user: 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.
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Question: Abstract: Osteoarthrosis is a physiologic imbalance, a "joint failure" similar to "heart failure," in which mechanical factors play a role. The initiation and progression of cartilage damage are distinct phenomena. One of the mechanisms of initiation may be a steep stiffness gradient in the underlying subchondral bone. Progression of cartilage lesions probably requires stiffened subchondral bone. In such situations, transverse stresses at the base of the articular cartilage could cause deep horizontal splits in that tissue. The most likely cause of subchondral stiffening in an otherwise congruent joint is repeated failure of the musculoskeletal peak dynamic force attenuation mechanisms. The health and integrity of the overlying articular cartilage depends on the mechanical properties of its bony bed. In certain models of osteoarthrosis, alterations of the bony bed occur before the cartilage changes and suggest that this can occur in clinical conditions. Stiffening of the subchondral bone also can effect joint conformation, which involves deformation of articular cartilage and bone to create maximum contact areas under load.

Answer: Animal


Question: Abstract: From a large series of patients referred for endoscopic retrograde cholangiopancreatography to one endoscopist, 49 patients had the duodenoscopic appearance of a periampullary tumour. Thirty eight of these lesions were neoplastic, but the remaining 11 patients had inflammatory non-neoplastic lesions (pseudotumours). These could not be distinguished from the neoplasms on endoscopic appearances. The cholangiopancreatograms were similar except that the diameter of the pancreatic duct tended to be higher in the tumour group and gall stones were present significantly more often in the patients with pseudotumour. Endoscopic biopsy correctly diagnosed 28 of 34 ampullary carcinomas. Two of the 11 pseudotumour patients were subjected to surgical excision biopsy because of suspicious histological features of endoscopic biopsy. In the neoplastic group 19 patients underwent Whipple's procedure, seven surgical bypass, seven endoscopic sphincterotomy only and five died without successful biliary drainage. The overall one year survival was 44.7%. By contrast, the patients with pseudotumours were clinically well at a median follow up 24 months (range 12-41 months), after endoscopic sphincterotomy except for one 89 year old patient who died 22 months later from unrelated causes.

Answer: Adult


Question: Abstract: To evaluate the efficacy of a mild anxiolytic, alprazolam, in relieving dyspnea, we conducted a randomized, placebo-controlled double-blind study on patients with chronic obstructive lung disease. Twenty-four patients had alprazolam (0.5 mg bid) or placebo administered for one week, followed by placebo for one week, then either placebo or alprazolam for the third week. Assessment tests were performed at the outset, end of the first and second weeks, and finally end of the third week. The parameters measured were: pulmonary function, exercise testing on a bicycle ergometer, and the distance covered in a 12 minute walk. Subjective sensations of dyspnea at rest and during guarded exercise, as well as subjective feelings of calmness or anxiety were also recorded. There was no difference in mechanical lung function, but the PO2 tended to decrease and PCO2 to increase after alprazolam administration. The maximum exercise level attained and the distance covered in the 12 minute walk was unchanged. The subjective perception of dyspnea was the same before and after alprazolam, at rest and during exercise. We conclude that alprazolam is not effective in relieving exercise dyspnea in patients with obstructive lung disease.

Answer:

assistant: Aged