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排序方式: 共有911条查询结果,搜索用时 15 毫秒
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Rachel M. Haywood Andrew W. D. Claxson Geoffrey E. Hawkes David P. Richardson Declan P. Naughton Gregory Coumbarides Jane Hawkes Edward J. Lynch Martin C. Grootveld 《Free radical research》1995,22(5):441-482
High field (400 and 600 MHz) proton NMR spectroscopy has been employed to investigate the thermally-induced autoxidation of glycerol-bound polyunsaturated fatty acids present in intact culinary frying oils and fats. Heating of these materials at 180°C for periods of 30, 60 and 90 min. generated a variety of peroxidation products, notably aldehydes (alkanals, trans-2-alkenals and alka-2, 4-dienals) and their conjugated hydroperoxydiene precursors. Since such aldehydes appear to be absorbed into the systemic circulation from the gut in vivo, the toxicological significance of their production during standard frying practices is discussed. 相似文献
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R W Bolton H Rozmiarek F W Chorpenning 《Journal of immunology (Baltimore, Md. : 1950)》1977,118(4):1154-1158
Normal adult Sprague-Dawley rats were bled serially over a 30-week period and their sera were examined for antibodies to polyglycerophosphate (PGP) by a standardized passive hemolysis test. Levels of "natural" antibodies to PGP fluctuated during this period with a majority of animals exhibiting pronounced cycling of serum antibody levels, however, the individual cycles were not synchronized with each other. Feeding of radiolabeled Gram-positive bacilli to these animals and examination of lymphoid tissue by liquid scintillation counting revealed that the antigen persisted mainly in the mesenteric lymph nodes. A second group of rats was injected i.v. with radiolabeled Gram-positive bacilli and tissues were examined for plaque-forming cells (PFC) of PGP specificity, and the sera were examined by passive hemolysis. Cycling of both anti-PGP antibodies and PFC became synchronized in the injected animals with peaks of serum antibody evident at 16 and 28 days post-injection and splenic PFC peaks at 4 and 16 days post-injection. Cycling was also observed in the mesenteric lymph nodes and bone marrow Examination of lymphoid tissue from the rats injected i.v. revealed that antigen introduced by this route also perisisted mainly in the mesenteric lymph nodes, This report demonstrates individual cycling of natural responses to environmental antigen and to the same determinant in secondary responses, indicating its importance as a regulatory mechanism. 相似文献
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Summary
Allolobophora rosea (Savigny) was found to be common in mull type soils beneath bramble (Rubus fruticosus L.). Burrow construction in this soil type in the laboratory at 4.4, 10.0 and 14.8°C ranged between 133 and 516 mm g-1 fresh wt of worm day-1. Burrowing was affected by both body size and temperature. Rates of soil displacement during burrowing were estimated from burrowing rates, burrow dimensions and soil density; depending on body size and temperature they were in the range 809–1,928 mg dry wt of soil g-1 fresh wt of worm day-1. These values were in reasonable agreement with measured egestion rates (range: 1,000–2,000 mg dry wt of egesta g-1 fresh wt of worm day-1). It was concluded that A. rosea eats its way through the soil and is adapted to its rapid turnover. Gut turnover times were calculated to be between 1 and 2.5 h.Direct observation indicated that feeding was by a grazing procedure and it was shown that A. rosea preferentially selects the more organic fractions of the soil for ingestion.The evaluation of energy budgets for individual small immature, large immature and adult worms at 10°C revealed respiration to production ratios (R/P) of 1.0, 1.8 and 4.1, respectively. Assimilation efficiencies (A/C) were always less than 2.5%. 相似文献
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P. M. Bolton C. Teasdale A. M. Mander Susan L. James Joyce M. Davidson R. H. Whitehead R. G. Newcombe L. E. Hughes 《Cancer immunology, immunotherapy : CII》1976,1(4):251-258
Summary The immune competence of a group of 276 patients with suspected breast cancer has been assessed using a spectrum of tests: the peripheral lymphocyte count, serum immunoglobulin levels, lymphocyte response to phytohemagglutinin (PHA), Mantoux test, and dinitrochlorobenzene (DNCB) skin test. All tests were completed prior to any form of treatment as the initial part of an ongoing, long-term assessment which will ultimately relate immune competence to prognosis. 225 patients with breast cancer were allocated into stages based on their TNM status. The remaining 51 patients proved to have benign breast disease and made up the control group. In analysis, control patients were compared with early breast cancer patients, while the effect of advancing disease was assessed by betweenstage comparisons in the cancer group.There were no significant differences between early breast cancer and control patients or between cancer stages in peripheral lymphocyte count, serum immunoglobulin levels, lymphocyte response to PHA, or Mantoux responses. Age was found to have a crucial effect on some of these parameters and some apparent differences between the various groups lost significance after appropriate allowances were made for age.Important differences seen with the DNCB test persisted after allowing for age effects. Responses to DNCB were significantly depressed in patients with early breast cancer compared to controls. Patients with disseminated cancer showed greater depression than early breast cancer patients, but surprisingly, patients with locally advanced tumors had good responses to DNCB. Possible reasons for the paradoxical preservation of DNCB reactivity in patients with locally advanced cancer are discussed.The DNCB test is the most discriminating of the five tests of immune function studied. 相似文献
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Elsabbagh M Mercure E Hudry K Chandler S Pasco G Charman T Pickles A Baron-Cohen S Bolton P Johnson MH;BASIS Team 《Current biology : CB》2012,22(4):338-342
Autism spectrum disorders (henceforth autism) are diagnosed in around 1% of the population [1]. Familial liability confers risk for a broad spectrum of difficulties including the broader autism phenotype (BAP) [2, 3]. There are currently no reliable predictors of autism in infancy, but characteristic behaviors emerge during the second year, enabling diagnosis after this age [4, 5]. Because indicators of brain functioning may be sensitive predictors, and atypical eye contact is characteristic of the syndrome [6-9] and the BAP [10, 11], we examined whether neural sensitivity to eye gaze during infancy is associated with later autism outcomes [12, 13]. We undertook a prospective longitudinal study of infants with and without familial risk for autism. At 6-10 months, we recorded infants' event-related potentials (ERPs) in response to viewing faces with eye gaze directed toward versus away from the infant [14]. Longitudinal analyses showed that characteristics of ERP components evoked in response to dynamic eye gaze shifts during infancy were associated with autism diagnosed at 36 months. ERP responses to eye gaze may help characterize developmental processes that lead to later emerging autism. Findings also elucidate the mechanisms driving the development of the social brain in infancy. 相似文献