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: A number of gene therapy applications would benefit from vectors capable of expressing multiple genes. In this study we explored the feasibility and efficiency of expressing two or three transgenes in HIV-1 based lentiviral vector. Bicistronic and tricistronic self-inactivating lentiviral vectors were constructed employing the internal ribosomal entry site (IRES) sequence of encephalomyocarditis virus (EMCV) and/or foot-and-mouth disease virus (FMDV) cleavage factor 2A. We employed enhanced green fluorescent protein (eGFP), O6-methylguanine-DNA-methyltransferase (MGMT), and homeobox transcription factor HOXB4 as model genes and their expression was detected by appropriate methods including fluorescence microscopy, flow cytometry, immunocytochemistry, biochemical assay, and western blotting.', 'All the multigene vectors produced high titer virus and were able to simultaneously express two or three transgenes in transduced cells. However, the level of expression of individual transgenes varied depending on: the transgene itself; its position within the construct; the total number of transgenes expressed; the strategy used for multigene expression and the average copy number of pro-viral insertions. Notably, at limiting MOI, the expression of eGFP in a bicistronic vector based on 2A was approximately 4 times greater than that of an IRES based vector.
Answer: The small and efficient 2A sequence can be used alone or in combination with an IRES for the construction of multicistronic lentiviral vectors which can express encoded transgenes at functionally relevant levels in cells containing an average of one pro-viral insert.
[A]: Do multicistronic lentiviral vectors containing the FMDV 2A cleavage factor demonstrate robust expression of encoded genes at limiting MOI?

[Q]: Context: Animal and human studies suggest that programing of the hypothalamic-pituitary-adrenal (HPA) axis may be involved in the development of obesity, but human studies of biological indicators of HPA axis activity are lacking. We studied the association between levels of the stress hormone cortisol during pregnancy and overweight offspring during childhood into adolescence.', 'Salivary samples from 655 Danish pregnant women with singleton pregnancies (1989-1991) were collected once in the morning and once in the evening in their second and third trimester. We followed the offspring from two to 16 years of age with at least one measurement of height and weight, and classified their body mass index into overweight and normal weight. The adjusted relative difference in median salivary cortisol (with 95% confidence interval (CI)) during pregnancy (the four samples), in second and third trimester (morning and evening samples) between overweight and normal weight offspring was estimated. Furthermore, the adjusted median ratio between morning and evening maternal salivary cortisol level was estimated for normal weight and overweight children. All the analyses were stratified into the equal age groups: 2-6, 7-11, and 12-16 years.', 'We found non-significant higher maternal cortisol levels during pregnancy in offspring that were overweight at the age of 2-6, 7-11 and 12-16 years than in normal weight peers; adjusted relative difference in median salivary cortisol 11% (95% CI: -2; 25), 6% (95% CI: -7; 20), and 9% (95% CI: -4; 24), respectively. A statistically significantly higher level of maternal cortisol was found in the second trimester in 2-6-year-old and 12-16-year-old overweight offspring; relative difference 19% (95% CI: 3; 37), and 20% (95% CI: 3; 41), respectively. The median ratio between morning and evening maternal salivary cortisol level was similar for overweight and normal weight children; e.g. at age 2-6 years in third trimester 4.31 (95% CI: 4.05; 4.60)nmol/l and 4.28 (95% CI: 3.60; 5.09)nmol/l, respectively (P=0.93).
Answer: Our findings suggest a relatively consistent association between pregnancy cortisol levels and overweight offspring, especially in the second trimester.
[A]: Are maternal salivary cortisol levels during pregnancy positively associated with overweight children?

[Q]: Context: Leaks of the blood-brain barrier can be detected on postcontrast-enhanced T1-weighted MRIs. Although early disruptions of the blood-brain barrier appear to be an important risk factor for tissue plasminogen activator-related hemorrhages in rodents, little is known about their incidence and consequences in human stroke.', "This is a retrospective analysis of a prospectively collected stroke database over the past 6 years. In 52 patients, multimodal MRI (including diffusion-weighted, perfusion-weighted, and postcontrast-enhanced T1-weighted MRI to detect blood-brain barrier changes) had been performed immediately before systemic thrombolysis and in 48 patients within a median of 30 minutes (interquartile range: 30 to 60 minutes) after recombinant tissue plasminogen activator treatment. The incidence of symptomatic hemorrhage (SICH), defined as any parenchymal hemorrhage leading to deterioration in the patient's clinical condition, was related to several clinical and imaging variables, including early blood-brain barrier changes.", 'Overall, SICH was detected in 9 (9%) patients and among these, 2 died. Although no blood-brain barrier changes were detectable before thrombolysis, 3 of 48 patients (6.25%) had a parenchymal gadolinium enhancement in the areas of initial infarction after tissue plasminogen activator treatment. All 3 patients developed SICHs at sites corresponding to the areas of enhancement. The presence of a parenchymal enhancement was significantly associated with SICH (P<0.01), whereas other clinical and imaging variables did not predict SICH in this series.
Answer: Early parenchymal enhancement after intravenous tissue plasminogen activator is significantly associated with subsequent SICH and could therefore become a useful imaging sign for the rapid initiation of preventive strategies in the future.
[A]:
Does early disruption of the blood-brain barrier after thrombolytic therapy predict hemorrhage in patients with acute stroke?