instruction:
Given a passage, 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.
question:
Dengue is a mosquito-borne viral disease caused by the four dengue viruses (DENV-1 to 4) that can also be transmitted by blood transfusion and organ transplantation. The distribution of DENV in the components of blood from infected donors is poorly understood.', 'We used an in-house TaqMan qRT-PCR assay to test residual samples of plasma, cellular components of whole blood (CCWB), serum and clot specimens from the same collection from blood donors who were DENV-RNA-reactive in a parallel blood safety study. To assess whether DENV RNA detected by TaqMan was associated with infectious virus, DENV infectivity in available samples was determined by culture in mosquito cells.', 'DENV RNA was detected by TaqMan in all tested blood components, albeit more consistently in the cellular components; 78.8% of CCWB, 73.3% of clots, 86.7% of sera and 41.8% of plasma samples. DENV-1 was detected in 48 plasma and 97 CCWB samples while DENV-4 was detected in 21 plasma and 31 CCWB samples. In mosquito cell cultures, 29/111 (26.1%) plasma and 32/97 (32.7%) CCWB samples were infectious. A subset of samples from 29 donors was separately analyzed to compare DENV viral loads in the available blood components. DENV viral loads did not differ significantly between components and ranged from 3-8 log10 PCR-detectable units/ml.
answer:
Does distribution of Dengue Virus type 1 and 4 in Blood Components from Infected Blood Donors from Puerto Rico?


question:
Vascular endothelial growth factor (VEGF) has been well documented to stimulate cell proliferation and differentiation; however, we have observed that copper (Cu)-induced regression of heart hypertrophy was VEGF-dependent. The present study was undertaken to test the hypothesis that Cu causes alterations in the distribution of VEGF receptors (VEGFRs) in hypertrophic cardiomyocytes so that it switches the signalling pathway from stimulation of cell growth to reversal of cell hypertrophy.', 'Primary cultures of neonatal rat cardiomyocytes were exposed to phenylephrine (PE) at a final concentration of 100 microM in cultures for 48 h to induce cell hypertrophy. The hypertrophic cardiomyocytes were exposed to copper sulfate at a final concentration of 5 microM in cultures for 24 h with a concomitant presence of PE. Flow cytometry, gene silencing, and ELISA procedures were used to analyse the changes in VEGFRs and their relationship with regression of cardiomyocyte hypertrophy. Cu did not change the concentration of VEGF in culture media, but increased the ratio of VEGFR-1 to VEGFR-2 two-fold. Gene silencing of VEGFR-2, in the absence of Cu addition, reversed PE-induced cardiomyocyte hypertrophy, which was suppressed by an anti-VEGF antibody. Gene silencing of VEGFR-1 blocked Cu-induced regression of cell hypertrophy and decreased the activity of cGMP-dependent protein kinase-1 (PKG-1). A PKG-1 antagonist, Rp-8-pCPT-cGMPS, blocked both Cu- and VEGFR-2 gene silencing-induced regression of cardiomyocyte hypertrophy.
answer:
Is copper-induced regression of cardiomyocyte hypertrophy associated with enhanced vascular endothelial growth factor receptor-1 signalling pathway?


question:
To determine if oligosaccharides of hyaluronan (o-HA) promotes wound recovery by accelerating angiogenesis and to study the mechanisms by which o-HA stimulates endothelial cell (EC) proliferation.', 'Using hyaluronidase digestion, we prepared a mixture of hyaluronan (HA) fragments sizesd 2 to 10 disaccharides units, and studied their effects on EC growth and migration in mimicking wound recovery in vitro. The effects of o-HA on EC growth in vitro were studied by counting cell numbers. The roles of 2 hyaluronan receptors on EC cells, CD44 and RHAMM (Receptor for HA-Mediated Motility), were studied in initiating signaling cascades, using immunoblot assay. Signal transduction was determined by blocking antibodies to CD44 and RHAMM. An in vitro wound healing model was prepared by scratching the cellular layer of cultured EC, and movement of cells into the denuded area was quantified.', 'o-HA was a strong stimulator to EC proliferation at low concentration 10microg/ml compared with native high molecular weight HA (n-HA) (P < 0.01). Signal transduction may be initiated by o-HA via RHAMM receptor on EC membrane, but not CD44. In the in vitro model, the lesion area was nearly completely recovered when the EC layer was exposed to o-HA 40hrs post-injury, whereas the wound area remained half recovered pretreated with native undegraded large HA and control medium.(P < 0.05 from 24 to 40hrs).
answer:

Are hyaluronan oligosaccharides potential stimulators to angiogenesis via RHAMM mediated signal pathway in wound healing?