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.

Context: Frontotemporal dementia is a neurodegenerative disease affecting mostly the frontal and/or temporal lobes, with neuronal loss and intraneuronal and/or intraglial inclusions composed of hyperphosphorylated microtubule-associated protein tau and ubiquitin. Missense and splice site mutations in the TAU gene have been identified in approximately 15% of all frontotemporal dementia cases. In this study, we evaluated the involvement of mutations in the TAU gene in development of frontotemporal dementia phenotype in patients of French or English Canadian origins.', 'Fourteen patients with frontotemporal dementia phenotype and 98 normal controls were recruited for the study. The TAU gene was screened by sequencing and denaturing high performance liquid chromatography.', 'No mutations, except some new polymorphisms, were detected in the TAU gene of these patients. One polymorphism, however, may play a role in pathogenesis.
Answer: Our results agree with previous work suggesting that mutations in this gene are not a frequent cause of the frontotemporal dementia phenotype in Canadian patients.
Are tAU mutations a predominant cause of frontotemporal dementia in Canadian patients?

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.
Answer: 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.
Is the activity of camptothecin analogues enhanced in histocultures of human tumors and human tumor xenografts by modulation of extracellular pH?

Context: R136K is a mutation of fibroblast growth factor-1 (FGF-1) in which arginine replaces lysine at the primary thrombin cleavage site. This may be important in vivo in inducing endothelial cell (EC) migration and coverage of arterial injury sites by allowing R136K to be used in a fibrin glue delivery system, without thrombin-induced degradation, in the absence of heparin. The objectives of this study were to determine whether R136K, with and without heparin, can induce migration of EC and smooth muscle cells (SMC) through fibrin glue, and to compare these results with those of wild-type FGF-1; and to determine the resistance of R136K to thrombin-induced degradation versus FGF-1.', 'The dose-response migration through fibrin glue induced by wild-type FGF-1 and the R136K mutant in the presence and absence of heparin was tested with EC and SMC. Migration was tested with 50, 100, and 200 ng/mL of both FGF-1 and R136K, either with or without 5 U/mL of heparin. Migration of EC was also assessed after growth inhibition with mitomycin C. A novel modified Boyden chamber-type migration assay using fibrin glue on the upper surface of the chamber filter was used to test migration. The fluorescent marker calcein was used to identify those cells that had migrated through the fibrin glue and were embedded in the filter. Molecular degradation by thrombin was assessed with sodium dodecylsulfate polyacrylamide gel electrophoresis.', 'For EC, R136K in the absence of heparin induced significantly more migration than did FGF-1 at 50 (P <.002), 100 (P <.0001), and 200 (P <.0001) ng/mL. In the presence of heparin, a chemotactic response of EC to cytokine was seen at all doses, with no significant difference between FGF-1 and R136K. A dose-dependent difference was noted in this group between the 100 and 200 ng/mL concentrations of cytokine (for FGF-1, P <.0001; for R136K, P <.0001). SMC showed no difference in migration with FGF-1, R136K, or negative control at any dose in the presence or absence of heparin. Gel electrophoresis demonstrated that R136K was more resistant to thrombin degradation than was FGF-1.
Answer: Site-directed mutagenesis of FGF-1 to R136K enables induction of heparin-independent migration of EC through fibrin glue at an optimal concentration of 100 ng/mL. Neither FGF-1 nor R136K elicits SMC migration through fibrin glue. The ability of R136K to induce EC migration through fibrin glue in the absence of heparin may prove useful in vivo by inducing EC migration and coverage of arterial injury sites, thus potentially reducing thrombogenicity and intimal hyperplasia.

Does r136K fibroblast growth factor-1 mutant induce heparin-independent migration of endothelial cells through fibrin glue?