In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Context: Nicotinamide adenine dinucleotide (NAD(+)) and its phosphorylated form (NADP(+)) are key molecules in ubiquitous bioenergetic and cellular signaling pathways, regulating cellular metabolism and homeostasis. Thus, supplementation with NAD(+) and NADP(+) precursors emerged as a promising strategy to gain many and multifaceted health benefits. In this proof-of-concept study, we sought to investigate whether chronic nicotinamide riboside administration (an NAD(+) precursor) affects exercise performance.', 'Eighteen Wistar rats were equally divided in two groups that received either saline vehicle or nicotinamide riboside at a dose of 300mg/kg body weight/day for 21days via gavage. At the end of the 21-day administration protocol, both groups performed an incremental swimming performance test.', 'The nicotinamide riboside group showed a tendency towards worse physical performance by 35% compared to the control group at the final 10% load (9453s for the nicotinamide riboside group and 14559s for the control group; P=0.071).\Question: Does the NAD ( + ) precursor nicotinamide riboside decrease exercise performance in rats?
Our results do not confirm thepreviously reported ergogenic effect of nicotinamide riboside. The potentially negative effect of nicotinamide riboside administration on physical performance may be attributed to the pleiotropic metabolic and redox properties of NAD(+) and NADP(+).

Context: Celastrol is an active ingredient of traditional herbal medicine and has recently been identified as a potent natural proteasome inhibitor. In the present study, we evaluated the radiosensitizing potential of celastrol in the human prostate cancer PC-3 model.', 'Clonogenic assays were performed to determine the radiosensitizing effect of celastrol. Apoptosis was examined by flow cytometry using Annexin V and propidium iodide staining and by a caspase-3 activation assay. DNA damage processing was examined by immunofluorescent staining and Western blot for phosphorylated H2AX (gammaH2AX). The PC-3 xenograft model in the athymic nude mouse was used for the determination of the in vivo efficacy of celastrol combined with radiotherapy. The tumor samples were also analyzed for apoptosis and angiogenesis.', 'Celastrol sensitized PC-3 cells to ionizing radiation (IR) in a dose- and schedule-dependent manner, in which pretreatment with celastrol for 1 h followed by IR achieved maximal radiosensitization. Celastrol significantly prolonged the presence of IR-induced gammaH2AX and increased IR-induced apoptosis. Celastrol, combined with fractionated radiation, significantly inhibited PC-3 tumor growth in vivo without obvious systemic toxicity. The combination treatment increased gammaH2AX levels and apoptosis, induced cleavage of poly(adenosine diphosphate-ribose)polymerase and Mcl-1, and reduced angiogenesis in vivo compared with either treatment alone.\Question: Does celastrol potentiate radiotherapy by impairment of DNA damage processing in human prostate cancer?
Celastrol sensitized PC-3 cells to radiation both in vitro and in vivo by impairing DNA damage processing and augmenting apoptosis. Celastrol might represent a promising new adjuvant regimen for the treatment of hormone-refractory prostate cancer.

Context: The previous use of antibiotics is known to correlate positively with antibiotic resistance; whether this is also the case in the eradication of Helicobacter pylori infection is unclear.', 'To investigate the relationship between the previous use of antibiotics and the failure of eradication therapy in H. pylori infection.', 'The relationship between the clinical parameters and the failure of H. pylori eradication was analyzed in patients administered standard triple therapy and then assessed for the eradication of H. pylori based on a C13-urea breath test.', 'In a multivariate analysis, failure rates increased significantly in patients with a history of clarithromycin (odds ratio [OR], 4.445) or other macrolides (OR, 2.407) use, who were female (OR, 1.339), or who were older than 60 years of age (OR, 1.326). The eradication failure rate in patients with a history of macrolides use for >2 weeks was significantly higher than if the duration of use was <2 weeks (44.8% vs. 29.3%, p=0.047).\Question: Do the relationship between the failure to eradicate Helicobacter pylori and previous antibiotics use?
A patient's history of macrolides is a useful predictor of the likelihood of standard triple therapy failure in H. pylori eradication. The alternatives such as a bismuth-based quadruple or a levofloxacin-containing therapy should be considered in patients treated with macrolides for >2 weeks.