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.
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Question: Mitochondrial permeability transition pore (mPTP) opening is a terminal event leading to mitochondrial dysfunction and cell death under conditions of oxidative stress (OS). However, mPTP blockade with cyclosporine A (CsA) has shown variable efficacy in limiting post-ischemic dysfunction and arrhythmias. We hypothesized that strong feedback between energy dissipating (mPTP) and cardioprotective (mKATP) channels determine vulnerability to OS.', 'Guinea pig hearts (N = 61) were challenged with H2O2 (200 μM) to elicit mitochondrial membrane potential (ΔΨm) depolarization. High-resolution optical mapping was used to measure ΔΨm or action potentials (AP) across the intact heart. Hearts were treated with CsA (0.1 μM) under conditions that altered the activity of mKATP channels either directly or indirectly via its regulation by protein kinase C. mPTP blockade with CsA markedly blunted (P < 0.01) OS-induced ΔΨm depolarization and delayed loss of LV pressure (LVP), but did not affect arrhythmia propensity. Surprisingly, prevention of mKATP activation with the chemical phosphatase BDM reversed the protective effect of CsA, paradoxically exacerbating OS-induced ΔΨm depolarization and accelerating arrhythmia onset in CsA treated compared to untreated hearts (P < 0.05). To elucidate the putative molecular mechanisms, mPTP inhibition by CsA was tested during conditions of selective PKC inhibition or direct mKATP channel activation or blockade. Similar to BDM, the specific PKC inhibitor, CHE (10 μM) did not alter OS-induced ΔΨm depolarization directly. However, it completely abrogated CsA-mediated protection against OS. Direct pharmacological blockade of mKATP, a mitochondrial target of PKC signaling, equally abolished the protective effect of CsA on ΔΨm depolarization, whereas channel activation with 30 μM Diazoxide protected against ΔΨm depolarization (P < 0.0001). Conditions that prevented mKATP activation either directly or indirectly via PKC inhibition led to accelerated ΔΨm depolarization and early onset of VF in response to OS. Investigation of the electrophysiological substrate revealed accelerated APD shortening in response to OS in arrhythmia-prone hearts.

Answer: Do functional crosstalk between the mitochondrial PTP and KATP channels determine arrhythmic vulnerability to oxidative stress?


Question: Are submaximal and maximal exercise tests reliable, valid and acceptable in people with chronic pain, fibromyalgia and fatigue disorders?', 'Systematic review of studies of the psychometric properties of exercise tests.', 'People older than 18 years with chronic pain, fibromyalgia and chronic fatigue disorders.', 'Studies of the measurement properties of tests of physical capacity in people with chronic pain, fibromyalgia or chronic fatigue disorders were included.', "Studies were required to report: reliability coefficients (intraclass correlation coefficient, alpha reliability coefficient, limits of agreements and Bland-Altman plots); validity coefficients (intraclass correlation coefficient, Spearman's correlation, Kendal T coefficient, Pearson's correlation); or dropout rates.", 'Fourteen studies were eligible: none had low risk of bias, 10 had unclear risk of bias and four had high risk of bias. The included studies evaluated: Åstrand test; modified Åstrand test; Lean body mass-based Åstrand test; submaximal bicycle ergometer test following another protocol other than Åstrand test; 2-km walk test; 5-minute, 6-minute and 10-minute walk tests; shuttle walk test; and modified symptom-limited Bruce treadmill test. None of the studies assessed maximal exercise tests. Where they had been tested, reliability and validity were generally high. Dropout rates were generally acceptable. The 2-km walk test was not recommended in fibromyalgia.

Answer: Are several submaximal exercise tests reliable , valid and acceptable in people with chronic pain , fibromyalgia or chronic fatigue : a systematic review?


Question: Monocytes are cellular components of wound repair, arteriogenesis, and atherogenesis. Vascular endothelial growth factor (VEGF)-A and placental growth factor recruit monocytes to sites of arteriogenesis via stimulation of VEGF receptor-1 (VEGFR-1). The chemotactic response of monocytes to VEGF-A is attenuated in individuals with diabetes mellitus (DM). This VEGF resistance correlates with impaired collateral growth. The aim of this study is to elucidate the molecular basis of VEGF resistance and impaired monocyte response in DM.', 'Phosphorylation of Akt, p38, and extracellular signal-regulated kinase 1/2 (ERK1/2) could be stimulated with either placental growth factor-1 or VEGF-A in monocytes from non-DM but not DM individuals. In contrast, formyl-methionyl-leucyl-phenylalanine caused a comparable activation of these molecules in both DM and non-DM monocytes. Baseline phosphorylation of Akt, p38, and ERK1/2 was significantly elevated in monocytes from DM compared with non-DM subjects. Of note, H(2)O(2) activated Akt, p38, and ERK1/2 in non-DM monocytes ex vivo. Protein tyrosine phosphatases had stronger oxidative modifications in monocytes from DM than from non-DM individuals, which reflects functional protein tyrosine phosphatase inhibition, similar to that seen after H(2)O(2) challenge. Overall, protein tyrosine phosphatase and protein tyrosine phosphatase-1B activity were reduced in DM monocytes. DM monocytes revealed higher expression of the receptor for advanced glycation end products. Stimulation with advanced glycation end products ligands resulted in activation of non-DM monocytes and inhibition of VEGFR-1-mediated chemotaxis. The elevated baseline phosphorylation/activation of Akt, p38, and ERK1/2 in DM monocytes likely causes the resistance to further stimulation with specific stimuli such as VEGF-A, revealing a molecular explanation of the DM-related signal transduction defect.

Answer:
Does diabetes mellitus activate signal transduction pathways resulting in vascular endothelial growth factor resistance of human monocytes?