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1.
Ethylene glycol ethers and acetates are used as intermediates, solvents, and plasticizers. They primarily enter the environment from manufacturing effluents and emissions and during their use in commercial products. Therefore, an examination of their ultimate fate and toxicity, as well as their potential for exposure, was performed. Overall, these data show that ethylene glycol ethers and acetates are not persistent in the environment, are not bioaccumulative, are generally classified by U.S. Environmental Protection Agency (EPA) procedures as "practically non-toxic" to aquatic organisms based on acute toxicity, and that conservatively calculated exposures are mostly below concentrations of concern for chronic risks to aquatic life.  相似文献   

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OBJECTIVE: Our purpose was to investigate the putative association between immunoglobulin G antibodies to Chlamydia trachomatis and recurrent spontaneous abortions. STUDY DESIGN: Sera from 106 idiopathic recurrent aborters and 81 of their partners were tested for immunoglobulin G antichlamydial antibodies by whole inclusion immunofluorescence and compared with 3890 sera from a general antenatal population. Positive sera were further investigated by microimmunofluorescence to determine species (Chlamydia trachomatis, Chlamydia pneumoniae, Chlamydia psittaci) specificity. RESULTS: Twenty-six (24.5%) of women with recurrent spontaneous abortions had immunoglobulin G antichlamydial antibodies compared with 28 (34.6%) of their partners (chi 2 2.25, p < 0.05) and 788 (20.3%) of the general antenatal population (chi 2 1.16, p < 0.05), and the incidence of antibody positivity showed no trend with increasing number of previous abortions. Fourteen women with recurrent spontaneous abortions had antibodies to Chlamydia trachomatis, 12 to Chlamydia pneumoniae. The prevalence of antibodies to C. trachomatis did not differ significantly between women with recurrent spontaneous abortions and their partners, but the male partners had a significantly (p = 0.005) higher prevalence of Chlamydia pneumoniae antibodies. Chlamydial antibody seropositivity did not correlate with subfertility or subsequent pregnancy outcome. CONCLUSION: There is no association between immunoglobulin G antibodies to Chlamydia trachomatis and recurrent spontaneous abortion.  相似文献   

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A balance method for the measurement of digestible and metabolizable energy in rats is described. Experimentally determined metabolizable energies of 2 diets for rats were closer to those values for metabolizable energy calculated from tabulated values for pigs rather than chickens. Some drawbacks in the use of tables of energy values to predict the energy of diets are discussed.  相似文献   

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A 19-year-old woman was admitted 45 min after ethylene glycol (EG) ingestion. The initial serum EG concentration was 1.34 g/l (21.6 mmol/l), the anion gap 14.5, and the osmolal gap 24. Renal function was preserved (serum creatinine 75.1 micromol/l). As the patient was seen soon after poisoning, before the development of metabolic acidosis, therapy with 4-methylpyrazole (4-MP) was proposed as an antidote. 4-MP was administered via the intravenous route (7 mg/kg as loading dose, followed by 3.6, 1.2, 0.6, and 0.6 mg/kg at intervals of 12 h). 4-MP alone was effective in preventing EG biotransformation to toxic metabolites (absence of metabolic acidosis and renal injury). Ethanol therapy, hemodialysis, and sodium bicarbonate administration were not required. The half-life of EG during 4-MP therapy was 11 h, with a mean EG renal clearance of 26.9 ml/min, and a total of 65.3 g EG was eliminated unchanged in the urine. 4-MP therapy was also well tolerated.  相似文献   

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The results of a greenhouse experiment on the translocation rate of 134Cs from potato leaves to tubers were compared with calculations of the radioecological model ECOSYS-87 and other literature values. The 134Cs activities applied at three development stages (three pinnate leaves fully developed, onset of flowering, onset of yellowing) to leaves of the plant were taken as starting points for the model to calculate the activity in the tubers at harvest. The default yield in the model was replaced by the experimentally obtained values. The translocation rate measured in the greenhouse experiment was 4 to 14 times higher than the calculations of the model. Some possible reasons for such a high translocation rate, compared with the literature data, are discussed. Based on these comparisons, it is concluded that maximal translocation occurs at the growth stage of flowering of a crop and that the development stage of a crop might be a stronger parameter to describe the time dependency of translocation than the usually applied parameter 'days before harvest'.  相似文献   

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Fibrinopeptide B (M(r) 1552.58) was employed as a calibration compound for matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) post-source decay (PSD) fragment ion analysis in the negative mode. Experiments were performed by using both continuous and delayed extraction, with the maximum reflectron voltages being 30 and 21 kV, respectively. For comparison, a common positive ion PSD calibrant, ACTH(18-39) (M(r) 2466.7), was also employed with positive ion calibration constants being applied to negative ion spectra. Using fibrinopeptide B as the calibrant, the negative ion PSD results for angiotensin II (M(r) 1046.2), renin substrate tetradecapeptide (horse) (M(r) 1759.0), and the custom-synthesized peptide (K2G4)2 (M(r) 987.1) showed a factor of 1.5-2 improvement in absolute mass accuracy. Typical absolute mass-to-charge ratio accuracies were within +/- 1 Thompson and were achieved even when the peptide being analyzed was more massive than fibrinopeptide B. In addition, both calibrants showed increased accuracy when experiments were conducted in the delayed extraction mode. Other advantages of using fibrinopeptide B are its moderate cost and the ability to perform calibration and sample analysis for negative ion PSD under the same instrumental conditions.  相似文献   

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BACKGROUND: Cigarette smoking and cocaine use may be risk factors for spontaneous abortion, but data supporting such a link are limited. METHODS: We studied the associations between cocaine and tobacco use and spontaneous abortion among pregnant adolescents and women (age range, 14 to 40 years) who sought care at an inner-city emergency department. A total of 400 adolescents and women had spontaneous abortions either at study entry or during follow-up (which lasted until 22 weeks' gestation), and 570 adolescents and women remained pregnant past 22 weeks' gestation. Cocaine use was measured at base line by self-reports and analysis of urine and hair samples. Cigarette smoking was measured by self-reports and urine analysis. RESULTS: The adolescents and women in both groups were predominantly black and of lower socioeconomic status. Among those who had spontaneous abortions, 28.9 percent used cocaine on the basis of hair analysis and 34.6 percent smoked on the basis of a urine cotinine assay, as compared with 20.5 percent and 21.8 percent, respectively, of the adolescents and women who did not have spontaneous abortions. The presence of cocaine in hair samples was independently associated with an increase in the occurrence of spontaneous abortion (odds ratio, 1.4; 95 percent confidence interval, 1.0 to 2.1) after adjustment for demographic and drug-use variables. However, the use of cocaine as measured by self-reports and by urine analysis was not. The presence of cotinine in urine was also independently associated with an increased risk of spontaneous abortion (odds ratio, 1.8; 95 percent confidence interval, 1.3 to 2.6). Twenty-four percent of the risk of spontaneous abortion could be related to cocaine or tobacco use. CONCLUSIONS: Cocaine and tobacco use were common in our study population and were associated with a significant risk of spontaneous abortion.  相似文献   

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The role of endocrine factors as a cause of recurrent spontaneous abortion is controversial. Diabetes mellitus and thyroid disease do not represent a significant risk factor for recurrent pregnancy loss. Luteal-phase defect has been questioned because there are no accurate methods for diagnosis and no convincing evidence of correction with treatment exists. The corpus luteum is an unusual endocrine gland, highly diverse in function and important for successful reproduction in all mammalian species. Much controversy exists about the luteal function in humans and how defects in luteal function affects reproduction. Disagreement has been due to lack of accurate diagnosis and controlled studies to determine whether correction of the luteal-phase defect is worthwhile when treating female reproductive problems. The donor egg recipient model from assisted reproductive technology programs has shown that corpus luteum function can be replaced by estrogen and progesterone administration. The mechanism by which these steroids stimulate a uterus to be receptive to implantation of the embryo is not known. Several proteins produced by the endometrium are candidate markers for uterine receptivity. Further work needs to be done to correlate these markers with subsequent pregnancy outcome. A noninvasive marker for uterine receptivity is ultrasonographic evaluation of the endometrium. Although the sensitivity of this test is high (100%), its specificity is low (only 20% to 60%).  相似文献   

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In the present study, we assessed the ability of increasing doses of intranasal calcitonin to suppress urinary deoxypyridinoline cross-link (DPD), a specific biochemical marker of bone resorption, in early postmenopausal women. Subjects consisted of 30 healthy Thai women within 5 years of postmenopause, randomly assigned to 50, 100, or 200 IU of intranasal calcitonin 5 days/week for 3 months. Calcium supplementation by calcium carbonate capsules at 750 mg of elemental calcium per day was given to all subjects. Twenty four-hour urine for DPD and creatinine assays was collected at baseline, 1 month, and 3 months after treatment. All DPD values were corrected with urinary creatinine before analyses. Data were expressed as mean +/- SEM. DPD decreased significantly 1 month after intranasal calcitonin treatment (P < 0.01). However, at 3 months, DPD increased when compared with the values at 1 month (P < 0.01), suggesting that there may be a reduction in the suppression of bone resorption after prolonged calcitonin therapy. Using a stepwise multiple regression model to address whether dosage and DPD at baseline influence the response to intranasal calcitonin, it was found that DPD suppression after intranasal calcitonin was not related to dosage but was strongly associated with baseline DPD (P < 0.0001). Suppression of bone resorption in early postmenopausal women by intranasal calcitonin is determined more by the state of bone turnover at baseline than the dosage of calcitonin.  相似文献   

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We examined the relations between spontaneous abortion and the consumption of caffeine, individual caffeine-containing beverages (coffee, tea, and soda), and decaffeinated coffee in a prospective study of 5,144 pregnant women. We collected information about potential risk factors for spontaneous abortion, including consumption of caffeinated beverages and decaffeinated coffee before and during pregnancy, by interview in the first trimester. Neither total estimated caffeine nor individual caffeinated beverage consumption during the first trimester was associated with an appreciable increase in risk for spontaneous abortion. The adjusted odds ratio for consumption of greater than 300 mg per day of caffeine was 1.3 [95% confidence interval (CI) = 0.8-2.1] after adjustment for maternal age, pregnancy history, cigarette and alcohol consumption, employment, race, gestational age at interview, and marital and socioeconomic status. The adjusted odds ratio for spontaneous abortion related to consumption of three or more cups of decaffeinated coffee during the first trimester was 2.4 (95% CI = 1.3-4.7) in the same model. Although we could not demonstrate this with available data, we suspect that this association was due to bias resulting from the relations among fetal viability, symptoms of pregnancy such as nausea, and consumption patterns during pregnancy.  相似文献   

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In multiple pregnancies, survival of remaining fetuses after premature death and delivery of one fetus is uncommon. We report a case of a triplet pregnancy that was reduced to twins at the 14th gestational week and then had preterm premature rupture of membranes and intrauterine fetal death of one twin at the 17th gestational week. To save the surviving fetus, delivery of the dead fetus and ligation of the umbilical cord at the cervical level were performed. We also performed McDonald cervical cerclage to keep the placenta of the dead fetus as well as that of the surviving one in the uterine cavity. After a series of aggressive procedures, including immediate administration of tocolytic agents, and antibiotic prophylaxis to prevent infection and preterm labor, the surviving fetus was delivered vaginally 73 days later due to intractable uterine contractions. After a 10-week hospital stay, the infant boy, weighing 2,500 g, was discharged without any sequelae. To our knowledge, this was the longest interval between deliveries in a triplet pregnancy reported in Taiwan. With adequate intensive management, a satisfactory outcome of the fetus and mother in such cases is possible.  相似文献   

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The present nationwide, multicenter clinical study was carried out in 26 departments of surgery to define the incidence and attendant mortality of intestinal infarction following abdominal aortic surgery, and to identify patients at risk of it. The data consist of 1752 patients who underwent abdominal aortic reconstruction during 1991-1993 as recorded in the Finnish national vascular registry (FINNVASC). Among the 1752 operations, 27 patients treated at 14 different hospitals had intestinal ischemia, and the complete patient records of all 27 cases were reanalyzed. The incidence of bowel infarction was 1.2%. Among patients operated on for a ruptured aneurysm it was 3.1%, whereas 1.0% of patients with nonruptured aneurysm and 0.6% of those operated on for aortoiliac occlusive disease developed intestinal infarction. In 14 patients (67%) the lesion affected the left colon. The overall 30-day mortality rate was 13% but reached 67% among those with intestinal infarction. We conclude that acute intestinal ischemia with bowel infarction is an infrequent but serious complication of abdominal aortic surgery. It is mainly related to surgery due to aneurysmal disease, and patients with occlusive aortoiliac disease present ischemic complications in the intestines less often. Hypotensive patients being treated for ruptured aneurysm are at greatest risk of intestinal ischemia.  相似文献   

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OBJECTIVE: This study examines three specific questions about obesity and overweight, using a nationally representative sample of Canadians. Are sociodemographic and lifestyle behaviors associated with body weight? Is body weight correlated with specific health outcomes? Has the prevalence of obesity in Canada changed since 1978? METHODS: Secondary data analysis of a cross-sectional survey. SAMPLE: This study uses the 1994 National Population Health Survey (NPHS) by Statistics Canada. It is a stratified random sample of 19600 Canadians across all provinces. RESULTS: The results show that age, gender, education, birth place and region, are significantly associated with obesity. When a lower criterion is used for overweight and obesity (body mass index, BMI > or = 25), dummy variables for marital status and occupation are also significant. Second, obesity is associated with poorer self-rated health, high blood pressure, heart disease, diabetes, arthritis, respiratory and stomach problems. For those respondents who have a BMI score of 25 or greater, there is also an association with stroke. Finally, it is unclear whether the prevalence of obesity has changed. However, there appears to be a systematic difference between studies using actual height and weight measurements (anthropometric) vs self-reported measurements. CONCLUSIONS: Weight can be considered a modifiable risk factor and reductions in the prevalence of obesity should reduce the risk of specific chronic conditions. Provincial variations in the prevalence of obesity (BMI > or = 27) and overweight and obesity (BMI > or = 25) suggest that collapsing provinces into regions may obscure important inter-provincial differences in body weight. More research is required to assess whether or not obesity is decreasing in Canada. Some of the limitations of self-reported data are discussed.  相似文献   

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The aim of this paper was to identify the mechanism/s responsible of the antimetastatic effect of a single low dose of cyclophosphamide (Cy), previously demonstrated by us in the rat lymphoma LTACB. No direct cytotoxic antimetastatic activity of Cy could be proved. In vitro treatment of L-TACB cells with mafosfamide did not alter their invasiveness or their motility. The adoptive transfer of splenocytes from Cy-treated tumor-bearing rats, together with L-TACB cells inhibited their metastatic growth. The single low dose Cy treatment of T-immunodeficient nude mice did not show the antimetastatic effect on L-TACB observed in immunocompetent mice. An inhibition of the metastatic ability due to immunomodulation by Cy is proposed.  相似文献   

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