TASK DEFINITION: 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.
PROBLEM: Context: The development of human leukocyte antigen (HLA) antibody responses has been associated with worse clinical outcomes, such as bronchiolitis obliterans syndrome (BOS) and death, in lung transplant recipients (LTRs). However, the role of donor-specific HLA antibody (DSA) responses as a risk factor for poor outcomes remains controversial.', 'We prospectively screened 445 LTRs for DSA at our institution at the time of surveillance bronchoscopies for the first 2 years after transplantation between 2003 and 2008, and evaluated clinical outcomes. For this purpose, we used the combination of panel-reactive antibodies (PRA) by enzyme-linked immunosorbent assay (ELISA) and the Luminex single-antigen bead (SAB) assay (One Lambda, Canoga Park, CA).', 'We detected de novo DSA (dnDSA) in 58 of 445 (13%) LTRs in our cohort. Freedom from BOS was significantly reduced in LTRs with dnDSA versus those without dnDSA (p < 0.001). Using a Cox proportional hazards model, the development of dnDSA was associated with a significantly increased hazard ratio (HR = 6.59 [4.53 to 9.59]; p < 0.001) for BOS and high-grade BOS (Stage 2) (HR = 5.76 [3.48 to 9.52]; p < 0.001). Freedom from death was significantly reduced in LTRs with dnDSA (p < 0.001), including mortality attributable to BOS (HR = 9.86 [4.91 to 19.78]; p < 0.001).\Question: Are de novo donor-specific HLA antibodies associated with early and high-grade bronchiolitis obliterans syndrome and death after lung transplantation?

SOLUTION: Taken together, our findings provide evidence that dnDSA is associated with accelerated BOS kinetics and severity, as well as death due to BOS after lung transplantation. In addition, these data support regular monitoring for the development of dnDSA in LTRs and underscore the need for novel strategies to mitigate the increased risk of poor outcomes associated with dnDSA.

PROBLEM: Context: Different apoptosis pathways activate caspase-3. In a study involving 27 patients with traumatic brain injury (TBI), higher caspase-3 levels were found in contusion brain tissue resected from non-survivors than from survivors. The objective of this study was to determine whether there is an association in TBI patients between serum caspase-3 levels (thus using an easier, quicker, less expensive and less invasive procedure) and mortality, in a larger series of patients.', 'We carried out a prospective, observational and multicenter study in six Spanish Hospital Intensive Care Units including 112 patients with severe TBI. All had Glasgow Coma Scale (GCS) scores lower than 9. Patients with an Injury Severity Score (ISS) in non-cranial aspects higher than 9 were excluded. Blood samples were collected on day 1 of TBI to measure serum caspas-3 levels. The endpoint was 30-day mortality.', 'We found that non-surviving patients (n = 31) showed higher (p = 0.003) serum caspase-3 levels compared to survivors (n = 81). Kaplan-Meier survival analysis showed a higher risk of death in TBI patients with serum caspase-3 levels >0.20 ng/mL than in patients with lower concentrations (Hazard Ratio = 3.15; 95% CI = 1.40 to 7.08; P < 0.001). Multiple logistic regression analysis showed that serum caspase-3 levels > 0.20 ng/mL were associated with mortality at 30 days in TBI patients controlling for Marshall CT classification, age and GCS (Odds ratio = 7.99; 95% CI = 2.116 to 36.744; P = 0.001).\Question: Are serum caspase-3 levels and mortality associated in patients with severe traumatic brain injury?

SOLUTION: The association between serum caspase-3 levels and mortality in TBI patients was the major novel finding of our study.

PROBLEM: Context: The objective of this study was to describe a pattern of recovery and histological nerve cell loss in Sprague-Dawley rats exposed to severe brain ischemia and to compare it to that of Wistar rats.', 'Ether- and ketamine-anesthetized Sprague-Dawley rats were exposed to 3, 5, 6 and 10 min of normothermic severe brain ischemia (4 groups) induced by hypotension and neck compression. In group No. 5, the brain temperature was rapidly lowered, after 10 min of ischemia, to 30 degrees C during 45-50 min of recirculation. Wistar rats (group No. 6) served as controls (10-min normothermic ischemia).', 'In Sprague-Dawley (S-D) rats, post-ischemic audiogenic seizures (PAS) increased with the duration of ischemia and reached 86% (6/7 rats), after 10 min of ischemia. Mortality rate was high (50% = 7/14 rats). No seizure activity was observed after 10 min of ischemia in 6 Wistar (W) rats, and all survived. In the S-D rats, 10 min of ischemia produced histopathological damage in all brain regions examined, except in the thalamus. Damage was less severe in the W rats. Post-ischemic hypothermia ameliorated hippocampal and cortical nerve cell damage, but had no effect on the incidence of PAS activity and mortality. In W rats, hippocampal nerve cell loss was much less severe than in the S-D rats and cortical damage was not observed.\Question: Does post-ischemic hypothermia ameliorate ischemic brain damage but not post-ischemic audiogenic seizures in rats?

SOLUTION:
Sprague-Dawley rats develop post-ischemic audiogenic seizures more frequently than Wistar rats and mortality rate is high. The incidence of post-ischemic audiogenic seizures and mortality correlates well with the duration of ischemia. Post-ischemic moderate hypothermia (30 degrees C) significantly ameliorated the hippocampal and cortical nerve cell losses after 10 min of severe brain ischemia, but did not improve outcome. It appears that the high mortality rate of S-D rats following brain ischemia is related to frequent post-ischemic audiogenic seizures.