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: Aggrecanase cleavage at the 392Glu-393Ala bond in the interglobular domain (IGD) of aggrecan, releasing N-terminal 393ARGS fragments, is an early key event in arthritis and joint injuries. Here, we use a quantitative immunoassay of aggrecan ARGS neoepitope fragments in human synovial fluid to determine if this cleavage-site specific method better identifies joint pathology than previously available less specific aggrecan assays.', 'Synovial fluid (SF) from 26 people with healthy knees (reference) and 269 patients were analyzed in a cross-sectional study. Patient groups were acute inflammatory arthritis, acute knee injury, chronic knee injury and knee osteoarthritis (OA). Aggrecan ARGS fragments were assayed by ELISA using the monoclonal antibody OA-1. Total aggrecan content was analyzed by an ELISA using the monoclonal antibody 1-F21, and sulfated glycosaminoglycan by Alcian blue precipitation.', 'Aggrecan ARGS fragment concentrations in all groups differed from the reference group (P < 0.001). The acute inflammatory arthritis group had the highest median level, 177-fold greater than that of the reference group. Median levels (in pmol ARGS/ml SF) were: reference 0.5, acute inflammatory arthritis 88.5, acute knee injury 53.9, chronic knee injury 0.5 and OA 4.6. In contrast, aggrecan and sulfated glycosaminoglycan concentrations varied much less between groups, and only acute inflammatory arthritis and acute knee injury were found to have a two-fold increase in median levels compared to the reference.
Answer: Levels of aggrecan ARGS fragments in human synovial fluid are increased in human arthritis, OA and after knee injury, likely reflecting an enhanced cleavage at the 392Glu-393Ala bond in the IGD by aggrecanase. An assay that specifically quantified these fragments better distinguished samples from joints with pathology than assays monitoring aggrecan or glycosaminoglycan concentrations. The newly developed ARGS fragment assay can be used to monitor aggrecanase activity in human joint disease and experimental models.
Is synovial fluid level of aggrecan ARGS fragments a more sensitive marker of joint disease than glycosaminoglycan or aggrecan levels : a cross-sectional study?

Context: Recently, the Arg389Gly beta1-adrenoceptor (beta1AR) gene polymorphism has been detected. The Arg variant exhibited increased responsiveness to agonist-induced stimulation in vitro. Functional studies in isolated human atrial muscle strips and in-vivo studies revealed contradictory results regarding the functional relevance of this polymorphism. We sought to characterize the functional consequences of the Arg389Gly beta1-AR polymorphism in 30 consecutive healthy male volunteers in vivo.', 'beta1-AR genotype was determined by PCR and restriction analysis, which was confirmed by DNA sequencing. We compared heart rate, blood pressure, and contractile response of the various genotype carriers with a modified dobutamine stress echocardiography protocol.', 'Subjects homozygous for the Arg389 beta1AR showed a significantly higher increase in fractional shortening upon cumulative doses of dobutamine as compared to subjects carrying one or two copies of the Gly389 allele. A statistically significant difference was observed at a dobutamine dose of 10 microg/kg/min (46.5 +/- 1.3 vs. 41.8 +/- 1.0 %; P = 0.023) and was maximal at 40 microg/kg/min (61.9 +/- 1.4 vs. 52.8 +/- 1.6; P = 0.001). As a result, the systolic blood pressure response to dobutamine was significantly enhanced in individuals homozygous for the Arg389 allele, whereas the effect on heart rate did not differ between the two groups. Normalization for changing afterload conditions by calculating the pressure-dimension ratio revealed similar effects, indicating that the beta1AR-mediated effects are mainly a result of increased myocardial inotropy.
Answer: These data indicate that the Arg389Gly beta1AR polymorphism is functionally relevant in vivo and determines contractile responsiveness to catecholamines in humans.
Does the Arg389Gly beta1-adrenoceptor gene polymorphism determine contractile response to catecholamines?

Context: Recent data provide evidence of a systemic inflammatory response in severe acute pancreatitis; in contrast, the exact immune mechanisms underlying chronic pancreatitis remain unclear.', 'To investigate the immune response in the clinical features of chronic pancreatitis, we investigated the gene expression of tumor necrosis factor-alpha (TNF-alpha), tumor necrosis factor receptor (TNFR)-p55 and -p75 and inducible nitric oxide synthase (iNOS) in peripheral blood mononuclear cells (PBMC) of 18 patients with late-stage alcoholic chronic pancreatitis of different disease activity (Balthazar criteria).', 'Semiquantitative reverse transcriptase-polymerase chain reaction revealed a significantly enhanced gene expression of TNF-alpha (P < 0.05), TNFR-p55 (P < 0.05) and TNFR-p75 (P < 0.01) in unstimulated PBMC of patients with advanced chronic pancreatitis (11/18 with calcifications) compared to healthy controls (n = 8). No significant difference was found between patients with mild acute pancreatitis and patients with an inactive quiescent pancreatitis. Moreover, no expression of inducible nitric oxide synthase was detectable.
Answer: The enhanced gene expression of TNFR-p75, TNFR-p55 and TNF-alpha in unstimulated PBMC demonstrates an enhanced leucocyte activation in patients with late-stage chronic pancreatitis and suggests a pathogenetic role of the cytotoxic TNF-alpha pathway in the clinical features of alcoholic chronic pancreatitis. The pathogenetic role of nitric oxide in chronic pancreatitis remains to be fully elucidated.

Does cytokine gene expression in peripheral blood mononuclear cells reflect a systemic immune response in alcoholic chronic pancreatitis?