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.

The clinical significance of the hepatitis B virus core-related antigen (HBcrAg) assay in monitoring the antiviral effects of lamivudine is reviewed.', 'The HBcrAg assay simultaneously measured serum levels of hepatitis B core (HBc) and e (HBe) antigens using monoclonal antibodies which recognize common epitopes of these two denatured antigens.', 'Although serum HBcrAg levels correlated linearly with those of hepatitis B virus (HBV) DNA in natural course, the decrease in HBcrAg was significantly slower than in HBV DNA after initiation of lamivudine administration. We analyzed the clinical significance of HBV DNA and HBcrAg levels to predict the occurrence of lamivudine resistance. HBV DNA measurement may be useful to identify patients who are at high risk of developing lamivudine resistance, and HBcrAg measurement may help to detect patients who are at low risk of drug resistance. The measurement of HBcrAg was also found to be a useful prognosticator for reactivation of hepatitis after cessation of lamivudine administration.
Is hepatitis B core-related antigen assay useful for monitoring the antiviral effects of nucleoside analogue therapy?

Beta blockers and calcium antagonists are widely used in the management of angina pectoris in the belief that the combination is more efficacious than either drug alone.', 'This double blind randomised crossover placebo controlled study compares the effects of nicardipine, atenolol and their combination in 30 patients with chronic stable angina. Each treatment period lasted 6 weeks with dose titration after 3 weeks. Symptom limited treadmill exercise testing and radionuclide ventriculography at rest was carried out at the end of each treatment period.', 'Total exercise duration and time to 1-mm ST-segment depression was significantly prolonged by nicardipine and atenolol when compared to placebo, the combination offered no additional benefit. Time to onset of angina was significantly prolonged by nicardipine and the combination but not by atenolol. Indices of left ventricular function were not significantly affected by any treatment other than an increase in left ventricular end diastolic volume on atenolol and the combination.
Is atenolol or nicardipine alone as efficacious in stable angina as their combination : a double blind randomised trial?

Adenosine diphosphate (ADP) is involved in shear-induced platelet activation, which may be important for platelet responses to stress. We therefore tested the hypothesis that ADP receptor antagonism by clopidogrel treatment would attenuate exercise-induced platelet activation.', 'Fifteen healthy volunteers performed exhaustive exercise without and with clopidogrel pretreatment (75 mg/day; 7 days) in a randomised crossover study. Filtragometry readings (reflecting platelet aggregability in vivo) and 11-dehydro-thromboxane B(2) (TxM) in plasma were determined before and after exercise. Platelet and leukocyte activity, platelet-platelet (PPA), and platelet-leukocyte aggregates (PLAs) in vivo and their responsiveness to agonist stimulation in vitro were assessed by flow cytometry. Clopidogrel treatment inhibited ADP-induced platelet P-selectin expression by 72% (54-85%). Exercise increased platelet aggregation (filtragometry and PPAs), elevated plasma TxM, increased single platelet P-selectin expression, elevated circulating PLAs, and enhanced ADP and thrombin-stimulated P-selectin expression. Clopidogrel prolonged filtragometry readings and attenuated agonist stimulated P-selectin expression at rest, but did not influence TxM in plasma or urine or attenuate platelet or leukocyte responses to exercise. Clopidogrel treatment did not influence plasma CD40L (ligand) at rest or after exercise.

Are prothrombotic responses to exercise little influenced by clopidogrel treatment?