Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Ex Input:
Context: The failure of in utero transplantation in immune-competent recipients suggests the existence of a fetal immune barrier. The importance of donor major histocompatibility complex (MHC) class I expression in the induction of prenatal tolerance remains undefined. We hypothesized that donor cell MHC class I expression facilitates engraftment in prenatal allogeneic recipients rather than promoting immune rejection.', 'B6.Ly5.2 (class I(+)) or B6.TAP(-/-) (class I(-)) murine fetal liver cells were transplanted into age-matched allogeneic fetal recipients. Survival to weaning and subsequent growth was assessed. Engraftment rates and peripheral blood chimerism levels were measured serially.', 'The presence or absence of class I expression did not affect survival or growth of recipients and no graft-vs-host disease developed. Allogeneic recipients of B6.Ly5.2 cells exhibited significantly higher levels of donor hematopoietic chimerism when compared to recipients of B6.TAP(-/-) cells (27% + 10% vs 11% + 8%; P = .004) that deteriorated further over time.
Answer: Donor class I MHC antigen expression is essential for stable long-term engraftment and maintenance of donor-specific tolerance. Further studies are needed to better characterize the role of the fetal innate immune system in prenatal allotransplantation.

Ex Output:
Does donor major histocompatibility complex class I expression determine the outcome of prenatal transplantation?


Ex Input:
Context: Altered cerebrospinal fluid (CSF) levels of lactate have been described in neurodegenerative diseases and related to mitochondrial dysfunction and neuronal degeneration. We investigated the relationship between CSF lactate levels, disease severity, and biomarkers associated with neuroaxonal damage in patients with multiple sclerosis (MS).', 'One-hundred eighteen subjects with relapsing-remitting multiple sclerosis (RRMS) were included, along with one-hundred fifty seven matched controls. CSF levels of lactate, tau protein, and neurofilament light were detected at the time of diagnosis. Patients were followed-up for a mean of 5 years. Progression index (PI), multiple sclerosis severity scale (MSSS), and Bayesian risk estimate for multiple sclerosis (BREMS) were assessed as clinical measures of disease severity and progression. Differences between groups and correlation between CSF lactate, disease severity and CSF biomarkers of neuronal damage were explored.', 'CSF lactate was higher in RRMS patients compared to controls. A negative correlation was found between lactate levels and disease duration. Patients with higher CSF lactate concentration had significantly higher PI, MSSS, and BREMS scores at long-term follow-up. Furthermore, CSF lactate correlated positively and significantly with CSF levels of both tau protein and neurofilament light protein.
Answer: Measurement of CSF lactate may be helpful, in conjunction with other biomarkers of tissue damage, as an early predictor of disease severity in RRMS patients. A better understanding of the alterations of mitochondrial metabolic pathways associated to RRMS severity may pave the way to new therapeutic targets to contrast axonal damage and disease severity.

Ex Output:
Is cerebrospinal fluid lactate associated with multiple sclerosis disease progression?


Ex Input:
Context: This study aimed to evaluate the long-term outcomes and the soft-tissue response to osseous genioplasty in patients with chin retrusion caused by early life facial burn injury.', 'Twenty-two consecutive patients with retrusive chin as a result of severe childhood facial burn were included in this study. Cephalometric analysis and photographs were used to assess the patients for eligibility of a surgical correction. Horizontal hard-tissue advancement and soft-tissue responses were measured as the primary outcomes at the early and late postoperative follow-up visits.', 'A total of 22 patients fulfilled the study requirements. Average preoperative distance between the pogonion, as the most anterior point of the anterior mandibular contour, and a perpendicular line connecting the nasion and the supramental point of the mandible was 0.82 ± 1.1 mm, which increased significantly to 7.8 ± 0.8 mm after genioplasty (p < 0.0001). Soft tissue was repositioned on average 6.1 ± 0.4 mm anteriorly on average, which is in comparison with the amount of chin skeleton advancement, and a response ratio of 0.8:1 was calculated at late follow-up.
Answer: Burn-related retrusive chin can appropriately be treated with sliding osseous genioplasty and will require slight overcorrection compared with patients without a history of lower face burn.

Ex Output:

Do soft-tissue response rate to chin skeletal advancement in patients with lower facial burn scar?