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.

[EX Q]: Context: Cyclosporine causes intrarenal vasoconstriction, which may account for its nephrotoxic side effects. Plasma levels of the vasoconstrictor peptide endothelin-1 are increased after cyclosporine administration, and endothelin-1 has been shown to cause renal vasoconstriction. In this study we used in vivo microscopy to investigate the role of endothelin-1 in cyclosporine-induced vasoconstriction.', 'Hydronephrotic kidneys in decerebrate rats were suspended in an environmentally controlled tissue bath with neurovascular supply intact. Interlobular, afferent, and efferent arteriolar diameters and flow were measured by videomicroscopy and Doppler velocimetry. Cyclosporine was added to the tissue bath, and measurements were repeated for 60 minutes. In study groups endogenous endothelin-1 was blocked by infusion of either specific endothelin antiserum or an endothelin-1 receptor antagonist.', 'Cyclosporine caused constriction of the interlobular artery by 20% +/- 2% and a corresponding decrease in blood flow by 66% +/- 4%. The afferent and efferent arterioles constricted to a similar degree. This vasoconstriction was entirely prevented by infusion of either the endothelin antiserum or the receptor antagonist. The antagonist reagents alone had no effect on hemodynamic parameters or renal microvessel diameters.
Answer: The acute renal vasoconstriction induced by cyclosporine is mediated by endothelin-1. Endogenous endothelin-1 has little role in maintaining basal vascular tone.
[EX A]: Is acute cyclosporine-induced renal vasoconstriction mediated by endothelin-1?

[EX Q]: Context: The aim of the current study was to test the impact of dentin powder on the antimicrobial efficacy of bioactive glass S53P4 (BAG).', 'BAG was suspended (preincubated) in saline at 37 degrees C for different time periods with or without human dentin powder, hydroxylapatite, or decalcified dentin. Subsequently, Enterococcus faecalis ATCC 29212 cells were added to these suspensions and bacterial recovery measured with and without the use of gentle sonication. Furthermore, survival of bacteria in test and control suspensions was assessed over time. Supernatants of suspensions were analyzed for their element contents using atomic absorption spectrophotometry. The effects of pH, silica, and osmolarity on E faecalis viability were assessed using specifically prepared solutions.', 'BAG preincubated with dentin powder caused a significant (P < .05) decrease in viability compared to pure BAG suspensions. This was not based on adherence of bacteria to solid particles or agglutination of the cells, because sonication did not increase bacterial yields. Hydroxylapatite and decalcified dentin did not increase BAG killing efficacy. The additive effect of BAG + dentin powder was dose dependent, occurred only with solids in suspension, and increased with suspension time. An augmented dissolution of glass components, especially silicon, was measured in BAG + dentin powder compared to pure BAG suspensions or counterparts containing hydroxylapatite or decalcified dentin. High osmolarity per se did not affect E faecalis viability, whereas high pH and silica levels did.
Answer: The observed phenomenon was related to an increased BAG dissolution triggered by dentin powder, causing elevated local pH and silica levels.
[EX A]: Does dentin enhance the effectiveness of bioactive glass S53P4 against a strain of Enterococcus faecalis?

[EX Q]: Context: Many patients require temporary inotropic support after cardiac surgery, and dobutamine is one of the commonly used drugs for this purpose. However, dobutamine infusion is frequently associated with unwanted sinus tachycardia. Selective sinus node electrical vagal stimulation through a discrete epicardial ganglionic plexus (fat pad) approach can achieve sinus rate slowing. Because sinus node fat pad vagal stimulation (SNFP-VS) can easily be applied during or after cardiac surgery, we hypothesized that combining selective SNFP-VS with dobutamine could produce desired hemodynamic improvement while avoiding sinus tachycardia in patients when inotropic drug support is needed.', 'This exploratory experimental study was performed in 7 open-chest dogs. Dobutamine (2.5 to 10 microg x kg(-1) x min(-1)) was infused at a rate producing at least 30% increase in sinus rate and cardiac output. Then electrical SNFP-VS was applied in the epicardial ganglionic plexus located at the right pulmonary vein-atrial junction, to slow the sinus rate back to control level. Hemodynamic data during control, with steady-state dobutamine infusion, and with dobutamine plus SNFP-VS were collected and compared.', 'Dobutamine significantly increased heart rate, systolic and diastolic blood pressures, peak left ventricular systolic pressure, positive and negative maximal derivatives of left ventricular pressure, and cardiac output. Combining SNFP-VS with dobutamine eliminated sinus rate increase while preserving all major hemodynamic benefits. Selective SNFP-VS itself had no direct effect on cardiac contractility during atrial pacing.
Answer: Combining SNFP-VS with dobutamine could achieve hemodynamic improvement while avoiding sinus tachycardia in this dog model, suggesting that similar strategy may also be applied in patients.
[EX A]:
Does cardiac vagal stimulation eliminate detrimental tachycardia effects of dobutamine used for inotropic support?