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:
The SARS coronavirus (SARS-CoV) 3a protein functions as an ion channel, induces apoptosis and is important for viral pathogenesis. It is expressed on the cell surface and contains a tyrosine-based sorting motif and a di-acidic motif, which may be crucial for its intracellular trafficking. However the role of these motifs is not fully understood in the case of 3a protein.', 'The subcellular distribution of the 3a protein was studied by immunofluorescence staining of cells transfected with wild type and mutant constructs along with markers for different intracellular compartments. Semi-quantitative RT-PCR was performed to estimate the mRNA where as western blotting was carried out to detect protein levels of wild type and mutant 3a proteins. In vitro transcription- translation was performed to estimate cell free protein synthesis.', 'While the wild type 3a protein is efficiently transported to the plasma membrane, the protein with mutations in the tyrosine and valine residues within the YXXV motif (YXX) accumulated in the Golgi compartment. However the 3a protein with mutations within the EXD di-acidic motif (EXD) showed an intracellular distribution similar to the wild type protein. Increased retention of the YXX protein in the Golgi compartment also increased its association with lipid droplets. The YXX protein also expressed at significantly lower levels compared to the wild type 3a protein, which was reversed with Brefeldin A and Aprotinin.
answer:
Is the YXX motif within the severe acute respiratory syndrome coronavirus ( SARS-CoV ) 3a protein crucial for its intracellular transport?

question:
To describe the variability in rheumatology visits and referrals to other medical specialties of patients with spondyloarthritis (SpA) and to explore factors that may influence such variability.', 'Nation-wide cross-sectional study performed in 2009-2010. Randomly selected records of patients with a diagnosis of SpA and at least one visit to a rheumatology unit within the previous 2years were audited. The rates of rheumatology visits and of referrals to other medical specialties were estimated-total and between centres-in the study period. Multilevel regression was used to analyse factors associated with variability and to adjust for clinical and patient characteristics.', "1168 patients' records (45 centres) were reviewed, mainly ankylosing spondylitis (55.2%) and psoriatic arthritis (22.2%). The patients had incurred in 5908 visits to rheumatology clinics (rate 254 per 100 patient-years), 4307 visits to other medical specialties (19.6% were referrals from rheumatology), and 775 visits to specialised nurse clinics. An adjusted variability in frequenting rheumatology clinics of 15.7% between centres was observed. This was partially explained by the number of faculties and trainees. The adjusted intercentre variability for referrals to other specialties was 12.3%, and it was associated with urban settings, number of procedures, and existence of SpA dedicated clinics; the probability of a patient with SpA of being referred to other specialist may increase up to 25% depending on the treating centre.
answer:
Do centre characteristics determine ambulatory care and referrals in patients with spondyloarthritis?

question:
Potential xenozoonosis is a concern for the clinical application of xenotransplantation. Human cytomegalovirus (HCMV) is one of the most important pathogens in allotransplantation, but the consequences of HCMV cross-species infection of porcine xenografts are unknown. Therefore, we investigated the effects of HCMV infection of porcine endothelial cells (pEC) on cell surface molecule expression and human leukocyte recruitment.', 'Infection of pEC inoculated with untreated, UV-inactivated, or heparin-treated HCMV at a multiplicity of infection (MOI) of 1 was analyzed by immediate early (IE) antigen expression. Cell surface receptor expression was studied by flow cytometry on pEC bulk cultures and differentially on IE-positive and -negative pEC. Adhesion of human leukocytes was tested on pEC monolayers. pEC supernatants were analyzed for cytokine content, chemotactic activity, and stimulatory effect on resting secondary pEC cultures.', 'At day 2 postinfection, IE staining was evident in 10% to 20% of HCMV-infected cells. Cell-surface expression of E-selectin and vascular cell adhesion molecule-1 (VCAM-1) was upregulated in both IE-negative and -positive fractions of HCMV-infected pEC. In contrast, porcine major histocompatibility complex class I expression was upregulated in IE-negative cells, but reduced in IE-positive cells. The receptor alterations in the IE-negative fraction were mediated by pEC-derived soluble factors. The increased adhesion receptor expression was paralleled by enhanced human leukocyte chemotaxis and adhesion to infected pEC cultures. Pretreatment of HCMV with heparin, but not UV-inactivation, prevented adhesion-receptor modulation and reversed the increased adhesion and chemotaxis.
answer:
Does human CMV infection of porcine endothelial cells increase adhesion receptor expression and human leukocyte recruitment?