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.

Ex Input:
Context: Perls' stain is routinely used to demonstrate iron in liver biopsies. We tested the hypothesis that it may be unnecessary in cases, where no iron or another similar pigment was seen on the routine hematoxylin and eosin (H and E) stained section.", "The aim of this study was to evaluate the efficiency of H and E stain in demonstrating iron in liver biopsies as well as to determine the possibility of replacing Perls' stain with H and E stain.", "Two hundred pairs of slides of liver biopsies were taken from the archival files of the Department of Pathology from 2006 to 2011. Perls' and H and E slides were independently reviewed for the presence of iron.", "Hundred and one cases showed the presence of iron using H and E stain. 84 of 86 cases showed positive iron using both Perls' and H and E stains. Seventeen cases were positive using H and E stain but negative with Perls'. Only two cases did not show the presence of iron using H and E stain. Ninety-seven cases were negative using both Perls' and H and E stains. H and E stain showed a sensitivity, specificity, accuracy, positive predictive valve, and negative predictive value of 97.67%, 85.08%, 90.5%, 83.16%, and 97.98%, respectively.\Question: Do hematoxylin and eosin stain shows a high sensitivity but sub-optimal specificity in demonstrating iron pigment in liver biopsies?

Ex Output:
We demonstrate that the H and E stain is a sensitive method to detect iron pigment in liver biopsies, particularly when present in large quantities. A negative H and E stain might obviate the need for extra Perls' staining, thus saving costs and shortening report turn-around times.

Ex Input:
Context: The purpose of this study was to examine the effectiveness of ankle bracing and taping in preventing recurrencess of ankle sprains, specifically in female athletes.', "Varsity soccer players' medical records over a five-year period were retrospectively reviewed at a Division III women's college. Data were extracted regarding any history of ankle sprain(s), type of intervention used as prophylaxis after the ankle sprain, number of exposures, and any incidence of recurrence.", 'All collegiate varsity soccer players who had suffered a previous sprain to either one or both ankles (38 players) were identified as subjects.', 'Each previously injured ankle (n = 56) was considered as a case for the analysis. Ankles that had a previous sprain received one of four interventions: 1) a canvas, laced ankle brace (n = 19), 2) taping (n = 12), 3) a combination of taping and ankle bracing (n = 8), or 4) no treatment (n = 17).', 'The four intervention groups had a total of 1717 practice exposures and 650 competitive game exposures; exposures did not differ among the 4 groups. Ankle sprain recurrence frequency was 0%, 25%, 25%, and 35% for the braced, taped, combination, and untreated groups, respectively. The recurrence incidence for the braced group was significantly lower than that of the other three groups. The ankle sprain recurrence frequency did not differ among the taped, combination, and no treatment groups.\Question: Does ankle brace effectively reduce recurrence of ankle sprains in female soccer players?

Ex Output:
We suggest that prophylactic ankle bracing is effective in reducing the incidence of ankle sprains in female soccer players with a previous history of ankle sprains.

Ex Input:
Context: Cirrhosis is associated with prominent changes in sinusoidal structure and function. Although the resident pericyte in liver, the hepatic stellate cell (HSC), is well characterized in the process of fibrogenesis, signaling pathways that regulate HSC vascular function are less developed. Because pericyte populations outside the liver are increasingly being recognized as a key cell type for angiogenesis and changes in vascular structure, in this study, we explore new HSC-signaling pathways that regulate sinusoidal structure and function.', 'Real-time video microscopy and quantitative software analysis of vascular tube formation were used to measure HSC angiogenesis in vitro. Platelet-derived growth factor (PDGF) and ephrin-signaling pathways were modulated using molecular and pharmacologic techniques. Complementary whole animal studies were performed to correlate in vitro findings with pericyte functions in vivo.', 'We show that PDGF promotes a phenotype of HSC evidenced by enhanced HSC-driven vascular tube formation in vitro and enhanced HSC coverage of sinusoids in vivo. This angiogenic phenotype modulates specific pericyte vascular functions including permeability and pressure regulation. Furthermore, we identify a key role for ephrin-B2 as a downstream effector of PDGF signaling.\Question: Does platelet-derived growth factor signaling through ephrin-b2 regulate hepatic vascular structure and function?

Ex Output:
These studies elucidate novel HSC-signaling pathways that regulate microvascular structure and function in liver.