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: Approximately 12% of bound blood calcium is linked to various anions including phosphate. In patients with end-stage kidney disease (ESKD), serum phosphate is highly variable. We propose that establishing a formula to calculate albumin- and phosphate-corrected total calcium would be more appropriate to estimate free calcium in ESKD patients.', 'In 82 haemodialysis patients, serum ionized calcium (Ca(ion)) and pH were measured by blood gas analyser with ion-selective electrodes at the point-of-care, while bicarbonate, phosphate, albumin, magnesium and total calcium (Ca(tot)) were measured at the central laboratory. Linear regression analysis of measured variables was used to best fit adjusted calcium versus Ca(ion).', 'The most parsimonious multiple linear regression model (r(2) = 0.81) of variables associated with Ca(ion) included Ca(tot) (coeff 0.820, P < 0.0001), albumin (coeff -0.016, P < 0.0001) and phosphate (coeff -0.063, P < 0.002). Modelling of available variables yielded the following equation to adjust calcium for albumin and phosphate: Ca(albPh) = Ca(tot) + (0.015 x (40 - [albumin]) + 0.07 x (1.5 - [phosphate])). At an ambient albumin of 40 g/L, Ca(albPh) would be 0.07 mmol/L lower than Ca(tot) for every mmol/L of phosphate. In vitro data using three different albumin levels and increasing phosphate concentrations demonstrated this relationship, with the slope of the phosphate effect being stronger at lower albumin concentrations.
Answer: Because guidelines recommendations indicate that corrected serum calcium should be maintained within the normal range in ESKD patients, inclusion of phosphate to correct Ca(tot) in these patients may have clinical implications on the choice of phosphate binders and the prescription of vitamin D or calcimimetic agents.

A: Is serum phosphate an important determinant of corrected serum calcium in end-stage kidney disease?
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Q: Context: This study was conducted to quantify the effect of multidisciplinary care (MDC) on amputation-free survival (AFS) and wound healing within a chronic critical limb ischemia (CLI) population.', 'We performed a retrospective, single-center cohort study of consecutive CLI patients presenting to the Vascular Surgery Service. Patients who received initial and follow-up wound care from the MDC were compared with patients who received standard wound care (SWC). The MDC team consisted of vascular, plastic, and podiatric surgeons who jointly managed wound care and directed any other consults or services as deemed necessary. SWC consisted of an inconsistent mix of providers without a defined manager, including nurses, wound care midlevel providers, general surgeons, internists, or the patients themselves. The referring physician determined the allocation of patients. The primary outcome variable was AFS, with a secondary evaluation of wound healing. The effects of baseline demographics, comorbid medical conditions, laboratory values, ischemic lesion severity and location, Rutherford classification, and participation in MDC were assessed. Significant univariate predictors (P < .10) of AFS were entered into a multivariate Cox regression model and assessed at an α = .05.', 'Between August 2010 and June 2012, 146 CLI patients (91 male [63%]) were evaluated by the Vascular Surgery Service and were followed up for a median of 539 days (interquartile range 314-679 days). Ischemic tissue loss was present in 85 patients (38 at Rutherford category 5, and 47 at Rutherford category 6). Within this cohort, 51 (60%) had MDC, and 34 (40%) had SWC. Fifty-eight patients (68%) underwent revascularization (open in 17, endovascular in 35, and hybrid in 6), 14 (8%) were managed with primary major amputation, and 13 (15%) declined revascularization. AFS was superior for patients in the MDC arm vs the SWC arm (593.3 ± 53.5 days vs 281.0 ± 38.2 days; log-rank, P = .02). Wound-healing times favored the MDC arm over the SWC arm (444.5 ± 33.2 days vs 625.2 ± 126.5 days), although this was not statistically significant (log-rank, P = .74). Multivariate modelling revealed that independent predictors of major amputation or death, or both, were nonrevascularized patients (hazard ratio [HR], 3.76; 95% confidence interval [CI], 1.78-8.02; χ(2), P < .01), treatment by SWC (HR, 2.664; 95% CI, 1.23-5.77; χ(2), P = .012), and baseline nonambulatory status (HR, 1.89; 95% CI, 1.17-2.85; χ(2), P < .01).
Answer: MDC pathways for the management of a population of CLI patients improved AFS by greater than twofold and should be the standard of care for the CLI population. Baseline nonambulatory status and unrevascularized patients also predict worse AFS. Wound healing remains prolonged regardless of preoperative or postoperative wound care. Future study is required to evaluate the costs and functional outcomes for MDC in the management of CLI.

A: Does multidisciplinary care improve amputation-free survival in patients with chronic critical limb ischemia?
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Q: Context: Hypertrophic scarring (HTS) is hypothesized to have a genetic mechanism, yet its genetic determinants are largely unknown. The mitogen-activated protein kinase (MAPK) pathways are important mediators of inflammatory signaling, and experimental evidence implicates MAPKs in HTS formation. We hypothesized that single-nucleotide polymorphisms (SNPs) in MAPK-pathway genes would be associated with severity of post-burn HTS.', 'We analyzed data from a prospective-cohort genome-wide association study of post-burn HTS. We included subjects with deep-partial-thickness burns admitted to our center who provided blood for genotyping and had at least one Vancouver Scar Scale (VSS) assessment. After adjusting for HTS risk factors and population stratification, we tested MAPK-pathway gene SNPs for association with the four VSS variables in a joint regression model. In addition to individual-SNP analysis, we performed gene-based association testing.', 'Our study population consisted of 538 adults (median age 40 years) who were predominantly White (76%) males (71%) admitted to our center from 2007-2014 with small-to-moderate-sized burns (median burn size 6% total body surface area). Of 2,146 SNPs tested, a rare missense variant in the PTPN5 gene (rs56234898; minor allele frequency 1.5%) was significantly associated with decreased severity of post-burn HTS (P = 1.3×10-6). In gene-based analysis, PTPN5 (P = 1.2×10-5) showed a significant association and BDNF (P = 9.5×10-4) a borderline-significant association with HTS severity.
Answer: We report PTPN5 as a novel genetic locus associated with HTS severity. PTPN5 is a MAPK inhibitor expressed in neurons, suggesting a potential role for neurotrophic factors and neuroinflammatory signaling in HTS pathophysiology.

A:
Does missense Variant in MAPK Inactivator PTPN5 be Associated with Decreased Severity of Post-Burn Hypertrophic Scarring?
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