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排序方式: 共有892条查询结果,搜索用时 15 毫秒
11.
N Weiss V Gudnasson P Ostwald S Humphries H Schuster C Keller 《Canadian Metallurgical Quarterly》1997,13(3):141-151
The DNA adduct 8-hydroxy-2'-deoxyguanosine (8-OHdG) has been widely used as a biomarker for oxidative stress. Bulky DNA adducts, which are detectable by the 32P-postlabelling method, provide evidence for exposure to and metabolic activation of large, mainly apolar compounds, e.g. polycyclic aromatic hydrocarbons. We determined both types of adducts in placental tissues of 30 term pregnancies and related the adduct levels to the exposure to tobacco smoke and the plasma antioxidant status. Urine and plasma continine concentrations were used to select 10 nonsmokers, 9 nonsmokers exposed to environmental tobacco smoke (ETS) and 11 smoking women. Placental levels of 8-OHdG were 0.84 +/- 0.11, 0.90 +/- 0.21 and 0.83 +/- 0.20/10(5) deoxyguanosine bases (dG) for nonsmokers, nonsmokers exposed to ETS and smokers, respectively. The differences between the groups were not significant. Smoking women had significantly lower plasma vitamin C and beta-carotene concentrations than nonsmoking women or nonsmoking women exposed to environmental tobacco smoke. The 8-OHdG adduct level in placental DNA was inversely correlated with the plasma vitamin E concentration (r = -0.47, P < 0.05). There was no association between placental 8-OHdG adducts and vitamin A, C and beta-carotene in plasma. In total, 15 different adducts could be identified in the 30 placenta samples by the 32P-postlabelling method. There was a strong inter-individual variation in both the number of adducts and adduct intensities. No smoking-related or vitamin-related effects on adduct patterns or intensities were found. Our findings suggests that, within the limits of the methods used, tobacco smoke exposure during pregnancy does not lead to a measurable increase in placental DNA adduct levels and that vitamin E appears to have a protective effect on placental 8-OHdG formation. 相似文献
12.
RJ Mayer RB Davis CA Schiffer DT Berg BL Powell P Schulman GA Omura JO Moore OR McIntyre E Frei 《Canadian Metallurgical Quarterly》1994,331(14):896-903
BACKGROUND: About 65 percent of previously untreated adults with primary acute myeloid leukemia (AML) enter complete remission when treated with cytarabine and an anthracycline. However, such responses are rarely durable when conventional postremission therapy is administered. Uncontrolled trials have suggested that intensive postremission therapy may prolong these complete remissions. METHODS: We treated 1088 adults with newly diagnosed AML with three days of daunorubicin and seven days of cytarabine and randomly assigned patients who had a complete remission to receive four courses of cytarabine at one of three doses: 100 mg per square meter of body-surface area per day for five days by continuous infusion, 400 mg per square meter per day for five days by continuous infusion, or 3 g per square meter in a 3-hour infusion every 12 hours (twice daily) on days 1, 3, and 5. All patients then received four courses of monthly maintenance treatment. RESULTS: Of the 693 patients who had a complete remission, 596 were randomly assigned to receive postremission cytarabine. After a median follow-up of 52 months, the disease-free survival rates in the three treatment groups were significantly different (P = 0.003). Relative to the 100-mg group, the hazard ratios were 0.67 for the 3-g group (95 percent confidence interval, 0.53 to 0.86) and 0.75 for the 400-mg group (95 percent confidence interval, 0.60 to 0.94). The probability of remaining in continuous complete remission after four years for patients 60 years of age or younger was 24 percent in the 100-mg group, 29 percent in the 400-mg group, and 44 percent in the 3-g group (P = 0.002). In contrast, for patients older than 60, the probability of remaining disease-free after four years was 16 percent or less in each of the three postremission cytarabine groups. CONCLUSIONS: These data support the concept of a dose-response effect for cytarabine in patients with AML who are 60 years of age or younger. The results with the high-dose schedule in this age group are comparable to those reported in similar patients who have undergone allogeneic bone marrow transplantation during a first remission. 相似文献
13.
14.
B Nygaard L Hegedüs FN Bennedbaek A Veje JO Faber JE Hansen 《Canadian Metallurgical Quarterly》1998,160(37):5349-5352
Traditional treatment modalities of diffuse nontoxic goitre are thyroid hormone suppression or surgery. When treating nodular nontoxic goitre with 131I treatment, a reduction in thyroid volume to about 50% is seen. In the present study we evaluated the effect of 131I treatment in 21 patients treated for a diffuse nontoxic goitre and followed by evaluation of thyroid volume measured by ultrasound. Thyroid volume declined in all patients from median of 66 ml (range 27-160 ml) to 21 ml (9-108 ml) over a year, a reduction of 62%. Three patients developed hypothyroidism in the follow-up period (14%), one of these had a temporary hyperthyroid fase. In conclusion, 131I treatment of diffuse nontoxic goitre reduces thyroid volume by approximately 60% within 12 months. Hypothyroidism developed in 14% during a limited follow-up period. 相似文献
15.
Patients suffering from Alzheimer's disease (AD) have severe difficulties in tasks requiring the use of semantic knowledge. The semantic deficits associated with AD have been extensively studied by using behavioral methods. Many of these studies indicate that AD patients have a general deficit in voluntary access to semantic representations but that the structure of the representations themselves might be preserved. However, several studies also provide evidence that to some extent semantic representations in AD may in fact be degraded. Recently, a few studies have utilized event-related brain potentials (ERPs) that are sensitive to semantic factors in order to investigate the electrophysiological correlates of the semantic impairment in AD. Interest has focused on the N400 component, which is known to reflect the on-line semantic processing of linguistic and pictorial stimuli. The results from studies of N400 changes in AD remain somewhat controversial: Some studies report normal or enlarged N400 components in AD, whereas others report diminished ones. One issue not reported in previous studies is whether word-elicited ERPs other than N400 remain normal in AD. In the present study our aim was to find out whether the ERP waveforms N1, P2, N400, and Late Positive Component (LPC) to semantically congruous and incongruous spoken words are abnormal in AD and whether such abnormalities specifically reflect deficiencies in semantic activation in AD. Auditory ERPs from 20 scalp sites to semantically congruous and incongruous final words in spoken sentences were recorded from 17 healthy elderly adults and 9 AD patients. The early ERP waveforms N1 and P2 were relatively normal for the AD patients, but the N400 and LPC effects (amplitude difference between congruous and incongruous conditions) were significantly reduced. We interpret the present results as showing that semantic-conceptual activation and other high-level integration processes are defective in AD. However, a word congruity effect earlier than N400 (phonological mismatch negativity), reflecting lexical selection processes, is at least to some extent preserved in AD. 相似文献
16.
H Miyachi Y Koiso R Shirai S Niwayama JO Liu Y Hashimoto 《Canadian Metallurgical Quarterly》1998,46(7):1165-1168
The synthesis and tumor necrosis factor (TNF)-alpha production enhancing activity of substituted 3'-methylthalidomides on human leukemia cell line HL-60 stimulated with 12-O-tetradecanoyl-phorbol 13-acetate (TPA) are described. Though the introduction of an electron-donating amino group at the phthaloyl moiety of alpha-methylthalidomides enhanced the activity, substituted alpha-methylthalidomides showed decreased stereoselectivity as compared to that of non-substituted alpha-methylthalidomide. The data indicates that the TNF-alpha production enhancing activity of thalidomide derivatives depends on both the electronic-state of substituents at the fused benzene ring and the stereochemistry of the glutarimide moiety. 相似文献
17.
J Svensson C Ohlsson JO Jansson G Murphy D Wyss D Krupa K Cerchio W Polvino B Gertz D Baylink S Mohan BA Bengtsson 《Canadian Metallurgical Quarterly》1998,13(7):1158-1166
The effect of 2 months of treatment with the oral growth hormone (GH) secretagogue MK-677 on markers of bone metabolism was determined in healthy obese male subjects. This was a randomized, double-blind, parallel, placebo-controlled study. Twenty-four healthy obese males, 19-49 years of age, with body mass index > 30 kg/m2 were treated with MK-677 (25 mg/day; n = 12) or placebo (n = 12) for 8 weeks. MK-677 increased markers of bone formation; a 23% increase in the carboxy-terminal propeptide of type I procollagen levels and a 28% increase in procollagen III peptide levels were seen with as little as 2 weeks of MK-677 treatment (p < 0.01 and p = 0.001 vs. placebo, respectively) while a 15% increase in serum levels of osteocalcin was not detected until 8 weeks of treatment (p < 0.01 vs. placebo). Markers of bone resorption were induced within 2 weeks of treatment with MK-677; serum levels of the carboxy-terminal cross-linked telopeptide of type I collagen were increased 26% at 8 weeks (p = 0.001 vs. placebo), and urine hydroxyproline/creatinine and calcium/creatinine ratios at 8 weeks were increased by 23% (p < 0.05 vs. placebo) and 46% (p < 0.05 vs placebo), respectively, MK-677 increased serum insulin-like growth factor binding protein-5 (IGFBP-5) by 43-44% after 2-8 weeks of treatment (p < 0.01 vs. placebo). Serum IGFBP-4 was increased by 25% after 2 weeks of treatment (p < 0.001 vs. placebo) but no significant change from baseline was observed after 8 weeks of treatment. Plasma interleukin-6 was not significantly changed by active treatment. In conclusion, short-term treatment of healthy obese male volunteers with the GH secretagogue MK-677 increases markers of both bone resorption and formation. Large increases in serum levels of IGF-1 and IGFBP-5 and a transient increase in serum IGFBP-4 were found. Future long-term studies are needed to investigate if prolonged treatment with MK-677 increases bone mass. 相似文献
18.
RasGRP, a Ras guanyl nucleotide- releasing protein with calcium- and diacylglycerol-binding motifs 总被引:1,自引:0,他引:1
JO Ebinu DA Bottorff EY Chan SL Stang RJ Dunn JC Stone 《Canadian Metallurgical Quarterly》1998,280(5366):1082-1086
RasGRP, a guanyl nucleotide-releasing protein for the small guanosine triphosphatase Ras, was characterized. Besides the catalytic domain, RasGRP has an atypical pair of "EF hands" that bind calcium and a diacylglycerol (DAG)-binding domain. RasGRP activated Ras and caused transformation in fibroblasts. A DAG analog caused sustained activation of Ras-Erk signaling and changes in cell morphology. Signaling was associated with partitioning of RasGRP protein into the membrane fraction. Sustained ligand-induced signaling and membrane partitioning were absent when the DAG-binding domain was deleted. RasGRP is expressed in the nervous system, where it may couple changes in DAG and possibly calcium concentrations to Ras activation. 相似文献
19.
JO Larsson G Aurelius L Nordberg PA Rydelius R Zetterstr?m 《Canadian Metallurgical Quarterly》1996,85(12):1450-1455
Home visiting is a part of the Swedish child health surveillance programme. In the present study, part of a longitudinal prospective project, the predictive power of observations at home visits to 338 newborn babies was evaluated. The regular home visit was made by the nurse at a Child Welfare Centre also using a check-list developed for this project. Her check-list assessments seemed valid in identifying families with stressful psychosocial conditions. When the general home situation was judged as "poor" or "dubious", the boys showed signs of a delayed mental development at 4-5 years of age. Assessments of "feeding problems" among boys were associated with behavioural problems at 4-5 years of age. The results underline the importance of an early home visit as a base for the developmental surveillance at Child Welfare Centres. However, the results of the home visit observations were not followed by any extra interventions at CWC. It seems the nurse should feel confident in her check-list judgement and initiate interventions where appropriate. 相似文献
20.
WR Hart DE Townsend JO Aldrich BE Henderson M Roy B Benton 《Canadian Metallurgical Quarterly》1976,37(2):763-775
A total of 98 colposcopically directed biopsies were obtained from the vagina, cervix, and cervicovaginal ridge (hood) of 80 young women believed to have had intrauterine exposure to stilbestrol (DES). Specific investigation of the patient's medical records corroborated the history of maternal stilbestrol administration in 36 patients (45%), while in the remainder the drug history was regarded as presumptive since medical records were unavailable for review. The findings did not differ significantly in those biopsies taken from patients with confirmed or presumptive drug histories. Histologic evidence of vaginal adenosis was detected in vaginal biopsies from 43 patients. In 30 cases (70%) benign Müllerian-type glandular epithelium was in the superficial vaginal wall, residing on the mucosal surface and/or in the lamina propria. The glandular epithelium predominantly was of endocervical type, but in six instances it resembled endometrial or fallopian tubal epithelium. The glands were accompanied by varying degrees of squamous metaplasia in 22 cases. When extensive the metaplasia produced transformation zones similar to those seen in the normal cervix. Vaginal biopsies of adenosis from the other 13 patients (30%) revealed squamous metaplasia without demonstrable glands due to complete transformation of all antecedent glandular epithelium by squamous metaplasia. Our studies indicate that squamous metaplasia is a component of major importance in the natural history of adenosis and that the concept of adenosis should be broadened to include those examples comprised exclusively of metaplastic epithelium. In such examples metaplasia is identified by the immaturity and poor glycogenation of the squamous cells and their accompanying squamous pegs which often contain residual gland openings or squamous "eddies." Similar findings were present in biopsies of seven cervicovaginal ridges and in cervical biopsies from 37 patients, except for the absence of endometrial or tubal type glands in the latter site. Although no adenocarcinomas were detected, six patients had squamous dysplasia of the vagina and/or cervix. In no case were premalignant or dysplastic changes of glandular cells found. Our findings support the thesis that stilbestrol-associated adenosis represents anomalous embryologic localization of the original squamocolumnar junction in the vagina rather than in the cervix. It is closely related to so-called cervical "erosions." The development of squamous metaplasia accounts for modifications in the clinical and histologic appearances by producing transformation zones which then may be subject to the same oncogenic stimuli for squamous neoplasia as are their counterparts in the cervix. 相似文献