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41.
Lipoprotein lipase regulates the hydrolysis of circulating triglyceride and the uptake of fatty acids by most tissues, including the mammary gland and adipose tissue. Thus, lipoprotein lipase is critical for the uptake and secretion of the long-chain fatty acids in milk and for the assimilation of a high-fat milk diet by suckling young. In the lactating female, lipoprotein lipase appears to be regulated such that levels in adipose tissue are almost completely depressed while those in the mammary gland are high. Thus, circulating fatty acids are directed to the mammary gland for milk fat production. Phocid seals serve as excellent models in the study of lipoprotein lipase and fat transfer during lactation because mothers may fast completely while secreting large quantities of high fat milks and pups deposit large amounts of fat as blubber. We measured pup body composition and milk fat intake by isotope (deuterium oxide) dilution and plasma post-heparin lipoprotein lipase activity in six grey seal (Halichoerus grypus) mother-pup pairs at birth and again late in the 16-day lactation period. Maternal post-heparin lipoprotein lipase activity increased by an average of four-fold by late lactation (P = 0.027), which paralleled an increase in milk fat concentration (from 38 to 56%; P = 0.043). Increasing lipoprotein lipase activity was correlated with increasing milk fat output (1.3-2.1 kg fat per day) over lactation (P = 0.019). Maternal plasma triglyceride (during fasting) was inversely correlated to lipoprotein lipase activity (P = 0.027) and may be associated with the direct incorporation of long-chain fatty acids from blubber into milk. In pups, post-heparin lipoprotein lipase activity was already high at birth and increased as total body fat content (P = 0.028) and the ratio of body fat: protein increased (P = 0.036) during lactation. Although pup plasma triglyceride increased with increasing daily milk fat intake (P = 0.023), pups effectively cleared lipid from the circulation and deposited 70% of milk fat consumed throughout lactation. Lipoprotein lipase may play an important role in the mechanisms involved with the extraordinary rates of fat transfer in phocid seals. 相似文献
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Preliminary investigations have been made in normally hearing alert adults to establish whether the 40 Hz modulation-following response (MFR) can be used to predict 400 Hz uncomfortable loudness levels (ULLs). The MFR stimulus was a 400 Hz carrier, amplitude- and frequency-modulated by a 40 Hz sine function. Subjective ULLs were obtained using standard procedures. Objective ULLs were obtained from MFR parameter intensity functions using rms amplitude, phase angle and magnitude-squared coherence (40 Hz components). The best predictions of the subjective ULL were made using objective ULLs calculated from the gradients of linear best-fit lines for individual phase-intensity functions (80 per cent predicted within 10 dB of the subjective ULL; maximum deviation=16 dB). Poorest predictions were based on inter-subject average rms amplitude-intensity functions, where as few as 14 per cent were within 10 dB of the subjective value. The best predictions were considered sufficiently accurate to warrant further investigation using a variety of modulation and carrier frequencies in different age groups and with varying degrees of hearing loss. 相似文献
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Data from an anonymous survey of 3,690 adolescents were used to assess how much of the unique variance in adolescents' self-reported drug use was accounted for by number of parents in comparison to the adolescents' sex, age, social class, and peer drug use. Multiple regression revealed that the contribution of number of parents was small and nonsignificant compared to peer use, student age, parental occupation and remarriage, student sex, and parental unemployment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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FG Surawicz DR Brightwell WD Weitzel E Othmer 《Canadian Metallurgical Quarterly》1976,133(11):1306-1309
The authors review recent and current literature on the relationship between psychological factors and cancer. They discuss the roles of predisposing personality patterns and emotional stress in the development, site, and course of cancer; the influence of awareness of terminal illness on the behavior of cancer patients; and the management of psychiatric symptoms in these patients. 相似文献
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PURPOSE: Organized interscholastic athletics are an integral part of the educational program at almost every school level. With this growing popularity of sports and their inclusion in more public school programs, it becomes increasingly apparent that additional consideration must be given to the injury problem associated with sport. The North Carolina High School Athletic Injury Study (NCHSAIS) was undertaken to identify patterns of injury among male and female athletes in North Carolina high schools participating in any of 12 sports. Specific aims are to measure the incidence, severity and etiology of injuries; to determine the relationship of demographic factors and protective equipment, exposure to play, and school characteristics to injuries; to study the relationship of coaches' training and experience to injury occurrence; and to compare the incidence and severity of injury among female and male athletes in the same or comparable sports. METHODS: A two-stage cluster sample of 100 high schools in North Carolina was selected for this 4-yr prospective study. RESULTS: Participation by the initial sample or a random replacement was achieved for 91 of the 100 schools. Nonresponse occurred at multiple levels of the sample for this study, and the weekly participation form posed the greatest respondent burden. CONCLUSIONS: The NCHSIAS offers a successful methodology for addressing sports injuries. In this paper we describe the design, methodology, and implementation issues that emerge in conducting a large scale epidemiological study in a population of high school athletes. 相似文献