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: 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?

SOLUTION: 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.

PROBLEM: Context: Hepatic expression of growth hormone (GH)-inducible genes serine protease inhibitor (Spi 2.1) and insulin-like growth factor (IGF)-I are inhibited by interleukin (IL)-1. The current study examines the role of the nuclear factor kappaB (NFkappaB) pathway and suppressor of cytokine signaling (SOCS)-3 expression as potential mechanisms for IL-1-mediated GH resistance.', 'CWSV-1 hepatocytes were cotransfected with Spi 2.1 or IGF-1 promoter luciferase constructs and empty pCMV4 vector or dominant negative inhibitor-kappaBalpha (IkappaBalpha)S/A construct. Cells were treated with or without IL-1 and then stimulated with or without recombinant human GH. Cell extracts were assayed for luciferase activity and protein, normalized and expressed as fold-induction. CWSV-1 cells transfected with pCMV4 or IkappaBalphaS/A were treated with or without IL-1 then SOCS-3 mRNA was measured. Finally, CWSV-1 cells were cotransfected with a SOCS-3 promoter construct with or without pCMV4 or IkappaBalphaS/A and then stimulated with or without IL-1 to investigate SOCS-3 promoter activity.', 'CWSV-1 cells cotransfected with pCMV4 demonstrated a three- to fivefold induction of Spi 2.1 or IGF-1 promoter activity after GH stimulation that was almost completely inhibited by IL-1. Cotransfection with IkappaBalphaS/A increased GH-inducible Spi 2.1 and IGF-1 promoter activity, but the inhibitory effects of IL-1 on both promoters were attenuated by cotransfection with IkappaBalphaS/A. IL-1 stimulated SOCS-3 mRNA expression and promoter activity. Cotransfection with IkappaBalphaS/A increased IL-1-inducible SOCS-3 promoter activity, but not SOCS-3 mRNA or protein.\Question: Does nuclear factor kappaB mediate the inhibitory effects of interleukin-1 on growth hormone-inducible gene expression?

SOLUTION: Signaling via the NFkappaB pathway is responsible for the inhibitory effects of IL-1 on GH-inducible gene expression by a mechanism that does not seem to involve increased SOCS-3 expression.

PROBLEM: Context: Flow-mediated dilation (FMD) is a complex mechanism involving several mediators, and different hemodynamic forces. Temporally distinct FMD patterns can be elicited by ischemic stimulus. Some subjects dilate early after cuff release, while others dilate later or do not dilate at all. Aim of the present research was to verify if hemorheological and hemodynamic factors might influence different FMD pattern.', '148 free-living subjects were studied. FMD was measured at 50 s, 2 min and 3 min. Blood viscosity was measured and shear stress calculated. Shear stress stimulus was quantified as the area under the curve after ischemia (SSAUC) over the first 40-s post-occlusion.', 'Based on the timing or absence of arterial dilation, 82 subjects were classified as Early dilators, 37 as Late dilators and 29 as No dilators. Peak FMD was 7.9 4.3 % in Early dilators, and 9.1 5.7 in Late dilators (p = NS). SSAUC was not significantly different among three groups, while blood viscosity was significantly higher in Late FMD subjects. Regression analyses showed the independent predictive role of age and blood viscosity on FMD patterns, and the lack of any association between FMD pattern and the magnitude of SS.\Question: Does blood viscosity but not shear stress associate with delayed flow-mediated dilation?

SOLUTION:
The present study demonstrates that age and blood viscosity but not the magnitude of SS explain the different timing of the dilatory response to ischemia.