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21.
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
22.
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
23.
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
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Advances in neuroscience research over the last few decades have increased our understanding of how individual neurons acquire their specific properties and assemble into complex circuits, and how these circuits are affected in disease. One of the important motives driving neuroscience research is the development of new scientific techniques and interdisciplinary cooperation. Compared to developed countries, many countries on the African continent are confronted with poor facilities, lack of funding or career development programs for neuroscientists, all of which deter young scientists from taking up neuroscience as a career choice. This article highlights some steps that are being taken to promote neuroscience education and research in Africa. 相似文献
28.
This study reports on infective endarteritis in 14 children with patent ductus arteriosus over a period of 6 years. Infective endarteritis mostly involved the small ducts and was previously undiagnosed. These patients were given antibiotic treatment for a variable period of 4 to 10 weeks, and all except 1 underwent subsequent closure. 相似文献
29.
Bhatia E Choudhuri G Sikora SS Landt O Kage A Becker M Witt H 《Gastroenterology》2002,123(4):1020-1025
BACKGROUND & AIMS: Tropical calcific pancreatitis (TCP) is a chronic pancreatitis unique to developing countries in tropical regions. The cause of TCP is obscure. Whereas environmental factors, such as protein energy malnutrition and ingestion of cassava, have been implicated, a genetic predisposition to the disease also may be important. In the present study we report on mutations in the serine protease inhibitor, Kazal type 1 (SPINK1) gene in north Indian patients with TCP. METHODS: We studied 66 unrelated TCP patients (44 men, 49 with diabetes, and 6 with family history of TCP), 25 relatives, and 92 healthy control subjects. Samples were analyzed for SPINK1 variants (-53C>T, L14P, N34S, P55S, and 272T>C) and cationic trypsinogen (PRSS1) variants (A16V, K23R, N29I, and R122H) by melting curve analysis. RESULTS: Twenty-nine patients (44%) carried the N34S missense mutation, of whom 9 (14%) were homozygotes. In contrast, only 2 (2.2%) control subjects were N34S heterozygotes (prevalence ratio 20.2; 95% confidence interval 5.0-81.8; P < 0.0001 vs. TCP). The severity of pancreatitis did not differ between TCP patients with or without N34S, or among those heterozygous or homozygous for N34S. Among TCP patients with or without diabetes, the frequency of N34S carriers (43% vs. 47%) and N34S homozygotes (14% vs. 12%) was similar. CONCLUSIONS: TCP is highly associated with the SPINK1 N34S mutation. The high prevalence of N34S in TCP patients with and without diabetes suggests that these 2 subtypes have a similar genetic predisposition. The genetic predisposition to TCP resembles, at least in part, the idiopathic chronic pancreatitis found in industrialized countries. 相似文献
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