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.

Q: 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.

A: Does donor major histocompatibility complex class I expression determine the outcome of prenatal transplantation?
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Q: Context: Serum ghrelin levels are elevated in uremic patients. However, no data are available on the relationship between metabolic syndrome and serum ghrelin levels in peritoneal dialysis (PD) patients.', 'Metabolic syndrome and its components were defined using diagnostic criteria recommended by the International Diabetes Federation. Fasting serum samples were taken from 30 PD patients. Serum ghrelin levels were measured by using a commercial enzyme-linked immunosorbent assay kit.', 'Of the 30 PD patients, 53.3% (16/30) had metabolic syndrome. Fasting serum ghrelin corrected inversely with metabolic syndrome among these PDs patients (p = 0.002). By odds ratio (OR) analysis of metabolic syndrome and metabolic syndrome diagnostic criteria, the predictors for metabolic syndrome are fasting glucose [OR: 39.00; 95% confidence interval (CI): 3.80 to 399.85; p < 0.001], triglycerides (OR: 37.50; 95% CI: 3.64 to 386.51; p < 0.001), and waist circumference (OR: 4.20; 95% CI: 1.95 to 9.03; p < 0.001). Univariate linear regression analysis showed that body weight (r = -0.461, p = 0.010), waist circumference (r = -0.390, p = 0.033), and body mass index (r = -0.438, p = 0.016) were negatively correlated with serum ghrelin, and serum high density lipoprotein [HDL (r = 0.626, p < 0.001)] was positively correlated with serum ghrelin. Multivariate forward stepwise linear regression analysis of the significant variables showed that HDL (R(2) change = 0.392; p < 0.001) was the independent predictor of serum ghrelin in PD patients and explained 39.2% of the variance.
Answer: These results indicate an inverse association between circulating fasting ghrelin and metabolic syndrome in PD patients. Serum HDL was associated with serum ghrelin among PD patients.

A: Is fasting serum ghrelin level associated with metabolic syndrome in peritoneal dialysis patients?
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Q: Context: With rising obesity rates in children, it is increasingly difficult to differentiate between type 1 and type 2 diabetes mellitus (T1DM, T2DM) on clinical grounds alone. Using C-peptide as a method of classifying diabetes mellitus (DM) has been suggested. This study aimed to find a correlation between fasting C-peptide level and DM types in children and adolescents.', 'A total of 223 diabetic children, newly diagnosed at 5 hospitals between January 2001 and December 2012, were enrolled in this study. Initial DM classification was based on clinical and laboratory data including fasting C-peptide at diagnosis; final classification was based on additional data (pancreatic autoantibodies, human leukocyte antigen type, and clinical course).', 'Of 223 diabetic children, 140 were diagnosed with T1DM (62.8%) and the remaining 83 with T2DM (37.2%). The mean serum C-peptide level was significantly lower in children with T1DM (0.80 ng/mL) than in children with T2DM (3.91 ng/mL). Among 223 children, 54 had a serum C-peptide level <0.6 ng/mL; they were all diagnosed with T1DM. The proportion of children with T2DM increased in accordance with C-peptide level. Forty-nine of 223 children had a C-peptide level >3.0 ng/mL; 48 of them (97.9%) were diagnosed with T2DM.
Answer: In this study, we found that if the C-peptide level was <0.6 ng/mL at diagnosis, T2DM could be excluded; if C-peptide level was >3.0 ng/mL, a T1DM diagnosis is unlikely. This finding suggests that serum fasting C-peptide level is useful for classifying DM type at the time of diagnosis in youth.

A:
Is fasting serum C-peptide useful for initial classification of diabetes mellitus in children and adolescents?
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