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.

Q: Context: Na-K-Cl cotransporter 1 (NKCC1) and K-Cl cotransporter 2 (KCC2) have fundamental roles in neuron differentiation that are integrated with gamma-aminobutyric acid (GABA) and glutamate receptors, GABA synthesized by GAD25/65/67 encoded by GAD1/GAD2 genes, and GABA transporters (GATs). Cells in the eye lens express at least 13 GABA receptor subunits, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl D-aspartate (NMDA) glutamate receptors, GAD1/GAD2, GAT1-4 and vGAT, and NKCC1. NKCC1:KCC2 ratios determine the switch in GABA actions from trophic/growth promoting early in development to their classic inhibitory roles in adult neurons. Lens epithelial cells cover the anterior surface and differentiate to elongated fiber cells in the lens interior with comparable morphology and sub-cellular structures as neurons. NKCC1 is expressed before KCC2 in neuron development and increases cell chloride, which stimulates differentiation and process formation. Subsequently, KCC2 increases and extrudes cell chloride linked with maturation. KCC2 has an additional structural moonlighting role interacting with F-actin scaffolding in dendritic spine morphogenesis. We examined KCC2 versus NKCC1 spatial expression in relation to fiber cell developmental status within the lens.', 'Immunofluorescence and immunoblots were used to detect expression in mouse and rabbit lenses.', 'NKCC1 was restricted to peripheral elongating lens fiber cells in young adult mouse and rabbit lenses. Lens KCC2 expression included the major KCC2b neuronal isoform and was detected in interior fiber cells with decreased NKCC1 expression and localized at the membranes. Lens expression of RE-1 silencing transcription factor (REST) regulated KCC2 is consistent with GAD1 and GAD2, several GABA and glutamate receptor subunits, miR-124, and other REST-regulated genes expressed in lenses.\Question: Does kCC2 expression supersede NKCC1 in mature fiber cells in mouse and rabbit lenses?

A: NKCC1 in peripheral elongating fiber cells is superseded by KCC2 expression in interior mature fiber cells that also express >20 additional integral GABA biology genes, AMPA/NMDA glutamate receptors, and an array of accessory proteins that together underlie morphogenesis in neurons. The present findings provide further evidence that this fundamental neuronal regulation is extensively conserved in lens and identify additional parallels in the morphogenetic programs that underlie lens fiber cell and neuronal differentiation and contribute to the development of visual acuity.
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Q: Context: Analyses of the pattern of p53 mutations have been essential for epidemiologic studies linking carcinogen exposure and cancer. We were concerned by the inclusion of dubious reports in the p53 databases that could lead to controversial analysis prejudicial to the scientific community.', 'We used the universal mutation database p53 database (21,717 mutations) combined with a new p53 mutant activity database (2,300 mutants) to perform functional analysis of 1,992 publications reporting p53 alterations. This analysis was done using a statistical approach similar to that of clinical meta-analyses.', 'This analysis reveals that some reports of infrequent mutations are associated with almost normal activities of p53 proteins. These particular mutations are frequently found in studies reporting multiple mutations in one tumor, silent mutations, or lacking mutation hotspots. These reports are often associated with particular methodologies, such as nested PCR, for which key controls are not satisfactory.\Question: Does meta-analysis of the p53 mutation database for mutant p53 biological activity reveal a methodologic bias in mutation detection?

A: We show the importance of accurate functional analysis before inferring any genetic variation. The quality of the p53 databases is essential in order to prevent erroneous analysis and/or conclusions. The availability of functional data from our new p53 web site (http://p53.free.fr and http://www.umd.be:2072/) will allow functional prescreening to identify potential artifactual data.
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Q: Context: Human and ovine fetuses demonstrate an enhanced rate of spontaneous and angiotensin II-stimulated swallowing. Angiotensin II and nitric oxide synthase have been localized to thirst centers in the brain. This study was performed to determine whether central nitric oxide contributes to the regulation of angiotensin II-induced fetal swallowing.', 'Six pregnant ewes with near-term singleton fetuses were chronically prepared with fetal vascular and lateral ventricle catheters and electrocorticogram and esophageal electromyogram electrodes. After a 2-hour control period, fetuses were administered serial lateral ventricle injections (1 mL) of angiotensin II (3.2 microg; time, 2 hours) and N omega-nitro-L -arginine methyl ester (3 mg; time, 3 hours) and a repeat angiotensin II injection (3.2 microg; time, 5 hours). All fetuses received an additional control study of lateral ventricle injections of artificial cerebrospinal fluid on a previous day.', 'Angiotensin II injection significantly increased mean +/- SEM fetal swallowing (0.9 +/- 0.1 to 2.7 +/- 0.4 swallows/min). N omega-nitro-L -arginine methyl ester significantly decreased fetal swallowing to below the basal rate (0.4 +/- 0.1 swallows/min), and swallowing did not increase with the second angiotensin II dose (in the presence of nitric oxide blockade).\Question: Does nitric oxide modulate angiotensin II-induced drinking behavior in the near-term ovine fetus?

A:
These results demonstrate that inhibition of central nitric oxide suppresses fetal swallowing behavior in response to central angiotensin II. We speculate that tonic nitric oxide facilitates angiotensin II swallowing stimulation by maintenance of glutamate activation of hypothalamic N -methyl-D -aspartate receptors.
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