instruction:
Given a passage, 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.
question:
Thyroid-stimulating hormone (TSH) levels within populations do not follow Gaussian distribution, and normal limits are derived after mathematical normalization. The clinical relevance of these limits is unknown. The objective of this study was to compare upper and lower TSH limits by four data normalization methods with non-normalized data and assess their clinical relevance.', 'Results of blood samples taken by community physicians and stored in a computerized database were analysed after removing samples from patients with evidence of thyroid illness. TSH values were normalized by the Hoffmann and Tukey methods and each method with natural log transformation. Non-normalized data for TSH in the uppermost and lowermost percentile were also calculated. Clinical relevance was determined by alterations in thyroid hormone levels at, below and above the limits for each method.', 'The maximal reduction from non-normalized data for the upper normal limit (UNL) was by the Hoffman method 43% = 3·1 mIU/l). The maximal increase for the lower normal limit (LNL) was also by the Hoffman method (708% = 0·81 mIU/l). There was very limited difference in average FT3 and FT4 between patients with TSH within, below or above the normal range for all methods.
answer:
Do normal limits for serum thyrotropin vary greatly depending on method?


question:
The cancer stem cell model links neoplastic cells with normal stem cell biology, but little is known on how normal stem cells are transformed into cancer stem cells.', 'To investigate the processes underlying the transformation of normal stem cells we developed in vitro a cancer stem cell model from human amniotic and chorionic placenta membranes. In this model we studied the expression of specific stem cell molecules by flow cytometry, and genes, by real time RT-PCR. Microscopy immunfluorescence was employed to investigate the proliferative and differentiation patterns. Fluorescence microscopy and FACS were employed to investigate the proliferative and differentiation patterns. To evaluate the tumorigenic potential of our model we injected the cells into NOD.CB17-Prkdcscid/NCrHsd mice.', 'Normal human stem cells from amniotic and chorionic placenta membranes were converted into neural cell lineages, under specific conditions, to form secondary neurospheres with a capacity for self-renewal. After extensive in vitro culture, these cells underwent spontaneous transformations and acquired a neuroblastoma (NB)-like phenotype with an elevated proliferative potential that is comparable to established neuroblastoma cell lines. The ability of these cells to transform their phenotype was evidenced by increased clonogenic ability in vitro; by augmented expression level of certain proliferation- and transformation-related genes (e.g., CCNA2, MYCN, ENPP2, GRIA3, and KIT); by the presence of multinucleated and hyperdiploid cells. We further demonstrated that the transformed phenotype is an NB by measuring the expression of NB-specific markers, disialoganglioside GD2 and N-Myc proteins.
answer:
Are human placenta-derived neurospheres susceptible to transformation after extensive in vitro expansion?


question:
In this report are reviewed two unrelated patients with typical normokalemic periodic paralysis (normoKPP) features and the results of screening the SCN4A gene for the disease-related mutation.', 'Two sporadic cases with normoKPP were screened for previously known mutations in SCN4A gene (T704M, A1156T, M1360V, I1495F, M1592V) that lead to hyperKPP; denaturing high performance liquid chromatography (DHPLC) was used. Then the rest exons of SCN4A gene were screened by DHPLC, and sequence analysis was performed on those with DHPLC chromatogram variation when compared with unaffected control.', "Two cases and one patient's father were detected with V781I, which was proved to be a singular missense mutation in SCN4A gene.
answer:

Does [ The mutation V781I in SCN4A gene exist in Chinese patients with normokalemic periodic paralysis ]?