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: Cysteine, a sulfur-containing amino acid, plays an important role in a variety of cellular functions such as protein biosynthesis, methylation, and polyamine and glutathione syntheses. In trypanosomatids, glutathione is conjugated with spermidine to form the specific antioxidant thiol trypanothione (T[SH]2) that plays a central role in maintaining intracellular redox homeostasis and providing defence against oxidative stress.', 'We cloned and characterised genes coding for a cystathionine -synthase (CS) and cysteine synthase (CS), key enzymes of the transsulfuration and assimilatory pathways, respectively, from the hemoflagellate protozoan parasite Trypanosoma rangeli.', 'Our results show that T. rangeli CS (TrCS), similar to its homologs in T. cruzi, contains the catalytic domain essential for enzymatic activity. Unlike the enzymes in bacteria, plants, and other parasites, T. rangeli CS lacks two of the four lysine residues (Lys26 and Lys184) required for activity. Enzymatic studies using T. rangeli extracts confirmed the absence of CS activity but confirmed the expression of an active CS. Moreover, CS biochemical assays revealed that the T. rangeli CS enzyme also has serine sulfhydrylase activity.
Answer: These findings demonstrate that the RTS pathway is active in T. rangeli, suggesting that this may be the only pathway for cysteine biosynthesis in this parasite. In this sense, the RTS pathway appears to have an important functional role during the insect stage of the life cycle of this protozoan parasite.

SOLUTION: Is transsulfuration an active pathway for cysteine biosynthesis in Trypanosoma rangeli?

PROBLEM: Context: The aim of this study was to visualize early stage prostate cancer (Cap) in a clinical setting. In previous studies, the results of magnetic resonance imaging (MRI) for screening Cap have rarely been confirmed by well-designed multisite prostate biopsy.', 'The prostate glands of 90 men with elevated prostate-specific antigen (PSA) were imaged by dynamic contrast-enhanced MRI (DCE-MRI) before transrectal ultrasound-guided 14-cores prostate biopsy. Each core was divided into three subcore fractions (total of 42 fractions) to generate a histological localization diagram, which was compared with localization-visualized DCE-MRI.', "The detection rate of Cap in 57 patients with PSA < 10.0 ng/ml was 36.8% as determined by the initial biopsy. DCE-MRI uncovered 92.9% of the clinically significant Caps and its specificity was 96.2% for the first biopsy session. One case with positive DCE-MRI and a negative primary biopsy was positive with additional biopsies. All of 26 DCE-MRI positive cases had significant Cap, and two of eight patients with histological Cap and negative or equivocal imaging had significant cancer. In total, 9 of 20 cases with DCE-MRI stage T2 underwent radical prostatectomy. All of them had organ-confined disease, although 33-77% (mean 63%) of them were expected to be rated T3 or higher by Partin's table.
Answer: DCE-MRI can identify early stage Cap with high sensitivity and specificity, and can predict the histological grade to some extent. DCE-MRI prior to biopsy should be applied to younger patients with surgical indications. Otherwise, we recommend the definitive diagnosis of Cap by utilizing DCE-MRI alone.

SOLUTION: Is dynamic contrast-enhanced magnetic resonance imaging ( DCE-MRI ) a useful modality for the precise detection and staging of early prostate cancer?

PROBLEM: Context: This study was to investigate whether the expression of a disintegrin and metalloproteinase-9 (ADAM9) is correlated with the expression of hepatoma-derived growth factor (HDGF) in surgically resected non-small cell lung cancer (NSCLC), to evaluate the significance of HDGF and ADAM9 as novel molecular staging biomarkers, prognostic biomarkers and predictive biomarkers for postoperative adjuvant chemotherapy in surgically resected stage I NSCLC, to provide essential consistence proof to the possible novel pathway of HDGF-ADAM9 pathway.', 'Sixty-three cases of resected stage I NSCLC with mediastinal N2 lymph node dissection were immunohistochemically analyzed for HDGF and ADAM9 protein expression. Multivariate analysis and survival analysis were conducted.', "HDGF and ADAM9 were observed highly expressed in NSCLC compared with normal control lung tissues (P < 0.05). HDGF high expression cases showed significantly lower survival rate (55.6 vs. 84.7 %, P = 0.009). HDGF high expression was an independent factor of shortened survival time in resected stage I NSCLC (P = 0.015). ADAM9 high expression cases showed significantly lower survival rate (56.9 vs. 88.7 %, P = 0.015). ADAM9 high expression was an independent factor of shortened survival time in resected stage I NSCLC (P = 0.021). Pearson's correlation analysis revealed that ADAM9 expression was correlated positively and significantly with HDGF expression in 63 cases of stage I NSCLC (r = 0.547, P = 0.000).
Answer: These results clearly demonstrate that ADAM9 high expression is correlated positively and significantly with HDGF high expression, which provides essential evidence for the novel HDGF-ADAM9 pathway, through which HDGF promotes invasion and metastasis of NSCLC cells; HDGF and ADAM9 are novel molecular staging biomarkers, prognostic biomarkers, which might become useful predictive biomarkers for the selection of postoperative adjuvant chemotherapy treatment in surgically resected stage I NSCLC.

SOLUTION:
Are hDGF and ADAM9 novel molecular staging biomarkers , prognostic biomarkers and predictive biomarkers for adjuvant chemotherapy in surgically resected stage I non-small cell lung cancer?