Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

Example Input: Abstract: The T-cell antigen receptor binds antigen in association with a cell surface molecule encoded by the major histocompatibility complex (MHC). MHC restricted recognition of antigen by this receptor leads to the complex pattern of programmed gene expression that characterizes T-cell activation. The eventual understanding of human T-cell function will require the complete elucidation of the structure of the human T-cell antigen receptor. On human T cells, clonally determined, disulphide-linked alpha and beta chains of the receptor are non-covalently and stoichiometrically associated with three additional polypeptides known as the T3 complex. These receptor subunits are glycoproteins of relative molecular mass (Mr) 25,000 (25K) and 20K (gamma and delta) and a non-glycosylated 20K protein (epsilon). Our studies of murine T cells show that the mouse T-cell antigen receptor consists of at least seven distinct polypeptide chains. In addition to clonotypic alpha and beta chains, the murine complex consists of glycoproteins of 26K and 21K and endoglycosaminidase F (endo F)-insensitive polypeptides of 25K, 21K and 16K. The latter, which we have termed zeta (zeta), exists as a homodimer within the complex. The 26K component (gp26) has been shown to be the murine analogue of the human delta chain. Other cross species homologies remain to be established, however none of the described human receptor components appear similar to the murine zeta polypeptide. We report here the use of an antiserum raised against the murine zeta subunit to identify a previously unrecognized component of the human T-cell antigen receptor. This human protein is T-cell specific and biochemically similar to the murine zeta polypeptide.
Example Output: Animal

Example Input: Abstract: An 87-year-old woman presented with the nephrotic syndrome 12 months after administration of ketoprofen, 100 mg daily for osteoarthritis. Clinical course and laboratory data were consistent with drug-induced nephropathy. Kidney biopsy showed membranous glomerulonephritis. Evolution was favorable with resolution of proteinuria after drug withdrawal and steroid administration. A review of the literature on nephrotic syndrome associated with NSAID reveals membranous glomerulonephritis to be an unusual complication.
Example Output: Aged

Example Input: Abstract: In recent years it has become increasingly apparent that cough is frequently the sign of airway hyperreactivity. While the association between cough and wheezing is well recognized in asthmatics, cough may be the only clinical manifestation of this problem. Emergency physicians frequently have occasion to evaluate the coughing patient. Awareness of this clinical entity should facilitate appropriate evaluation, management, and referral of these patients.
Example Output:
Airway Obstruction