TASK DEFINITION: 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.
PROBLEM: Context: Helicobater (H.) pylori eradication rates with standard first-line triple therapy have declined to unacceptable levels. To date, amoxicillin-resistant H. pylori strains have rarely been detected. Whether increasing the dosage of amoxicillin in a standard 7 days eradicating regimen may enhance its efficacy is not known. The aim of this paper is to compare the efficacy of a 7 days high-dose amoxicillin based first-line regimen with sequential therapy.', 'We have retrospectively analyzed data from 300 sex and age matched patients, who underwent 3 different therapeutic schemes: (1) standard LCA, lansoprazole 30 mg bid, clarithromycin 500 mg bid and amoxicillin 1000 mg bid for 7 days; (2) high dose LCA (HD-LCA), lansoprazole 30 mg bid, clarithromycin 500 mg bid and amoxicillin 1000 mg tid for 7 days; (3) sequential LACT, lansoprazole 30 mg bid plus amoxicillin 1000 mg bid for 5 days, followed by lansoprazole 30 mg bid, clarithromycin 500 mg bid and tinidazole 500 mg bid for 5 days. Eradication was confirmed by 13C-urea breath test. Compliance and occurrence of adverse effects were also assessed.', 'Eradication rates were: 55% for LCA, 75% for HD-LCA and 73% for LACT. Eradication rates were higher in HD-LCA group compared to LCA (p<0.01), while no significant differences were observed in HD-LCA group compared to LACT (p=ns). Compliance and occurrence of adverse effects were similar among groups.\Question: Is high dose amoxicillin-based first line regimen equivalent to sequential therapy in the eradication of H. pylori infection?

SOLUTION: High-dose amoxicillin based eradicating treatment is superior to standard triple therapy and equivalent to sequential therapy; compared to the latter, the shorter duration may represent an advantage.

PROBLEM: 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?

SOLUTION: 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.

PROBLEM: Context: Most melanomas harbor oncogenic BRAF(V600) mutations, which constitutively activate the MAPK pathway. Although MAPK pathway inhibitors show clinical benefit in BRAF(V600)-mutant melanoma, it remains incompletely understood why 10% to 20% of patients fail to respond. Here, we show that RAF inhibitor-sensitive and inhibitor-resistant BRAF(V600)-mutant melanomas display distinct transcriptional profiles. Whereas most drug-sensitive cell lines and patient biopsies showed high expression and activity of the melanocytic lineage transcription factor MITF, intrinsically resistant cell lines and biopsies displayed low MITF expression but higher levels of NF-κB signaling and the receptor tyrosine kinase AXL. In vitro, these MITF-low/NF-κB-high melanomas were resistant to inhibition of RAF and MEK, singly or in combination, and ERK. Moreover, in cell lines, NF-κB activation antagonized MITF expression and induced both resistance marker genes and drug resistance. Thus, distinct cell states characterized by MITF or NF-κB activity may influence intrinsic resistance to MAPK pathway inhibitors in BRAF(V600)-mutant melanoma.\Question: Does a melanoma cell state distinction influence sensitivity to MAPK pathway inhibitors?

SOLUTION:
Although most BRAF(V600)-mutant melanomas are sensitive to RAF and/or MEK inhibitors, a subset fails to respond to such treatment. This study characterizes a transcriptional cell state distinction linked to MITF and NF-κB that may modulate intrinsic sensitivity of melanomas to MAPK pathway inhibitors.