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: Besides chronic stress, chronic pain is a prevalent determinant for depression. Changes induced in specific brain regions by sustained pain may alter the processing of affective information, thus resulting in anxiodepressive disorders. Here, we compared the role of the anterior cingulate cortex (ACC) and the posterior insular cortex in the anxiodepressive, sensory, and affective aspects of chronic pain.', 'Neuropathic pain was induced by cuffing the right sciatic nerve of C57BL/6J mice. Lesions were performed by local injection of ibotenic acid and chronic activation of the ACC by optogenetic stimulation. Anxiodepressive-related behaviors were evaluated through the novelty suppressed feeding, marble burying, splash, and forced swimming tests. Mechanical thresholds were determined using von Frey filaments, and the relief of spontaneous pain was determined by using place conditioning.', 'The ACC lesion prevented the anxiodepressive consequences of chronic pain without affecting the sensory mechanical allodynia. Conversely, the tonic or spontaneous pain and the anxiodepressive consequences of pain remained present after posterior insular cortex lesion, even though the mechanical allodynia was suppressed. Furthermore, optogenetic stimulation of the ACC was sufficient to induce anxiety and depressive-like behaviors in naïve animals.
Answer: Our results show that, at cortical level, the sensory component of chronic pain remains functionally segregated from its affective and anxiodepressive components. Spontaneous tonic pain and evoked allodynia can be experimentally dissociated. Furthermore, the ACC appears as a critical hub for mood disorders, including for the anxiodepressive consequences of chronic pain, and thus constitutes an important target for divulging the underlying mechanism.

A: Is the anterior cingulate cortex a critical hub for pain-induced depression?
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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.
Answer: The low incidence and benign nature of contralateral hernia development in infants undergoing a unilateral inguinal herniotomy does not justify routine contralateral groin exploration.

A: Is contralateral groin exploration justified in infants with a unilateral inguinal hernia?
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Q: Context: Reactive oxygen species (ROS) are involved in a wide range of cellular processes. However, few studies have examined the generation and function of ROS in human embryonic vascular development. In this study, the sources of ROS and their roles in the vascular differentiation of human embryonic stem cells (hESCs) were investigated.', 'During vascular differentiation of hESCs, CD34(+) cells had quiescence-related gene expression profiles and a large fraction of these cells were in G0 phase. In addition, levels of ROS, which were primarily generated through NOX4, were substantially higher in hESC-derived CD34(+) cells than in hESC-derived CD34(-) cells. To determine whether excess levels of ROS induce quiescence of hESC-derived CD34(+) cells, ROS levels were moderately reduced using selenium to enhance antioxidant activities of thioredoxin reductase and glutathione peroxidase. In comparison to untreated CD34(+) cells, selenium-treated CD34(+) cells exhibited changes in gene expression that favoured cell cycle progression, and had a greater proliferation and a smaller fraction of cells in G0 phase. Thus, selenium treatment increased the number of hESC-derived CD34(+) cells, thereby enhancing the efficiency with which hESCs differentiated into vascular endothelial and smooth muscle cells.
Answer: This study reveals that NOX4 produces ROS in CD34(+) cells during vascular differentiation of hESCs, and shows that modulation of ROS levels using antioxidants such as selenium may be a novel approach to increase the vascular differentiation efficiency of hESCs.

A:
Do reactive oxygen species regulate the quiescence of CD34-positive cells derived from human embryonic stem cells?
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