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.

[Q]: Abstract: A 58-year-old subject with a history of occupational asthma to red-cedar sawdust underwent specific inhalation challenges with this product. Significant increases in airway responsiveness to histamine (tenfold fall in PC20 FEV1) were documented 7 hours after exposure for 5 minutes to red cedar while baseline spirometry remained unchanged. A dual asthmatic reaction was induced during the following days by exposing the subject to red-cedar sawdust for 30 minutes and plicatic acid for 7 minutes. After recovery of PC20, the subject was reexposed to plicatic acid for 15 and 30 seconds on 2 consecutive days. No significant changes in FEV1, forced vital capacity, and residual volume were demonstrated in the following 8 hours, although minimal changes in forced expiratory flow rate between 25% and 75% of FVC were observed. PC20 dropped significantly and required 2 weeks to recover. This example illustrates that bronchial hyperresponsiveness to histamine can precede the changes in airway caliber after an antigen challenge. It also demonstrates that such changes can persist for up to 2 weeks after the challenge, even when no significant changes in FEV1 are induced.
[A]: Airway Resistance

[Q]: Abstract: Instability of the knee is frequently found in association with congenital leg-length discrepancy. We have studied six such patients clinically, radiologically and arthroscopically. Clinical signs of knee instability and significant radiological changes were present in all, and at arthroscopy the anterior cruciate ligament was completely absent in four patients and functionless in the other two. This deficiency appears to be a congenital condition which may predispose to meniscus injury or retropatellar pain; it may also lead to subluxation or dislocation of the knee during leg-lengthening procedures.
[A]: Adolescence

[Q]: Abstract: To acquire information about the characteristics of U.S. citizens who had recently studied medicine abroad, the Educational Commission for Foreign Medical Graduates (ECFMG) and the Association of American Medical Colleges merged independently collected data on a study group of 10,460 U.S. citizens who attended 359 medical schools in 75 foreign countries and who took their first ECFMG examination between 1978 and 1982. The study group was markedly heterogeneous: 21 percent were not U.S. citizens at birth, 32 percent did not have English as a native language, and 12 percent had two or more years of undergraduate college education in Puerto Rico. Sixty-seven percent resided in New York, New Jersey, California, Florida, or Puerto Rico, and 74 percent studied medicine in Mexico or the Caribbean. Forty-six percent passed the ECFMG examination on their first attempt, and 22 percent passed a subsequent examination. Only 45 percent had applied to a U.S. medical school, and 65 percent had taken the Medical College Admission Test. The means of the college grade-point averages, known for 39 percent of the study group, and of the scores on the admission test, known for 65 percent, were lower than those of both accepted and unaccepted applicants to U.S. medical schools in the 1976 and 1978 entering classes. The finding that 55 percent of the study group did not apply to a U.S. medical school does not support the widely held belief that most, if not all, U.S. citizens who attend foreign medical schools do so only after several unsuccessful attempts to gain admission to a U.S. school.
[A]:
Adult