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At least 361 records · Page 20Linked to original sources
PubMed2004

DNA adduct formation by 7H-dibenzo[c,g]carbazole and its tissue- and organ-specific derivatives in Chinese hamster V79 cell lines stably expressing cytochrome P450 enzymes.

The cytochrome P4501A subfamily (CYP1A) is involved in the metabolic activation of 7H-dibenzo[c,g]carbazole (DBC) and its tissue- and organ-specific derivatives, N-methyldibenzo[c,g]carbazole (MeDBC)and 5,9-dimethyldibenzo[c,g]carbazole (diMeDBC). In this study, we have evaluated the relationship between the tissue specificity and (32)P-postlabeled adduct patterns produced by these compounds by using a panel of Chinese hamster V79 cell lines stably expressing human CYP1A1 and CYP1A2 and/or N-acetyltransferase. Treatment of the parental cell lines V79MZ and V79NH, which are devoid of any CYP activity, with DBC and its derivatives did not result in detectable adducts. The highest DNA adduct levels were found in CYP1A1-expressing V79MZh1A1 cells after DBC and MeDBC treatment (24.5 +/- 7.2 and 16.2 +/- 3.6 adducts/10(8) nucleotides, respectively). Exposure of this cell line to DBC resulted in five distinct spots, while six spots with different chromatographic mobilities were detected in MeDBC-treated cells. DiMeDBC produced only very low levels of DNA adducts in V79MZh1A1 cells. DBC and MeDBC formed relatively low levels of DNA adducts in CYP1A2-expressing V79MZh1A2 cells (0.7 +/- 0.2 and 2.1 +/- 1.2 adducts/10(8) nucleotides, respectively). DBC formed three weak spots and MeDBC five spots in V79MZh1A2 cells, and all the spots had different chromatographic mobilities. In contrast, diMeDBC did not induce any DNA adducts in these cells, although diMeDBC induced a significant dose-dependent increase in micronucleus frequency under similar treatment conditions (r = 0.76; P < 0.001). The significant increase in DNA damage in the Comet assay following incubation of exposed cells with a repair-specific endonuclease (Fpg protein) suggests that base modifications such as 8-oxodG or Fapy-adducts might be responsible for the genotoxicity of diMeDBC in V79MZh1A2 cells. The similarities between the DNA adduct patterns produced by DBC and MeDBC in V79MZh1A1 and V79MZh1A2 cells suggest that biotransformation mediated via CYP1A1 and CYP1A2 might depend on a PAH-type pathway involving the aromatic ring system.

Acetyltransferases↗
PubMed1984

Organ-specific properties of cytochromes P-450s21 (steroid 21-hydroxylases) of liver and adrenocortical microsomes.

Organ specificities of cytochrome P-450s21 (steroid 21-hydroxylase) were investigated. The substrate specificity of the liver cytochrome P-450s21 was found to be different from that of adrenocortical cytochrome P-450s21. The steroid 21-hydroxylase activity of liver microsomes decreased with treatment by sodium phenobarbital or beta-naphthoflavone and was inhibited by anti-cytochrome b5 immunoglobulin, although that of adrenocortical microsomes was not. The liver cytochrome P-450s21 was immunochemically similar to adrenocortical cytochrome P-450s21. The bovine liver and adrenocortical cytochromes P-450s21 showed immunoprecipitin lines against antibody to bovine adrenocortical cytochrome P-450s21. The molecular masses of the bovine liver and adrenocortical cytochromes P-450s21 were 60 +/- 1 and 50 +/- 1 kDa, respectively. The content of cytochrome P-450s21 and its percentage for the total microsomal cytochrome P-450 were immunochemically determined using the antibody to the bovine adrenocortical cytochrome P-450s21.

Adrenal Cortex↗
PubMed2003

High prevalence of non-organ-specific autoantibodies in hepatitis C virus-infected cirrhotic patients from southern Italy.

Non-organ-specific autoantibodies (NOSAs) are frequently found in patients with hepatitis C virus (HCV) chronic infection. Genetics is likely involved in the development of autoimmune reactivities, and differences in the prevalence of HCV-related autoantibodies among populations of various geographic areas should be expected. We evaluated the prevalence and the clinical impact of NOSAs in a series of HCV-infected patients from southern Italy. We studied 283 consecutive anti-HCV positive patients (162 men, 121 women, mean age 54.5 +/- 13.5 years), 94 of whom were cirrhotics and 189 noncirrhotics. Serum from each patient and from 41 hepatitis B surface antigen (HBsAg)-positive/anti-HCV negative control subjects were tested (dilution 1:40) for autoantibodies by indirect immunofluorescence. Qualitative/quantitative HCV-RNA determinations were also performed. The prevalence of NOSAs was significantly higher in anti-HCV-positive subjects than in HBsAg-positive patients (P < 0.006). Autoantibodies were significantly associated with both cirrhosis (P < 0.0001) and older age (P < 0.05). No significant association between NOSAs and either female gender or virological parameters (HCV-RNA positivity, viral load, and genotype) was found. In conclusion, the autoantibody positivity in HCV-infected patients from southern Italy is significantly related to cirrhosis and older age, although its general prevalence is similar to that reported in populations from the north of the country.

Adult↗
PubMed1987

[Determination of non-organ specific autoantibodies. Their relevance for the differentiation of autoimmune diseases].

The determination of non-organ-specific autoantibodies is a major tool in the serological diagnosis of rheumatic disorders. Antinuclear antibodies (ANA) are routinely determined by indirect immunofluorescence (IFL) testing on cryostat sections, but the use of cultured cell lines now allows to detect new antibody specificities that are obscured on tissue sections. Titres and IFL patterns of antibodies add further information to the interpretation of results. Homogeneous or perimembranous patterns point to systemic lupus erythematosus (SLE) which is better characterized by the presence of antibodies to double-stranded DNA or to the Smith-antigen (Sm-antigen) detected by other methods. Antibodies to extractable nuclear antigens (ENA) are strongly correlated with connective tissue disease, the main representatives of which may now be identified serologically by the presence of marker anti-ENA antibodies.

Antibody Specificity↗
PubMed2002

Organ-specific alterations in RAR alpha:RXR alpha abundance regulate rat Mrp2 (Abcc2) expression in obstructive cholestasis.

BACKGROUND & AIMS: Obstructive cholestasis is associated with adaptive changes in expression of hepatocyte transport proteins. These include a significant reduction in hepatic expression of Mrp2 (Abcc2), the principal canalicular multispecific organic anion transporter. Renal Mrp2 expression is preserved under these conditions. We have recently reported that the rat Mrp2 promoter is activated by RAR alpha:RXR alpha, and that interleukin 1 beta (IL-1 beta) repressed promoter activity via this element. We hypothesized that cytokines, which are up-regulated in obstructive cholestasis, would reduce nuclear RAR alpha:RXR alpha levels, and that this would be associated with suppression of hepatic Mrp2 expression. METHODS: Male Sprague-Dawley rats were subjected to bile duct ligation (BDL) or sham surgery, and liver and kidney RNA and protein were isolated. Primary rat hepatocytes were treated with bile acids, retinoids, or cytokines, and RNA and protein were isolated. Mrp2 and RAR alpha:RXR alpha protein abundance and activity were assessed by using electrophoretic mobility shift assays (EMSA) and immunoblots. IL-1 beta abundance was determined by enzyme-linked immunosorbent assay. RAR alpha, RXR alpha, and Mrp2 RNA levels were determined by using ribonuclease protection assays (RPA). RESULTS: Mrp2 down-regulation and IL-1 beta up-regulation were observed in liver after BDL. This was temporally associated with down-regulation of liver RAR alpha:RXR alpha nuclear protein levels and binding to the Mrp2 promoter cis element. Renal RAR alpha:RXR alpha and Mrp2 expression were preserved under these conditions. IL-1 beta treatment of primary hepatocytes reduced Mrp2 and RXR alpha expression. CONCLUSIONS: Organ-specific regulation of Mrp2 expression in obstructive cholestasis is associated with cytokine-dependent alterations in RAR alpha:RXR alpha nuclear receptors. Preservation of renal Mrp2 expression may permit urinary excretion of toxic organic anions and xenobiotics under conditions in which biliary excretion is impaired.

ATP-Binding Cassette Transporters↗
PubMed2005

Organ specificity in the circadian control of plant gene expression.

Of the many plant genes whose expressions are controlled by the circadian clock, one of the phosphoenolpyruvate carboxylase kinase genes in soya bean (Glycine max) exhibits the unusual property that its control is organ-specific--it is under circadian control in leaves but not in roots. Preliminary experiments suggest that the same is true for at least one gene in Arabidopsis thaliana. It will be important to define the extent and function of this phenomenon and the underlying mechanism.

Arabidopsis↗
PubMed1995

Major organ-specific glycoproteins in isolated brain and kidney membranes identified as Na,K-ATPase subunits by combined glycan-, lectin-, and immunoblotting.

In the present work combined glycan-, lectin-, and immunoblotting of isolated brain and kidney membranes shows that the alpha and beta subunits of Na,K-ATPase are the most abundant glycoproteins. Further, Datura stramonium and Galanthus nivalis agglutinins recognize the Na,K-ATPase subunits in a mutually exclusive manner in membranes from human, rabbit and rat brain or human, rabbit, rat, pig and dog kidney indicating the presence of species-independent organ-typical glycoforms. The glycosylation status is not related to the ouabain-sensitivity. Taken together, the data reveals organ-specific glycoforms of Na,K-ATPase which might have roles for organ identification and recognition.

Animals↗
PubMed2002

Organ-specific cytokine polarization induced by adoptive transfer of transgenic T cells.

There are two distinct phenotypes of T cell cytokine responses that lead to different effector functions and different outcomes in disease processes. Although evidence suggests a possible role of the local microenvironment in the differentiation or localization of T cells with these phenotypes, there are no examples of divergent T cell cytokine phenotypes with the same Ag specificity concurrently existing in different tissue compartments. Using a CD8(+) T cell adoptive transfer model for graft-vs-host disease, we demonstrate that a potent type 2 cytokine response develops in the spleen while a potent type 1 cytokine response simultaneously develops in the testis. These experiments demonstrate for the first time that cytokine production can be oppositely polarized in different organs of the same individual. This may have important implications for organ-specific pathology in infection or autoimmunity: infections or autoimmune diseases that affect multiple organs may have heterogeneity in tissue cytokine responses that is not revealed in systemic lymphocyte cytokine responses. Therefore, attempts to modulate the immune response phenotype may ameliorate pathology in one organ while exacerbating pathology in another.

Adoptive Transfer↗
PubMed2004

Genome-wide transcriptome mapping analysis identifies organ-specific gene expression patterns along human chromosomes.

The Human Genome Project has revealed that there about 32,000 protein-encoding genes, which are distributed throughout the genome. It is unclear, however, whether genes are distributed on the chromosomes according to patterns linked to organ specificity. To explore the relationship between genes actively transcribed in normal tissues and their chromosomal locations, we analyzed serial analysis of gene expression libraries of normal human liver, brain, breast, and colon tissues. Transcriptome mapping analysis revealed that transcriptional activity in each tissue varied according to the chromosomal domains, and a weak positive correlation was observed between transcription density and gene density. We identified six liver-related and five colon-related chromosomal domains highly transcribed in each tissue, whereas no brain-related or breast-related chromosomal domains were identified. Representative genes located on these chromosomal domains were associated with the function of each organ and were highly conserved in both mouse and rat genomes. These data revealed that the transcriptional activities of normal human tissues are well orchestrated at chromosomal levels, suggesting that highly expressed genes may share physical proximity.

Chromosome Mapping↗
PubMed1989

Experimental liver metastasis. Implications of clonal proclivity and organ specificity.

"Spontaneous" lung metastases develop in over 50% of the animals bearing subcutaneous isografts of WB-2054, a rat colon carcinoma. A metastatic variant has been developed by "Fidler" type in vivo selection, yielding 100% lung metastasis. In a five-week assay to test the organ specificity of this lung metastatic variant, however, "experimental" liver and lung metastases could be induced in 100% and 60% of animals on portal venous and intravenous injections, respectively. The results demonstrate selection of a metastatic variant from heterogeneous primary tumor, and suggest at least two interacting mechanisms: (1) mechanical (the anatomy of the blood-borne metastatic pathways) and (2) biologic (factors intrinsic to primary tumor subpopulations that can be selected for metastatic proclivity). In addition, liver metastases were successfully established from colon tumors induced by cecal wall injection of tumor cells. Such a spontaneous liver metastasis model will be useful to study the specific mechanisms involved during metastasis of colon cancer to the liver.

1,2-Dimethylhydrazine↗
PubMed2000

Control of organ-specific demethylation by an element of the T-cell receptor-alpha locus control region.

DNA methylation is important for mammalian development and the control of gene expression. Recent data suggest that DNA methylation causes chromatin closure and gene silencing. During development, tissue specifically expressed gene loci become selectively demethylated in the appropriate cell types by poorly understood processes. Locus control regions (LCRs), which are cis-acting elements providing stable, tissue-specific expression to linked transgenes in chromatin, may play a role in tissue-specific DNA demethylation. We studied the methylation status of the LCR for the mouse T-cell receptor alpha/delta locus using a novel assay for scanning large distances of DNA for methylation sites. Tissue-specific functions of this LCR depend largely on two DNase I-hypersensitive site clusters (HS), HS1 (T-cell receptor alpha enhancer) and HS1'. We report that these HS induce lymphoid organ-specific DNA demethylation in a region located 3.8 kilobases away with little effect on intervening, methylated DNA. This demethylation is impaired in mice with a germline deletion of the HS1/HS1' clusters. Using 5'-deletion mutants of a transgenic LCR reporter gene construct, we show that HS1' can act in the absence of HS1 to direct this tissue-specific DNA demethylation event. Thus, elements of an LCR can control tissue-specific DNA methylation patterns both in transgenes and inside its native locus.

Animals↗
PubMed2003

Prevalence of non-organ specific autoantibodies in HCV-infected subjects in the general population.

The significance of non-organ specific antibodies (NOSAs) in HCV-related chronic hepatitis is largely unclear. In this study we evaluated the prevalence of NOSAs in a non-selected population of HCV-infected subjects. One hundred and seventy anti-HCV positive and 192 anti-HCV negative sex and age-matched subjects (median age 64 years, range 7-91 years, female 68%) enrolled from the general population of a small Italian town were evaluated for NOSAs by indirect immunofluorescence on rat tissue sections and HEp-2 cells, and by counterimmunoelectrophoresis with thymus and spleen extracts as the antigen source. One hundred and sixty-three (96%) HCV-infected subjects had normal ALT serum levels and no evidence of liver disease. NOSAs were found in 31 out of 170 (18%) anti-HCV positive subjects and in 20 out of 192 (10%) controls (P = NS), with similar median titre (1:40) and range (1:40 to 1:160). Neither liver/kidney microsomal antibody type 1 nor antiactin reactivity were detected. No significant association between NOSAs and HCV genotypes was observed. In the general population, HCV-infected subjects and healthy controls have a similar prevalence of NOSAs. Without continuous liver damage HCV infection is unlikely to induce the appearance of NOSAs.

Adolescent↗
PubMed1987

Organ specificity, metabolism and reaction with DNA of aliphatic nitrosomethylalkylamines.

Aliphatic nitrosomethylalkylamines are carcinogens with a remarkable organ specificity in rats, the principal targets being liver, oesophagus and bladder. We have determined the extent of DNA methylation in these tissues following a single oral dose (0.1 mmol/kg; 6-h survival) of each of 12 homologues, ranging from N-nitrosodimethylamine (NDMA, C1) to N-nitrosomethyldodecylamine (C12). Methylpurines (7- and O6-methylguanine; 7-meGua and O6-meGua) were determined by cation-exchange high-performance liquid chromatography with fluorescence detection. Highest levels of hepatic DNA methylation were found with NDMA (C1) and N-nitrosoethylmethylamine (NEMA, C2), the most potent hepatocarcinogens in this series. Concentrations of methylpurines in liver DNA decreased with increasing chain length from C1 to C5. Administration of the higher homologues (C6-C12) caused levels of DNA methylation which by themselves were considered too low to account for their hepatocarcinogenicity. In rat oesophagus, DNA methylation closely paralleled carcinogenicity, the most effective agents being the butyl and pentyl derivatives (C4 and C5). Levels of DNA methylation in bladder epithelium were close to the limit of detection (C6,C9,C10,C12) and there was no apparent correlation with carcinogenicity. It is concluded that initiation of malignant transformation by DNA methylation alone (through hydroxylation of the nitrosamine at the methylene alpha-carbon) could be operative for C1-C5. For the higher homologues, this type of DNA modification is insufficient to explain the complex pattern of tissue specificity.

Animals↗
PubMed1996

Organ-specific autoantibodies in vitiligo patients and their relatives.

BACKGROUND: Recent data have supported an autoimmune etiology of vitiligo. Genetic factors also seem to play an important role in this disorder. The purpose of this study was to determine the presence and frequency of organ-specific autoantibodies in vitiligo patients and their relatives. METHODS: Twenty patients with vitiligo and two first or second degree relatives of each patient were interviewed and their sera analyzed for the presence of antithyroglobulin (ATg), antithyroid microsomal (ATM), antiparietal cell (APC), and antiadrenal (AAd) autoantibodies. The sera of 20 normal patients were used as control. RESULTS: A significantly increased frequency of ATg, ATM, and APC antibodies was found in vitiligo patients when compared to normal controls. First and second degree relatives had significantly increased frequencies of ATg and ATM. A high incidence of autoimmune/endocrine diseases was found in the patients' relatives, including a 25% prevalence of vitiligo. CONCLUSIONS: These findings not only support an autoimmune etiology for vitiligo, but also highlight the strong genetic contribution to this pigmentary disorder.

Adolescent↗
PubMed1988

Comparison by leukocyte adherence inhibition of human immune response to cancer-associated immunogens, Thomsen-Friedenreich (T) and Tn, myelin basic protein, and organ-specific cancer neoantigens.

Peripheral blood leukocytes from cancer patients exhibit nonadherence to glass as an index of antigen recognition when incubated individually with four distinct, soluble tumor-related substances. Crude cancer extracts, purified antigens, T and Tn, myelin basic protein (MBP), and organ-specific cancer neoantigens (OSN), all elicited narrow dose-dependent leukocyte adherence inhibition (LAI) response curves. The present study focused on the reasons for the narrow antigen dose-LAI response relationship. Between 9 and 20 pmol of antigens elicited the maximum number of nonadherent leukocytes; cleavage products of T antigen and the nonapeptide (T18) of MBP required about a 10-fold increase in molar concentration for the same LAI response. When crude cancer extracts were combined with pure antigen or the pure antigens were combined at concentrations shown to give maximum LAI responses, the positive LAI responses were negated. The chemoattractant LTB4 at 10(-11) M triggered maximum LAI. But when MBP was added with the LTB4 at progressively increasing concentrations, there was dose-dependent negation of LAI. The magnitude of LAI depended on the total amount of mediator released rather than the rate of release. When leukocytes from cancer patients were incubated with optimum to high concentrations of MBP, the supernatants contained a mediator that gave similar bell-shaped dose-LAI responses on control leukocytes indicating that leukocytes from cancer patients react to a much broader range of antigen concentration than indicated by the LAI assay alone. High antigen dose negated LAI because of excess mediator production. Antigen-generated mediators had a biphasic effect inducing nonadherence and then adherence of leukocytes.

Antigens, Neoplasm↗
PubMed2000

[Diabetes mellitus type 1 and associated organ-specific autoimmunity].

Autoimmune type 1 diabetic patients show a high prevalence of thyroid peroxidase (TPO), parietal cell (PCA), anti-adrenal (AAA) and anti-endomysium antibodies (EmA-IgA), which may be accompanied with clinical disease. We studied the grade of associated organ-specific autoimmunity and the pattern of prevalence of TPO and PCA by age, gender, duration, age at onset of diabetes, and HLA DR haplotype in 783 type 1 diabetic patients, consisting of 286 children and 497 adults (M/F: 389/394), with a mean diabetes duration of 11.8 +/- 10.1 years. The relationship between islet cell (ICA), glutamic acid decarboxylase-65 (GADA) and thyro-gastric auto-antibodies was also investigated. TPO were present in 21.6%, PCA in 18.3%, AAA in 2.2% and EmA-IgA in 2.1% of the patients. The presence of TPO is determined by gender (p < 0.0001), age (P = 0.0008), and PCA status (p = 0.029). The presence of PCA is only influenced by age (p = 0.0027) and TPO status (p = 0.0155). Patients with ICA+ > or = 3 years had a higher prevalence of thyro-gastric auto-antibodies (p = 0.045) than ICA- subjects. Also, PCA were more prevalent in GADA+ than GADA- patients (p = 0.005). We observed an association between HLA DR5 and PCA (p = 0.0012). Dysthyroidism was more prevalent in TPO+ than TPO- subjects (p < 0.0001). PCA+ subjects had a higher prevalence of iron deficiency anaemia (p = 0.0099) and pernicious anaemia (p < 0.0001) than PCA- patients. In conclusion, particularly type 1 diabetic patients with persisting ICA > or = 3 years or with GADA, show a high prevalence of thyro-gastric auto-antibodies. Based on antibody-positivity we observed a high prevalence of thyroid disease, iron deficiency anaemia and pernicious anaemia, which can compromise the health of the diabetic patient.

Adolescent↗
PubMed1979

Diethylstilbestrol metabolic transformation in relation to organ specific tumor manifestation.

Oxidative biotransformation of the synthetic estrogen diethylstilbestrol (DES) gives rise to several reactive compounds. Two mechanisms are proposed concerning the possible involvement of reactive metabolites in the organotropic tumorigenesis of DES. The first mechanism suggests an affinity of the metabolite to the estradiol receptor present in estrogen target organs. This has been shown for the olefinic epoxide of DES. The second mechanism is based on the organ specific oxidation of DES by peroxidase. The intermediates of this reaction were found to bind to nucleic acid and protein in a manner characteristic of chemical carcinogens.

Animals↗
PubMed1992

Developmental and organ-specific expression of an ABA- and stress-induced protein in barley.

An mRNA species, HVA1, has been shown to be rapidly induced by abscisic acid (ABA) in barley aleurone layers (Hong, Uknes and Ho, Plant Mol Biol 11: 495-506, 1988). In the current work we have investigated the expression of HVA1 in other organs of barley plants. In developing seeds, HVA1 mRNA is not detected in starchy endosperm cells, yet it accumulates in aleurone layers and embryo starting 25 days after anthesis, and its level remains high in these organs in dry seeds. Although the levels of HVA1 mRNA are equivalent in the dry embryos of dormant and nondormant barley seeds, upon imbibition HVA1 mRNA declines much slower in the dormant than in the nondormant embryos. The HVA1 mRNA and protein levels are highly induced by ABA treatment in all organs of 3-day-old seedlings. However, the induction in the leaf of 7-day-old seedlings is less than one tenth the level observed in the leaf of 3-day-old seedlings. In the leaf, HVA1 mRNA and protein are induced mainly at the base. These observations indicate that the expression of HVA1 is under developmental regulation. Besides the HVA1 protein, a smaller protein (p20) of approximately 20 kDa cross-reacting with anti-HVA1 polyclonal antibodies, is induced by ABA in barley seedlings but not in seeds. HVA1 mRNA is induced by drought, NaCl, cold or heat treatment. Similar to ABA treatment, the drought induction of HVA1 occurs in all the tissues of 3-day-old seedlings, but the induction decreases dramatically in the leaf of 7-day-old plants. The significance of organ-specific, developmentally regulated, and stress-induced expression of HVA1 is discussed.

Abscisic Acid↗