirus infections are major etiological factors in myocarditis and dilated cardiomyopathy. Using an experimental murine model of this disease, previous studies have shown that myocarditis susceptibility depends upon activation of T lymphocytes expressing the gamma delta T cell receptor (TcR), and that only mouse strains which accumulate gamma delta T cells in the myocardium show apoptosis of myocytes or evidence of dilated cardiomyopathy-like disease. The objective of the present studies is to demonstrate that gamma delta T cells directly induce greater Fas-dependent apoptosis of cultured myocytes than T cells expressing the alpha beta TcR.', 'Bl.Tg.E alpha mice were infected for 7 days with coxsackievirus B3 (CVB3). Hearts were removed and were either formalin-fixed, sectioned and stained with hematoxylin and eosin for inflammation, and using TdT-TUNEL for apoptosis, or were minced and collagenase digested for isolation of gamma delta+ and alpha beta+ T cells using immunomagnetic bead separation. Neonatal cultures of cardiac myocytes were isolated from mice less than 2 days old by collagenase and pancreatin digestion, and were either untreated or infected with virus. Levels of Fas (CD95) were measured using FITC-conjugated hamster anti-mouse Fas monoclonal antibody and flow cytometry. Susceptibility of myocytes to Fas-dependent killing was measured by 51Cr-release by labeled myocytes incubated for 4 h on either 3T3-mock or 3T3-FasL transfected cell monolayers. Killing by T cells was also measured in a 4 h 51Cr-release assay. Fas-dependent and perforin-dependent cytotoxicity was determined by specific blocking using either Fas-Fc or concanamycin A.', 'Virally infected myocyte cultures showed significantly enhanced Fas expression compared to uninfected cells, with maximal upregulation of Fas occurring 18-24 h after virus infection. Both infected and uninfected myocytes were selectively killed by FasL-transfected 3T3 cells but not by mock control cells. Approximately 38% of CD3+ lymphocytes isolated from the heart express the gamma delta TcR with the remainder expressing the alpha beta TcR. Both gamma delta+ and alpha beta+ T cells lysed myocyte targets. Blocking studies indicate that gamma delta+ T cells induced predominantly Fas-mediated killing, while alpha beta+ cell produced more perforin-mediated death, although these effectors were capable of Fas-dependent killing as well.\Question: Do t cells expressing the gamma delta T cell receptor induce apoptosis in cardiac myocytes?
answer:
These studies demonstrate that T cells expressing the gamma delta TcR are more effective mediators of myocyte apoptosis than alpha beta+ T cells in vitro and suggests that these effectors may be primarily responsible for myocardial injury associated with dilated cardiomyopathy-like signs during coxsackievirus B3-induced myocarditis.

question:
Context: Transforming growth factor beta 1 (TGF1) is strongly induced following brain injury and polarises microglia to an anti-inflammatory phenotype. Augmentation of TGF1 responses may therefore be beneficial in preventing inflammation in neurological disorders including stroke and neurodegenerative diseases. However, several other cell types display immunogenic potential and identifying the effect of TGF1 on these cells is required to more fully understand its effects on brain inflammation. Pericytes are multifunctional cells which ensheath the brain vasculature and have garnered recent attention with respect to their immunomodulatory potential. Here, we sought to investigate the inflammatory phenotype adopted by TGF1-stimulated human brain pericytes.', 'Microarray analysis was performed to examine transcriptome-wide changes in TGF1-stimulated pericytes, and results were validated by qRT-PCR and cytometric bead arrays. Flow cytometry, immunocytochemistry and LDH/Alamar Blue®️ viability assays were utilised to examine phagocytic capacity of human brain pericytes, transcription factor modulation and pericyte health.', 'TGF1 treatment of primary human brain pericytes induced the expression of several inflammatory-related genes (NOX4, COX2, IL6 and MMP2) and attenuated others (IL8, CX3CL1, MCP1 and VCAM1). A synergistic induction of IL-6 was seen with IL-1/TGF1 treatment whilst TGF1 attenuated the IL-1-induced expression of CX3CL1, MCP-1 and sVCAM-1. TGF1 was found to signal through SMAD2/3 transcription factors but did not modify nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) translocation. Furthermore, TGF1 attenuated the phagocytic ability of pericytes, possibly through downregulation of the scavenger receptors CD36, CD47 and CD68. Whilst TGF did decrease pericyte number, this was due to a reduction in proliferation, not apoptotic death or compromised cell viability.\Question: Does tGF-beta1 regulate human brain pericyte inflammatory processes involved in neurovasculature function?
answer:
TGF1 attenuated pericyte expression of key chemokines and adhesion molecules involved in CNS leukocyte trafficking and the modulation of microglial function, as well as reduced the phagocytic ability of pericytes. However, TGF1 also enhanced the expression of classical pro-inflammatory cytokines and enzymes which can disrupt BBB functioning, suggesting that pericytes adopt a phenotype which is neither solely pro- nor anti-inflammatory. Whilst the effects of pericyte modulation by TGF1 in vivo are difficult to infer, the reduction in pericyte proliferation together with the elevated IL-6, MMP-2 and NOX4 and reduced phagocytosis suggests a detrimental action of TGF1 on neurovasculature.

question:
Context: Carotid stiffening is considered a key element in the pathogenesis of stroke. However, results of studies evaluating the association between carotid stiffness and incident stroke have been inconsistent.', 'This study investigated whether carotid stiffness (as determined by ultrasonography) is associated with incident stroke and whether this association is independent of aortic stiffness as estimated by carotid-femoral pulse wave velocity (cfPWV). Additionally, we evaluated the incremental value of carotid stiffness for stroke risk prediction beyond Framingham risk factors and cfPWV.', 'This study included a systematic review and meta-analyses of aggregate and individual participant data (IPD), the latter of which was obtained by requesting individual-level data of all cohort studies with available data on carotid stiffness and cfPWV.', 'Ten studies (n= 22,472) were included in the aggregate data meta-analysis and 4 (n= 4,540) in the IPD meta-analysis. After adjusting for cardiovascular (CV) factors, the aggregate data meta-analysis showed that greater carotid stiffness (per SD) was associated with stroke (hazard ratio: 1.18; 95% confidence interval: 1.05 to 1.33). In addition, carotid stiffness was associated with total CV events and CV and all-cause mortality, but not with coronary heart disease events. In the IPD meta-analysis, additional adjustment for cfPWV did not materially change these associations. Carotid stiffness did improve stroke risk prediction beyond Framingham and cfPWV (integrative discrimination improvement: 0.4 percentage point [95% confidence interval: 0.1 to 0.6 percentage point] and continuous net reclassification improvement: 18.6% [95% confidence interval: 5.8% to 31.3%]).\Question: Is carotid stiffness associated with incident stroke : a systematic review and individual participant data meta-analysis?
answer:
Carotid stiffness is associated with incident stroke independently of CV factors and aortic stiffness. Inaddition, carotid stiffness improves stroke risk prediction beyond Framingham and aortic stiffness.