instruction:
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.
question:
Context: Increased expression of chemokine mRNA is observed in allogeneic but not syngeneic skin grafts 3-4 days after transplantation. The recipient cells mediating this early inflammatory response in allografts remain unidentified.', 'Isogeneic and allogeneic skin grafts were transplanted to euthymic and athymic nude mice. mRNA expression and protein production of macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, and the murine homolog of Gro(alpha), i.e. KC, from graft homogenates retrieved 3-4 days posttransplantation was tested by Northern blot hybridization and ELISA. To deplete NK cells, recipients were treated with antiasialo GM1 (ASGM1) antisera or with anti-NK1.1 mAb before transplantation.', 'Expression of KC, MIP-1alpha, and MIP-1beta mRNA was equivalent in C57BL/6 allogeneic skin grafts and BALB/c isografts at day 2 posttransplant. At day 3 posttransplant, chemokine mRNA levels decreased in isografts but were maintained at high levels in the allografts. Increased early chemokine mRNA was also observed in C57BL/6, but not BALB/c++ grafts on BALB/c athymi(nu/nu) recipients. Treatment of allograft recipients with ASGM1 or with anti-NK1.1 antibody eliminated NK cells from the spleen and allograft infiltrating cell populations and decreased early chemokine mRNA levels in allografts 60-70%. Analyses of allograft homogenates indicated increased levels of KC, MIP-1alpha, and MIP-1beta protein at day 4 posttransplant that were decreased in recipients depleted of NK cells. Early chemokine mRNA levels were equivalent in isogeneic and semiallogeneic F1 grafts.\Question: Is early increased chemokine expression and production in murine allogeneic skin grafts mediated by natural killer cells?
answer:
Early chemokine mRNA expression and protein production in allogeneic skin grafts is amplified by recipient natural killer (NK) cells. These results indicate a novel function for infiltrating NK cells in mediating early increased intra-allograft chemokine production and inflammation during the initiation of acute rejection.


question:
Context: Radiation induces an important apoptosis response in irradiated organs. The objective of this study was to investigate the radioprotective effect of tetramethylpyrazine (TMP) on irradiated lymphocytes and discover the possible mechanism of protection.', 'Lymphocytes were pretreated for 12 h with TMP (25-200 μmol·L(-1)) and then exposed to 4 Gy radiation. Cell apoptosis and the signaling pathway were analyzed.', 'Irradiation increased cell death, DNA fragmentation, activated caspase activation and cytochrome c translocation, downregulated B-cell lymphoma 2 (Bcl-2) and up-regulated Bcl-2-associated X protein (Bax). Pretreated with TMP significantly reversed this tendency. Several anti-apoptotic characteristics of TMP, including the ability to increase cell viability, inhibit caspase-9 activation, and upregulate Bcl-2 and down-regulate Bax in 4Gy-irradiated lymphocytes were determined. Signal pathway analysis showed TMP could translate nuclear factor-κB (NF-κB) from cytosol into the nucleus.\Question: Does tetramethylpyrazine protect lymphocytes from radiation-induced apoptosis through nuclear factor-κB?
answer:
The results suggest that TMP had a radioprotective effect through the NF-κB pathway to inhibit apoptosis, and it may be an effective candidate for treating radiation diseases associated with cell apoptosis.


question:
Context: Several case-control studies examined an association between schizophrenia and the 40-bp variable number tandem repeat (VTNR) polymorphism in the 3'-UTR of the dopamine transporter gene (SLC6A3). The results of these studies have been equivocal due to small sample size and low power. This meta-analysis has the aim to evaluate the collective evidence for an association between the VTNR polymorphism and schizophrenia.", 'Different meta-analyses were performed, sequentially considering the 9- and 10-repeat alleles and different genotypes (genotypes 9/9, 9/10, 10/10) as risk factors for schizophrenia. Analyses of the alleles included 659 cases and 563 controls from six case-control studies.', 'The pooled OR from each analysis approximated 1.0, and none were significant. Lack of significance attributable to the negative effects of single large studies or to heterogeneity between the studies was excluded.\Question: Does meta-analysis show schizophrenia is not associated with the 40-base-pair repeat polymorphism of the dopamine transporter gene?
answer:

Despite over 90% power to detect a significant odds ratio as small as 1.3, no association was observed. Considering the cumulative evidence from six case-control studies and results from additional family-based studies, it seems unlikely that the 40-base-pair VTNR polymorphism of the SLC6A3 gene influences risk for schizophrenia.