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.
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Question: Context: Current diagnostic tests for gastroesophageal reflux disease (GERD) do not consistently measure chronicity of reflux. Mucosal impedance (MI) is a minimally invasive measurement to assess esophageal conductivity changes due to GERD. We aimed to investigate MI pattern in patients with symptoms of extraesophageal reflux (EER) in a prospective longitudinal cohort study.', 'Patients with potential symptoms of EER undergoing esophagogastroduodenoscopy (EGD) with wireless pH monitoring were studied. Participants included those with erosive esophagitis (E+), normal EGD/abnormal pH (E-/pH+), and normal EGD/normal pH (E-/pH-). MI was measured from the site of injury in patients with E+, as well as at 2, 5, and 10 cm above the squamocolumnar junction (SCJ) in all participants.', 'Forty-one patients with symptoms of EER were studied. MI measurements at 2\u2009cm above the SCJ were significantly (P\u2009=\u20090.04) different among the three groups, with MI lowest for E+ and greatest for E-/pH- patients. Although not statistically significant, there is a graded increase in median (interquartile range) MI axially along the esophagus at 5\u2009cm (P\u2009=\u20090.20) and at 10\u2009cm (P\u2009=\u20090.27) above the SCJ, with those with reflux (E+ and E-/pH+) having a lower MI than those without.
Answer: Patients with symptoms of EER and evidence of acid reflux have an MI lower than those without at 2 cm above the SCJ, with a trend at 5 cm and 10 cm as well. MI may be a tool to assess presence of GERD in patients presenting with EER symptoms.

Answer: Is esophageal Mucosal Impedance Pattern Distinct in Patients With Extraesophageal Reflux Symptoms and Pathologic Acid Reflux?


Question: Context: Tumor necrosis factor-alpha (TNF-alpha) is a major pro-inflammatory cytokine. Recently, the G-308A polymorphism of the TNF-alpha gene has been associated with modified gene expression and increased TNF-alpha production in the -308A allele. We evaluated its influence on the incidence and clinical course of membranous glomerulonephritis.', 'We studied 53 patients with biopsy-proven primary membranous glomerulonephritis followed up for 5.7 +/- 4.9 years. 100 volunteers were analyzed as controls. According to the slope of the curve of reciprocal serum creatinine against time, group A (slow progressors, n = 35) and group B (fast progressors, n = 18) were defined. TNF-alpha G-308A polymorphism was determined by polymerase chain reaction amplification.', 'The frequency of the A-allele (associated with higher TNF-alpha levels) was significantly higher in patients than control subjects (patients: G-allele: 0.66, A-allele: 0.34; controls: G-allele 0.85, A-allele 0.15, p < 0.001). Similarly, the genotype distribution differed significantly between our study and control populations (patients: GG-genotype: 41.5%, GA: 49.1%, AA 9.4%; controls: GG: 71%, GA: 27%, AA 2%, p = 0.001). Age, renal function, proteinuria and blood pressure were similar at the time of renal biopsy between patients with different genotypes (NS). There was also a tendency towards an overpresentation of the A-allele in group B indicating a possible impact on the progression of membranous nephropathy, but a significance was not reached. Furthermore, no impact on renal survival in the Kaplan- Meier analysis was detected (NS).
Answer: Our results suggest that TNF-alpha gene G-308A polymorphism is a risk factor for the development of membranous glomerulonephritis.

Answer: Is tumor necrosis factor-alpha gene G-308A polymorphism a risk factor for the development of membranous glomerulonephritis?


Question: Context: Recent reviews of reproductive isolation (RI) in plants propose that boundaries between closely related species are maintained predominantly through prezygotic mechanisms. However, few experimental studies have explored how boundaries are maintained in long-lived species. Hawaiian Cyrtandra presents an intriguing challenge to our understanding of RI, as it comprises 60 shrub or small tree species that are almost exclusively restricted to wet forests, where sympatry of multiple species is common.', "We assessed the relative strengths of pre- and postzygotic barriers among four species of Cyrtandra occurring at the extremes of the main Hawaiian Island's natural island-age gradient, Kaua'i (4.7 Myr) and Hawai'i Island (0.6 Myr), to contrast the strengths and stages of reproductive isolation among species at different stages of divergence.", 'A combination of F1 seed germination, F1 seedling survival, and F1 seedling growth isolated (61-91%) three of the species from sympatric relatives. In contrast, the fourth species was isolated (59%) from its sympatric relative through phenological differences alone. Significant postzygotic barriers in between-island crosses were also observed in one species.
Answer: Results suggest that boundaries between sympatric Cyrtandra species in Hawaii are maintained predominantly through postzygotic barriers. Observations from between-island crosses indicate that postzygotic barriers can arise in allopatry, which may be important in the initial divergence of populations. Future studies of RI in Cyrtandra should include a broader range of species to determine if postzygotic isolating barriers are foremost in the maintenance of species boundaries in this large genus.

Answer:
Do postzygotic barriers isolate sympatric species of Cyrtandra ( Gesneriaceae ) in Hawaiian montane forest understories?