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排序方式: 共有1247条查询结果,搜索用时 15 毫秒
11.
Assessment of the mutagenicity of dichloroacetic acid in lacI transgenic B6C3F1 mouse liver 总被引:2,自引:0,他引:2
Dichloroacetic acid (DCA) is a chlorination byproduct found in finished
drinking water. When administered in drinking water this chemical has been
shown to produce hepatocellular adenomas and carcinomas in B6C3F1 mice over
the animal's lifetime. In this study, we investigated whether mutant
frequencies were increased in mouse liver using treatment protocols that
yielded significant tumor induction. DCA was administered continuously at
either 1.0 or 3.5 g/l in drinking water to male transgenic B6C3F1 mice
harboring the bacterial lacI gene. Groups of five or six animals were
killed at 4, 10 or 60 weeks and livers removed. At both 4 and 10 weeks of
treatment, there was no significant difference in mutant frequency between
the treated and control animals at either dose level. At 60 weeks, mice
treated with 1.0 g/l DCA showed a 1.3-fold increase in mutant frequency
over concurrent controls (P = 0.05). Mice treated with 3.5 g/l DCA for 60
weeks had a 2.3-fold increase in mutant frequency over the concurrent
controls (P = 0.002). The mutation spectrum recovered from mice treated
with 3.5 g/l DCA for 60 weeks contained G:C-->A:T transitions (32.79%)
and G:C-->T:A transversions (21.31%). In contrast, G:C-->A:T
transitions comprised 53.19% of the recovered mutants among control
animals. Although only 19.15% of mutations among the controls were at T:A
sites, 32.79% of the mutations from DCA-treated animals were at T:A sites.
This is consistent with the previous observation that the proportion of
mutations at T:A sites in codon 61 of the H-ras gene was increased in
DCA-induced liver tumors in B6C3F1 mice. The present study demonstrates
DCA-associated mutagenicity in the mouse liver under conditions in which
DCA produces hepatic tumors.
相似文献
12.
Fatty acid balance studies in term infants fed formula milk containing long-chain polyunsaturated fatty acids 总被引:1,自引:0,他引:1
C Morgan L Davies F Corcoran J Stammers J Colley SA Spencer D Hull 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(2):136-142
Long-chain polyunsaturated fatty acids (LCP) are thought to be required for optimal nervous system development in the newborn. A commercial milk formula containing LCP (Aptamil-LCP) with a fatty acid profile closely resembling breast milk, has recently been introduced for term infants. The absorption of fatty acids in term infants was examined in a double-blind randomized controlled trial comparing Aptamil-LCP ( n = 20) and standard Aptamil ( n = 20). Formula-fed newborn infants were studied from birth for 14 d. Fat balances (3 d) were performed from d 10. A 3-d stool collection was performed from d 10 in a parallel breastfed group ( n = 21). Plasma samples were taken on d 6. Median fat excretion (mg kg−1 ) was 897.1, 615.0 and 355.2 with Aptamil, Aptamil-LCP and breastfeeding, respectively. The median total fat absorption coefficient in Aptamil-LCP-fed infants was higher than in those fed standard Aptamil ( p < 0:01). These findings were accounted for by differences in the excretion and absorption of long-chain saturated fatty acids (C14:0, C16:0 and C18:0). Higher fat excretion was associated with bulkier and firmer stools. Only trace amounts of LCP were detected in the stools of all groups. This accounted for less than 4% of dietary intake in Aptamil-LCP-fed infants. No differences in the utilization of LCP from Aptamil-LCP and breast milk feeding were apparent. Plasma phospholipid fatty acid composition data reflected differences in dietary LCP intake. Thus, PL LCP levels were highest in the breastfed infants and lowest in the Aptamil-fed infants, with values for the Aptamil-LCP-fed group falling in between. 相似文献
13.
Characterization of the insulin-like growth factor axis in a human hepatoma cell line (PLC) 总被引:4,自引:0,他引:4
Scharf JG; Schmidt-Sandte W; Pahernik SA; Ramadori G; Braulke T; Hartmann H 《Carcinogenesis》1998,19(12):2121-2128
14.
Remote memory in epilepsy 总被引:3,自引:0,他引:3
PURPOSE: There is now a considerable amount of research relating to memory functioning in epilepsy. The majority of studies have focused on the retention of new information, and few reports have measured memory for past events. This study aims to redress this and measure the efficiency of remote memory in epilepsy. METHODS: A remote memory questionnaire was prepared and administered to three groups of patients with epilepsy and a control group without epilepsy. The questionnaire assessed knowledge of public events that occurred between 1980 and 1991, inclusive. The epilepsy groups comprised 33 patients with temporal lobe epilepsy (TLE), 33 with extratemporal epilepsy (ExTE), and 10 with primary generalized epilepsy (PGE). Thirty control subjects were tested. RESULTS: Patients with TLE performed significantly less well on the questionnaire than all other groups (p = 0.001), but no effect of laterality was recorded; patients with extratemporal or primary generalised epilepsy did not differ from controls. Performance on the questionnaire was not determined by verbal IQ, educational achievement, social class, or drug treatment, but was related to the number of generalised convulsions that had occurred since 1980. The strongest neuropsychological predictors of performance on this questionnaire were measures of verbal memory. CONCLUSIONS: The study demonstrated weak memory for past events in patients with TLE, thereby providing evidence of a broader memory disturbance in this group than has been previously highlighted. A test of remote memory, such as the one designed for this study, is easy to administer and provides clinically important information not available from conventional neuropsychological tests. 相似文献
15.
16.
舌黏膜尿道成形治疗尿道狭窄的初步报告 总被引:3,自引:0,他引:3
目的:探讨舌黏膜补片法尿道成形治疗尿道狭窄的疗效。方法:采用舌黏膜尿道成形治疗尿道狭窄14例。尿道狭窄段3.5~14cm,平均6.2cm;术前耻骨上膀胱造瘘8例,余6例排尿均较为困难,最大尿流率2.5~5.5ml/s,平均3.8ml/s。结果:术后随访2~8个月,1例因伤口感染致尿道皮肤瘘,余患者均排尿通畅,最大尿流率增至22~51ml/s,平均29.6ml/s。结论:舌黏膜具有取材方便、对患者创伤小、抗感染力强等特点,是一种较好的尿道替代物,尤其适合尿道狭窄段<6cm的患者。 相似文献
17.
[目的]评价蒙药胃舒安对束缚-水浸应激所致大鼠胃溃疡的预防作用。[方法]将Wistar实验大鼠,分正常组、给药组和对照组3组,正常组不给药,无束缚-水浸应激压力,对照组给淀粉,给药组灌胃给蒙药胃舒安,给药剂量为0.9~1.3mL/只(82.5g/L),连续给胃舒安7d后,停食24h,建立3h束缚-水浸应激性胃溃疡模型,取胃,肉眼观察胃黏膜损伤,用Image J图像分析法测定胃黏膜溃疡面积,并进行比较。用酶联免疫吸附测定法检测胃溃疡大鼠血清转化生长因子(TGF-β1)含量并进行比较。[结果]蒙药胃舒安对3h束缚-水浸应激所致大鼠胃溃疡形成有抑制作用。胃舒安组大鼠血清TGF-β1含量明显低于对照组。[结论]蒙药胃舒安对实验大鼠束缚-水浸应激3h所致胃溃疡的形成有显著抑制作用。 相似文献
18.
目的 分析未净化Z:ZCLA长爪沙鼠封闭群繁育和生长指标,并利用直接测序法分析其遗传稳定性.方法 随机选择40对Z:ZCLA长爪沙鼠,记录其繁殖胎次、产子数等指标,分析其仔鼠的生长发育情况.遗传稳定性分析选择Z:ZCLA长爪沙鼠非同胞、非亲代个体33只,提取肝脏基因组DNA,PCR扩增D-Loop序列,产物纯化后双向测序,测序结果与Z:ZCLA长爪沙鼠标准序列比对.结果 Z:ZCLA长爪沙鼠每胎产仔7只,胎间隔多在20~60d间,雄性体重高于雌性.遗传稳定性分析检测发现33只Z:ZCLA长爪沙鼠序列与标准序列完全一致.结论 Z:ZCLA长爪沙鼠群体内未发现遗传多态性,说明该群体具有较好的遗传稳定性. 相似文献
19.
目的了解安徽省志贺氏菌的流行菌型,并建立脉冲场凝胶电泳(PFGE)分子分型方法,为菌痢防控提供理论基础。方法对22株志贺氏菌进行血清分型、药物敏感试验和PFGE试验。结果22株志贺氏菌血清分型:B群19株,占总数86.5%;C群1株,占总数的4.5%;D群2株,占总数的9.0%。成功建立了菌痢的PFGE分子分型方法,并将我省22株流行株分为若干带型。试验结果进一步作聚类分析。结论安徽省菌痢流行株以福氏为主;安徽省PFGE分子分型方法和初步带型数据库对提高细菌检测水平有一定意义。 相似文献
20.