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1.
Copper nanoparticles have enhanced the germination and wheat development. To explain the effects of copper nanoparticles on shoot of Pakistan-13 and NARC-11, proteomic technique was used. The physiological responses such as weights/lengths of seedling, shoot, and root of wheat varieties were increased on 10-ppm copper nanoparticle exposure. The number of proteins related to protein metabolism was increased in Pakistan-13 while protein metabolism and photosynthesis-related proteins were increased in NARC-11, treated with copper nanoparticles compared to untreated plants. Abundance of proteins related to glycolysis and tricarboxylic acid cycle was increased on copper nanoparticle exposure in Pakistan-13 and NARC-11. However, the abundance of proteins related to photosynthesis and tetrapyrole synthesis was decreased on copper nanoparticle exposure in Pakistan-13 and NARC-11. Chlorophyll content such as chlorophyll a, chlorophyll b, and total chlorophyll was decreased on copper nanoparticle exposure in Pakistan-13 and NARC-11. The rate of photosynthesis and carbon assimilation decreased on copper nanoparticle exposure. These results suggest that copper nanoparticles mend the seedling growth of wheat, which might be concomitant with the enhancement of protein abundance related to glycolysis and tricarboxylic acid cycle in wheat varieties.  相似文献   

2.
The responsiveness to sex pheromone of males of Epiphyas postvittana was reduced by previous brief exposure to pheromone. Males were exposed to a standard quantity of pheromone for various durations and at various intervals before the time at which bioassay was performed.The reduction in responsiveness was related both to the duration of the previous exposure and to the time at which the previous exposure was given in relation to the bioassay. It was not related to the occurrence or intensity of any behavioural response elicited at the time of previous exposure to the pheromone.  相似文献   

3.
Exposure to solar radiation is increasingly being associated with a risk of cutaneous melanoma, and some risk has also been attributed to exposure to fluorescent lights. The risk of cutaneous melanoma associated with exposure to some sources of artificial ultraviolet radiation was examined in a case-control study in a Scottish population with fairly low exposure to natural ultraviolet radiation. The risk was not significantly or consistently raised for exposure to fluorescent lights at home or at work. The use of ultraviolet lamps and sunbeds, however, was associated with a significantly increased risk (relative risk = 2.9; 95% confidence interval 1.3 to 6.4), and the risk was significantly related to duration of use. The risk was particularly raised among people who have first used [corrected] ultraviolet beds or lamps more than [corrected] five years before presentation (relative risk = 9.1; 95% confidence intervals 2.0-40.6), in whom it was significantly related to cumulative hours of exposure. The risks associated with exposure to ultraviolet lamps and sunbeds remained significant after adjustment for other risk factors for melanoma.  相似文献   

4.
秦晓群  孙秀泓 《生理学报》1996,48(2):190-194
本研究观察到臭氧(O3)对体外培养经3H-UdR标记的免气道上皮细胞有明显细胞毒性作用,且损伤程度与O3作用时间呈正相关。O3暴露组细胞内丙二醛(MDA)产生增多(P<0.01),提示O3损伤细胞的机制与胞膜脂质过氧化有关。表皮生长因子(EGF)可明显降低O3所致的3H释放率(P<0.01)、降低O3的细胞毒指数及细胞内MDA含量(P<0.01),证明EGF对气道上皮细胞有保护作用。进一步还观察到浓度为5ng/ml的EOF可以取消O3所引起的细胞内还原型谷胱甘肽(GSH)含量降低(P<0.01),并增加细胞内谷胱甘肽总含量(P<0.05),但不能改变O3所致的氧化型谷胱甘肽(GSSG)含量的增加(P>0.05),对GSH/GSSG比值也无明显提高,这些都提示EGF的细胞保护机理可能与其促进细胞内谷胱甘肽合成有关,而对GSSG转化为GSH的还原过程影响不明显。  相似文献   

5.
The effect of previous exposure to low temperatures on freezing tolerance was determined for second-stage juveniles of Meloidogyne hapla. Juveniles in 5% polyethylene glycol 20,000 were exposed to 0-24 C for 12-96 hours, and then freezing tolerance was assessed by freezing samples at -4 C for 24 hours, thawing, and determining survival. Freezing tolerance was inversely related to prefreeze temperatures of 4-24 C. Prefreeze exposure to 4 C resulted in fourfold greater freezing tolerance than did exposure to 24 C. Mortality occurred during prefreeze exposure to 0 C. Most of the increase in freezing tolerance at 4 C occurred during the first 12 hours. In soil, prefreeze exposure to 4 C resulted in greater freezing tolerance than did prefreeze exposure to 24 C.  相似文献   

6.
The mechanisms underlying age-related changes in the signal from the biological clock have yet to be determined. The authors sought to determine if the phase advance of circadian melatonin rhythm during the middle years of life is related to different patterns of habitual light exposure. Forty-one healthy subjects between the ages of 22 and 58 y were studied. Habitual light exposure was measured by a wrist monitor for 7 days. Participants underwent a 25-h constant routine. They provided saliva samples every 30 min, and melatonin concentration was determined by radioimmunoassay to assess salivary dim light melatonin onset (S-DLMO(1.3)). Aging was associated with earlier S-DLMO(1.3). Increasing age was not related to the time spent at different light intensities. However, it was associated with lower percentage of light exposure during the night (between 0200-0400, 0600-0700, and 2300-2400 h) and with higher percentage of light exposure in the morning (between 0800-1100 h). Earlier S-DLMO(1.3) was associated with lower percentage of light exposure early on in the night (between 2200-0000, 0000-0100, and 0200-0300 h) as well as in the afternoon (between 1500-1600 h) and with higher percentage of light exposure in the morning (between 0800-1100 h). When the effects of age were controlled, there was no significant relationship between S-DLMO(1.3) and percentages of light exposure. Yet increasing age was associated with earlier S-DLMO(1.3) regardless of light exposure patterns. Earlier habitual wake time explained the earlier light exposure patterns of older subjects. Both habitual wake time and age contributed to the prediction of S-DLMO(1.3). The results suggest a phase advance of circadian rhythms in the middle years of life. Whereas a clear change in habitual light exposure patterns was associated with aging and with shifts in S-DLMO(1.3), it did not explain entirely the age-related advance of melatonin circadian phase.  相似文献   

7.
Evidence from epidemiological and animal studies showed that exposure to extremely low frequency magnetic fields (ELF‐MF) could produce deleterious effects on reproduction. In order to investigate the possible mechanism of MF exposure on reproductive effects, first trimester human chorionic villi at 8–10 weeks' gestation were obtained, and trophoblasts were isolated, cultured, and exposed to a 50‐Hz MF for different durations. The human chorionic gonadotropin (hCG) and progesterone in the culture medium was measured by electrochemiluminescence immunoassay. The mRNA levels of apoptosis‐related genes bcl‐2, bax, caspase‐3, p53, and fas in trophoblasts were analyzed using real‐time RT‐PCR. The results showed that exposure of trophoblasts to MF at 0.2 mT for 72 h did not affect secretion of hCG and progesterone from these cells. There was also no significant change in secretion of these hormones when trophoblasts were exposed to a 0.4 mT MF for 48 h. However, MF significantly inhibited hCG and progesterone secretion of trophoblasts after exposure for 72 h at 0.4 mT. Results of apoptosis‐related gene expression analysis showed that, within 72 h of exposure at 0.4 mT, there was no significant difference between MF exposure and control on the expression pattern of each gene. Based on results of the present experiment, it is suggested that exposure to MF for a longer duration (72 h) could inhibit secretion of hCG and progesterone by human first trimester villous trophoblasts, however, the effect might not be related to trophoblast apoptosis. Bioelectromagnetics 31:566–572, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   

8.
ObjectiveThe purpose of this study was to examine the association between pre and post environmental tobacco smoke (ETS) exposure and behavioral problems in schoolchildren.MethodsIn the cross-sectional 6 cities Study conducted in France, 5221 primary school children were investigated. Pre- and postnatal exposure to secondhand tobacco smoke at home was assessed using a parent questionnaire. Child’s behavioral outcomes (emotional symptoms and conduct problems) were evaluated by the Strengths and Difficulties Questionnaire (SDQ) completed by the parents.ResultsETS exposure during the postnatal period and during both pre- and postnatal periods was associated with behavioral problems in children. Abnormal emotional symptoms (internalizing problems) were related to ETS exposure in children who were exposed during the pre- and postnatal periods with an OR of 1.72 (95% Confidence Interval (CI)= 1.36-2.17), whereas the OR was estimated to be 1.38 (95% CI= 1.12-1.69) in the case of postnatal exposure only. Abnormal conduct problems (externalizing problems) were related to ETS exposure in children who were exposed during the pre- and postnatal periods with an OR of 1.94 (95% CI= 1.51-2.50), whereas the OR was estimated to be 1.47 (95% CI=1.17-1.84) in the case of postnatal exposure only. Effect estimates were adjusted for gender, study center, ethnic origin, child age, low parental education, current physician diagnosed asthma, siblings, preterm birth and single parenthood.ConclusionPostnatal ETS exposure, alone or in association with prenatal exposure, increases the risk of behavioral problems in school-age children.  相似文献   

9.
The effects of glucose extremes on vascular physiology and endothelial cell function have been examined across a range of time scales. Not unexpectedly, chronic glucose exposure induces long term tissue effects. Yet short term exposure can also impose lasting consequences. The persistence of vascular pathology after euglycemic restoration further suggests a glucose exposure memory. Slow turnover reservoirs such as basement membrane are candidates for prolongation of acute events. We hypothesized that glucose-induced vascular dysfunction is related to altered vasoactive compound handling within the endothelial cell-basement membrane co-regulatory unit. Endothelial cell basement membrane-associated fibroblast growth factor-2 increased linearly with culture glucose within days of elevated glucose exposure. Surprisingly, basement membrane fibroblast growth factor-2 binding kinetics remained unchanged. The glucose-induced increase in basement membrane fibroblast growth factor-2 was instead related to enhanced endothelial cell fibroblast growth factor-2 release and permeability. Cellular fibroblast growth factor-2 release occurred concomitant with apoptosis but was not blocked by caspase inhibitors. These data suggest that release was associated with sub-lethal early apoptotic cell membrane damage, perhaps related to reactive oxygen species formation. High glucose basement membrane in turn enhanced endothelial cell proliferation in a fibroblast growth factor-2-dependent manner. We now show that glucose-induced alterations in endothelial cell function promote changes in basement membrane composition, and these changes further affect endothelial cell function. These data highlight the interrelationship of cell and basement membrane in pathological conditions such as hyperglycemia. These phenomena may explain long term effects on the endothelium of short term exposure to glucose extremes.  相似文献   

10.
A K Ghosh  A Sharma  G Talukder 《Cytobios》1992,71(285):85-91
The ability of Sumicidin, a synthetic pyrethroid, to induce cytotoxicity in Swiss albino mice was evaluated before completion of the first cell division following oral exposure. Mice were administered orally different concentrations (32.50, 75 and 150 mg/kg body wt) of Sumicidin in a single dose. Mitotic index and chromosomal aberrations were screened after 6, 12 and 24 h following exposure. The frequency of dividing cells decreased significantly, indicating mitostatic action. The frequency of chromosomal aberrations was directly related to the concentrations used and the duration after exposure, and was significant at all concentrations. The highest frequency of aberrations was observed 24 h after exposure.  相似文献   

11.
Effects of pressure on uptake and release of calcium by brain synaptosomes   总被引:1,自引:0,他引:1  
Uptake of radioactive calcium from guinea pig brain fractions enriched in synaptosomes could be significantly and reproducibly decreased by exposure to high pressure. Calcium efflux from preloaded synaptosomes was unaffected by pressure exposure. It was hypothesized that the development of pressure-induced encephalopathy may be related to an effect of pressure on the central nervous system calcium transport system.  相似文献   

12.
Total arsenic in urine is often the principal means for assessing chronic exposure to arsenic-contaminated drinking water. This approach ignores many components of the human diet, especially fish and seafood that contain arsenic at significant concentrations. The toxicity differences between the inorganic forms and the dietary forms suggest both should be evaluated when attempting to assess risk from arsenic exposure. Urine biomonitoring for 53 participants was used to confirm reduction in arsenic exposure resulting from well water remediation removing inorganic arsenic from drinking water. Initially, only total arsenic urine assays were performed, but spikes in total arsenic urine concentrations were determined to be diet related and demonstrated the need for analytical methods that differentiate the arsenic species. A secondary analysis was added that quantified inorganic-related arsenic in urine and the dietary forms related to fish and seafood by subtraction from total arsenic. Significant differences were found between the inorganic arsenic component and the total arsenic measured in their urine. On average, approximately 76% of total arsenic in urine was attributed to fish and other organo-arsenic dietary sources, implying a potential significant overestimate of exposure, and demonstrating the need for differentiation of the inorganic-related arsenic from dietary arsenic.  相似文献   

13.
OBJECTIVE--To quantify the relation between lung cancer and exposure to asbestos in men in west Scotland and to estimate the proportion of lung cancer which may be attributed to exposure to asbestos. DESIGN--An ecological correlation study of the incidence of lung cancer in men and past asbestos exposure. The unit of analysis was the postcode sector. Correction was made for past cigarette smoking, air pollution, and deprivation. SETTING--The region covered by the west of Scotland cancer registry, containing 2.72 million people and including Glasgow and the lower reaches of the River Clyde, where shipbuilding was once a major industry. SUBJECTS--All men diagnosed with lung cancer between 1975 and 1984 whose residence at the time of registration was within the west of Scotland. MAIN OUTCOME MEASURE--The population attributable risk for asbestos related lung cancer. RESULTS--An estimated 5.7% (95% confidence interval 2.3 to 9.1%) of all lung cancers in men registered in the west of Scotland during the period 1975-84 were asbestos related, amounting to 1081 cases. CONCLUSIONS--A considerable proportion of cases of lung cancer in men in Glasgow and the west of Scotland from 1975 to 1984 were asbestos related. Most of these may not have been considered for compensation by the Department of Social Security. Given the very small annual number of recorded cases of asbestosis this condition is probably not a prerequisite for the development of asbestos related lung cancer. A heightened awareness of the increasing incidence of asbestos related neoplasms and their more thorough investigation are recommended.  相似文献   

14.
Day-old domestic chicks previously exposed to a constant light approached a flashing rotating light more rapidly than chicks previously kept in darkness. The speed of approach was inversely related to the length of exposure, and effects were apparent after 18 min of exposure. Responsiveness was not affected by a prior reduction in air temperature of 4°C for 60 min. After exposure in the dark to the sound of a chick loudly calling for 60 min, chicks were less responsive to the flashing light than those previously kept in relative silence.  相似文献   

15.
The effects of night-time exposure to traffic noise (TN) or low frequency noise (LFN) on the cortisol awakening response and subjective sleep quality were determined. Twelve male subjects slept for five consecutive nights in a noise-sleep laboratory. After one night of acclimatisation and one reference night, subjects were exposed to either TN (35dB L(Aeq), 50dB L(Amax)) or LFN (40dB L(Aeq)) on alternating nights (with an additional reference night in between). Salivary free cortisol concentration was determined in saliva samples taken immediately at awakening and at three 15-minute intervals after awakening. The subjects completed questionnaires on mood and sleep quality. The awakening cortisol response on the reference nights showed a normal cortisol pattern. A significant interaction between night time exposure and time was found for the cortisol response upon awakening. The awakening cortisol response following exposure to LFN was attenuated at 30 minutes after awakening. Subjects took longer to fall asleep during exposure to LFN. Exposure to TN induced greater irritation. Cortisol levels at 30 minutes after awakening were related to "activity" and "pleasantness" in the morning after exposure to LFN. Cortisol levels 30 minutes after awakening were related to sleep quality after exposure to TN. This study thus showed that night time exposure to LFN may affect the cortisol response upon wake up and that lower cortisol levels after awakening were associated with subjective reports of lower sleep quality and mood.  相似文献   

16.
The effect of the in vitro exposure to extremely low frequency pulsed electromagnetic fields (PEMFs) on the proliferation of human lymphocytes from 24 young and 24 old subjects was studied. The exposure to PEMFs during a 3-days culture period or during the first 24 hours was able to increase phytohaemagglutinin-induced lymphocyte proliferation in both groups. Such effect was greater in lymphocytes from old people which showed a markedly reduced proliferative capability and, after PEMF exposure, reached values of 3H-TdR incorporation similar to those of young subjects. The relevance of these data for the understanding and the reversibility of the proliferative defects in cells from aged subjects and for the assessment of risk related to the environmental exposure to PEMFs has to be considered.  相似文献   

17.
BACKGROUND: The United States Surgeon General declared 2005 as the "Year of Healthy Child." To improve the health of all children, we need to start before pregnancy, with their mothers. Unfortunately, protein deficiency in the diets of poor pregnant mothers in developing countries is widespread. Carbon monoxide (CO) pollution is serious public health problem in developed and developing countries. METHODS: A two-way factorial experimental design was used. Mice were maintained on 27%, 16%, 8%, or 4% protein diets. Dams were exposed to 0 ppm (control), 65 ppm, or 125 ppm CO in air, in environmental chambers for 6 hr/day during the first 2 weeks of pregnancy. Controls were also subjected to environmental chamber conditions. Food and water were available at all times. Animals were allowed to deliver, and data on pup mortality was recorded. RESULTS: Litter size was not affected by CO exposure, but was directly related to the dietary protein levels. Pup weight was inversely related to the CO exposure level, and directly related to the dietary protein levels. Pup mortality on date of birth was increased by CO exposure and was inversely related to the dietary protein levels. Pup mortality at 1 week of age was increased by CO exposure and 55% of all pups died in 125 ppm CO exposed group. Pup mortality at 1 week of age was inversely related to dietary protein levels. All pups in the 4% dietary protein and in all concentrations of CO died. All pups in the 8% protein group and in all CO concentrations died except in 125 ppm CO group. Pup mortality in the 16% dietary protein group ranged from 14.8% in 0 ppm to 36.8% in 65 ppm CO groups. Pup mortality in the 27% dietary protein group ranged from 14.3% in the 0 ppm to 41.1% in the 125 ppm CO groups. CONCLUSIONS: DATA suggest that protein deficiency and CO exposure enhance pup mortality. The protein and CO also interact to increase pup mortality in 16% and 27% protein groups. Carbon monoxide exposure, along with protein deficiency during gestation, may be contributing factors for high rates of infant mortality in developing countries. The results of the study also suggest that un-vented combustion for heating and cooking, ambient pollution, and biomass smoke may have a major impact on the health of children worldwide; and may explain the causes of high infant mortality in poor countries and some sections of the United States population.  相似文献   

18.
Tomato and lettuce plants were exposed to vapour of the herbicide 14C 2,4-D butyl at concentrations in the range of 1–660 pg/l for 6, 24 or 72 hr. The relationship between herbicide uptake, measured as amount of radiolabel in the plant, and vapour concentration was linear and independent of the duration of exposure for both species. The rate of uptake of herbicide vapour at any one concentration by tomato was about twice that of lettuce. Immediately after exposure, the leaves of lettuce plants contained similar amounts of herbicide residue, whereas leaves at the base of tomato plants usually contained the least herbicide, and those at the apex the most. In terms of leaf area, both species had highest residue contents in the apical leaves. Different exposure periods did not affect the amounts of herbicide residue in the apical leaves or the leaf below, indicating that herbicide present in the apex is largely due to uptake and not to translocation. Both species developed visible symptoms of phytotoxicity following exposure, the severity being directly related to the amount of herbicide vapour received. Leaf contents of herbicide residue in tomato plants 40 days after exposure were related to the total plant content measured immediately after exposure; the leaf below the apex at the time of exposure retained about 17% of the herbicide originally present. Shoot dry weight, 40 days after exposure, was reduced by 10% following uptake of about 250 ng/plant in tomato, whereas for lettuce, about twice this amount of 2,4-D butyl was required to cause noticeable weight reduction. Doses of this magnitude are of the order of 10−5 the amount used in field application, and so it is clear that 2,4-D vapour is a potential hazard to tomato and lettuce crops.  相似文献   

19.
Contact dermatitis to Biobrane   总被引:1,自引:0,他引:1  
Contact dermatitis to Biobrane has not been reported previously. We report a patient who developed a bullous skin reaction directly related to a second exposure to Biobrane. The second exposure occurred 18 days after initial use of Biobrane, and the bullous reaction developed within 48 hours of repeat exposure. Sensitivity was confirmed by patch testing. Clinicians should be aware of the possibility of contact dermatitis to Biobrane.  相似文献   

20.
Effects of 50 Hz magnetic field exposure on tumor experimental models   总被引:3,自引:0,他引:3  
The aim of this study was to investigate the interaction between a 50 Hz, 2 mT magnetic field (MF) exposure and cell growth of mammary murine adenocarcinoma, injected into experimental mice. Six different experimental protocols were performed over 2 years; several different protocols of timing of exposure were tested. X-ray radiation was adopted as the positive control. Tumor incidence and the tumor development time were calculated. No effect was observed in any experiment, and there was no statistically significant difference related to time courses among the protocols used. Neither the time of tumor cell injection nor the time of exposure produced differences between unexposed, sham, and exposed mice. When X-ray radiation was applied, the cytotoxic effect of ionizing radiation was clear, but was not increased or modified by MF exposure. Finally, the study revealed how the host-tumor system has shown a distinctive variability, unmodified by MF exposure.  相似文献   

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