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.

[EX Q]: Context: Ischemic postconditioning protects the reperfused heart from infarction, and this protection is dependent on the occupancy of adenosine receptors. We further explored the role of adenosine receptors in this salvage.', 'In situ rabbit hearts underwent 30 min of regional ischemia and 3 h of reperfusion, and postconditioning was effected with four cycles of 30-s reperfusion/30-s coronary artery occlusion at the end of ischemia.', "Postconditioning reduced infarct size from 40.2+/-3.4% of the risk zone in untreated hearts to 15.5+/-2.5%. Protection by postconditioning was blocked by either the non-selective adenosine receptor blocker 8-p-(sulfophenyl)theophylline or the A2b-selective antagonist MRS 1754, injected intravenously 5 min before reperfusion. The protein kinase C (PKC) antagonist chelerythrine also aborted postconditioning's salvage, indicating a PKC-dependent mechanism. Neither the A1-selective antagonist 8-cyclopentyl-1,3-dipropylxanthine nor the A2a-selective antagonist 8-(13-chlorostyryl)caffeine had an effect on protection. The non-selective but A2b-potent adenosine agonist 5'-(N-ethylcarboxamido)adenosine (NECA) infused from 5 min before to 1h after reperfusion mimicked postconditioning's effect on infarct size (17.2+/-2.7% infarction) and MRS 1754 blocked the NECA-induced cardioprotection, confirming that A2b activation was protective. The PKC activator phorbol 12-myristate 13-acetate delivered just before reperfusion also duplicated the protective effect of postconditioning (16.3+/-4.1% infarction), and co-administration of the PKC antagonist chelerythrine aborted PMA's protection, confirming that the protection was the result of PKC activation. NECA's protective effect was not affected by chelerythrine, but rather MRS 1754 blocked PMA's salutary effect (42.8+/-1.0% infarction), suggesting that the A2b receptor's effect is under control of PKC. Finally, wortmannin, a blocker of phosphatidylinositol 3-kinase, also abrogated protection by PMA.\Question: Does postconditioning protect rabbit hearts through a protein kinase C-adenosine A2b receptor cascade?
[EX A]: Salvage of ischemic myocardium by postconditioning is dependent on activation of A2b receptors, which in turn depends on activation of PKC. It is still unclear why PKC activation is required to make the heart's adenosine become protective.

[EX Q]: Context: Contralateral groin exploration in children with unilateral inguinal hernia is still controversial, particularly in infants. The patency rate of processus vaginalis is highest in infants but there are few data on the subsequent risk of contralateral hernia development in infants. In this retrospective study, we aimed to find out the incidence of contralateral inguinal hernia following unilateral inguinal herniotomy in infants aged less than one year.', 'All infants who underwent a unilateral Inguinal herniotomy between January 1990 and December 1998 were studied retrospectively. Infants with bilateral hernia (n = 7) were excluded from the study.', 'One hundred and one infants (93 boys and 8 girls) were studied. Median age at operation was 23 (range 2-52) weeks. The herniotomy was right-sided in 75% of the infants. Follow-up ranged from three and a half years to 11 years. A contralateral hernia developed in nine infants (9.0%). One of the initial hernias was incarcerated. Median time from operation to occurrence of contralateral hernia was 18 (range 2-60) months. None of the contralateral hernia was incarcerated. Age, sex, incarceration and side of initial hernia did not influence the development of contralateral hernia.\Question: Is contralateral groin exploration justified in infants with a unilateral inguinal hernia?
[EX A]: The low incidence and benign nature of contralateral hernia development in infants undergoing a unilateral inguinal herniotomy does not justify routine contralateral groin exploration.

[EX Q]: Context: THE AIM OF THE STUDY WAS: Is primary Arterio-venous fistula the vascular access of choice for adequate dialysis and better patient outcome in end stage renal disease.', 'The present study was done in the department of cardiovascular and thoracic surgery at Sher-i-Kashmir institute of medical sciences, Soura, Srinagar Kashmir. Native Arterio-Venous (AV) fistulas were made in the patients with end stage renal disease for performing hemodialysis. They were followed for patency and adequacy of blood flow during hemodialysis. All the patients were operated under local anesthesia.', 'The results showed that 77% of the AV fistulas based on radial artery with side-to-side anastomosis and 80% of those with end-to-side anastomosis were functionally patent after one year. After two years, the patency rate in side-to-side and end-to-side anastomosis was 50% and 55%, respectively. In addition, the patency rate was 90% in brachial artery based AV fistula with end-to-side anastomosis, whether done primarily or secondarily, at the end of one year. However, a rapid decline was observed in the patency rate during the third year in both radial artery based and brachial artery based AV fistulas.\Question: Is native arterio-venous fistula the vascular access of choice for hemodialysis in end stage renal disease?
[EX A]:
We concluded that Arterialised arm superficial veins after primary AV fistula was the optimal and rational vascular access for hemodialysis providing adequate blood flow during this process. Besides, failure of primary AV fistula should be replaced by secondary AV fistula preferably based on brachial artery.