TASK DEFINITION: Given a passage with a context and an answer, 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.
PROBLEM: Context: Photodynamic therapy (PDT) is linked with oxidative damage of biomolecules causing significant impairment of essential cellular functions that lead to cell death. It is the reason why photodynamic therapy has found application in treatment of different oncological, cardiovascular, skin and eye diseases. Efficacy of PDT depends on combined action of three components; sensitizer, light and oxygen. In the present study, we examined whether higher partial pressure of oxygen increases lethality in HeLa cell lines exposed to light in the presence of chloraluminium phthalocyanine disulfonate (ClAlPcS2).', 'ClAlPcS2- sensitized HeLa cells incubated under different oxygen conditions were exposed to PDT. Production of singlet oxygen ((1)O2) and other forms of reactive oxygen species (ROS) as well as changes in mitochondrial membrane potential were determined by appropriately sensitive fluorescence probes. The effect of PDT on HeLa cell viability under different oxygen conditions was quantified using the standard methylthiazol tetrazolium (MTT) test.', 'At the highest oxygen concentration of 28 ± 2 mg/l HeLa cells were significantly more sensitive to light-activated ClAlPcS2 (EC50=0.29 ± 0.05 μM) in comparison to cells incubated at lower oxygen concentrations of 8 ± 0.5 and 0.5 ± 0.1 mg/l, where the half maximal effective concentration was 0.42 ± 0.06 μM and 0.94 ± 0.14 μM, respectively. Moreover, we found that the higher presence of oxygen is accompanied with higher production of singlet oxygen, a higher rate of type II photodynamic reactions, and a significant drop in the mitochondrial membrane potential.
Answer: These results demonstrate that the photodynamic effect in cervical cancer cells utilizing ClAlPcS2 significantly depends on oxygen level.

SOLUTION: Does high oxygen partial pressure increase photodynamic effect on HeLa cell lines in the presence of chloraluminium phthalocyanine?

PROBLEM: Context: Previous studies have suggested that post-irradiation GH insufficiency results from a loss of GHRH secretion, since many patients were able to release GH following exogenous GHRH stimulation. However, supramaximal doses of GHRH were used and the response may decline with time after radiotherapy. We re-evaluated the GHRH dose-response curve in patients post cranial irradiation and in controls.', 'Randomized controlled study.', 'Five adult male long-term survivors of childhood brain tumours (median age 21.8 years (18.4-26.7); 13.7 years (11.4-15.7) post-radiotherapy, >30Gy) and five matched controls were studied. An intravenous bolus of GHRH(1-29)NH(2) was administered in doses at the lower (0.05 microg/kg) and upper (0.15 microg/kg) range of the dose-response curves for young males, as well as the standard supramaximal dose (1. 0 microg/kg). GH was measured before stimulation, every 2min for the first hour and every 5min for the second hour. All studies were conducted in a random fashion.', 'Significantly lower peak and area under the curve (AUC) GH concentrations occurred in the irradiated group using 0.15 microg/kg (median peak Irradiated, 4. 5mU/l vs median Controls, 37.4mU/l; P<0.01) and 1.0 microg/kg (median peak Irradiated, 4.8mU/l vs median Controls, 15.2mU/l; P<0. 05) GHRH(1-29)NH(2). In irradiated subjects there was an incremental rise in GH output with increasing doses of GHRH(1-29)NH(2 )(median AUC: 122mU/l.min vs 179mU/l.min vs 268mU/l.min; P=0.007) reflecting altered pituitary sensitivity and reduced responsiveness.
Answer: The GH response to bolus GHRH(1-29)NH(2) is attenuated in adult long-term survivors of childhood brain tumours. This may reflect direct pituitary damage and/or the loss of the tropic effects of chronic GHRH deficiency.

SOLUTION: Is the GH response to low-dose bolus growth hormone-releasing hormone ( GHRH ( 1-29 ) NH2 ) attenuated in patients with longstanding post-irradiation GH insufficiency?

PROBLEM: Context: The clinical significance of chemokine receptor CCR7 expression in pancreatic ductal cancer was investigated.', 'Immunohistochemical staining of 89 pancreatic cancers treated macroscopically with curative resection without hematogenous metastases or peritoneal dissemination were analyzed in association with clinicopathological data.', 'The positivity of CCR7 in pancreatic cancer was 32.6% (29/89). A significant correlation was detected between CCR7-positive expression and lymph node metastasis. Patients with CCR7-positive tumors had significantly shorter survival times than those with CCR7-negative tumors (median, 12.8 vs. 21.9 months, respectively; p = 0.0039). CCR7 expression was an independent prognostic factor (hazard ratio, 1.949; p = 0.0364) by multivariate survival analysis; however, it was not an indicator for any particular site of recurrence.
Answer: The survival impact of CCR7 expression on resectable pancreatic cancer may be associated with lymphatic spread. The results from the present study should foster further investigation of treatments using an inhibitor for the CCR7 protein to improve the survival of pancreatic cancer.

SOLUTION:
Does chemokine receptor CCR7 expression correlate with lymph node metastasis in pancreatic cancer?