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.

[EX Q]: 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?
[EX A]: 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.

[EX Q]: Context: Total shoulder arthroplasty (TSA) results in superior clinical outcomes to hemiarthroplasty (HA); however, TSA is a more technical and invasive procedure. This study retrospectively compares perioperative complications after HA and TSA using the National Surgical Quality Improvement Program (NSQIP) database.', 'The NSQIP user file was queried for HA and TSA cases from the years 2005 through 2010. Major complications were defined as life-threatening or debilitating. All complications occurred within 30 days of the initial procedure. We performed multivariate analysis to compare complication rates between the two procedures, controlling for patient comorbidities.', 'The database returned 1,718 patients (HA in 30.4% [n = 523] and TSA in 69.6% [n = 1,195]). The major complication rates in the HA group (5.2%, n = 29) and TSA group (5.1%, n = 61) were similar (P = .706). Rates of blood transfusions for postoperative bleeding in patients undergoing HA (2.3%, n = 12) and TSA (2.9%, n = 35) were indistinguishable (P = .458). Venous thromboembolism was a rare complication, occurring in 0.4% of patients in each group (2 HA patients and 5 TSA patients, P > .999). On multivariate analysis, the operative procedure was not associated with major complications (P = .349); however, emergency case, pulmonary comorbidity, anemia with a hematocrit level lower than 36%, and wound class of III or IV increased the risk of a major complication (P < .05 for all).\Question: Are perioperative complications after hemiarthroplasty and total shoulder arthroplasty equivalent?
[EX A]: Multivariate analysis of patients undergoing TSA or HA in the NSQIP database suggests that patient factors-not the procedure being performed-are significant predictors of major complications. Controlling for patient comorbidities, we found no increased risk of perioperative major complications in patients undergoing TSA compared with HA.

[EX Q]: Context: Adjuvant chemotherapy improves survival in patients with gastric cancer. However, the relationship between the timing of adjuvant chemotherapy and survival has not been investigated.', 'Patients with D2-resected stage 2 and 3 gastric cancer that received adjuvant chemotherapy from 2005 to 2011 at Yonsei University Health System were included. The patients were grouped according to intervals between surgery and adjuvant chemotherapy.', 'Among 840 patients, the interval from surgery to the start of adjuvant therapy was less than 4 weeks in 337 (40.1 %) patients (early group), 4-8 weeks in 467 (55.6 %) patients (intermediate group), and more than 8 weeks in 36 (4.3 %) patients (late group). The 5-year RFS was 55.7 % in the early group, 54.4 % in the intermediate group, and 43.6 % in the late group (p = 0.076). The corresponding 5-year OS rates were 63.4, 62.8, and 51.7 % (p = 0.037).\Question: Does proper timing of adjuvant chemotherapy affect survival in patients with stage 2 and 3 gastric cancer?
[EX A]:
There is insufficient evidence to suggest starting adjuvant chemotherapy within 4 weeks after surgery for patients with D2 resected stage 2 and 3 gastric cancer. However, delayed treatment of adjuvant chemotherapy after 8 weeks showed worse survival outcomes than early and intermediate treatment initiation, suggesting that adjuvant chemotherapy should be considered start within 8 weeks after radical resection.