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51.
We obtained data on smoking by parents from 438 cancer cases and 470 controls to investigate whether cancer risk in adult life is related to transplacental or childhood exposure to cigarette smoke. Cancer cases were between ages 15 and 59 at time of diagnosis. All sites but basal cell cancer of the skin were included. Cancer risk was increased 50 per cent among offspring of men who smoked. Increased risk associated with father's smoking was not explained by demographic factors, social class, or individual smoking habits, and was not limited to known smoking related sites. Relative risk (RR) estimates associated with father's smoking tended to be greatest for smokers, males, and non-Whites. There was only a slight increase in overall cancer risk associated with maternal smoking. Mother's and father's smoking were both associated with risk for hematopoietic cancers, and a dose-response relationship was seen. The RR for hematopoietic cancers increased from 1.7 when one parent smoked to 4.6 when both parents smoked. Although they should be considered tentative, study findings suggest a long-term hazard from transplacental or childhood passive exposure to cigarette smoke.  相似文献   
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Ciliary neurotrophic factor (CNTF) is a 200-amino acid protein expressed in high concentrations by peripheral nerves and is thought to be important for the survival and regeneration of injured motoneurons (Lin et al., J Biol Chem 265:8942-8947, 1990). To better understand CNTF's role in nerve injury we have characterized the effects of crush injury on the expression of CNTF in adult rat sciatic nerves using specific antibody and RNA probes. Following a crush injury, both the protein and mRNA levels undergo pronounced decreases distal to the crush. These changes in CNTF expression were qualitatively distinct from changes in the expression of the low-affinity NGF receptor (p75NGFR), which increases following crush. Thus, the changes in CNTF levels do not reflect an overall down-regulation of mRNA during degeneration, and are inconsistent with the proposed role of CNTF in neuronal injury, since its levels are decreasing at the same time as the requirement for neurotrophic support is increasing.  相似文献   
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For a continuous self mapping f of a locally convex topological vector space which is locally compact (i.e., f maps a neighborhood of each point into a relatively compact set), it is shown that a sufficient condition for the existence of a fixed point is the existence of a compact attractor K0 such that each orbit under f has a point of K0 in its closure. The proof is based upon the circle of ideas of the Lefschetz fixed point theorem.  相似文献   
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In an effort to identify new trends in the presentation and treatment of primary hyperparathyroidism, 66 patients treated since 1975 were compared with 100 patients diagnosed and treated from 1948 to 1970. Despite widespread use of multichannel analyzers, the late patients had an insignificant increase in diagnosis while asymptomatic (18 percent versus 9 percent in the early group). Hypertension was the most common presenting complaint in patients seen since 1975, compared with renal disease in patients seen before 1970. Findings of diffuse hyperplasia were more common in the late patients (17 percent versus 3 percent in the early patients). There were no differences in rates of operative complications or persistent postoperative hypercalcemia. In the late series of patients persistent hypercalcemia after surgery for hyperplasia was due to inadequate resection of parathyroid tissue. In the adenoma patients, failure to locate the abnormal parathyroid gland was the cause of operative failure.  相似文献   
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