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Query: EC:3.4.15.1 (
ACE
)
18,300
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
In a chronic study by the National Toxicology Program (NTP), dimethyl hydrogen phosphite (DMHP) caused neoplastic and nonneoplastic changes in the lungs and forestomach of F344/N rats following gavage administration for 2 years. The current investigation was designed to study the effect of a short-term exposure on a series of biochemical systems in target and nontarget tissues which may be involved in the metabolism and/or the manifestation of DMHP toxicity. Rats were treated daily with a dose similar to that used in the NTP study (200 mg/kg) for 4, 5, or 6 weeks. Two groups of animals were also treated for 4 weeks and then treatment was discontinued and the rats were allowed to recover for 1 or 2 weeks. An equal number of animals was treated similarly with the vehicle and used as control. The microsomal and soluble fractions were separated from liver, lungs, kidneys, forestomach, and glandular stomach from the 6-week treatment group. Another group of rats treated for 6 weeks was prepared for pathology examination of the lungs, forestomach, and glandular stomach. There was a significant increase in the weight of the forestomach of rats treated for 4, 5, or 6 weeks relative to control animals, while no significant difference was observed in the weight of liver, lungs, kidneys, and glandular stomach. The forestomach weight of rats treated for 4 weeks returned to the control value after 1 week of recovery. Microscopic examination of the forestomach of rats treated for 6 weeks revealed a thickened stratified squamous epithelium characterized by hyperplasia, hyperkeratosis, and subepithelial inflammation and edema. There were no microscopic changes in the lungs or glandular stomach of animals treated for 6 weeks. The activity of
angiotensin converting enzyme
in the serum of rats treated for 4, 5, or 6 weeks was significantly increased over that of control animals. The activity of this enzyme returned to near levels seen in the control animals after 1 week of recovery following 4 weeks of treatment. No treatment-related effect was observed in the activities of the microsomal p-nitroanisole demethylase, soluble
glutathione S-transferase
, and soluble superoxide dismutase in the five tissues studied. There was a significant increase in the level of nonprotein soluble sulfhydryls in the forestomach but in no other tissue of rats treated for 6 weeks. Also the activity of soluble carboxylesterase was significantly reduced in the lungs and forestomach, but not in any other tissue of the 6-week-treated rats.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Pathological and biochemical effects of dimethyl hydrogen phosphite in Fischer 344 rats. 283 31
The acinar distribution of
glutathione S-transferase
(
GST
), glutathione peroxidase (GPx), glutathione reductase (GR), and glucose-6-phosphate dehydrogenase (G-6-PDH) was examined by analyzing periportal (p.p.) and perivenous (p.v.) rat hepatocytes selectively isolated by the digitonin-collagenase perfusion. The cytosolic
GST
activity was higher in p.v. cells, but the microsomal
GST
and cytosolic GR were found to be evenly distributed in the acinus. In contrast, the activity of both the Se-dependent GPx and the microsomal (Se-independent) GPx, as well as G-6-
PDH
, was much lower in the p.v. than in the p.p. cells. The heterogeneous distribution of
GST
, GPx and G-6-
PDH
was confirmed by analyzing liver perfusion effluents collected after ante- or retrograde digitonin infusion. The relatively low activities of GPx and G-6-
PDH
in the p.v. cells could partly explain the susceptibility of this region to chemical injury.
...
PMID:Acinar distribution of glutathione-dependent detoxifying enzymes. Low glutathione peroxidase activity in perivenous hepatocytes. 359 5
In 14 patients (4 males and 10 females) with systemic hypertension plasma and erythrocyte lipid peroxides, plasma and erythrocyte catalase activity, plasma
glutathione S-transferase
(
GST
) activity, blood reduced glutathione (GSH) content and erythrocyte oxidant stress were investigated. All parameters were performed after clinical examination and then the patients were assigned to receive
ACE
inhibitor therapy, captopril (25-50 mg given twice per day) or enalapril (10-40 mg given twice per day). After six months the determination of lipid peroxides and antioxidative factors was repeated. At the beginning of the study both treated groups showed significantly higher plasma lipid peroxides compared to the control group. Both used
ACE
inhibitors produced significant decrease of plasma lipid peroxides after six months. Blood GSH content was also significantly higher in both patient groups before the treatment compared to the controls. Neither captopril nor enalapril produced any significant effect on GSH. Initial values of plasma
GST
activity in the patients were similar to the control group and did not significantly change after six month treatment. The patients assigned to receive enalapril showed significantly enhanced initial plasma catalase activity according to the controls. After six months treatment both
ACE
inhibitors significantly decreased plasma catalase activity. Erythrocyte lipid peroxides, erythrocyte catalase activity and oxidant stress of erythrocytes in both groups studied neither differ significantly at initial time of investigation according to the control group nor during or after six month treatment.
...
PMID:Changes of lipid peroxides and antioxidative factors levels in blood of patients treated with ACE inhibitors. 912 91
Site-specific proteases play critical roles in regulating many cellular processes. To identify novel site-specific proteases, their regulators, and substrates, we have designed a general reporter system in Saccharomyces cerevisiae in which a transcription factor is linked to the intracellular domain of a transmembrane protein by protease cleavage sites. Here, we explore the efficacy of this approach by using caspases, a family of aspartate-specific cysteine proteases, as a model. Introduction of an active caspase into cells that express a caspase-cleavable reporter results in the release of the transcription factor from the membrane and subsequent activation of a nuclear reporter. We show that known caspases activate the reporter, that an activator of caspase activity stimulates reporter activation in the presence of an otherwise inactive caspase, and that caspase inhibitors suppress caspase-dependent reporter activity. We also find that, although low or moderate levels of active caspase expression do not compromise yeast cell growth, higher level expression leads to lethality. We have exploited this observation to isolate clones from a Drosophila embryo cDNA library that block
DCP
-1 caspase-dependent yeast cell death. Among these clones, we identified the known cell death inhibitor DIAP1. We showed, by using bacterially synthesized proteins, that
glutathione S-transferase
-DIAP1 directly inhibits
DCP
-1 caspase activity but that it had minimal effect on the activity of a predomainless version of a second Drosophila caspase, drICE.
...
PMID:A cloning method to identify caspases and their regulators in yeast: identification of Drosophila IAP1 as an inhibitor of the Drosophila caspase DCP-1. 1007 6
A comparative study has been performed on populations of Unionidae from the Lake Suszek and Brda river situated in the centre of Tucholski Landscape Park, around which there are no factories and the Pilica river--affected by the influence of the nearby town agglomeration. Mussels collected from Suszek were also treated (72 h) with various concentrations of dichlorophenol (
DCP
; 0.1, 0.15, 0.2 ppm) and paraquat (PQ; 1, 5, 10 ppm) in laboratory conditions (aquarium). The activities of
glutathione S-transferase
(
GST
) and cytochrome P450 monooxygenase system (NAD(P)H ferricyanide reductase, NAD(P)H cytochrome c reductase), cytochrome P450 content and b(5) in microsomal and cytosolic fractions of digestive gland were investigated. The differences in enzyme activities between groups of mussels, which were exposed to various concentrations of chemical pollutants, as well as the dependence on geographical distribution in Poland, were observed. In experiments with
DCP
the dose-dependent increase in
GST
activity was found, but no changes after PQ treatment were observed. Results, in experiments with
DCP
and PQ, have varied from no change to increase or decrease in the measured monooxygenase activities and cytochrome P450 content. Increases have been recorded in two cases (NADPH ferricyanide reductase and cytochrome P450) after exposure to
DCP
and in the case of NADH ferricyanide reductase following the exposure to PQ. NAD(P)H cytochrome c reductase activity and content of P450 decreased considerably in 5 and 10 ppm PQ-treated mussels. Thus, the treatment with
DCP
and PQ in water changed the properties of the mussels digestive gland cytochrome P450 monooxygenase system. These changes may be used as a bioindicator, at the molecular level, of exposure to those xenobiotics not only in controlled experiments (aquaria) but also in the natural environment.
...
PMID:Comparative study of the xenobiotic metabolising system in the digestive gland of the bivalve molluscs in different aquatic ecosystems and in aquaria experiments. 1229 71
There were few reports on the antioxidant response of aquatic organisms exposed to 2,4-dichlorophenol (2,4-
DCP
). This research explored the hepatic antioxidant responses of fish to long-term exposure of 2,4-
DCP
for the first time. Freshwater fish Carassius auratus were chosen as experimental animals. The fish were exposed to six different concentrations of 2,4-
DCP
(0.005-1.0 mg/l) for 40 days and then liver tissues were separated for determination. As shown from the results, 40 days afterwards, the activities of catalase (CAT) and selenium-dependent glutathione peroxidase (Se-GPx) and the content of oxidized glutathione (GSSG) were induced significantly on the whole compared to control group; superoxide dismutase (SOD) responded to 2,4-
DCP
exposure at only 0.005 mg/l; the content of reduced glutathione (GSH) was suppressed continuously except Group 7; the activity of glutathione reductase was inhibited initially and then restored to control level from Group 4 on;
glutathione S-transferase
had only slight responses in Groups 3 and 4. Total glutathione (tGSH) and GSH/GSSG ratio were also calculated to analyze the occurrence of oxidative stress. Besides, good dose-effect relations, which cover most of the exposure concentration range, were found between 2,4-
DCP
level and CAT activity, GSSG content, Se-GPx activity, respectively. In conclusion, SOD and Se-GPx may be potential early biomarkers of 2,4-
DCP
contamination in aquatic ecosystems, and further studies will be necessary.
...
PMID:Effects of chronic exposure of 2,4-dichlorophenol on the antioxidant system in liver of freshwater fish Carassius auratus. 1476 89
Genetic polymorphisms have the potential to predict disease susceptibility. This may be especially useful among individuals with a high-risk lifestyle, so that the genotyping could be adopted for disease prevention through modifications toward a lower-risk lifestyle. We started a program of free genotype announcements in a polymorphism study among health checkup examinees at the Nagoya University Hospital on June 9, 2003. Since such announcements remain controversial for fear of unexpected harmful effects and counseling system, the accumulated evidence on the association between disease risk and genotypes announcements in our study was reviewed in this article. The genotypes used were those of alcohol dehydrogenase 2 (ADH2) Arg47His, aldelhyde dehydlrogenase 2 (ALDH2) Glu487Lys, NAD(P)H: quinone oxidoreductase (NQO1) C609T, glutathlione S transferase M1 (GSTM1),
glutathione S-transferase
T1 (GSTT1), interleukin-1B (IL-1B) C-31T, and tumor necrosis factor A (TNF-A) T-1031C,
angiotensin converting enzyme
(
ACE
) Ins/Del. Since showed a potential for widespread use in health checkups, the information on the above polymorphisms seems worth documenting. Although there have been no complaints from the participants to date, careful treatments are requested.
...
PMID:Associations between disease risk and eight polymorphisms adopted for genotype announcements at Nagoya University Hospital. 1527 68
1,1-Dichloropropene (1,1-
DCP
) is a contaminant present in both ground and surface waters used as sources for drinking water. Structural similarity to several compounds with known mutagenicity and carcinogenicity, and recent demonstration of mutagenicity in vitro, suggest this compound may be similarly mutagenic in vivo. A transgenic fish model, the lamda transgenic medaka, was used to evaluate the potential mutagenicity of this contaminant in vivo following sub-chronic exposure for 6 weeks. Mutant frequencies of the cII target gene (MF) increased six-fold in the livers of fish exposed to the lowest 1,1-
DCP
exposure concentration (0.44 mg/L, MF = 18.4 x 10(-5), and increased with each treatment, culminating in a 32-fold induction in fish from the highest 1,1-
DCP
treatment (16.60 mg/L, MF = 96.3 x 10(-5). Mutations recovered from treated fish showed a distinctive mutational spectrum comprised predominantly of +1 frameshift mutations, induced 166-fold above that of untreated animals. The majority of frameshifts were +1 insertions at thiamine and adenine. These results represent the first evidence of mutagenicity of 1,1-
DCP
in vivo, and of the highly characteristic spectrum of induced mutations dominated by +1 frameshift mutations. Based upon results from previous in vitro studies, the similar role of
glutathione S-transferase
(GSTT1-1) in the activation of 1,1-
DCP
to a mutagen in vivo is also suggested. This study further illustrates the utility of the lamda transgenic medaka as a model for identifying and characterizing potential genetic health risks associated with chemical exposures in the environment.
...
PMID:Sub-chronic exposure to 1,1-dichloropropene induces frameshift mutations in lambda transgenic medaka. 1633 49
The effect of prefeeding dehydrated amaranth leaves (AL), at 10 and 20% levels on hexachlorocyclohexane (HCH)-induced free radical stress in rat liver was evaluated. The HCH-induced raise in malonadialdehyde (MDA), conjugated dienes and hydroperoxides was diminished by AL. The effect of AL was highly effective with respect to reduction in these cytotoxic products, especially at 20% level. AL intake resulted in a significant increase in hepatic vitamin A and glutathione (GSH). However, the AL consumption reduced hepatic tocopherols. Feeding of AL at 10% level increased the hepatic glucose-6-phosphate dehydrogenase (G-6-PDH) activity while that at 20% level increased the hepatic glutathione reductase (GSSGR) as well, in addition to G-6-
PDH
. Amaranth leaves at 10 and 20% levels of feeding reduced the hepatic superoxide dismutase and glutathione peroxidase (GSH-Px) activities. The pre-feeding of AL resulted in the reversal of HCH-induced alteration in GSH-Px and G-6-
PDH
activities. The significant reduction in the level of
glutathione S-transferase
brought about by HCH was restored to control level by feeding 20% AL. It is concluded that the consumption of AL at 20% level produces reduction in the HCH-induced impairment of antioxidant status in rat liver.
...
PMID:Amelioration of hexachlorocyclohexane-induced oxidative stress by amaranth leaves in rats. 1712 63
Northern leopard frogs Rana pipiens exposed to PCB 126 (3,3',4,4',5-pentachlorobiphenyl) were examined for hepatic oxidative stress. In a dose-response study, northern leopard frogs were injected intraperitoneally with either PCB 126 in corn oil (0.2, 0.7, 2.3, or 7.8 mg/kg body weight) or corn oil alone. In a time-course study, frogs received 7.8 mg/kg or corn oil alone, and were examined at 1, 2, 3, and 4 wk after dosing. Hepatic concentrations of reduced glutathione (GSH), thiobarbituric acid-reactive substances (TBARS), and total sulfhydryls (total SH), as well as activities of glutathione peroxidase (GSH-P), GSSG reductase (GSSG-R), glucose-6-phosphate dehydrogenase (G-6-PDH), and
glutathione S-transferase
(GSH-S-T) were measured. In the dose-response experiment, few effects were apparent 1 wk after dosing. In the time-course experiment, significant changes were observed in the 7.8-mg/kg group at 2 wk or more posttreatment. Hepatic concentrations of GSH and TBARS were higher than in corresponding controls at wk 3 and 4; the activities of GSSG-R and GSH-S-T were higher than in controls at wk 2 and 4; and the activity of G-6-
PDH
was increased at wk 2 and 4. These data collectively indicate that altered glutathione metabolism and oxidative stress occurred and were indicative of both toxicity and induction of protective mechanisms in frogs exposed to PCB. A similar delay in response was reported in fish and may relate to lower metabolic rate and physiological reactions in ectothermic vertebrates.
...
PMID:Oxidative stress induced in PCB 126-exposed northern leopard frogs, Rana pipiens. 1736 21
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