Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.

Input: Consider Input: Abstract: Fat cells were isolated from sedentary and exercise trained female Sprague-Dawley rats and cyclic AMP phosphodiesterase (cyclic AMP-PDE) activities were determined from crude homogenates of the fat cells in the whole homogenate, P5, P48, and S48 fractions. Exercise training resulted in a significant increase in the mean specific activity of cyclic AMP-PDE (pmol X min-1 X mg-1) from the whole homogenate and S48 fraction at cyclic AMP concentrations of 4, 8, and 16 microM and in the P48 fraction at 8 and 16 microM cyclic AMP. Cyclic AMP-PDE kinetic plots according to Lineweaver-Burk for the calculation of Michaelis constants (Km) and maximum enzyme velocities (Vmax) were nonlinear, indicating both a low and high enzyme form. The Michaelis constants were significantly lower in trained rats than those of its control for the high Km form of cyclic AMP-PDE in the whole and soluble fractions and for the low Km form of the P5 particulate fraction. The Vmax of the high Km form of the P48 particulate fraction from trained animals was also significantly higher than that found in its control. Phosphodiesterase inhibition by methylxanthines in the various fractions was similar in both trained and sedentary animals. These changes in specific activity, Michaelis constants, and Vmax of cyclic AMP-PDE from crude homogenates of isolated fat cells from exercise trained animals may account for the decreased intracellular levels of cyclic AMP following catecholamine stimulation of isolated fat cells from trained rats.

Output: Distribution of cyclic AMP phosphodiesterase in adipose tissue from trained rats.

Input: Consider Input: Abstract: Progression of coronary artery stenosis was measured using a quantitative, computer-assisted cinevideodensitometric method in 144 arterial segments in 44 subjects undergoing coronary arteriography on two separate occasions at least 6 months apart. Projected coronary arteriograms were digitized into 512 X 512 pixel mode and percent stenosis was calculated by comparing background-corrected videodensitometric values over stenotic and normal segments. Subjects underwent repeat coronary arteriography because of worsening symptoms of angina or heart failure; subjects with renal failure, coronary artery bypass grafts or cardiac transplant were excluded. Clinical variables determined at the time of the first arteriogram included age, sex, serum cholesterol, systolic blood pressure and presence or absence of cigarette smoking, diabetes mellitus and left ventricular hypertrophy. The mean interval between arteriograms was 29.3 months. Overall progression of coronary stenosis was observed in 40 of the 44 subjects; the mean progression at 24 months was 39% (90% confidence interval, 33 to 45%) and at 36 months was 48% (40 to 56%). The degree of overall progression was related to the length of time between arteriograms (F = 5.81, p less than 0.05) and to serum cholesterol level (F = 4.37, p less than 0.05). These data indicate that using an accurate, quantitative method, it is possible to measure progression of coronary artery atherosclerosis within 2 to 3 years of the initial arteriogram. Serum cholesterol appears to be an important determinant of disease progression.

Output: Progression of coronary atherosclerotic disease assessed by cinevideodensitometry: relation to clinical risk factors.

Input: Consider Input: 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.
Output: United States citizens studying medicine abroad. Their backgrounds and test performance.