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.

[Q]: Context: Globally, heterosexual intercourse is the primary route of HIV-1 (HIV) transmission. It follows that mechanisms that protect against HIV infection are likely operative at the genital mucosa. In HIV-resistant Kenyan sex workers who are highly exposed to HIV infection yet remain uninfected, protection correlates with HIV-specific immune responses and genetic factors. However, these factors do not entirely explain this model of natural immunity to HIV. We hypothesized that protection may be mediated by innate immune proteins in the genital tract of HIV-resistant sex workers.', 'The genital proteome of mucosal secretions from HIV-resistant women was examined using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. Cervical lavage samples were collected from 315 HIV-resistant, HIV-uninfected and HIV-infected commercial sex workers.', 'Univariate analysis identified a 6 kDa biomarker of HIV resistance in genital secretions from these women. This protein was identified by tandem mass spectrometry as elafin and was found to be overexpressed in HIV-resistant women compared with HIV-uninfected (P = 0.001) and infected (P = 0.002) women. The elevated levels of elafin/trappin-2 in HIV-resistant women were confirmed using ELISA. The prospective association of elevated cervicovaginal elafin/trappin-2 levels with protection from HIV acquisition was then confirmed in an independent cohort of high-risk female sex workers.\Question: Does elevated elafin/trappin-2 in the female genital tract is associate with protection against HIV acquisition?
[A]: Using a unique proteomics approach in a large scale, cross-sectional cohort study, we identified elafin/trappin-2 as a novel innate immune factor, which is highly associated with resistance. This association was confirmed within an independent, prospective cohort study. Genital tract elafin/trappin-2 levels constitute a natural correlate of HIV protection in humans.


[Q]: Context: The purpose of this study was to investigate the ability of neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, and their combination in predicting the duration and severity of acute kidney injury (AKI) after cardiac surgery in adults.', 'Using data from a prospective observational study of 100 adult cardiac surgical patients, we correlated early postoperative concentrations of plasma NGAL and serum cystatin C with the duration (time during which AKI persisted according to the Acute Kidney Injury Network criteria) and severity of AKI (change in serum creatinine) and with length of stay in intensive care.', 'We found a mean AKI duration of 67.2 +/- 41.0 hours which was associated with prolonged hospitalization (p < 0.001). NGAL, cystatin C, and their combination on arrival in intensive care correlated with subsequent AKI duration (all p < 0.01) and severity (all p < 0.001). The area under the receiver operating characteristic curve for AKI prediction was 0.77 (95% confidence interval: 0.63 to 0.91) for NGAL and 0.76 (95% confidence interval: 0.61 to 0.91) for cystatin C on arrival in intensive care. Both markers also correlated with length of stay in intensive care (p = 0.037; p = 0.001). Neutrophil gelatinase-associated lipocalin and cystatin C were independent predictors of AKI duration and severity and of length of stay in intensive care (all p < 0.05). The value of cystatin C on arrival in intensive care appeared to be due to a carry-over effect from preoperative values.\Question: Do novel biomarkers early predict the severity of acute kidney injury after cardiac surgery in adults?
[A]: Immediately postoperatively, NGAL and cystatin C correlated with and were independent predictors of duration and severity of AKI and duration of intensive care stay after adult cardiac surgery. The combination of both renal biomarkers did not add predictive value.


[Q]: Context: Liver transplantation is limited by ischaemic injury which promotes endothelial cell and hepatocyte dysfunction and eventually organ failure. We sought to understand how endothelial state determines liver recovery after hepatectomy and engraftment.', 'Matrix-embedded endothelial cells (MEECs) with retained healthy phenotype or control acellular matrices were implanted in direct contact with the remaining median lobe of donor mice undergoing partial hepatectomy (70%), or in the interface between the remaining median lobe and an autograft or isograft from the left lobe in hepatectomised recipient mice. Hepatic vascular architecture, DNA fragmentation and apoptosis in the median lobe and grafts, serum markers of liver damage and phenotype of macrophage and lymphocyte subsets in the liver after engraftment were analysed 7\u2005days post-op.', 'Healthy MEECs create a functional vascular splice in donor and recipient liver after 70% hepatectomy in mouse protecting these livers from ischaemic injury, hepatic congestion and inflammation. Macrophages recruited adjacent to the vascular nodes into the implants switched to an anti-inflammatory and regenerative profile M2. MEECs improved liver function and the rate of liver regeneration and prevented apoptosis in donor liver lobes, autologous grafts and syngeneic engraftment.\Question: Does implantation of healthy matrix-embedded endothelial cells rescue dysfunctional endothelium and ischaemic tissue in liver engraftment?
[A]:
Implants with healthy endothelial cells rescue liver donor and recipient endothelium and parenchyma from ischaemic injury after major hepatectomy and engraftment. This study highlights endothelial-hepatocyte crosstalk in hepatic repair and provides a promising new approach to improve regenerative medicine outcomes and liver transplantation.