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 Input:
Context: Re-stenosis after percutaneous coronary angioplasty (PTCA) is related to clinical and angiographic features.', 'To describe the clinical and angiographic characteristic of our patients with coronary cardiopathy subjected to PTCA and the predictor factors for re-stenosis.', 'We gathered the clinical and angiographic characteristics of all patients who underwent a successful PTCA of a native coronary artery. All patients had a clinical assessment one year after the procedure. Patients were classified in Group 1, if they did not have angina or coronary events after the angioplasty or Group 2, if they had angina or a coronary event after the procedure. Only Group 2 patients were subjected to a coronary angiogram.', 'We collected 383 PTCA procedures. Follow up information was obtained in 92.2%. Three hundred forty two patients (89.3%) were assessed one year the procedure. Nine patients (2.3%) died of a cardiovascular cause. Ninety patients (26.3%) were classified in Group 2. In 65 patients, angiographic re-stenosis was demonstrated (19%). Re-stenosis occurred in 36 and 13% of patients with an without Diabetes Mellitus, respectively (p <0.01). The other clinical predictor variables were a history of myocardial infarction (p =0.007), obesity (p =0.041) and hypercholesterolemia (p =0.050). None of the angiographic characteristics predicted restenosis. Stents were protective factors against restenosis (15.6% in stented lesions vs 25.4% in nonstented; p =0.01).\Question: Do [ One year follow up of successful coronary angioplasty in non selected patients ]?

Ex Output:
Re-stenosis after angioplasty occurred in 19% of our patients with angina or coronary events. The clinical variables associated with a higher risk of re-stenosis were diabetes (the main risk factor), previous myocardial infarction, obesity and hypercholesterolemia. Angiographic variables were not associated with re-stenosis. The use of stents decreases the incidence of re-stenosis in all groups).


Ex Input:
Context: Most solid human tumors exist in an acidic microenvironment, due in part to inefficient vasculature and a higher intrinsic rate of glycolysis. This leads to a tumor-selective pH gradient, which can be exploited therapeutically with antitumor agents such as the camptothecins (CPTs). Previous work in this laboratory has shown that camptothecin activity is enhanced 40- to 60-fold in monolayer cell culture by reducing the extracellular pH to 6.8. Three-dimensional histoculture has been shown to be a technique that allows human tumor tissue to grow in an in vivo-like way with maintenance of tissue histology and function and drug sensitivity for long periods of time.', 'In the current study, we utilized these features of histoculture to study new analogues of camptothecin that have superior pharmacological properties.', 'We evaluated six CPT analogues in histocultures of human brain, neuroblastoma, breast, colon, and prostate tumors. Fragments were exposed to 10,11-methylenedioxy-CPT (MDC), 7-chloromethyl-MDC, SN-38, topotecan (TPT), 9-amino-CPT, 10-amino-CPT, paclitaxel, 5-fluorouracil, 4-hydroperoxycyclophosphamide and doxorubicin, and antitumor activity was assessed. For in vivo tumor outgrowth studies, fragments were treated in parallel, implanted into nude mice, and monitored for development of tumors. RESULTS. Against 15 of 16 tumor xenografts and all primary tumor samples tested, all compounds were cytotoxic at pH 7.4 (IC(50) range 13-921 microM). MDC, SN-38, TPT, and 9-amino-CPT achieved an average 5-fold increase in activity (range 3-14) at pH 6.8, while 7-chloromethyl-MDC was enhanced 8-fold (range 6-14). The most potentiated analogue was 10-amino-CPT at 27-fold (range 17-49). In contrast, the other agents were active against one or more tumor types but were not enhanced by acidic pH. Importantly, the toxicity of MDC in histoculture of D54 glioma xenografts strongly correlated with the outgrowth of treated fragments subsequently implanted in vivo.\Question: Is the activity of camptothecin analogues enhanced in histocultures of human tumors and human tumor xenografts by modulation of extracellular pH?

Ex Output:
Evaluation of anticancer drug activity in native-state histoculture supports the concept that pH modulation may be an important approach to improve the selectivity and antitumor effectiveness of camptothecin-based chemotherapy.


Ex Input:
Context: The Notch pathway stabilizes sprouting angiogenesis by favoring stalk cells over tip cells at the vascular front. Because tip and stalk cells have different properties in morphology and function, their transcriptional regulation remains to be distinguished. Transcription factor Sox17 is specifically expressed in endothelial cells, but its expression and role at the vascular front remain largely unknown.', 'To specify the role of Sox17 and its relationship with the Notch pathway in sprouting angiogenesis.', 'Endothelial-specific Sox17 deletion reduces sprouting angiogenesis in mouse embryonic and postnatal vascular development, whereas Sox17 overexpression increases it. Sox17 promotes endothelial migration by destabilizing endothelial junctions and rearranging cytoskeletal structure and upregulates expression of several genes preferentially expressed in tip cells. Interestingly, Sox17 expression is suppressed in stalk cells in which Notch signaling is relatively high. Notch activation by overexpressing Notch intracellular domain reduces Sox17 expression both in primary endothelial cells and in retinal angiogenesis, whereas Notch inhibition by delta-like ligand 4 (Dll4) blockade increases it. The Notch pathway regulates Sox17 expression mainly at the post-transcriptional level. Furthermore, endothelial Sox17 ablation rescues vascular network from excessive tip cell formation and hyperbranching under Notch inhibition in developmental and tumor angiogenesis.\Question: Does notch pathway target proangiogenic regulator Sox17 to restrict angiogenesis?

Ex Output:

Our findings demonstrate that the Notch pathway restricts sprouting angiogenesis by reducing the expression of proangiogenic regulator Sox17.