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:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An African lioness from the Zoo of Zurich had to be euthanized because of an inoperable tumor. The serum tested negative for feline leukemia virus (FeLV) p27 antigen by enzyme-linked immunosorbent assay (ELISA) but was strongly positive for feline immunodeficiency virus (FIV) antibodies by ELISA and Western blot. When her only offspring and mate were tested for FIV, high antibody titers to FIV were also found in their serum. Lymphocytes were prepared from these two lions on different occasions and co-cultivated with specific pathogen free (SPF) cat lymphocytes in the presence of concanavalin A and recombinant human interleukin-2 (IL-2) for 6 weeks. The cell culture supernatants tested negative for Mg(2+)-dependent reverse transcriptase and FIV p24 by a double antibody sandwich ELISA throughout the culture period. Whole blood and buffy coat cells collected from these two lions were transmitted by intraperitoneal injection into two SPF cats. The two cats did not seroconvert for a period of 11 months nor could reverse transcriptase activity and FIV p24 antigen be demonstrated in the supernatant of several lymphocyte cultures. To determine the importance of lentivirus infections in zoo-kept wild felids, 124 serum samples were obtained from African lions, Indian and Siberian tigers, snow leopards, panthers, cheetahs and other wild cats from nine European zoos. In addition, serum samples collected from 12 Asiatic lions originating from Gir forest in the Indian State of Gujarat were included in this study. The sera were tested for antibodies to FIV, FeLV and feline syncytium-forming virus (FeSFV) by ELISA and Western blot using the respective viruses after gradient purification. In addition, some of the sera were also tested for antibodies to equine infectious anemia virus (EIAV) and Visna-Maedi virus (VMV). Antibodies to FIV were found in 30/53 (57%) of African lions, one of 18 tigers and one of four panthers. All other sera including those collected from the 12 Asiatic lions were negative for FIV antibodies. Some of the FIV positive lion sera had high antibody titers producing strong bands on Western blot strips even in dilutions of >> 1:1000. The Western blot pattern of the lion sera differed from that of domestic cats in that primarily p24 and to a lesser degree p17 was recognized. Antibodies to FeSFV were found in 14 animals (seven with strong, seven with intermediate, reaction). No correlation was found between FIV and FeSFV infection. Antibodies to FeLV were found in two cheetahs which later turned out to have been vaccinated with Leukocell, a FeLV vaccine.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Retrovirus infections in non-domestic felids: serological studies and attempts to isolate a lentivirus. 133 98

The detection of human papillomavirus (HPV) type 16 early genes: E7, E5, and the late gene: L1 was attempted in 42 uterine cervical neoplasia (35 cervical carcinomas and 7 cervical dysplasias) using the polymerase chain reaction (PCR) method. Consequently, E7 gene was detected in 19 (54.3%) of 35 carcinomas and in 5 (71.4%) of 7 dysplasias, E5 gene was detected in 7 (20.0%) of 35 carcinomas and in 5 (71.4%) of 7 dysplasias, L1 gene was detected in 18 (51.4%) of 35 carcinomas and in 5 (71.4%) of 7 dysplasias, respectively. In order to elucidate the transcriptional pattern of HPV type 16 in each of the clinical stages, the expression of mRNA for E7, E5 and L1 genes was examined in HPV DNA positive cases using the reverse transcriptase polymerase chain reaction (RT-PCR) method. E7 gene mRNA was detected in 18 (94.7%) of 19 cervical carcinomas, whereas E5 and L1 genes mRNAs were detected in only 4 (57.1%) of 7 and in one (5.6%) of 18 carcinomas respectively. In cervical dysplasias, E7, E5 and L1 genes mRNA were detected in all cases. E7, E5 and L1 genes were transcriptionally active in all dysplasias, whereas E5 and L1 genes were not always transcriptionally active in carcinomas. These results suggest that the HPV type 16 early gene E7 is present preferentially as integrated form and transcriptionally active in the carcinoma cell, and plays an important role in the development of malignancy. On the other hand, E5 and L1 genes are present and transcribed in the dysplasia cell but their transcriptional activity is less frequent in the carcinoma cell.
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PMID:Occurrence and expression of human papillomavirus type 16 genes in uterine cervical carcinomas. 133 65

Paget's disease of bone is a disease of unknown etiology. The demonstration of viral-like particles on ultrastructural examination and the putative detection of viral antibodies and nucleic acids in the tissues suggest a possible viral association. The purpose of this study was to search for nucleic acid sequences homologous to measles virus using the recently described reverse transcriptase (RT) polymerase chain reaction (PCR) in situ hybridization (ISH) technique. After performing RT PCR ISH utilizing primers specific for the nucleocapsid region of the measles virus, an intense signal was evident in most measles-infected HeLa cells compared with a weak signal in few of these cells using standard cDNA-RNA ISH analysis. Amplified measles nucleic acid was detected in tissue from a patient who died of measles infection and was not detected in any of the 11 cases of Paget's disease of bone studied or in a giant cell tumor of bone that had tubuloreticular inclusions on electron microscopy. Therefore, these data suggest that infection by the measles virus is not associated with Paget's disease of bone.
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PMID:In situ analysis of Paget's disease of bone for measles-specific PCR-amplified cDNA. 134 74

A new method for estrogen receptor (ER) mRNA was performed on 33 human breast tumors, using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay by the method of Fuqua et al. In a preliminary experiment using the MCF-7 breast tumor cell line, ER/beta-actin ratio was almost same. ER protein was estimated by a dextran coated charcoal (DCC) assay and by an ER-immunocytochemical (ER-ICA) assay using a specific monoclonal antibody. We found RT-PCR assay correlates with ER-ICA assay (r = 0.664, p less than 0.01), whereas no significant correlation was seen between RT-PCR assay and DCC assay. These results suggests that RT-PCR assay is suitable for detection of ER from small amounts of tissue.
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PMID:[Detection of estrogen receptor (ER) mRNA by use of reverse transcriptase-polymerase chain reaction (RT-PCR) assay; comparison with dextran coated charcoal (DCC) assay and immunocytochemical assay]. 137 12

The presence of circulating tumor cells in patients with localized or disseminated neuroblastoma may be a significant prognostic factor at diagnosis and may antedate the detection of relapse by other diagnostic studies. We report the development of a highly sensitive detection assay for circulating neuroblasts based on the reverse transcriptase-polymerase chain reaction (RT-PCR), using the neuroendocrine protein gene product 9.5 (PGP 9.5) as the tumor marker. Analysis of RT-PCR products by agarose gel electrophoresis demonstrated that neuroblastoma cell lines were uniformly positive, whereas peripheral blood mononuclear cells were negative. Alkaline Southern blotting with a PGP 9.5-specific probe revealed scant expression of PGP 9.5 in peripheral blood mononuclear cells, well below the limits of detection by electrophoresis alone. The system was able to detect a single neuroblastoma cell in 10(7) peripheral blood mononuclear cells. Eighteen patient samples were analyzed by PGP 9.5 RT-PCR and the results compared with immunocytology in 16. Ten of the 18 were negative by both studies. Eight of the 18 were positive by PGP 9.5 RT-PCR, 4 of which were also positive by immunocytology. PGP 9.5 RT-PCR was able to detect circulating neuroblasts in two patients with negative immunocytology, the first with progressive bone marrow disease and the second at high risk for relapse but no other evidence of disease. PGP 9.5 RT-PCR allows the detection of circulating neuroblastoma cells with a sensitivity greater than immunocytology. It will be useful in evaluating the clinical significance of circulating tumor cells with respect to prognosis and early detection of relapse, and in the screening of peripheral stem cell harvests prior to autologous infusion.
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PMID:Sensitive detection of rare circulating neuroblastoma cells by the reverse transcriptase-polymerase chain reaction. 138 Aug 88

We investigated the frequency of rearrangements of the ret and trk proto-oncogenes in Japanese thyroid tumors. DNAs from 38 thyroid papillary carcinomas and 14 follicular adenomas were analyzed by Southern blotting. Rearrangements of the ret and trk proto-oncogenes were detected in one and two papillary carcinomas, respectively, but not in follicular adenomas. Analysis by a reverse transcriptase-polymerase chain reaction method showed that the ret rearrangement-positive tumor contained the PTC/retTPC chimeric transcript, which was reported to be found specifically in thyroid tumors and adenomatous goiter. We also found that rearranged mRNA of the trk proto-oncogene was expressed at high levels in one of two trk rearrangement-positive tumors. Our results indicated that the frequency of rearrangements of these proto-oncogenes in Japanese papillary carcinomas was much lower than that in Italian patients.
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PMID:Low frequency of rearrangements of the ret and trk proto-oncogenes in Japanese thyroid papillary carcinomas. 138 40

Polymerase chain reaction (PCR) is a highly sensitive technique to detect minimal residual disease (MRD) of hematological malignancy by amplifying tumor specific nucleotide sequences. When breakpoint is located over large lesions of genomic DNA, like t(9;22) leukemia, PCR amplifying cDNA of chimeric mRNA, called reverse transcriptase PCR (RT-PCR), can be utilized. We applied this method for the detection of MRD in patients with t(1; 19) acute lymphoblastic leukemia. RT-PCR detection of MRD in patients with leukemia might be useful for estimating of the depth of remission, for disclosing preclinical relapse, and for evaluating the efficacy of in vitro purging in autologous bone marrow transplantation.
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PMID:[Detection of minimal residual disease using reverse transcriptase polymerase chain reaction technique]. 138 48

The differentiation status of Sternberg-Reed (SR) cells is still not well defined, primarily because of their scarcity in tumor biopsies of Hodgkin's disease (HD). In this study we have determined the genomic differentiation status of SR cells by quantitation of recombinase activating gene (RAG) expression. RAG genes are selectively transcribed in immature lymphoid cells. In B cells they are silent after genomic rearrangement has occurred, whereas in T cells they are downregulated during positive selection of double-positive thymocytes into single-positive cells. RNA from tumor biopsies either with numerous (11 cases) or a with few SR cells (16 cases) was assessed by a sensitive reverse transcriptase polymerase chain reaction (RT-PCR) and the results compared with established positive and negative controls. In all except two cases levels of RAG expression were within the range of those determined in negative controls. In both positive cases and in the positive control RAG mRNA was further quantitated by competitive PCR. In cases with abundant SR cells RAG expression was still below that observed in 10(-2) dilutions of positive controls. These results suggest that SR cells are derived from lymphoid cells, more differentiated than the pre-B or common thymocyte stage, which have already undergone genomic rearrangement. They show the value of assessing RAG expression by RT-PCR in the characterization of lymphoid malignancies.
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PMID:Expression of human recombination activating genes (RAG-1 and RAG-2) in Hodgkin's disease. 145 Apr 11

The replication cycle of human immunodeficiency virus type 1 (HIV-1) consists of four distinct stages, each of which can be targeted for specific antiviral chemotherapy. The stages are (1) the attachment of virus to the CD4 receptor at the cell surface; (2) the uncoating of viral nucleic acid and its conversion via viral reverse transcriptase activity to DNA; (3) cellular multiplication, accompanied by the replication of integrated proviral DNA and production of viral RNA and proteins; and (4) the assembly and liberation of progeny virus from the cell and the potential reinitiation of the replication cycle in previously uninfected cells. Since each of these steps represents a potential target for anti-HIV chemotherapy, it is apparent that the rationale for the use of antiviral drugs is not dissimilar from the manner in which antineoplastic agents are targeted to specific stages in the replication cycle of tumor cells. As in the case of anticancer chemotherapy, it is hoped that combinations of drugs, which act against different steps in the viral replication cycle, might have synergistic potential. AZT or zidovudine is the most widely used drug to date to impede the replication of HIV-1; it is significant that this compound was designed initially with anticancer chemotherapy in mind. Although AZT therapy has been reasonably successful, this drug has had important toxic side effects. As in the case of many cancer chemotherapeutic agents, drug resistance to AZT is likely to be an important problem, and there have been several reports of the isolation of drug-resistant variants of HIV-1.
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PMID:Strategies in the treatment of AIDS and related diseases: the lessons of cancer chemotherapy. 155 Oct 24

The p53 gene is currently considered to function as a tumor-suppressor gene in various human malignancies. In hematologic malignancies, alterations in the p53 gene have been shown in some human leukemias and lymphomas. Although mutations in the p53 gene are infrequent in acute myelogenous leukemia (AML) patients, we show in this report that alterations in the p53 gene are frequent in myeloid leukemia cell lines. We studied alterations of the p53 gene in nine human myeloid leukemia cell lines by reverse transcriptase-polymerase chain reaction (RT-PCR), single-strand conformation polymorphism (SSCP) analysis, and direct sequencing. Expression of the p53 gene was not detected at all by RT-PCR in two of the nine cell lines. In these two cell lines, Southern blot analysis showed gross rearrangements and deletions in both of the p53 alleles. Six of the nine cell lines were found to express only mutant p53 mRNA by RT-PCR/SSCP analysis and direct sequencing, and wild-type p53 mRNA was not detected. Two of the mutant p53 mRNAs were shown to be products of abnormal splicing events induced by intronic point mutations. Taken together, eight of nine human myeloid leukemia cell lines expressed no or an undetectable amount of wild-type p53 mRNA. Three of the eight cell lines were growth factor-dependent. Our results suggest that inactivation of the p53 gene may be a common feature in myeloid leukemia cell lines and may play an important role in the establishment of these cell lines.
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PMID:Frequent mutations in the p53 gene in human myeloid leukemia cell lines. 157 49


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