首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Summary Diets containing 264.6 ppm o,p- or p,p-DDT were fed to 6-week-old male and female turkeys for 7 and 15 weeks. Such chronic feeding of DDT did not cause alterations of: Blood pressure; gross structure of body tissues; histology of heart, aorta, liver, testes, oviduct, ovary, thyroid, or kidney; plasma cholesterol or calcium levels; albumin-globulin ratio; or plasma lipoprotein patterns. The residue of DDT in body fat was determined. Trace amounts were found in birds fed the control diet. Minute quantities of o,p-DDT and large amounts of p,p-DDT were found in fat of turkeys fed p,p-DDT, and the converse was true of turkeys fed o,p-DDT.  相似文献   

2.
Residues of potentially toxic non-ortho chlorine substituted coplanar 3,3,4,4-tetra-,3,3,4,4,5-penta-, 3,3,4,4,5,5-hexachlorobiphenyl and their mono- and di-ortho analogs (2,3,4,4,5-penta-, 2,3,3,4,4-penta-, 2,3,3,4,4,5-hexa-and 2,2,3,3,4,4-hexa-, 2,2,3,4,4,5-hexa-chlorobiphenyl) were determined in humans, dogs, cats (terrestrial), a finless porpoise (Neophocoena phocoenoides-coastal), Dall's porpoises (Phocoenoides dalli,dalli), Baird's beaked whales (Berardius bairdii) and killer whales (Orcinus orca-open ocean). Among the coplanar polychlorinated biphenyl (PCB) congeners, the concentration of the di-ortho congeners was the highest and the non-ortho congeners was the lowest. However, all three coplanar PCBs occurred at significantly higher levels than toxic polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The relative bioconcentration and metabolic capacity of terrestrial and marine mammals to these chemicals, suggest that the toxic threat of coplanar PCBs increases from land to ocean, but the reverse is true for PCDDs and PCDFs. The toxic threat of coplanar PCBs to higher aquatic predators such as cetaceans was principally assessed by 2,3,7,8-T4CDD Toxic Equivalent Analysis which is based on the induction of arylhydrocarbon hydroxylase (AHH) and ethoxyresorufinO-deethylase (EROD). Analysis indicates, in particular, that the bioaccumulation of toxic 3,3,4,4,5-penta- and 2,3,3,4,4-pentachlorobiphenyls in carnivorous marine mammals is a cause for considerable concern.  相似文献   

3.
Data from the 1990 Ontario Health Survey were used to investigate the association of socio-economic status with the likelihood of meeting current recommendations for four health behaviours (smoking, fat intake, alcohol consumption, and physical activity level) in adults living in Ontario (Canada). Health behaviours were categorised as unhealthy if they did not meet current recommendations in Ontario (smoking, fat intake < 30% of dietary energy, alcohol intake < 14 units per week, low level of leisure-time physical activity). Two summary variables based on the number ofÔ unhealthyÕ behaviours were also examined: the crude number of unhealthy behaviours reported and the likelihood of reporting 3 or 4 unhealthy behaviours. Four measures of socio-economic status were used: educational achievement, household income status, source of household income, and occupational prestige. Multiple logistic and linear regression analyses were performed to explore the association of each unhealthy behaviour and of the summary variables with socio-economic status indicators (taken independently or simultaneously), controlling for demographic characteristics. Except for the positive relationship between income status and high alcohol intake, measures of unhealthy behaviours were inversely associated with the socio-economic indices, suggesting that individuals in lower socio-economic groups are at an increased risk for health problems.  相似文献   

4.
Study objective: To assess what healthy eating means for the European population and whether this concept differs between Spain and other European Countries. Design: A Pan-European survey was developed between October 1995 and February 1996 by the Institute of European Food Studies (Dublin). Each subject was asked to describe in his or her own words what he/she understood by healthy eating. Comparisons were made among four groups of European countries (Northern, Central, Spain, and other Mediterranean countries). Setting: The survey included participants from the 15 member states of the European Union, selecting quota-controlled samples to make them nationally representative. Subjects: The questionnaire was completed by 14,331 persons, approximately 1000 from each country. Results: The responses were grouped into 89 broad categories of similar answers concerning nutritional value and afterwards these responses were collapsed to simplify the presentation. The definition of healthy eating such as more fiber and less fat was more prevalent in other States, members of the European Union than in Mediterranean Countries, although the definition of balanced diet was more frequently mentioned in Spain than in the rest of the European Union. Conclusions: Our results show that the concept of balance and variety is more prevalent in Spaniards than in other traditional Mediterranean countries. Differences in the definitions of healthy eating among European countries could be explained, at least partially by differences in consumption patterns and in the nutrition education.  相似文献   

5.
Summary Concentrations of -HCH, HCB, p,p-DDE, p,p-DDT and PCBs were determined by gas chromatography in 50 human milk samples collected from the general population during 1981/1982 in a continental town in Croatia (Yugoslavia). The samples were collected between one and 22 weeks after delivery from mothers breast-feeding one child only. The mothers' age was 18 to 31 years, and they were nursing their first or second child. All 50 samples contained -HCH, HCB, p,p-DDE and PCBs, whereas p,p-DDT was present in 37 samples. The concentrations of -HCH, HCB, p,p-DDE, p,p-DDT and PCBs expressed on a whole milk basis were (median in g/kg): 11, 7.1, 67, 7.3 and 22 respectively, and expressed on a fat basis (median in mg/kg): 0.28, 0.21, 1.9, 0.18 and 0.62 respectively. The fat content was 3.7% (median). PCBs were present in a mixture containing penta-, hexa- and heptachlorobiphenyls.  相似文献   

6.
This article is based on data gathered through 60 qualitative interviews conducted within the realm of three research projects that have used culture-appropriate lenses to study the postmigration situation of late-in-life Iranian immigrants to Sweden. The findings gathered through these studies were interpreted against the backdrop that culturally appropriate nursing theories provide. This meant that it was, at times, these elders backgrounds as cultural others that were implicitly used to make sense of the various issues that were brought to the fore by these studies. The particular issue with which this article is concerned is the unusualness of these elders explanatory models of illness. Inspired by the concept definition of situation in the symbolic interactionist perspective and by the feeling that this perspective might bring about a different interpretation of the original findings regarding their understandings of illness and disease, we set out to conduct a secondary analysis of these elders explanatory models of illness. The findings presented in this article will show how the elderly Iranian immigrants interviewed in these three studies utilize the process of late in life migration as a point of reference for their understandings of what has caused the illnesses from which they suffered. Hereby we will suggest that the unusualness of their explanatory models of illness might be best understood if we focus on what they shared as immigrants (i.e., the fact that the process of late-in-life migration has made their culture obsolete) as opposed to what they shared as Iranians (i.e., their culture of origin).  相似文献   

7.
Polychlorobiphenyls (PCBs), DDT (p,p-DDT,p,p-DDD, andp,p-DDE and HCH isomers (hexachlorocyclohexanes including , , and isomers) were determined in a marine food chain, including seawater, zooplankton, myctophid, squid and striped dolphin collected from the western North Pacific waters. The concentrations of these pollutants increased in higher trophic levels, where the highest bioconcentration factors (concentration ratio in organisms to water), as much as 107, were obtained from both PCBs and DDT in striped dolphin. The proportions of highly chlorinated biphenyls,p,p-DDE and -HCH increased in higher-ranking predators. These observations suggest that the bioaccumulation mechanisms in lower trophic levels depend primarily on the physicochemical properties of pollutants, whereas those in higher trophic levels are affected by the biodegradability of the pollutants and the metabolic capacity and life-span of the organisms.  相似文献   

8.
Long-term investigations of polychlorinated hydrocarbon levels in mothers' milk were made from 1969 to 1976. The levels ofp,p-DDE, p,p DDT, dieldrin and PCB in mothers' milk were within the range reported by others. However, -BHC(Hexachlorocyclohexane) levels in the milk were 10 times that found in non-Japanese. A gradual decrease in the -BHC level in the milk was observed during this period. In contrast, the levelsof p,p-DDE,p,p-DDT, dieldrin and PCB were consistent for the 7-year period. A significant correlation between the levels of PCB andp,p-DDE in mothers' milk and blood was observed in the 1974–1976 samples. However, after prohibition of the use of chlorinated hydrocarbons, this relationship was less apparent in the 1972–1973 samples.  相似文献   

9.
Summary PCB, p,p-DDE and p,p-DDT residue levels were measured in human milk from New Brunswick and Nova Scotia. Preliminary results indicate that the levels of p,p-DDT and p,p-DDE are higher in the former area, possibly because of the wider use of insecticide sprays in the past. It should be emphasized that because of the limited number of samples analyzed, further work must be done before a significant difference in these areas can be established.  相似文献   

10.
The objective is to show how structural equation modeling can be used to detect reconceptualization, reprioritization, and recalibration response shifts in quality of life data from cancer patients undergoing invasive surgery. A consecutive series of 170 newly diagnosed cancer patients, heterogeneous to cancer site, were included. Patients were administered the SF-36 and a short version of the multidimensional fatigue inventory prior to surgery, and 3 months following surgery. Indications of response shift effects were found for five SF-36 scales: reconceptualization of general health, reprioritization of social functioning, and recalibration of role-physical, bodily pain, and vitality. Accounting for these response shifts, we found deteriorated physical health, deteriorated general fitness, and improved mental health. The sizes of the response shift effects on observed change were only small. Yet, accounting for the recalibration response shifts did change the estimate of true change in physical health from medium to large. The structural equation modeling approach was found to be useful in detecting response shift effects. The extent to which the procedure is guided by subjective decisions is discussed.  相似文献   

11.
Egg yolk was spiked withp,p-dicofol (p,p-DCF) (0.1–2.0 g/gm),p,p-dichlorobenzophenone (p,p-DCBP) (0.1–2.0 (g/gm), and 1,1-bis(4-chlorophenyl)-2,2-dichloroethylene (p,p- DDE) (0.05–1.0 g/gm). The fortified egg yolk (2–5 g) was mixed with acetonitrile to extract non-fat organic materials. After removal of acetonitrile, the spiked chemicals were separated with a column chromatograph packed with acid alumina. Recovery efficiencies forp,p-DCBP andp,p-DDE were determined by gas chromatography, and forp,p-dicofol by high performance liquid chromatography. The recovery efficiencies forp,p-dicofol,p,p-DCBP andp,p-DDE were 77.2–93.8%, 84.1–101.1%, and 88.5–96.0%, respectively.  相似文献   

12.
The purpose was to develop and validate a new instrument suitable for measuring perceived quality of life in women with breast cancer. The instrument is to be used within conventional cancer therapy as well as in complementary care, and is called the LSQ-32 (Life Satisfaction Questionnaire). The subjects were 362 women with breast cancer in all cancer stages. Cronbach's reliability coefficient of the LSQ was 0.89. The construct validity was estimated by a principal component analysis. Six orthogonal factors were identified: (1) Quality of family relation, (2) Physical symptoms, (3) Socioeconomic situation, (4) Quality of daily activities, (5) Sickness impact and (6) Quality of close friend relation. The criterion-related validity was estimated by comparing the LSQ-32 and the EORTC QLQ-C30. The scales/items of the EORTC QLQ-C30 were represented in the LSQ-32, but the factors Quality of family relation and Quality of close friend relation were not found in the EORTC QLQ-C30. It was concluded that the LSQ-32 as well as the EORTC QLQ-C30 are valuable tools in the measurement of quality of life in women with breast cancer. The LSQ-32, however, also contains an existential factor.The study was approved on 1992 04 08 by the Research Ethical Committee, Faculty of Health Sciences, University of Linköping.  相似文献   

13.
Concentrations of 15 organochlorine pesticides were determined by capillary gas chromatography in 59 human milk samples collected from the general population during 1989/1990 in the Jordanian capital of Amman. In addition to hexachlorbenzene (HCB), three groups of organochlorine compounds namely, DDT and its metabolites, hexachlorcyclohexane (HCH-isomers) and the cyclopentadiene group (aldrin, dieldrin, endrin, heptachlor, and heptachlor epoxide) were analyzed.The results show that almost all samples contained HCB, -HCH, p,p-DDE and p,p-DDT, whereas p,p-DDD, heptachlor, -HCH, -HCH and o,pDDT were found in 42, 40, 33, 22 and 20 analyzed samples, respectively. The concentration of HCB, -HCH, p,p-DDE, p,p-DDT and heptachlor expressed on a milk-fat basis (median in mg/kg milk fat): 0.29, 0.4, 2.04, and 0.7 respectively.For the comparative purposes and in order to try to find the possible sources of mother-milk contaminations, different types of locally produced and imported cow milk samples were also analyzed for the same organochlorine compounds. Almost all types of tested milk were contaminated with p,p-DDE.  相似文献   

14.
Isomer-specific concentrations of polychlorinated biphenyls (PCBs) including planar, mono- and di-ortho congeners and concentrations of DDT were determined in striped dolphins affected by a morbillivirus epizootic in the western Mediterranean in 1990. Extremely high concentrations of PCBs ranging from 94 to 670 g/g (wet wt) were detected in the blubber. Similarly, DDT concentrations were high, between 22 and 230 g/g (wet wt). The concentrations of three non-ortho coplanar PCBs were 43 (3,3,4,4-T4CB), 6.8 (3,3,4,4,5-P5CB), and 7.8 (3,3,4,4,5,5-H6CB) ng/g (wet wt), respectively, the highest residue levels reported to date. The estimated 2,3,7,8-TCDD toxic equivalents of non-, mono- and di-ortho PCB congeners in striped dolphins were several times higher than those observed for other marine mammals and humans. Mono-ortho congeners contributed greater 2,3,7,8-TCDD toxic equivalents than non-ortho members. The higher ratio of 3,3,4,4,5,5-H6CB/3,3,4,4,5-P5CB (IUPAC 169/126) suggested a strong induction of mixed function oxidase enzymes and highlighted the possibility of using this ratio as an index for risk assessment of PCB contamination in marine mammals. Elevated concentrations of PCBs may have played a role in the immune depression in striped dolphins, ultimately leading to the development of morbillivirus disease.  相似文献   

15.
Summary The large difference in retention times for the photoproducts of 3,4,34-tetrachlorobiphenyl can be explained on the basis of their chlorine content and the effect of vicinal chlorosubstitution as observed by V. Zitko and coworkers (4).The absence of biphenyl among the photoproducts of 4,4-dichlorobiphenyl was not surprising since 4-chlorobiphenyl (max 203, 253) does not absorb at the wavelength of irradiation (>286), 4,4-dichlorobiphenyl exhibits only marginal absorption at this wavelength (max 201, 259, 286) this explains the low yield of 4-chlorobiphenyl obtained (appx. .1%). The greater reactivity at the meta position may be the result of bond weakening due to steric interactions with the chlorine atom at the para position. Rate studies may provide an answer to this problem.  相似文献   

16.
The effects of atrazine and a combination of alachlor, atrazine, metolachlor, and metribuzin on the productivity and nutrient uptake rates of native streamAufwuchs communities were investigated in two separate artificial stream experiments. After an 8-day colonization period, the first experiment employed constant doses of atrazine at 0 g/L (control), 24 g/L and 134 g/L. The second experiment employed a pulsed dose having maximum concentrations of 35 g/L alachlor, 109 g/L atrazine, 90 g/L metolachlor, and 21 g/L metribuzin. Each 20-day experiment was run at both 10C and 25C. Constant exposure to 24 g/L atrazine yielded a significant reduction in both ash-free dry weight (AFDW) and chlorophylla at 25C but not at 10C. Constant exposure to 134 g/L atrazine yielded significantly less AFDW and chlorophylla at both temperatures. The pulsed exposure to four herbicides yielded significantly less AFDW at both temperatures, while chlorophylla was significantly less only at 10C. During continual exposure to 134 g/L atrazine, both NO2 + NO3 and silica uptake rates appeared to be reduced at both temperatures, although the differences were generally not statistically significant. At 10C uptake rates of soluble reactive phosphorus and NO2 + NO3 were depressed temporarily by exposure to the pulse of four herbicides, recovering to control rates within a few days, while no effect on uptake rates was discerned at 25C. The temperature difference between experimental runs had a greater effect on nutrient uptake rates than did the herbicide treatments during a run. The results indicate thatAufwuchs growth and nutrient uptake rates may be reduced temporarily by herbicide exposures in agricultural streams. However, greater effects on these processes may be exerted by other factors accompanying storm events, such as reduced temperatures.  相似文献   

17.
On the basis of ethnological research methods, the everyday life of one Danish and one American kindergarten class in school is described. In the American kindergarten class teaching of the three Rs (reading, writing and arithmetic) is predominant, whereas play constitutes the life in the Danish classroom. The study shows that the American teacher-controlled academic practice and the children's concrete cultural background contribute to the development of motivation for learning at the age of 6 years. On the other hand, the American children are very egocentric and have difficulties in participating in group activities. In contrast, the more child-controlled practice in the Danish kindergarten develops social competence but neglects the development of motivation for learning. With comprehensive development as the educational aim, neither the American teacher-controlled academic practice nor the Danish child-controlled play approach is quite adequate, which calls for a new paradigm in early childhood education.  相似文献   

18.
Summary To investigate the mechanism for bone disease caused by exposure to cadmium serum samples were collected from 5 itai-itai disease patients, 36 Cd-exposed residents with renal tubular damage and 17 non-exposed individuals and analyzed for 1,25-dihydroxyvitamin D[1, 25(OH)2D], parathyroid hormone, 2-microglobulin, calcium and inorganic phosphorus. Measurement of percentage tubular reabsorption of phosphate (%TRP) were performed only on the Cd-exposed subjects. Serum 1, 25(OH)2D], levels were lower in itai-itai disease patients and cadmium-exposed subjects with renal damage than in non-exposed subjects. Parathyroid hormone and 2-microglobulin concentrations in serum were higher in the Cd-exposed subjects. Decrease in serum 1,25(OH)2D levels were closely related to serum concentrations of parathyroid hormone, 2-microglobulin and %TRP. This study suggests that cadmium-induced bone effects were mainly due to a disturbance in vitamin D and parathyroid hormone metabolism, which was caused by the cadmium-induced kidney damage.  相似文献   

19.
The influences of peer, sibling, and parents smoking on adolescents initiation of tobacco use have been explained as a function of peer pressure, genetics, and social learning processes, but rarely in combination or with assessments of the quality of these relationships. This study examined the additional contributions of connectedness to friends, siblings, parents, and teachers beyond the effects of friend, sibling, and parental smoking using logistic regression analyses with a cross-sectional middle and high school sample of 303 rural adolescents. Friends and siblings smoking, and connectedness to friends, were the strongest predictors of experimental smoking. Parental smoking and connectedness to parents and to teachers were significant predictors of experimental smoking when considered independently, but not after accounting for friend and sibling factors. Connectedness to parents and teachers decreased the odds of experimental smoking, while connectedness to friends increased the odds.Editors Strategic Implications: This strategy of assessing connectedness to–and smoking behaviors of—friends, siblings, teachers, and parents shows promise in predicting teens cigarette smoking choices. The finding that the negative effects of unconventional connectedness and smoking by friends and siblings outweigh positive effects of connectedness to adults awaits replication with different samples and measures.  相似文献   

20.
The American cockroach (Periplaneta americana) was used to test 14 DDT analogs for their ability to cause a) death and b) repetitive firing in the abdominal nerve cord. P,p-DDT, p,p-DDD, p,p-methoxychlor, and o,p-DDT were all found to induce repetitive firing in the nerve cord after a twice threshold stimulus, but only p,p-DDT, p,p-DDD, and p,p-methoxychlor produced mortality within 4 days from injection of the pesticides. Also, cockroaches exposed to sublethal doses of p,p-DDT and p,p-methoxychlor were found to exhibit repetitive firing in the abdominal nerve cord three weeks after injection of the pesticide. The cause and effect relationship between neuroexcitation and lethality is therefore questioned, at least in the case of cockroaches.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号