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

---

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

Intact RNA from various rat organs was isolated by an efficient and rapid method. This method of RNA isolation is a modification of an earlier method that uses guanidinium isothiocynate followed by extraction in the presence of sarcosyl, acetate and phenol. The RNA obtained by the method reported here was comparable with the RNA prepared by the CsCl2 ultracentrifugation method and the commercially available kit based on published methods. The quality of RNA was found suitable for Northern blotting analysis, RNase protection assays and reverse transcriptase-polymerase chain reaction (RT-PCR). Since reverse transcriptase is active in the buffer used for Taq DNA polymerase, only one reaction needs to be set up. We also found that the use of aurintricarboxylic acid in the RNA preparation prevents the degradation of RNA during storage. Expression of low density lipoprotein (LDL) receptor, apolipoprotein (apo) AI, AII and AIV mRNAs were quantified in various rat organs. Our results indicated that rat LDL receptor mRNA is expressed in several organs whereas apoAI and AIV mRNAs were expressed mainly in the liver and intestine. However, apo AII mRNA is expressed mainly in the liver. Unlike mice and some species of monkeys, in the rat apoAI mRNA is expressed at 5-6 times higher levels in the intestine compared to liver. Apo AIV mRNA abundance was also found to be several fold higher in intestine compared to hepatic tissues. We present here, for the first time, data on the absolute amounts of LDL receptor, apoAI, AII and AIV mRNA in various rat organs which were quantified by a novel RNase protection/solution hybridization assay.
...
PMID:Expression of low density lipoprotein receptor, apolipoprotein AI, AII and AIV in various rat organs utilizing an efficient and rapid method for RNA isolation. 137 76

To investigate mother-to-infant transmission of hepatitis C virus, serial follow-up of anti-HCV and hepatitis C virus RNA was undertaken in 11 infants born to hepatitis C virus-infected mothers who had been screened from 11,688 pregnant women. None of the hepatitis C virus-infected mothers was infected by human immunodeficiency virus. Anti-HCV was checked by the second-generation enzyme immunoassay kit, and hepatitis C virus RNA was examined by reverse transcriptase-nested polymerase chain reaction. Hepatitis C virus RNA was found in more than two serum samples in two of these 11 infants; those two infants were regarded as hepatitis C virus-infected. One of the two had hepatitis C virus RNA at the age of 1, 3, and 6 months, but not later. The course of hepatitis C virus RNA and anti-HCV in this baby may reflect fluctuating viral replication in chronic infectious disease or viral clearance in acute infection. The other infant had hepatitis C virus RNA detectable at the age of 3 months and at 15, 18 and 24 months. In the other nine non-hepatitis C virus-infected infants, maternally acquired anti-HCV gradually disappeared by the age of 6 months. The liver function profile fell to the normal range in all the infants, including the two hepatitis C virus-infected infants. This may indicate the subclinical nature of hepatitis C virus infection in infancy. Seven fathers and four siblings of these 11 infants were checked for anti-HCV and liver function tests; none had evidence of hepatitis C virus infection.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Temporal profile of hepatitis C virus antibody and genome in infants born to mothers infected with hepatitis C virus but without human immunodeficiency virus coinfection. 807 41

There are several methods to detect human immunodeficiency virus (HIV) infection; the detection of antibodies against HIV, the detection of HIV particles, and the detection of HIV infected cells. The detection of anti-HIV antibodies is practical, but the antibodies are undetectable both on a seronegative person at the superacute phase, and the new-born baby from a seropositive mother. No other method is ideal for all purposes. Thus the detection of the HIV-specific nucleotide sequence especially using the PCR method has been expected. We developed a quantitational PCR method to assay HIV-infected PBMC cell number, and the result correlated with that of the quantitational culture method, and also correlated with the CD4 count, that is inversely related to the clinical stage of HIV infection. Our quantitational PCR method must be improved before application to a practical routine test. A new PCR kit to detect HIV infected cells qualitatively has been developed and purchased in Europe. This kit is especially workable to test specimens where the antibody detection method cannot be used. PCR can be used on other specimens and can be applied to HIV infection. HIV RNA (both genomic RNA and viral mRNA) can be detected by a combination with the reverse transcriptase reaction. This method (RT-PCR) will be ideal to detect HIV particles. With PCR, the sequence-differentiation between each clinical virus strain may be detected, thus the characterization of a virus strain such as drug resistance, latency, or the prognosis may be recognized. PCR is indeed a valuable method to detect HIV-infection, provided its limits are properly understood.
...
PMID:[The diagnosis of HIV infection by detecting specific nucleotide sequence]. 828 1

The human endometrium undergoes regular cyclical changes under the endocrine control of oestrogens and progesterone acting via specific nuclear receptors. The molecular and cellular events mediating these changes are not understood. The present study examined the changes in the endometrial progesterone receptor and its mRNA during the menstrual cycle. Forty-four endometrial samples obtained from women with normal menstrual cycles were divided into four categories: early proliferative (days 6-9), late proliferative (days 10-14), early secretory (days 15-21) and late secretory (days 22-28). The progesterone receptor protein was determined using a human progesterone receptor enzyme-linked immunoassay kit. Total RNA was extracted using RNAzol and the abundance of mRNA encoding the progesterone receptor was determined by reverse transcriptase-polymerase chain reaction and by northern blot analysis. The concentration of the progesterone receptor in the endometrium was highest during the late proliferative phase and was lowest in the late secretory phase. Significant differences were observed between the menstrual cycle phases (P < 0.003). No cyclical variation was observed in the concentration of mRNA encoding for the progesterone receptor in the endometrium when analysed by reverse transcriptase polymerase chain reaction or by northern analysis. There appears to be no association between the amounts of mRNA encoding the progesterone receptor and progesterone receptor protein during the menstrual cycle suggesting that the control of the expression of the progesterone receptor may not occur solely at the transcriptional level.
...
PMID:Endometrial progesterone receptor expression during the human menstrual cycle. 866 43

A quantitative hepatitis C virus reverse transcriptase PCR (HCV RT-PCR) assay established in our laboratory was compared with the Roche Amplicor HCV Monitor test kit for agreement of test results and intra-assay variability. Both assays rely on reverse transcription and amplification of extracted RNA from patients' sera together with an internal RNA standard derived from the 5'-noncoding region of HCV. A panel of clinical serum samples (n = 33) was quantitatively analyzed in parallel by both test systems. The methods demonstrated substantial agreement between 1 x 10(3) and 5 x 10(5) HCV RNA molecules per ml of serum. However, with sera containing more than 5 x 10(5) copies per ml, according to our in-house assay, the results diverged on average in a nonacceptable range of 2 orders of magnitude. Our in-house HCV RT-PCR assay measured up to 5 x 10(7) HCV-RNA molecules per ml in some serum samples. However, the Roche Amplicor HCV Monitor test kit did not detect more than 2 x 10(6) molecules in any of the serum samples tested. After dilution of serum samples prior to testing, an approximately 0.5 order of magnitude more HCV RNA molecules was detected by the Roche HCV test kit in sera containing high copy numbers (> 5 x 10(5) RNA copies according to the in-house assay). The in-house PCR and the Roche Amplicor HCV Monitor test kit revealed coefficients of variation of 6.2 and 7.5%, respectively.
...
PMID:Comparison of two quantitative hepatitis C virus reverse transcriptase PCR assays. 878 97

The variant MD strain of infectious bursal disease virus (IBDV) was examined using restriction fragment length polymorphism (RFLP) and the molecular variation was compared with published sequences of both variant and classic IBDV strains. Viral RNA was transcribed into cDNA using reverse transcriptase and then amplified by the polymerase chain reaction (PCR). Three separate but overlapping fragments of 1603 bp, 1496 bp, and 1066 bp containing the entire coding region for VP2, VP4, and VP3, respectively, were amplified. These amplified products were initially cloned using the TA Cloning kit and further subcloned into the pGEM-3Zf and pUC19. Eight restriction enzymes, PstI, BamHI, AvaI, EcoRI, HindII, XmaI, SmaI, and XbaI, were tested for their ability to digest the MD PCR products. The resulting RFLP was analyzed and compared with the published genome segment A sequences of the classic IBDV strain STC and the variant IBDV strain GLS. Differences in restriction fragment profiles were observed after digestion with BamHI, EcoRI, XmaI, and SmaI, with the absence of the EcoRI site in both variant strains, GLS and MD. The MD PCR products lacked both XmaI and SmaI sites, which were present in both STC and GLS. The MD PCR products contained a BamHI site within the hypervariable region of VP2, which is present in STC but not in the variant GLS. An additional BamHI site was identified in the VP4 gene of MD and GLS but not in STC.
...
PMID:Restriction analysis of the MD infectious bursal disease virus strain. 898 Aug 28

The product of the protooncogene c-kit is the receptor for the hematopoietic cytokine stem cell factor (SCF). C-kit is expressed on leukemic cells of the erythroid, myeloid, and mast-cell lineage and SCF has a proliferative effect on some of these cells. The role of SCF and c-kit in lymphoid malignancies is much less clear. Here we review the role of c-kit in normal lymphopoiesis and summarize its role in lymphoid malignancies. C-kit is expressed in normal lymphopoiesis and its ligand SCF synergizes with IL-7 to enhance the proliferation of B- and T-cell progenitors. In malignant lymphopoiesis, c-kit can also be expressed in B and T-lymphoblastic cells from children with non Hodgkin's lymphoma (NHL) or acute lymphoblastic leukemia (ALL) when analyzed by the highly sensitive reverse transcriptase polymerase chain reaction (RT-PCR). While c-kit receptors were detected by flow cytometric (FCM) analysis on about 40% of fresh T-lymphoblastic biopsy tumor cell preparations or T-lymphoblastic cell lines, no receptors were detected on B-lymphoblastic fresh cells or cell lines from children with B-ALL or Burkitt's lymphoma (BL). Almost all of the lymphoblastic cells expressing c-kit protein responded to recombinant human (rh)SCF with a downregulation of c-kit receptors. A proliferative response was detected only in a minority of these cells. B-ALL or BL cell lines showed no response to rhSCF. Upregulation of c-kit in T-lymphoblastic cells could be demonstrated by the addition of IL-1 beta, TNF-alpha, TGF-beta or A23187, and downregulation by rhSCF or phorbol myristate acetate (PMA). Despite upregulation of c-kit mRNA, protein remained undetectable on B-ALL or BL cells in the presence of A23187. The metabolic state of the cells seemed to influence c-kit expression, since c-kit was upregulated in T-lymphoblastic cells by the addition of new medium. C-kit appears to play a role in the growth of some malignant T-lymphoblastic but not B-lymphoblastic cells.
...
PMID:C-kit receptors in childhood malignant lymphoblastic cells. 916 31

The method of the poly A-linked colorimetric reverse transcriptase assay (PAC-RTA) was developed and evaluated for the measurement of Mg(2+)-dependent reverse transcriptase (RT) activity of feline immunodeficiency virus (FIV). PAC-RTA was first evaluated for the detection of RT activity in the culture supernatant of FIV Petaluma strain. The detection limit of RT activity by PAC-RTA was about 10-fold better than that by the conventional non-radioisotopic RT assay kit. Then, PAC-RTA was evaluated for the indication of FIV isolation from cats naturally infected with FIV. FIV was isolated from peripheral blood mononuclear cells of 9 FIV-seropositive cats. The time course appearance of RT activity measured by PAC-RTA corresponded with the analysis of FIV antigen expression by indirect immunofluorescence. Finally, PAC-RTA evaluated the drug susceptibility of FIV. MYA-1 cells (feline T-lymphoblastoid cells) were infected with FIV and were cultured in the presence of various concentrations of anti-human immunodeficiency virus agents such as azidothymidine (AZT) or dextran sulfate. An inverse relationship between the RT activities and the concentrations of these agents in the culture supernatant was confirmed by PAC-RTA. PAC-RTA is easy to perform without using radioactive materials, and one plate can handle 96 samples at one time. By monitoring the RT activity, this assay is a useful method for FIV studies such as viral replication and drug susceptibility.
...
PMID:Measurement of reverse transcriptase of feline immunodeficiency virus by poly A-linked colorimetric assay. 923 15

In a study involving 50 breast cancer tumours, we compared two oestrogen receptor (ER) detection methods developed by us--a microplate immunoenzymometric assay (EIA96) and an immunohistochemistry kit (HistoCIS-ER)--with the radioligand assay (RLA), the Abbott immunoenzymometric assay ER-EIA and the reverse transcriptase polymerase chain reaction technique (RT-PCR). Among the three ER protein cytosolic assays (EIA96, ER-EIA and RLA), the two EIAs showed the best agreement (y = 1.086x - 7.840; r2 = 0.876). At the calculated optimal cut-off values (8 and 14 fmol mg(-1) protein for EIA96 and RLA respectively), EIA96 was more sensitive than RLA (0.94 for EIA96, 0.88 for RLA), but slightly less specific (0.82 for EIA96, 0.94 for RLA). The Cox logistical regression model applied to EIA96, RLA and RT-PCR showed that EIA96 discriminated the best between ER-EIA+ and ER-EIA- samples. The RT-PCR technique and HistoCIS-ER both had a positivity-negativity concordance of 86% with EIA96.
...
PMID:Comparison of a new microplate oestrogen receptor (ER) enzyme immunoassay with other ER detection methods. 927 30

A heteroduplex tracking assay (HTA) was developed for genetic analyses of the hepatitis C virus (HCV) using single-stranded probes from the core (C)/E1 region. Nucleotide sequencing of reverse transcriptase (RT)-PCR products from 15 Italian dialysis patients confirmed the specificity and accuracy of the HTA genotyping method, which identified 5 of 15 (33.3%) 1b, 7 of 15 (46.7%) 3a, and 3 of 15 (20%) type 2 infections. The genotypes of an additional 12 HCV antibody-positive blood donors from different geographical locations were also in agreement with the genotypes determined by the Inno-LiPA HCV II kit (Innogenetics) and/or restriction fragment length polymorphism (RFLP). Isolates which had between 35 to 40% nucleotide divergence from control subtype 1a, 1b, 2a, 2b, or 3a standards could be typed. Surprisingly, HTA detected one 1b-2 coinfection which was missed by DNA sequencing. Three samples that were designated non-2a or 2b type 2 by HTA were found to be type 2a by both RFLP and direct nucleotide sequencing of the 5' untranslated region. The genetic distance between patient type 2 and control 2a, 2b, and 2c isolates indicated that a new subtype was present in the population being studied. Serotyping (RIBA serotyping strip immunoblot assay kit) of 23 dialysis patients showed that the genotype could be determined in 6 of 8 (75%) C/E1 RT-PCR-negative and 15 of 23 (65.2%) RT-PCR-positive samples, indicating that the two tests complement each other.
...
PMID:Hepatitis C virus heteroduplex tracking assay for genotype determination reveals diverging genotype 2 isolates in Italian hemodialysis patients. 943 53


1 2 3 4 5 6 7 8 9 10 Next >>

---