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: Osteoarthritis (OA) is associated with a gradual reduction in the interstitial osmotic pressure within articular cartilage. The aim of this study was to compare the effects of sudden and gradual hypo-osmotic challenge on chondrocyte morphology and biomechanics.', 'Bovine articular chondrocytes were exposed to a reduction in extracellular osmolality from 327 to 153 mOsmol/kg applied either suddenly (<5 s) or gradually (over 180 min). Temporal changes in cell diameter and the existence of regulatory volume decrease (RVD) were quantified along with changes in cortical actin and chromatin condensation. The cellular viscoelastic mechanical properties were determined by micropipette aspiration.', 'In response to a sudden hypo-osmotic stress, 66% of chondrocytes exhibited an increase in diameter followed by RVD, whilst 25% showed no RVD. By contrast, cells exposed to gradual hypo-osmotic stress exhibited reduced cell swelling without subsequent RVD. There was an increase in the equilibrium modulus for cells exposed to sudden hypo-osmotic stress. However, gradual hypo-osmotic challenge had no effect on cell mechanical properties. This cell stiffening response to sudden hypo-osmotic challenge was abolished when actin organization was disrupted with cytochalasin D or RVD inhibited with REV5901. Both sudden and gradual hypo-osmotic challenge reduced cortical F-actin distribution and caused chromatin decondensation.
Answer: Sudden hypo-osmotic challenge increases chondrocyte mechanics by activation of RVD and interaction with the actin cytoskeleton. Moreover, the rate of hypo-osmotic challenge is shown to have a profound effect on chondrocyte morphology and biomechanics. This important phenomenon needs to be considered when studying the response of chondrocytes to pathological hypo-osmotic stress.
[A]: Does the rate of hypo-osmotic challenge influence regulatory volume decrease ( RVD ) and mechanical properties of articular chondrocytes?

[Q]: Context: Impaired endothelial function, as assessed by brachial artery flow-mediated dilation (FMD), is an established risk factor for cardiovascular events. FMD is impaired in heart failure (HF) patients, but less is known about hyperemic brachial artery flow. We investigated the relationship between FMD and hyperemic flow with adverse clinical outcomes in HF patients.', 'Brachial artery FMD and hyperemic flow were assessed in 156 patients (70.5 % Male; 45.5% Caucasian; mean age ( SD) = 56.2 (12.4) years) with HF and reduced left ventricular ejection fraction (LVEF). Cox proportional hazard models were used to assess the potential explanatory association of FMD and hyperemic flow with the composite outcome of death or cardiovascular hospitalization over a median 5-year follow-up period.', 'Both FMD and hyperemic flow were negatively correlated with age, but unrelated to sex, race, body mass index, LVEF or N-terminal pro-B-Type natriuretic peptide (NT-ProBNP). Reduced hyperemic flow, but not FMD, was associated with an increased risk of death or cardiac hospitalization after controlling for traditional risk factors.
Answer: The association of reduced hyperemic flow with increased risk of adverse clinical outcomes suggests that micro-vascular function may be an important prognostic marker in patients with HF.
[A]: Is reactive hyperemia associated with adverse clinical outcomes in heart failure?

[Q]: Context: To analyze the effect of antiretroviral therapy, including drugs that have good penetration in cerebrospinal fluid (CSF), on neuropsychologic performance.', 'One hundred sixty-five HIV-1-infected patients exposed to a stable highly active antiretroviral therapy (HAART) regimen were studied. Neuropsychologic examinations were performed for all patients.', "A total of 50.3% of patients were impaired. In multivariate analysis, older age (for 10-year increase, odds ratio [OR] = 4.8, 95% confidence interval [CI]: 2.2 to 10.4; P< 0.0001) and higher plasma HIV-1 RNA levels (OR = 1.90, 95% CI: 1.1 to 3.2; P = 0.021) at testing were independently associated with an increased probability of impaired neurocognitive performance, whereas higher educational level was a protective factor (OR = 0.76, 95% CI: 0.65 to 0.90; P=0.001). A significant linear correlation was observed between the neuropsychologic z score for 8 tests (NPZ8) score, a quantitative parameter of neurocognitive impairment, and CD4 cell count at neuropsychologic testing (R = 0.273, P = 0.001) and between the NPZ8 score and the patient's age (R = 0.288, P = 0.001).
Answer: Our study indicates that the use of stable HAART, including multiple drugs that have good CSF penetration, was not associated with neuropsychologic performance. To prevent independent replication of HIV in CSF with better control of a relevant reservoir of HIV is one of the crucial aims of therapeutic strategy.
[A]:
Do neuroactive antiretroviral drugs influence neurocognitive performance in less advanced HIV-infected patients responding to highly active antiretroviral therapy?