首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Long-Evans Cinnamon (LEC) rats which have an abnormal copper accumulation in the liver develop hereditary hepatitis and subsequent hepatocellular carcinoma (HCC). We studied the correlation of MR images of the HCCs developed in LEC rats and histopathological features. The HCCs of LEC rats had high intensity on T 1-weighted images and iso-low intensity on T 2*-weighted images. Histopathological examination showed that the HCCs were highly differentiated. Copper concentration in the HCCs was lower than that in the surrounding non-cancerous liver tissues. From these results, we suggest that copper accumulation may not be responsible for the high intensity of HCCs on T 1-weighted images.  相似文献   

2.
An inherent defect of biliary Cu excretion and subsequent Cu deposition in the liver have been found in Long-Evans Cinnamon (LEC) rats, which are promising models of Wilson disease. LEC and Fischer rats were given water containing Cd (CdCl2) at a level of 5 ppm for 30 days. Regardless of drinking Cd water, LEC rats showed a very high concentration of Cu (200 to 250 microgram/g) and Cu-metallothionein (Cu-MT) (18 mg/g) in the liver. There was no difference of Cd accumulation in the liver between the two strains exposed to Cd (2.6 and 2.7 microgram/g in the Fischer and LEC groups, respectively). However, the renal Cd concentration was slightly but significantly higher in LEC rats (3.5 microgram/g) than in Fischer rats (2.0 microgram/g). The ratio of renal Cd contents to the sum of renal and hepatic Cd contents was significantly higher in LEC rats (0.25) than in Fischer rats (0.15). The serum Cd concentration in Cd-treated LEC rats increased threefold compared to Cd-treated Fischer rats. It seems likely that Cd from the liver is transported into the kidney in the form of Cd, Cu-MT. There was no difference in uptake of Cd in the hepatic MT fraction between the two strains. Although biliary Cu excretion in LEC rats was significantly lower than that in Fischer rats, reduced excretion of Cd into bile was not found in LEC rats. The gross amounts of Cu and Cu-MT influenced the accumulation of Cd in the kidney rather than in the liver when Cd was given orally at a low level to LEC rats. Our results suggest tht Cu and Cd do not share the same sites of hepatobiliary excretion in rats, although the main route of their excretion is via bile.  相似文献   

3.
The main aim of this research was to clarify that nutritional dietary copper may participate in the protective action against hepatocarcinogenesis in rats by N-nitrosodimethylamine (NDMA). The copper concentrations in serum and liver from 2 to 8d after rats were first fed a copper deficient diet (copper, 0.6 ppm) decreased significantly compared to those of pair-fed rats (copper in a control diet, 7 ppm). The subcellular distribution of copper in the liver at 5d after feeding of a copper deficient diet began was measured and the copper concentrations in soluble and nuclear fractions decreased at a similar rate in copper deficient rats treated with or without NDMA, compared to those of pair-fed rats. The incorporation of [3H]thymidine into rat liver DNA at 48 h after treatment with NDMA markedly increased under the experimental conditions used. By giving rats a copper deficient diet for a few days the increased incorporation of [3H]thymidine into liver DNA of rats treated with NDMA was enhanced compared to that of pair-fed rats treated with NDMA. The activity of thymidine kinase in liver of copper deficient rats treated with NDMA was also found to increase significantly compared to that of pair-fed rats treated with NDMA.  相似文献   

4.
Bis(2-ethylhexyl) phthalate (DEHP) is a compound widely used in plastics technology to impart flexibility to rigid polymers. We sought to determine whether the oral exposure of female rats to DEHP during gestation and suckling produces alterations in the litter. Female rats were exposed to different concentrations of DEHP suspended in drinking water (32.5 and 325 microl/litre) from day 1 of pregnancy to day 21 after delivery. Pup body weight gain and kidney, liver and testes weight was measured at different times (21, 28, 35, 42 and 56 days) after birth. Plasma concentrations of DEHP and histopathological alterations in kidneys, liver and testes were also studied. In addition, the ability of female pups (1 month of age) to perform a learned avoidance test, the 'beam walking' test, was evaluated. Perinatal exposure to DEHP produced no statistically significant changes in the body weight gain of offspring. Conversely, it produced a significant decrease in kidney and testes relative weight (organ/body weight) with a significant increase in relative liver weight. Signs of histological damage in kidneys, liver, and particularly testes, were observed. Pups exposed perinatally to the highest concentration of DEHP elicited a significant increase in the time necessary to perform the beam walking test.  相似文献   

5.
6.
7.
8.
9.
Because of the high incidence of pancreatic cancer in the United States and because of the correlation of pancreatic cancer to environmental exposure, we have undertaken experiments to measure the metabolism of the carcinogen 7,12-dimethylbenzanthracene in the pancreas of the Long-Evans male rat. This study examined the in vitro metabolism of the carcinogen and found the production of aqueous products in pancreas to be similar to that in liver, however, the pancreatic capability was not induced to greater metabolism by pretreatment with either phenobarbital or 3-methylcholanthrene. High pressure liquid chromatographic analysis of the in vitro products of pancreatic metabolism demonstrated a relatively greater abundance of 5,6-epoxy-7-hydroxymethyl-12-methylbenzanthracene than the liver and a relatively less abundance of 7-hydroxymethyl-12-methylbenzanthracene and 7-methyl-12-hydroxymethylbenzanthracene than the liver. Carcinogen levels were measured in pancreas, liver, bile and blood at 2, 5, 10, 16, 22 and 36 hours after injection.  相似文献   

10.
11.
Contamination of cathodic copper by Sb during electrowinning in chloride solutions is a surface phenomenon. A digitized scanning electron microscopy (SEM) micrograph indicates that the Sb is concentrated on the surface of the cathode. Energy-dispersive X-ray (EDX) analysis reveals that the Sb-containing layer is a complex salt of Cu, Sb, Cl, and O. Electrochemical measurements show-that the adsorption of Sb or Cu species decreases with the increase of acidity of the solution when the solution contains antimony chloride or cuprous chloride. The adsorption increases with the increase of the acidity when the solution contains both Sb and Cu. The discharge of cuprous ions in the adsorbed complex salt releases antimonious ions and then forms a new layer of the complex salt with cuprous ions from the solution. This newly formed complex salt is readsorbed on the surface of the cathode. Thus, Sb concentrates on the surface of the cathode instead of being evenly distributed throughout the copper product. This suggested mechanism also explains the fact that the presence of Sb in the electrolyte enhances the electrodeposition of Cu.  相似文献   

12.
An enzyme capable of hydrolyzing the substrate L-alanine p-nitroanilide has been found in 18 gram-negative Enterobacteriaceae and Pseudomonas that we tested. This enzyme might be located near the cell surface. Contrastingly we have not detected this activity on colonies of the 8 gram-positive Bacillus that we tested, which suggest a taxonomic value for this test. The aminoendopeptidases found in the various gram-negative bacteria showed similar electrophoretic mobilities and immunological cross-reactivity when tested again Escherichia coli anti-aminoendopeptidase antiserum. The regulation of aminoendopeptidase biosynthesis by the endogenous level of inorganic phosphate that we previously demonstrated in E. coli has been found to exist in all gram-negative organisms tested.  相似文献   

13.
The LEC rat is an inbred mutant strain which spontaneously develops liver injury and subsequent liver cancer. Liver injury in LEC rats has recently been shown to be closely related to abnormal copper accumulation in the liver. Previously, we reported that LEC rat hepatocytes lose their growth potential, probably allowing selective growth of preneoplastic cells. In this study, to elucidate the effects of copper accumulation on the growth activity of LEC rat hepatocytes, we examined the growth activity and the expression of p53 and p21(waf 1/cip 1) in the livers of LEC rats fed on either a control or a low-copper diet. Potential for cell proliferation of hepatocytes obtained from normal diet fed LEC rats was almost comparable to that of the cells from age-matched Sprague-Dawley (SD) rats. Northern blot analysis showed that the expression of p53 and p21(waf 1/cip 1) was significantly high in the livers of LEC rats fed a control diet, while the expression of p53 and p21(waf 1/cip 1) in the LEC rats fed a low-copper diet was as low as that of SD rat livers. Western blot analysis consistently showed that the amount of p21(waf 1/cip 1) bound to the nuclear matrix scaffold of the LEC rat liver was reduced by feeding a low-copper diet. These findings suggest that abnormal accumulation of copper induced the expression of p53 and p21(waf 1/cip 1), resulting in the inhibition of cell proliferation of LEC rat hepatocytes.  相似文献   

14.
OBJECTIVE: To assess the spontaneous fertility in couples with severe seminal conditions while waiting for artificial insemination donor. STUDY DESIGN: Prospective follow-up during a period of 24 months. SETTING: University Medical School. PARTICIPANTS: There were 285 couples in which the male had a very severe seminal pathology: 166 azoospermia, 86 oligozoospermia and 33 severe asthenozoospermia. OUTCOME MEASURES: Pregnancy rates after being included on waiting list. RESULTS: The spontaneous pregnancy rate was 3.2% (9/285), per month spontaneous pregnancy rate being 0.13%. Spontaneous pregnancy rate was 0% in azoospermia (0/166). versus 7.6% (9/119) in non-azoospermia cases. Spontaneous pregnancy rate was 8.5% (4/47) in the group with less than 0.1 million motile sperm/cc, 6.5% (3/46) in the group between 0.1 and 1 million/cc and 7.7% (2/26) in the group with 1-2 million/cc. CONCLUSION: In a 2-year follow-up, pregnancy rate among non-azoospermic couples before undergoing artificial insemination was 7.6%. Extramatrimonial pregnancy (based on anamnesis and sperm analysis) seemed to be uncommon. Even in cases with less than 0.1 million of motile sperm/cc there was not a negligible spontaneous pregnancy rate.  相似文献   

15.
16.
Mutations in the BMP-5 gene at the mouse short-ear locus alter size, shape, and number of many different skeletal elements, and greatly reduce the size of the external ear. The alterations in short-ear mice are confined to particular skeletal features and a human equivalent is not known. We report on 5 patients whose features fit into the clinical criteria of the EPS (ear, patella, short stature) syndrome characterized by very short external ears, small jaw, growth retardation, and different skeletal abnormalities including absent patellae. We postulate on clinical data and phenotype comparisons that some EPS cases might be a human equivalent to the short ear murine disorder.  相似文献   

17.
18.
A hydrogen peroxide-resistant mutant of the catalase-negative microaerophile, Spirillum volutans, constitutively expresses a 21.5 kDa protein that is undetectable and non-inducible in the wild-type cells. Part of the gene that encodes the protein was cloned using amino acid sequence data obtained by both mass spectrometry and NH2-terminal sequencing. The deduced 158 amino acid polypeptide shows high relatedness to rubrerythrin and nigerythrin previously described in the anaerobes Clostridium perfringens and Desulfovibrio vulgaris. The protein also shows high similarity to putative rubrerythrin proteins found in the anaerobic archeons Archaeoglobus fulgidus, Methanococcus jannaschii and Methanobacterium thermoautotrophicum. This is the first report of this type of protein in an organism that must respire with oxygen. It seems likely that the novel combination of methodologies used in this study could be applied to the rapid cloning of other genes in bacteria for which no genomic library yet exists.  相似文献   

19.
GB virus C (GBV-C) RNA and envelope antibody were assessed in a median of 4 samples collected over 6.5 years among injection drug users (IDUs). A marker of GBV-C infection was detected in 110 (94.8%) of 116 IDUs. GBV-C RNA was detected at all visits in 32, was never detected in 70, was acquired in 7, and was cleared in 8. The odds of detecting anti-GBV-C were 103-fold higher in participants without detectable RNA (64 of 70) than in IDUs with persistent RNA (3 of 32; P < 10(-7)). Anti-GBV-C was detected in all 8 instances of RNA clearance. GBV-C RNA never reappeared once it was cleared, and there were no new GBV-C infections among 61 anti-GBV-C-positive IDUs observed for 382 person-years, though all had ongoing drug use. Studies using RNA testing alone may significantly underestimate the occurrence of GBV-C infection. Anti-GBV-C is highly associated with viral clearance and protection from reinfection.  相似文献   

20.
Different routes of Cd intake may influence the intestinal distribution of Cd, metallothionein (MT), and trace metals differently. Therefore, we compared the effects of parenteral and enteral administration of Cd on the distribution of trace metals and MT along the small intestine. In a first experiment three groups of rats were employed: a control, one receiving CdCl2 within the drinking water, and another receiving sc injections of CdCl2. In a second experiment, rats were fed three different diets with either 0, 0.3, or 1 mmol CdCl2/kg for one and two weeks to study the time- and dose-dependent effects of orally administered Cd. Metal concentrations (Cd, Zn, Cu, Fe) were measured by atomic emission spectrometry and MT was determined by radioimmunoassay. Intestinal MT levels did not show proximodistal gradients in controls or after sc administration of Cd, but orally administered Cd increased mucosal MT levels longitudinally from the duodenum to the ileum. Cd levels paralleled those of MT. Compared with the metal concentrations in the controls, sc administration of Cd did not change intestinal Zn, Cu, and Fe levels. Oral administration of Cd, however, increased Cu and decreased Fe levels in the intestinal mucosa significantly. The second experiment revealed that only high dietary concentrations of Cd increase intestinal Cd and MT levels longitudinally toward the distal parts, whereas at lower dietary concentration the longitudinal distribution was reversed. This shows that different routes and doses of Cd intake lead to a different trace metal and MT distribution and emphasizes the role of dietary Cd in the local induction of small-intestinal MT.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号