instruction:
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.
question:
Context: The shape of the ionizing radiation response curve at very low doses has been the subject of considerable debate. Linear-no-threshold (LNT) models are widely used to estimate risks associated with low-dose exposures. However, the low-dose hyperradiosensitivity (HRS) phenomenon, in which cells are especially sensitive at low doses but then show increased radioresistance at higher doses, provides evidence of nonlinearity in the low-dose region. HRS is more prominent in the G2 phase of the cell cycle than in the G0/G1 or S phases. Here we provide the first cytogenetic mechanistic evidence of low-dose HRS in human peripheral blood lymphocytes using structural chromosomal aberrations.', 'Human peripheral blood lymphocytes from 2 normal healthy female donors were acutely exposed to cobalt 60 γ rays in either G0 or G2 using closely spaced doses ranging from 0 to 1.5 Gy. Structural chromosomal aberrations were enumerated, and the slopes of the regression lines at low doses (0-0.4 Gy) were compared with doses of 0.5 Gy and above.', 'HRS was clearly evident in both donors for cells irradiated in G2. No HRS was observed in cells irradiated in G0. The radiation effect per unit dose was 2.5- to 3.5-fold higher for doses ≤0.4 Gy than for doses >0.5 Gy.
Answer: These data provide the first cytogenetic evidence for the existence of HRS in human cells irradiated in G2 and suggest that LNT models may not always be optimal for making radiation risk assessments at low doses.
answer:
Is cytogenetic low-dose hyperradiosensitivity observed in human peripheral blood lymphocytes?


question:
Context: Neonatal respiratory distress syndrome is a restrictive lung disease characterized by surfactant deficiency. Decreased vascular endothelial growth factor (VEGF), which demonstrates important roles in angiogenesis and vasculogenesis, has been implicated in the pathogenesis of restrictive lung diseases. Current animal models investigating VEGF in the etiology and outcomes of RDS require premature delivery, hypoxia, anatomically or temporally limited inhibition, or other supplemental interventions. Consequently, little is known about the isolated effects of chronic VEGF inhibition, started at birth, on subsequent developing lung structure and function.', 'To determine whether inducible, mesenchyme-specific VEGF inhibition in the neonatal mouse lung results in long-term modulation of AECII and whole lung function.', 'Triple transgenic mice expressing the soluble VEGF receptor sFlt-1 specifically in the mesenchyme (Dermo-1/rtTA/sFlt-1) were generated and compared to littermate controls at 3 months to determine the impact of neonatal downregulation of mesenchymal VEGF expression on lung structure, cell composition and function. Reduced tissue VEGF bioavailability has previously been demonstrated with this model.', 'Triple transgenic mice demonstrated restrictive lung pathology. No differences in gross vascular development or protein levels of vascular endothelial markers was noted, but there was a significant decrease in perivascular smooth muscle and type I collagen. Mutants had decreased expression levels of surfactant protein C and hypoxia inducible factor 1-alpha without a difference in number of type II pneumocytes.
Answer: These data show that mesenchyme-specific inhibition of VEGF in neonatal mice results in late restrictive disease, making this transgenic mouse a novel model for future investigations on the consequences of neonatal RDS and potential interventions.
answer:
Does sequestration of Vascular Endothelial Growth Factor ( VEGF ) induce Late Restrictive Lung Disease?


question:
Context: To investigate B7-H4 expression and its correlation with the number of infiltrating T lymphocytes and cytokine production by those lymphocytes in human cervical cancer and to determine the effect of recombinant B7-H4 on the active peripheral blood T cells of the patients in vitro.', 'B7-H4 expression was detected in 67 cases of cervical cancer using immunohistochemical staining. Tumor-infiltrating CD8(+)T, CD4(+)T, and FOXP3(+) (Forkhead Box P3) T lymphocytes and their levels of IFN-γ and TGF-β₁ production were determined by immunofluorescent double-staining. After the peripheral blood T lymphocytes of patients were co-cultured with B7-H4, proliferation, apoptosis, and cell subtypes were analyzed using flow cytometry. Cytokines in the supernatant were detected by ELISA.', "B7-H4 was expressed in 46% (31/67) of the cases of cervical cancer. The number of infiltrating CD8(+)T lymphocytes and their IFN-γ production in positive B7-H4 expression cervical cancers was significantly lower than in negative B7-H4 cases (P<0.01, P<0.05), but there was no significant difference between cases positive and negative for B7-H4 with respect to infiltrating FOXP3(+)T and CD4(+)T cells or TGF-β1 production. After co-culture with B7-H4 for 48 h, the patients' activated T lymphocytes were arrested at G1/G2 phase. The Ki67 positive rates of CD4(+)T and CD8(+)T cells were 2.13 ± 0.13% and 1.03 ± 1.33%, and they were lower than in the blank group. The proportion of CD4(+)T and CD8(+)T cells decreased, but CD4(+)T/CD8(+)T and the proportion of CD4(+)CD25(+)Foxp3(+)T cells increased. In addition, concentrations of IL-10 and TGF-β1 in the supernatant of co-cultured T cells increased significantly (P<0.05, P<0.05), but that of IFN-γ decreased. B7-H4 had no significant effect on apoptosis of the T cells.
Answer: B7-H4 is overexpressed in human cervical cancers, and it is associated with lower numbers of tumor-infiltrating CD8(+)T lymphocytes and therefore less IFN-γ production. In vitro, B7-H4 inhibits the proliferation of CD4(+)T and CD8(+)T but promotes the proliferation of Tregs and the secretion of IL-10 and TGF-β1. B7-H4 plays an important role in depressing the anti-tumor immunity of CD8(+)T cell in microenvironments of cervical cancer.
answer:

Does b7-H4 overexpression impair the immune response of T cells in human cervical carcinomas?