Given an abstract, indicate which of the provided candidate titles (Option1 and Option2) best describes it (respond with the text of the title, not option1/2).

[Q]: Abstract: Physical activity has been associated with reduced risk of coronary heart disease. A mechanism for the reduced risk may be through increased high density lipoprotein cholesterol (HDL-C) and subfractions, in particular HDL2-C. Research associated with increased physical activity investigating HLD-C have assessed the effects of intense aerobic activity. The current research evaluated the relationship between low intensity, long duration activity to HDL-C and subfractions in 35 active postal carriers. Measurements of physical activity via the Large Scale Integrated monitor and reported miles walked, and lipoproteins were assessed at 3-month intervals over a 1-year period. Reported miles walked/day (5.3) was significantly correlated with HLD2-C (r = 0.50, P = 0.003) and approached significance for HDL-C (r = 0.29, P = 0.06). The Large Scale Integrated measures were correlated with HDL-C (r = 0.44, P = 0.008) and HDL2-C (r = 0.44, P = 0.007). Controlling for either age, alcohol consumption, body mass index, or leisure time activity did not reduce the relationship between reported miles walked or Large Scale Integrated readings and HDL2-C, suggesting that the increased HDL-C was the result of long duration, low intensity physical activity.
Which is the apt title for the abstract? option1: Chronic low level physical activity as a determinant of high density lipoprotein cholesterol and subfractions. option2: Levotransposition of the aorta: identification of segmental cardiac anatomy using MR imaging.
[A]: Chronic low level physical activity as a determinant of high density lipoprotein cholesterol and subfractions.

[Q]: Abstract: Following nephrectomy and acute potassium loading, animals previously maintained on a high potassium diet have a smaller increment in plasma potassium than do animals on a control diet. The mechanism of this "extrarenal potassium adaptation" is not known. To explore the role of potassium depletion in this process, we studied rats adapted to either a high potassium (HK) or control (C) diet. When dietary potassium was withdrawn, urinary potassium losses in HK rats greatly exceeded those in C rats for at least two days, leading to greater potassium depletion in HK than C animals. A smaller increment in plasma potassium in HK compared to C rats was seen only after prolonged fasting preceded nephrectomy and acute potassium loading. Correction of potassium depletion incurred during fasting abolished extrarenal potassium adaptation. We conclude: after withdrawal of dietary potassium, urinary potassium losses are much greater in HK than in C rats; if the duration of dietary potassium deprivation is sufficient, these urinary potassium losses will cause potassium-adapted animals to paradoxically become more potassium depleted than controls; and this paradoxical potassium depletion may be responsible for extrarenal potassium adaptation.
Which is the apt title for the abstract? option1: Paradoxical potassium depletion: a renal mechanism for extrarenal potassium adaptation. option2: A point-source epidemic of leptospirosis. Description of cases, cause, and prevention.
[A]: Paradoxical potassium depletion: a renal mechanism for extrarenal potassium adaptation.

[Q]: Abstract: The results of forty core-decompression procedures that were performed for ischemic necrosis of the femoral head in thirty-one patients over a four-year period were retrospectively reviewed to ascertain the effectiveness of the procedure. The data did not support the published rates of success of the procedure for Stage-1 and Stage-2 lesions. With a mean length of follow-up of eighteen months, 60 per cent of the hips that had a decompression prior to collapse of the femoral head demonstrated progression of the lesion and were judged to be a failure by clinical or radiographic criteria. Computerized tomographic scans and magnetic resonance imaging proved to be 100 per cent sensitive for diagnosis in preoperative testing; isotopic bone-scanning was less sensitive (80 per cent). Functional intraoperative testing by the method of Ficat did not provide added sensitivity or specificity to the results of the preoperative bone scan. A postoperative or intraoperative fracture occurred in four hips, for an incidence that exceeded any in previously published reports. We concluded that core decompression should be considered a relatively ineffective procedure with significant morbidity.
Which is the apt title for the abstract? option1: Core decompression of the femoral head for osteonecrosis. option2: Primary gastrointestinal lymphoma incidence, clinical presentation, and surgical approach.
[A]:
Core decompression of the femoral head for osteonecrosis.