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: Remote renal ischemia-reperfusion injury (IRI) following infra-renal aortic occlusion leads to acute kidney injury and systemic inflammation. Hydrogen sulfide is a mediator of IRI and can ameliorate tissue injury in many organ systems. Its role in vascular surgery has yet to be established. We assessed the role of hydrogen sulfide in a rodent model of aortic occlusion.', 'Wistar rats were divided into sham, control, and treatment groups (n = 6). Inflammation was assessed using a nonrecovery protocol. The infra-renal aorta was cross-clamped for 60 min and animals were reperfused for 120 min. Ten minutes before clamp release, treatment animals received hydrogen sulfide (10, 30, or 50 μg/kg) and control animals received 0.9% saline injected into the retroperitoneum. Renal injury and histology were assessed by a recovery protocol. The procedure was identical to the nonrecovery arm but with a single dose of hydrogen sulfide (30 μg/kg) and animals were recovered for 7 days.', 'There was no difference in animal weight between the groups (P = 0.337). In the nonrecovery arm, there was a reduction in serum levels of tumor necrosis factor alpha in sulfide-treated animals compared with controls (909 ± 98 vs. 607 ± 159 pg/mL; P = 0.0038). There was also a reduction in myeloperoxidase-positive cells in renal tissue in the sulfide-treated animals compared with controls (8 ± 4 vs. 17 ± 9; P = 0.03). There was no difference in histological injury score or endothelin-1 levels. In the recovery arm, there was no difference in renal function, Kidney Injury Molecule-1 levels, or histological injury scores.\Question: Does hydrogen sulfide reduce inflammation following abdominal aortic occlusion in rats?
[A]: Hydrogen sulfide has systemic and renal anti-inflammatory effects in remote IRI following aortic occlusion in rats.


[Q]: Context: To assist in the development of preventive strategies, we studied whether the neighbourhood environment or modifiable behavioural parameters, including cardiorespiratory fitness (CRF) and physical activity (PA), are independently associated with obesity and metabolic risk markers in children.', 'We carried out a cross-sectional analysis of 502 randomly selected first and fifth grade urban and rural Swiss schoolchildren with regard to CRF, PA and the neighbourhood (rural vs urban) environment. Outcome measures included BMI, sum of four skinfold thicknesses, homeostasis model assessment of insulin resistance (HOMA-IR) and a standardised clustered metabolic risk score.', 'CRF and PA (especially total PA, but also the time spent engaged in light and in moderate and vigorous intensity PA) were inversely associated with measures of obesity, HOMA-IR and the metabolic risk score, independently of each other, and of sociodemographic and nutritional parameters, media use, sleep duration, BMI and the neighbourhood environment (all p < 0.05). Children living in a rural environment were more physically active and had higher CRF values and reduced HOMA-IR and metabolic risk scores compared with children living in an urban environment (all p < 0.05). These differences in cardiovascular risk factors persisted after adjustment for CRF, total PA and BMI.\Question: Are reduced cardiorespiratory fitness , low physical activity and an urban environment independently associated with increased cardiovascular risk in children?
[A]: Reduced CRF, low PA and an urban environment are independently associated with an increase in metabolic risk markers in children.


[Q]: Context: Whether MHC molecules undergo concerted evolution or not has been the subject of a long-standing debate.', 'By comparing sequences of eight functional homologues of HLA-E from primates and rodents with those of MHC class Ia molecules from the same eight species, we find that different portions of MHC class I molecules undergo different patterns of evolution. By focusing our analyses sequentially on these various portions, we have obtained clear evidence for concerted evolution of MHC class I molecules, suggesting the occurrence of extensive interallelic and intergenic exchanges. Intra-species homogenisation of sequences is particularly noticeable at the level of exon 4, which codes for the alpha3 domain, but our results suggest that homogenisation also concerns certain residues of the alpha1-alpha2 codomain that lie outside the antigen recognition site.\Question: Is the orthology of HLA-E and H2-Qa1 hidden by their concerted evolution with other MHC class I molecules?
[A]:
A model is presented in which Darwinian selective pressures due to pathogens could, at the same time, favour diversification of MHC class Ia molecules and promote concerted evolution of separate loci by spreading advantageous motifs arising by mutations in individual MHC molecules to other alleles and to other loci of the MHC region. This would also allow MHC molecules to co-evolve with the proteins with which they interact to fulfil their functions of antigen presentation and regulation of NK cell activity. One of the raisons d'être of the MHC may therefore be to favour at the same time both diversification of MHC class Ia molecules and homogenisation of the whole pool of MHC class I molecules (Ia and Ib) involved in antigen presentation.