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.

[EX Q]: Class III antiarrhythmic agents exhibit reverse rate-dependent lengthening of the action potential duration (APD). In spite of the several theories developed so far to explain this reverse rate dependency (RRD), its mechanism has not yet been clarified. The aim of the present work was to further elucidate the mechanisms responsible for reverse rate-dependent drug effects.', 'Action potentials were recorded from multicellular canine ventricular preparations and isolated cardiomyocytes, at cycle lengths (CLs) varying from 0.3 to 5 s, using conventional sharp microelectrodes. APD was either modified by applying inward and outward current pulses, or by superfusion of agents known to lengthen and shorten APD. Net membrane current (I(m)) was calculated from action potential waveforms. The hypothesis that RRD may be implicit in the relationship between I(m) and APD was tested by numerical modelling. Both drug-induced lengthening (by veratrine, BAY-K 8644, dofetilide, and BaCl(2)) and shortening (by lidocaine and nicorandil) of action potentials displayed RRD, i.e. changes in APD were greater at longer than at shorter CL. A similar dependency of effect on CL was found when repolarization was modified by injection of inward or outward current pulses. I(m) measured at various points during repolarization was inversely proportional to APD and to CL. Model simulations showed that RRD is expected as a consequence of the non-linearity of the relationship between I(m) and APD.
[EX A]: Is reverse rate dependency an intrinsic property of canine cardiac preparations?

[EX Q]: Neuroendocrine (NE) differentiation in prostate cancer (PCa), promoted by NE cell secreted products, appears to be associated with tumor progression, poor prognosis, and hormone-refractory disease. We recently reported secretagogin, a hexa-EF-hand Ca(2+) binding protein, as a novel NE marker in carcinoid tumors of the lung and the gastrointestinal tract. The present study analyzes the expression of secretagogin in normal and malign prostate tissue.', 'We analyzed immunoreactivity for secretagogin, chromogranin A (CgA), neuron specific enolase (NSE), and synaptophysin (SYN) in consecutive sections from 87 formalin-fixed paraffin-embedded (FFPE) benign hyperplastic (n = 10) and prostate adenocarcinoma (n = 77) specimens. The intracellular distribution of secretagogin, CgA, and NSE was examined by confocal fluorescent microscopy, and we characterized secretagogin in eight samples by Western blotting.', 'Secretagogin is cytoplasmic and nuclear expressed in NE and NE differentiated cells, and to a lesser extent in epithelial cells, in the benign prostate and prostate adenocarcinoma cells. Secretagogin stained 82% (46/56) of benign and 71% (48/68) of prostate adenocarcinomas and co-localized with the NE markers CgA and NSE. The expression of secretagogin is significantly correlated to CgA (P < 0.001) and NSE (P < 0.048) in prostate adenocarcinoma and to CgA in normal epithelium (P < 0.028).
[EX A]: Is secretagogin a new neuroendocrine marker in the human prostate?

[EX Q]: Intravenous paclitaxel, 100 mg/m(2), given over 3 hours every 2 weeks is associated with a response rate of 59% in patients with recurrent or refractory acquired immunodeficiency syndrome (AIDS)-related Kaposi sarcoma (KS). However, this regimen is associated with significant myelosuppression, and the inconvenience of a 3-hour infusion. Moreover, no effective therapies have been defined for use after treatment failure with this agent. A Phase II trial was conducted with weekly docetaxel in patients with advanced-stage KS to assess safety and antitumor activity.', 'Docetaxel was administered at a dose of 25 mg/m(2) intravenously over 15-30 minutes weekly for 8 weeks. Thereafter, if the patient experienced stable disease or better response, treatment doses were given every other week until complete disease remission, disease progression, or unacceptable toxicity occurred.', 'Twelve patients were accrued-9 had > 25 mucocutaneous lesions, 1 had lymphedema, and 2 had visceral involvement. Ten patients (83%) had previous systemic chemotherapy, including 4 who received previous paclitaxel. Treatment was well tolerated, with no Grade 4 toxicity of any type. Grade 3 neutropenia occurred in 33% of patients but no patient had neutropenic fever. Five patients (42%) achieved a partial response, including 1 who had previously failed to respond to paclitaxel. The median time to disease progression was 26 months (range, 5-53 months). With a median follow-up period of 45 months, the median survival point had not been reached.
[EX A]:
Is weekly docetaxel safe and effective in the treatment of advanced-stage acquired immunodeficiency syndrome-related Kaposi sarcoma?