Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sclerosing hemangioma of the lung remains poorly understood, and it is still unclear whether this lesion is neoplastic or not. It consists of two major cell types, pale cells and cuboidal cells. We analyzed the clonality of each cell types from six female cases of surgically resected sclerosing hemangioma. The pale cells and cuboidal cells were separated by microdissection from methanol-fixed sections, and DNA was extracted for clonal analysis based on an X-chromosome-linked polymorphic marker, the human androgen receptor (HUMARA) gene or the phosphoglycerate kinase (PGK) gene. The HUMARA and PGK genes were found to be amplified with or without digestion by the methylation-sensitive restrictive endonuclease HpaII. Five of six cases were informative. Pale cells and cuboidal cells showed the same monoclonality in all of the informative cases, whereas the control cells showed a polyclonal pattern. Our results demonstrated that sclerosing hemangioma is caused by monoclonal expansion of cells, confirming that it is a neoplasia. Moreover, the present data indicate that both pale cells and cuboidal cells are derived from the same cell.
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PMID:Monoclonality of both pale cells and cuboidal cells of sclerosing hemangioma of the lung. 954 67

Borderline ovarian tumors (BOTs), or ovarian tumors of low malignant potential, represent a distinct category of epithelial ovarian neoplasms that have a clinically more favorable outcome than invasive epithelial ovarian cancer. Histologically, BOTs and invasive ovarian carcinomas both show cellular proliferation and pleomorphism, but unlike invasive ovarian carcinomas, BOTs lack stromal invasion. Although serous BOTs are frequently confined to a single ovary at the time of diagnosis, bilateral or extra-ovarian spread occurs in 30-40% of cases. The purpose of this study is to determine whether bilateral or extraovarian serous borderline lesions are metastatic sites from the original tumor, or represent separate primary tumors. DNA specimens from multiple tumor sites and normal tissue controls were obtained in eight women with bilateral or extra-ovarian serous borderline tumors. The pattern of loss of heterozygosity at the androgen receptor locus on the X chromosome was evaluated in the multiple tumor sites. In addition, the pattern of X-chromosome inactivation was determined using HpaII restriction endonuclease digestion, followed by PCR amplification of the androgen receptor locus. Multifocality was determined when alternate patterns of X-chromosome inactivation occurred. In two of the eight patients, the left and right ovarian tumor sites had different androgen receptor alleles inactivated, indicating that the bilateral tumors derived independently. In a third patient, the X inactivation pattern in the left ovarian tumor differed from the two peritoneal implants, suggesting that the implants were separate primary tumors, and not metastatic, from the left ovarian tumor. The remaining five patients had the same pattern of loss of heterozygosity and X inactivation in the tumor sites studied. These results suggest that bilateral and advanced stage serous BOTs may be multifocal in origin. This result is in contrast to invasive epithelial ovarian cancer, which has been shown to be unifocal in origin.
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PMID:Evidence for the multifocal origin of bilateral and advanced human serous borderline ovarian tumors. 962 67

The analysis of patterns of X-chromosome inactivation is becoming increasingly utilized as a marker of clonal composition of tissues from women. To date, however, no analogous system has been found for the study of clonality in tissue from men. In the current study, the methylation patterns for portions of the amelogenin genes are tested, which are encoded on both the X- and Y-chromosome (AMGX and AMGY). The polymerase chain reaction (PCR) was used to amplify portions of AMGX and AMGY from genomic DNA of carcinomas of the colon, lung, liver and kidney, as well as from matched normal somatic tissues. The amplification target included Alu I methylation sensitive restriction endonuclease sites as well as a 189 bp sequence which is present in AMGX but is absent in AMGY. Polymerase chain reaction amplification of AMGX and AMGY was successful using genomic DNA from both tumour and normal control tissue in 24 of the 26 cases. Pretreatment of genomic DNA with Alu I blocked amplification of AMGX in all cases from both normal tissue and tumour. This indicates that AMGX and AMGY undergo a non-random pattern of methylation in both normal tissues and in tumours, precluding their use as a marker of clonality. Methylation of Alu I sites in AMGY suggests that the amelogenin genes undergo dosage compensation, which raises the possibility that the expression of amelogenin is not restricted to the development of the tooth bud but may also play some other role in various tissues of the body.
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PMID:Amelogenin dosage compensation in carcinoma of colon, lung, liver and kidney, is not a marker of clonality in males. 972 93

Atypical adenomatous hyperplasia (AAH) of the lung has been postulated as a possible precursor lesion of bronchioloalveolar carcinoma (BAC). The clonality of AAHs from seven female patients was analyzed to determine whether AAH is a monoclonal expansion. All AAHs were identified in lungs surgically resected for BAC. The clonality of the BAC and bronchiolar metaplasia in each case was also analyzed. Approximately 500 cells in each lesion were precisely microdissected from methanol-fixed sections. Adjacent normal lung tissue was collected as a normal control. DNA was extracted for clonal analysis based on an X-chromosome-linked polymorphic marker, the human androgen receptor gene (HUMARA). HUMARA was found to be amplified with or without previous digestion by the methylation-sensitive restriction endonuclease Hpa II. Five cases were informative. All 10 AAHs and 7 BACs obtained from the informative cases showed monoclonality, whereas the control cells showed polyclonality. Three different AAH lesions in a single case showed both possible patterns of monoclonality. BAC and contiguous AAH showed identical monoclonality in two cases. Two lesions of bronchiolar metaplasia, which was considered reactive, were polyclonal. Our results demonstrated the monoclonal nature of AAH, and this finding suggests that AAH is a precursor of BAC or a preneoplastic condition.
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PMID:Monoclonality of atypical adenomatous hyperplasia of the lung. 991 39

The histogenesis of meningothelial-like nodule or so-called minute pulmonary chemodectoma remains unclear, with various immunohistochemical analyses giving inconsistent results. We performed an immunohistochemical and clonal analysis of minute pulmonary meningothelial-like nodules. Thirty-one histologically defined meningothelial-like nodules in 14 cases were stained immunohistochemically. One case had multiple lesions with brown pigment granules, which were positively stained with Berlin blue method, indicating the presence of hemosiderin. All meningothelial-like nodules were positive for vimentin and epithelial membrane antigen (EMA), but not for S-100 protein, chromogranin A, or synaptophysin. Five of 13 cases (13 of 28 lesions) were positive for CD68 by KP-1. Ten cases (24 lesions) stained for CD68 by PG-M1 were weakly positive. All lesions were negative for lysozyme, myosin, actin, keratin, and melanoma-associated antigen. Alveolar macrophages were intensely positive for CD68 and lysozyme in all examined cases. We analyzed the clonality of 11 minute pulmonary meningothelial-like nodule lesions in two female cases based on an X-chromosome-linked polymorphic marker, the human androgen receptor gene (HUMARA). The HUMARA was found to be amplified with or without prior digestion by the methylation-sensitive restriction endonuclease HpaII. Six of 11 lesions showed monoclonal expansion. Five lesions in a multiple case showed different patterns of monoclonality. Our findings showed that minute pulmonary meningothelial-like nodules have meningothelial-like and phagocytic characteristics but no muscular phenotype. Furthermore, some minute pulmonary meningothelial-like nodules may show monoclonal expansion, whereas others are polyclonal. Our data indicate that minute pulmonary meningothelial-like nodules are reactive rather than neoplastic.
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PMID:Immunohistochemical and clonal analysis of minute pulmonary meningothelial-like nodules. 1020 64

The clonal composition of 34 benign and malignant sporadic pancreatic endocrine tumours (PETs) of female patients was studied using a sensitive polymerase chain reaction (PCR)-mediated non-isotopic clonality analysis, which is based on the inactivation patterns of polymorphic X-linked genes encoding the androgen receptor (AR) and phosphoglycerate kinase (PGK-1) proteins. Predigestion of DNA with the methylation-sensitive restriction endonuclease Hpa II permitted selective PCR amplification of the methylated (uncleaved) allele. Amplification was successful in 27 of 34 samples. Twenty patient samples were heterozygous for the AR microsatellite region or Bst XI polymorphic site of the PGK-1 gene, permitting analysis of clonality. A monoclonal pattern of X-chromosome inactivation was found in 7 of 20 PETs (35 per cent), since DNA pretreatment with Hpa II blocked amplification of one of the two AR or PGK-1 alleles. One additional tumour exhibited an oligoclonal inactivation pattern and two others a loss of heterozygosity (LOH) at the AR locus, indicative of monoclonality. A random pattern of X-chromosome inactivation and polyclonal cellular composition was observed in the remaining ten PETs (50 per cent). When comparing informative benign and malignant PETs, only 2/7 (29 per cent) benign tumours showed a monoclonal pattern and 8/13 (61 per cent) malignant tumours a monoclonal (5), oligoclonal (1), or LOH (2) pattern. The clonal composition of PETs was not associated with a particular growth pattern, proliferation index or immunohistochemical expression pattern. These findings suggest that PETs might initially represent poly-/oligoclonal neoplastic lesions which are eventually outgrown by a single, more aggressive cell clone with the potential for invasive growth and metastatic spread.
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PMID:Clonal analysis of sporadic pancreatic endocrine tumours. 1020 84

Adenosquamous carcinoma of the lung is a subset of pulmonary carcinomas, and comprises less than 4% of lung carcinomas. Its histogenesis remains unclear. The clonality of adenosquamous carcinoma from four female patients was analyzed to determine whether the clonality between the squamous cell and adenocarcinomatous components coincides. Each lesion was precisely microdissected from methanol-fixed sections. Adjacent normal lung tissue was collected as a normal control. DNA was extracted for clonal analysis based on an X-chromosome-linked polymorphic marker, the human androgen receptor gene (HUMARA). HUMARA was found to be amplified with or without previous digestion by the methylation-sensitive restriction endonuclease HpaII. All four cases were informative. Squamous cell and adenocarcinomatous components showed identical monoclonal patterns in all four patients. In one case, only the squamous cell carcinomatous component showed loss of heterozygosity of the HUMARA locus. The results suggest that the squamous cell and adenocarcinomatous components originate from the same cell.
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PMID:Clonal analysis of adenosquamous carcinoma of the lung. 1062 36

To investigate X-chromosome inactivation (XCI) in human trophoblasts during early pregnancy, trophoblast genomic DNA was extracted and analyzed for a Bst XI restriction endonuclease site polymorphism in the X-linked phosphoglycerate kinase gene, after digestion with methylation-sensitive Hpa II (control samples were digested instead with Afa I). Six villous trophoblast DNA samples were informative for the polymorphism (ie, heterozygous) and were derived from women homozygous for the polymorphism. These samples were then evaluated for XCI. In five of the six samples with Hpa II predigestion, the sizes of the two heterozygous band peaks differed; maternal X-chromosome (X(M))-derived alleles showed smaller peak sizes than paternal X-chromosome (X(P))-derived alleles, but the differences varied in degree. In samples obtained by microdissection from formalin-fixed, paraffin-embedded tissues (30 samples from different anchoring villi, and 38 samples from different branch villi), monoclonal band patterns of X(P)-derived alleles were observed more frequently than those of X(M)-derived alleles, but almost half of the samples showed polyclonal patterns. Our results suggest that a skewing of XCI exists in the human trophoblast; however, the degree of nonrandomness due to predominant X(P) inactivation appears to be restricted. It is probable that transcription of the X inactivation center (XIC) begins earlier in mice than in humans.
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PMID:X-chromosome inactivation in the human trophoblast of early pregnancy. 1080 35

A specific inhibitor of DNA cytosine C5-methylases would be useful for studying genomic imprinting, X-chromosome inactivation, carcinogenesis, and regulation of tissue-specific gene expression, for these physiological phenomena appears to be regulated through DNA methylation in promoter sequences. This paper reports a novel convenient in vitro assay method for screening DNA cytosine C5-methylase inhibitor. Our method uses a commercially available Hae III methylase (cytosine C5 methylase), its corresponding Hae III endonuclease, and lambda DNA as their substrate.
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PMID:An in vitro screening method for DNA cytosine-C5-methylase inhibitor. 1194 78

Turner syndrome is caused by haploinsufficiency of the short arm of X-chromosome, and is usually diagnosed by karyotyping. This procedure is time-consuming, expensive and unfeasible for population screening. We propose molecular detection of 45XO Turner patients based on the ability of HpaII, a methylation sensitive endonuclease, to induce the cleavage of non-methylated DNA in the active X-allele. Genomic DNA was obtained from 22 patients with Turner syndrome confirmed by karyotype (45XO, N = 18; 45XO/46XX, N = 4). After digestion, DNA was amplified with primers directed to exon 1 of the androgen receptor (AR) gene and to the GAPDH control gene. Normal control females or mosaic patients, with a second methylated X-chromosome, escaped from HpaII digestion and produced a band corresponding to AR gene amplification. 45XO patients have just one active non-methylated X-chromosome, completely digested by HpaII, thus preventing the amplification of the AR gene. Three of the 45XO cases gave amplified bands, suggesting low-frequency mosaicisms that are not detected by karyotyping. Compared to classical karyotype studies for the detection of 45XO Turner patients, this new molecular method is simpler, faster and less expensive.
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PMID:Molecular detection of XO - Turner syndrome. 1496 34


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