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991.
992.
Lens epithelial cells from rats aged 5 days were grown in long-term cultures. These cells age, differentiate and transform spontaneously. Morphological observations indicate five different stages (A-E). The epithelial character is lost after the first two passages. Elongated cells appearing afterwards are considered as cells that have started differentiation to fiberlike cells. Big flattened cells are considered as senescent cells that have lost theie proliferative capacity. Data from population kinetics also reflect these five stages. Chromosome analysis shows that three of the five stages are no longer diploid. Two alternative modes of spontaneous transformation are possible. The proliferative capacity of rat lens epithelial cells is higher than that of rat embryonic fibroblast systems.  相似文献   
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To evaluate the potential of [1-(11)C]-3-(R,S)-methyloctanoate (BMOA), [1-(11)C]-2-octynoate, and [1-(11)C]-2-decynoate as PET tracers for studying particular steps in fatty acid beta-oxidation, we examined the pharmacokinetics of these compounds in rats and a cat. In rats given these compounds, high levels of radioactivity accumulated in the heart, liver, and kidneys, suggesting their potential as tracers for studying beta-oxidation in these tissues. These organs were clearly visible with PET in a cat given BMOA, indicating the utility of BMOA for imaging these organs.  相似文献   
995.
The usefulness of the fPSA fraction in the differential diagnosis of benign prostate hyperplasia (BPH) and prostate cancer was evaluated, with the aim of improving the diagnostic efficacy of PSA. Serum PSA and fPSA determinations were performed by an enzymoimmunoassay technique on an ES-300 system. fPSA constitutes a minor fraction both in normal subjects and in patients with prostate disease, being significantly lower in patients with untreated prostate cancer than in patients with BPH. Likewise, the authors have observed that the sensitivity of the fPSA/PSA ratio has an inversely proportional relationship with the stage of the disease. The results obtained in patients with PSA levels between 4 and 20 micrograms/l are also of note. In this series of patients, the efficacy of the fPSA/PSA ratio was higher than that of PSA, showing a sensitivity of 44% and a specificity of 95% at the cut-off of 0.08.  相似文献   
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Thallium-201 was found to be a reliable agent for detecting decreased myocardial perfusion in domestic pigs 1-4 hours after acute coronary occlusion. Substantial variation in myocardial-to-liver count ratios and diagnostic quality was observed in serial images performed in 3 normal pigs, although areas of 1-4 hours-old myocardial ischemia produced by acute circumflex coronary artery ligation in 6 pigs could be reliably detected by in vivo 201Ti imaging. After intravenous 201Ti administration, the animals were sacrificed and sections of normal and ischemic myocardium were counted in a scintillation well counter. The activity in the ischemic area in pigs averaged 12% of the activity in the normal area, and varied over a narrow range; in dogs the activity averaged 62% of normal, and varied over a wide range. The pig was a more consistent model than the dog.  相似文献   
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