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: Histologic evidence of the comparative neurotoxicity of lidocaine, mepivacaine, and prilocaine is incomplete. We compared the intrathecal neurotoxicity in rats among these 3 drugs based on morphologic and neurofunctional findings.', 'Rats (n=169) randomly received 0.12 microL/g of 0%, 2%, 5%, 7.5%, 10%, or 20% lidocaine, mepivacaine, or prilocaine or 25% glucose dissolved in distilled water via a chronically implanted intrathecal catheter. The effect of the agents on neurofunction was evaluated by movement of the hind limb (behavior test) and by sensory threshold (paw-stimulation test). The L1 spinal cord, the posterior and anterior roots, and the cauda equina were removed en bloc 5 days later and examined by light and electron microscopy.', 'A significant decrease in sensory threshold or irreversible hind-limb limitation was observed only in rats receiving 20% lidocaine. Morphologic abnormalities characterized by axonal degeneration were observed in rats receiving > or =7.5% lidocaine, 20% mepivacaine, and 20% prilocaine, at the posterior white matter and the proximal portion of the posterior root just at the entrance into the spinal cord. The incidence of lesions was significantly higher in rats receiving lidocaine than mepivacaine and prilocaine.
Answer: It is suggested that intrathecal mepivacaine and prilocaine are less neurotoxic than highly concentrated lidocaine in a rat intrathecal model.

A: Are intrathecal mepivacaine and prilocaine less neurotoxic than lidocaine in a rat intrathecal model?
****
Q: Context: Pandemic strains of HIV-1 (group M) encode a total of nine structural (gag, pol, env), regulatory (rev, tat) and accessory (vif, vpr, vpu, nef) genes. However, some subtype A and C viruses exhibit an unusual gene arrangement in which the first exon of rev (rev1) and the vpu gene are placed in the same open reading frame. Although this rev1-vpu gene fusion is present in a considerable fraction of HIV-1 strains, its functional significance is unknown.', 'Examining infectious molecular clones (IMCs) of HIV-1 that encode the rev1-vpu polymorphism, we show that a fusion protein is expressed in infected cells. Due to the splicing pattern of viral mRNA, however, these same IMCs also express a regular Vpu protein, which is produced at much higher levels. To investigate the function of the fusion gene, we characterized isogenic IMC pairs differing only in their ability to express a Rev1-Vpu protein. Analysis in transfected HEK293T and infected CD4+ T cells showed that all of these viruses were equally active in known Vpu functions, such as down-modulation of CD4 or counteraction of tetherin. Furthermore, the polymorphism did not affect Vpu-mediated inhibition of NF-кB activation or Rev-dependent nuclear export of incompletely spliced viral mRNAs. There was also no evidence for enhanced replication of Rev1-Vpu expressing viruses in primary PBMCs or ex vivo infected human lymphoid tissues. Finally, the frequency of HIV-1 quasispecies members that encoded a rev1-vpu fusion gene did not change in HIV-1 infected individuals over time.
Answer: Expression of a rev1-vpu fusion gene does not affect regular Rev and Vpu functions or alter HIV-1 replication in primary target cells. Since there is no evidence for increased replication fitness of rev1-vpu encoding viruses, this polymorphism likely emerged in the context of other mutations within and/or outside the rev1-vpu intergenic region, and may have a neutral phenotype.

A: Does a Naturally Occurring rev1-vpu Fusion Gene Confer a Fitness Advantage to HIV-1?
****
Q: Context: This study evaluated risk factors for acute wheeze in preschool children and investigated whether subnormal levels of vitamin D were associated with increased risk for acute wheeze, atopy or viral/bacterial respiratory infections.', 'We recruited 130 children with acute wheeze, aged 6\xa0months to 4\xa0years, from paediatric emergency departments in Stockholm, Sweden, and 101 age-matched controls with no history of wheeze or sensitisation to airborne allergens. Parents answered standardised questionnaires, and blood samples were analysed for specific IgE to airborne and food allergens and levels of 25 hydroxyvitamin D (25(OH)D). Nasopharyngeal virus samples were collected during the emergency department visit in the group of children with wheeze, and a subset were also tested for bacteria.', 'Vitamin D insufficiency (25(OH)D\xa0<\xa075\xa0nmol/L (30\xa0ng/mL)) was associated with an odds ratio of 2.7 (95% confidence interval 1.1-6.2) for acute wheeze. However, no association was found between vitamin D insufficiency and atopy, presence of virus or bacteria or recurrent infections. Children older than 24\xa0months were particularly at risk of subnormal vitamin D levels, irrespective of wheezing history.
Answer: Our findings support the hypothesis that subnormal levels of vitamin D are associated with acute wheeze in young children.

A:
Are subnormal levels of vitamin D associated with acute wheeze in young children?
****