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: People with a history of rheumatic fever (RF) are at high risk of recurrent attacks and of developing rheumatic heart disease following a streptococcal throat infection. Giving penicillin to these people can prevent recurrent attacks of RF and subsequent rheumatic heart disease. However, there is no agreement on the most effective method of giving penicillin.', 'To assess the effects of different penicillin regimens and formulations for preventing streptococcal infection and RF recurrence.', 'We searched the Controlled Trials Register (Cochrane Library Issue 2, 2001), Medline (January 1966-July 2000), Embase (January 1985-July 2000), reference lists of articles, and contacted experts in the field.', 'Randomised and quasi-randomised studies comparing: (i) oral with intramuscular penicillin; and (ii) 2- or 3-weekly with 4-weekly intramuscular penicillin in patients with previous RF.', 'Two reviewers independently assessed trial quality and extracted data.', 'Six studies were included (1,707 patients). Data were not pooled because of clinical and methodological heterogeneity of the trials. Four trials (1,098 patients) compared intramuscular with oral penicillin and all showed that intramuscular penicillin was more effective in reducing RF recurrence and streptococcal throat infections than oral penicillin. One trial (360 patients) compared 2-weekly with 4-weekly intramuscular penicillin. Penicillin given every 2 weeks was better at reducing RF recurrence (relative risk (RR) 0.52, 95% confidence interval (CI): 0.33-0.83) and streptococcal throat infections (RR 0.60, 95% CI: 0.42-0.85). One trial (249 patients) showed that 3-weekly intramuscular penicillin injections reduced streptococcal throat infections (RR 0.67, 95% CI: 0.48-0.92) compared with 4-weekly intramuscular penicillin.
Answer: Intramuscular penicillin seemed to be more effective than oral penicillin in preventing RF recurrence and streptococcal throat infections. Two-weekly or 3-weekly injections appeared to be more effective than 4-weekly injections. However, the evidence is based on poor-quality trials and the use of outdated formulations of oral penicillin.

A: Is intramuscular penicillin more effective than oral penicillin in secondary prevention of rheumatic fever -- a systematic review?
****
Q: Context: To distinguish whether the improvement of hepatic encephalopathy by benzodiazepine receptor antagonists is mediated by their antagonistic or their inverse agonistic properties, the neurobehavioral effects of a variety of benzodiazepine receptor ligands in rats with thioacetamide-induced acute liver failure were tested.', 'The neural inhibitory effect of the benzodiazepine agonist flunitrazepam and its reversibility by the "pure" antagonist Ro 14-7437 were examined in thioacetamide-treated rats and controls. The effects of Ro 14-7437, of the partial inverse agonist Ro 15-4513, and the inverse agonist DMCM in rats with hepatic encephalopathy grade II/III were tested. Encephalopathic rats were pretreated with Ro 14-7437 or vehicle and then injected with Ro 15-4513.', 'Thioacetamide-treated rats were more sensitive to flunitrazepam than controls. In both groups, its effect was completely antagonized with Ro 14-7437. Encephalopathy was significantly improved by Ro 15-4513, although Ro 14-7437 and vehicle had no effect. DMCM worsened the condition of encephalopathic rats but had no effect in controls. Pretreatment with Ro 14-7437 abolished the beneficial effects of Ro 15-4513.
Answer: In rats with thioacetamide-induced liver failure, endogenous benzodiazepines do not precipitate hepatic encephalopathy. The amelioration of hepatic encephalopathy is mediated by benzodiazepine receptor ligands with both antagonistic and inverse agonistic properties.

A: Is hepatic encephalopathy in rats with thioacetamide-induced acute liver failure mediated by endogenous benzodiazepines?
****
Q: Context: Cytotoxic immune elimination of transduced hepatocytes may limit gene therapy for inherited liver diseases. Using beta-galactosidase as a marker gene, we studied whether creation of mixed beta-galactosidase molecular hematopoietic chimerism could induce tolerance to beta-galactosidase-transduced hepatocytes.', 'Molecular hematopoietic chimerism was established in irradiated recipient mice by transplantation of either a mixture of wild-type and beta-galactosidase-transgenic bone marrow or autologous bone marrow stem cells that were transduced with beta-galactosidase lentiviral vectors. After transplantation, mice were hepatectomized and injected with beta-galactosidase recombinant retroviruses to transduce regenerating hepatocytes. We monitored the presence of beta-galactosidase-expressing hepatocytes as well as the appearance of anti-beta-galactosidase antibodies during the time.', 'In control animals, anti-beta-galactosidase antibodies and cytotoxic T-lymphocyte (CTL) response developed as early as 3 weeks after gene transfer. Transduced hepatocytes disappeared concomitantly. In bone marrow transplanted mice, tolerance could be observed in a significant proportion of animals. Tolerance resulted in permanent liver transgene expression and was absent unless a chimerism above 1% was achieved, demonstrating a threshold effect.
Answer: Creation of a molecular hematopoietic chimerism can result in transgene tolerance and evade immune rejection of retrovirally transduced hepatocytes. This strategy may be useful for hepatic inherited diseases in which the transgene product behaves as a non-self protein.

A:
Does mixed hematopoietic molecular chimerism result in permanent transgene expression from retrovirally transduced hepatocytes in mice?
****