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.

Q: 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.

A: Do functional crosstalk between the mitochondrial PTP and KATP channels determine arrhythmic vulnerability to oxidative stress?
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Q: Motor dysfunction in complex regional pain syndrome (CRPS) is often considered a functional movement disorder. Earlier studies in patients with functional movement disorders found evidence of cortical inhibition during explicit but not implicit motor tasks, suggesting active inhibition from other brain areas. In this study, we explored whether active inhibition occurs in CRPS patients. We compared patients with CRPS with 2 control groups: healthy controls matched for age and sex, and patients whose hand was immobilized to treat a scaphoid fracture. We used transcranial magnetic stimulation to measure corticospinal excitability at rest and during motor imagery (explicit motor task) and motor observation (implicit motor task). Motor corticospinal excitation measured at rest and during implicit and explicit motor tasks was similar for CRPS patients and healthy controls. Patients with an immobilized hand showed an absence of motor cortical excitation of the corresponding hemisphere during motor imagery of tasks involving the immobilized hand, but not during motor observation. The normal motor cortical processing during motor imagery and motor observation found in the corresponding hemisphere of CPRS patients suggests that the nature of motor dysfunction in this condition differs from that described in literature for patients with functional paresis or under circumstances of limb immobilization.

A: Is motor cortical activity during motor tasks normal in patients with complex regional pain syndrome?
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Q: To investigate how statin use is associated with the probability of having an abnormal screening prostate-specific antigen (PSA) result according to common PSA thresholds for biopsy (>2.5, >4.0, and >6.5 ng/mL).', 'We conducted a cross-sectional study of 323,426 men aged ≥65 years who had a screening PSA test in 2003 at a Veterans Affairs facility. The primary predictor was the use of statin medications at the time of index screening PSA test. The main outcome was the screening PSA value. Poisson regressions were performed to calculate adjusted relative risks for having an abnormal screening PSA result according to statin usage.', 'Percentages of men with PSA results exceeding commonly used thresholds of >2.5, >4.0, and >6.5 ng/mL were 21.0%, 7.6%, and 1.6%, respectively. These percentages decreased with statin use, increasing statin dose, duration of statin use, and potency of the statin. For example, after adjusting for age, the percentage of men having a PSA level >4.0 ng/mL ranged from 8.2% in non-statin users to 6.2% in men prescribed with >40 mg of simvastatin dose. Adjusted relative risks of having a PSA level >4.0 ng/mL were 0.89 (95% confidence interval [CI], 0.86-0.93), 0.87 (95% CI, 0.84-0.91), and 0.83 (95% CI, 0.80-0.87), respectively for men on simvastatin dose of 5-20, >20-40, and >40 mg vs non-statin users.

A:
Are statin medications associated with a lower probability of having an abnormal screening prostate-specific antigen result?
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