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.

Q: Context: Magnetic fields have been shown to affect cell proliferation and growth factor expression in cultured cells. Although the activation of endorphin systems is a recurring motif among the biological events elicited by magnetic fields, compelling evidence indicating that magnetic fields may modulate opioid gene expression is still lacking. We therefore investigated whether extremely low frequency (ELF) pulsed magnetic fields (PMF) may affect opioid peptide gene expression and the signaling pathways controlling opioid peptide gene transcription in the adult ventricular myocyte, a cell type behaving both as a target and as a source for opioid peptides.', 'Prodynorphin gene expression was investigated in adult rat myocytes exposed to PMF by the aid of RNase protection and nuclear run-off transcription assays. In PMF-exposed nuclei, nuclear protein kinase C (PKC) activity was followed by measuring the phosphorylation rate of the acrylodan-labeled MARCKS peptide. The effect of PMF on the subcellular distribution of different PKC isozymes was assessed by immunoblotting. A radioimmunoassay procedure coupled to reversed-phase high performance liquid chromatography was used to monitor the expression of dynorphin B.', 'Here, we show that PMF enhanced myocardial opioid gene expression and that a direct exposure of isolated myocyte nuclei to PMF markedly enhanced prodynorphin gene transcription, as in the intact cell. The PMF action was mediated by nuclear PKC activation but occurred independently from changes in PKC isozyme expression and enzyme translocation. PMF also led to a marked increase in the synthesis and secretion of dynorphin B.
Answer: The present findings demonstrate that an opioid gene is activated by myocyte exposure to PMF and that the cell nucleus and nuclear embedded PKC are a crucial target for the PMF action. Due to the wide ranging importance of opioid peptides in myocardial cell homeostasis, the current data may suggest consideration for potential biological effects of PMF in the cardiovascular system.

A: Do elf-pulsed magnetic fields modulate opioid peptide gene expression in myocardial cells?
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Q: Context: The aim of this study was to investigate the relationship between intraoperative vasopressin infusion and postoperative cardiac enzymes.', 'A prospective, double-blind, randomized, controlled study.', 'A single tertiary cardiac center.', 'One hundred consecutive patients undergoing cardiac surgery with or without cardiopulmonary bypass.', 'The study was approved by the Institutional Review Board, and patients provided informed consent to participate. Patients were randomized by computer into 2 equal groups: Vasopressin or control. The blinded study included vasopressin administered at a dose of 1.8 U/h or 1.8 mL/h of normal saline, along with catecholamines. The drug was administered continually during surgery while patients needed catecholamines. The intervention was discontinued upon admission to the intensive care unit when information regarding the true character of the drug was reported to the doctor in charge of patients in the intensive care unit by one of the investigators. Primary outcomes were CK-MB and troponin T levels measured at 0, 6, and 12 hours postoperatively.', 'Of the 100 patients, 8 were excluded; the remaining 92 were randomized to either the vasopressin (n = 47) or control (n = 45) group. There were no significant differences in demographic data between the groups. Postoperatively at 0, 6, and 12 hours, there were no differences in CK-MB (U/l) (37.5 57.9 v 32.0 21.5, 29.4 41.1 v 24.4 23.1, and 21.4 21.3 v. 21.8 32.4, respectively) and troponin T (752.4 638.2 v 762.7 557.1, 753.8 507.3 v 777.6 515.0, and 774.6 572.6 v 698.7 540.2, respectively) values.
Answer: Vasopressin infusion has been used to treat catecholamine-unresponsive shock. In this study, intraoperative vasopressin was used safely as a possible first-line drug for treating hypotension; however, it did not increase the levels of cardiac enzymes after cardiac surgery.

A: Does vasopressin raise cardiac enzymes following cardiac surgery : a randomized double-blind clinical trial?
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Q: Context: Formulation of DNA/cationic lipid complexes (lipoplexes) designed for nucleic acid delivery mostly results in positively charged particles which are thought to enter cells by endocytosis. We recently developed a lipoplex formulation called Neutraplex that allows preparation of both cationic and anionic stable complexes with similar lipid content and ultrastructure.', 'To assess whether the global net charge could influence cell uptake and activity of the transported oligonucleotides (on), we prepared lipoplexes with positive and negative charges and compared: (i) their physicochemical properties by zeta potential analysis and dynamic light scattering, (ii) their cell uptake by fluorescence microscopy and flow cytometry, and (iii) the biological activity of the transported ON using a splicing correction assay. We show that positively or negatively charged lipoplexes enter cells cells using both temperature-dependent and -independent uptake mechanisms. Specifically, positively charged lipoplexes predominantly use a temperature-dependent transport when cells are incubated OptiMEM medium. Anionic lipoplexes favour an energy-independent transport and show higher ON activity than cationic lipoplexes in presence of serum. However, lipoplexes with high positive global net charge and OptiMEM medium give the highest uptake and ON activity levels.
Answer: These findings suggest that, in addition to endocytosis, lipoplexes may enter cell via a temperature-independent mechanism, which could be mediated by lipid mixing. Such characteristics might arise from the specific lipoplex ultrastructure and should be taken into consideration when developing lipoplexes designed for in vivo or ex vivo nucleic acid transfer.

A:
Do physico-chemical characteristics of lipoplexes influence cell uptake mechanisms and transfection efficacy?
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