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)

Two commercial immunomagnetic separation (IMS) kits for Cryptosporidium were compared for recovery of oocysts from environmental samples. Oocyst recovery efficiencies with the Dynal and Crypto-Scan kits ranged from 62 to 100% and 34 to 74%, respectively, for seeded environmental water concentrates (turbidity of 210 to 11,480 nephelometric turbidity units). Recovery efficiencies were dependent on the mechanism of agitation during the magnetic capture procedure. An assay combining in vitro cell culture and reverse transcriptase PCR demonstrated that oocysts recovered by IMS retained their infectivity.
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PMID:Evaluation of immunomagnetic separation for recovery of infectious Cryptosporidium parvum oocysts from environmental samples. 992 26

Bone sialoprotein (BSP) and osteopontin (OPN) are two major noncollagenous matrix proteins in mineralized connective tissue that have discrete roles in bone matrix formation, mineralization, and remodeling. The osteotropic secosteroid, 1,25-dihydroxyvitamin D3, a potent regulator of bone remodeling required for normal bone development, has been shown to exert differential effects on OPN and BSP expression by bone cells in vitro. To investigate these effects in vivo, we induced vitamin D3 deficiency in a transgenic mouse line (rBSP2.7Luc) that has a 2.7 kb rat BSP promoter linked to a luciferase reporter gene in its genome. Pregnant rBSP2.7Luc mice were fed vitamin D3-deficient food and demineralized water for 6 weeks. Their offspring were weaned at 3 weeks of age and then fed vitamin D-deficient food for an additional week. The control group were fed normal rodent pellets and water during the entire experimental procedure. Bone tissues from 40, 4-week-old offspring in each group were analyzed for BSP, OPN and luciferase expression. Vitamin D3-deficient mice displayed a rachitic phenotype that included reduced size and malformation of bones. Assays of the BSP promoter transgene in calvariae, mandibles, and tibiae of the rachitic mice showed increases in luciferase activity of 3.1-, 1.9-, and 4.6-fold, respectively, when compared with control littermates. Semiquantitative reverse transcriptase polymerase chain reaction assays of BSP mRNA revealed increases of 7-, 74-, and 66-fold, respectively, in the same rachitic bones, while OPN mRNA was reduced 12.5-fold in calvariae and 2-fold in tibiae and mandibles. In situ hybridization using mouse cRNA probes revealed that the increased BSP expression and decreased OPN expression in the vitamin D3-deficient mice was primarily in osteoblastic cells on the surface of calvariae and endosteal spaces of alveolar bone, on newly formed epiphyseal bone, and in cementoblasts and in hypertrophic chondrocytes. These studies are the first to show that BSP and OPN are differentially regulated by vitamin D3 in vivo, reflecting the diverse roles of these protein in bone remodeling. Moreover, the increased expression of the BSP transgene in the rachitic mice demonstrates that vitamin D3 regulation of BSP expression is mediated, in part, by element(s) within the 2.7 kb promoter region.
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PMID:Altered expression of bone sialoproteins in vitamin D-deficient rBSP2.7Luc transgenic mice. 993 76

Abacavir (1592U89) is a nucleoside analog reverse transcriptase inhibitor that has been demonstrated to have selective activity against human immunodeficiency virus (HIV) in vitro and favorable safety profiles in mice and monkeys. A phase I study was conducted to evaluate the safety and pharmacokinetics of abacavir following oral administration of single escalating doses (100, 300, 600, 900, and 1,200 mg) to HIV-infected adults. In this double-blind, placebo-controlled study, subjects with baseline CD4+ cell counts ranging from < 50 to 713 cells per mm3 (median, 315 cells per mm3) were randomly assigned to receive abacavir (n = 12) or placebo (n = 6). The bioavailability of the caplet formulation relative to that of the oral solution was also assessed with the 300-mg dose. Abacavir was well tolerated by all subjects; mild to moderate asthenia, abdominal pain, headache, diarrhea, and dyspepsia were the most frequently reported adverse events, and these were not dose related. No significant clinical or laboratory abnormalities were observed throughout the study. All doses resulted in mean abacavir concentrations in plasma that exceeded the mean 50% inhibitory concentration (IC50) for clinical HIV isolates in vitro (0.07 microgram/ml) for almost 3 h. Abacavir was rapidly absorbed following oral administration, with the time to the peak concentration in plasma occurring at 1.0 to 1.7 h postdosing. Mean maximum concentrations in plasma (Cmax) and the area under the plasma concentration-time curve from time zero to infinity (AUC0-infinity) increased slightly more than proportionally from 100 to 600 mg (from 0.6 to 4.7 micrograms/ml for Cmax; from 1.0 to 15.7 micrograms.h/ml for AUC0-infinity) but increased proportionally from 600 to 1,200 mg (from 4.7 to 9.6 micrograms/ml for Cmax; from 15.7 to 32.8 micrograms.h/ml for AUC0-infinity. The elimination of abacavir from plasma was rapid, with an apparent elimination half-life of 0.9 to 1.7 h. Abacavir was well absorbed, with a relative bioavailability of the caplet formulation of 96% versus that of an oral solution (drug substance in water). In conclusion, this study showed that abacavir is safe and is well tolerated by HIV-infected subjects and demonstrated predictable pharmacokinetic characteristics when it was administered as single oral doses ranging from 100 to 1,200 mg.
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PMID:Safety and pharmacokinetics of abacavir (1592U89) following oral administration of escalating single doses in human immunodeficiency virus type 1-infected adults. 1004 74

Aqueous and methanolic extracts of 39 Panamanian medicinal plants were tested for anti-human immunodeficiency virus (HIV) effects. The extracts were tested for the inhibition of HIV-induced cytopathic effects in cultured cells, HIV-reverse transcriptase (RT) and HIV-protease (PR) enzymes. The water extract of the branches of Jatropha curcas (Euphorbiaceae) inhibited strongly the HIV-induced cytopathic effects with low cytotoxicity. On the other hand, the water extracts of the whole plant of Chamaesyce hyssopifolia (Euphorbiaceae), the leaves of Cordia spinescens (Boraginaceae) and the aerial parts of Hyptis lantanifolia (Labiatae), and the methanol extract of the aerial parts of Tetrapteris macrocarpa (Malpighiaceae) were potent inhibitors of HIV-RT (IC50: 6-8 microg/ml). Seven out of 39 plants were found to be moderate inhibitors of HIV-PR (IC50: 43-100 microg/ml). Furthermore, we report on the respective inhibitory substances of J. curcas, C. hyssopifolia and C. spinescens, and their possible mechanism of action.
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PMID:A search for anti-viral properties in Panamanian medicinal plants. The effects on HIV and its essential enzymes. 1007 18

A reverse transcriptase PCR (RT-PCR) targeting a 407 bp fragment of the nucleocapsid gene of bovine coronavirus (BCV) was developed for detection of BCV RNA in feces of experimentally inoculated cattle. The sensitivity and specificity of the RT-PCR were confirmed using tissue culture-adapted BCV strains and feces of 2 calves inoculated with BCV. Ten nonpregnant, BCV seropositive, adult dairy cows were inoculated with winter dysentery (WD) (n = 8) or calf diarrhea (CD) (n = 2) strains of BCV intranasally and orally (n = 2) or through a surgically-placed duodenal catheter (n = 8) with and without dexamethasone treatment or feeding ice water. The 6 cows inoculated with BCV intranasally and through a duodenal catheter (2 of 2 cows given CD BCV and 4 of 6 cows given WD BCV) developed mild diarrhea, and BCV was detected in diarrheal feces by RT-PCR, ELISA or immune electron microscopy. These results suggest that CD and WD strains of BCV can cause diarrhea in adult cows in conjunction with host or environmental factors and that RT-PCR might be useful to diagnose BCV infections in calves and adult cows.
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PMID:Experimental inoculation of adult dairy cows with bovine coronavirus and detection of coronavirus in feces by RT-PCR. 1007 17

The expression of midkine (MK) in lung tumors induced by N-nitrosobis(2-hydroxypropyl)amine (BHP) in rats was examined. The animals were administered 2000 p.p.m. of BHP in their drinking water for 12 weeks, then maintained without further treatment until being killed 20-28 weeks after the beginning of the experiment. MK mRNA expression of adenocarcinomas and squamous cell carcinomas assessed by means of the reverse transcriptase-polymerase chain reaction and northern blot analysis was significantly higher than in rat embryonic tissues (positive controls) and contrasted strongly with the lack in normal lungs. MK protein was detected immunohistochemically in 58.3% of alveolar hyperplasias, 92.3% of adenomas and 100% of adenocarcinomas and squamous cell carcinomas. The extent of staining significantly increased along with malignant progression in adenomatous (pre-)neoplastic lesions and tended to become more pronounced with malignant progression in squamous lesions. The results suggest that MK may play some essential roles in the development and progression of lung tumors induced by BHP in rats.
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PMID:Overexpression of midkine in lung tumors induced by N-nitrosobis(2-hydroxypropyl)amine in rats and its increase with progression. 1019 May 63

Newly developed antiviral compounds consisting of an adamantane derivative chemically linked to a water-soluble polyanionic matrix were shown to inhibit HIV-1 infection in lymphoblastoid cells, HeLa CD4+ beta-galactosidase (MAGI) cells and macrophages. The effect of the compounds was recorded by measuring viral reverse transcriptase activity and p24 by ELISA in culture supernatant and by immunoblotting of cell lysates. In this paper we describe the data obtained with one of the most promising compounds, Amant. Amant was not toxic for the host cells at concentrations as high as 1 mg/ml. The inhibition of HIV-1 replication in MT-4 and MAGI cells was observed when Amant was added either before infection or with the virus (0 h of infection), and was expressed even when the compound added at 0 h was removed 1.5 h after infection. Its inhibitory concentration (IC50) against HIV-1 and HIV-2 replication was 2-6 and 93 microg/ml, respectively. The anti-HIV-1 effect of the compound was gradually decreased when it was added 1 and 2 h post infection, and no inhibition was observed when the compound was added 4 h after infection, suggesting that the compound as a membranotropic drug blocks an early step of replication. It completely prevented the transport of Gag proteins into the nuclei. Pretreatment of the virus with Amant did not reduce its infectious activity. The classical adamantane derivatives amantadine and rimantadine hydrochloride did not inhibit HIV replication.
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PMID:Inhibition of HIV-1 replication by newly developed adamantane-containing polyanionic agents. 1032 46

Efavirenz (EFV, DMP-266) is a new antiretroviral agent belonging to the class of nonnucleoside reverse transcriptase inhibitors. It has recently been approved by the Food and Drug Administration in management of human immunodeficiency virus (HIV). Preliminary pharmacokinetic studies on EFV in healthy volunteers show that the drug may influence the metabolism of protease inhibitors. For the determination of EFV in human plasma, a validated and specific reverse-phase high-performance liquid chromatography (HPLC) method, with UV detection, was developed. We used 100 microL plasma sample for a liquid-liquid extraction with diethyl ether after basification. The mobile phase was a mixture of acetonitrile and water, pumped at a flow rate of 1.2 mL/min. Ultraviolet detection was carried out at a wavelength of 247 nm. Retention times for EFV and internal standard (IS) were 5.3 and 4.5 minutes, respectively, and there was no chromatographic interference from other commonly administered drugs. The limit of detection was 100 ng/mL. The described assay is a rapid and accurate method for measurement of EFV in plasma: the easy preparation and small sample size makes this assay highly suitable for pharmacokinetic studies and routine clinical analysis in patients with HIV. In addition, the reproducibility of the method is only moderately increased by including IS, so analyzing without IS may be an alternative.
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PMID:High-performance liquid chromatography method for analyzing the antiretroviral agent efavirenz in human plasma. 1036 51

We compared the efficacy of 4 methods for isolating circulating tumor cells: immunocapture with Ber-EP4-coated magnetic beads, density gradient separation, ammonium chloride, and distilled water-mediated erythrocyte lysis. Human blood from healthy volunteers was mixed with serial dilutions of prostate (LNCaP) and liver (HepG2) derived tumor cells. Isolation of circulating tumor cells was followed by reverse transcriptase-polymerase chain reaction with primers specific for prostate-specific antigen and alpha-fetoprotein. Ber-EP4 antigen expression was evaluated by immunohistochemistry in 27 hepatocellular carcinomas and 34 prostate adenocarcinomas. Peripheral blood samples from 12 patients with hepatocellular carcinoma and 10 with prostate adenocarcinoma also were tested. Density gradient separation and Ber-EP4 immunocapture were the most sensitive techniques for isolating circulating tumor cells in in vitro tests. Isolation by density gradient separation was significantly more sensitive than Ber-EP4 immunocapture when applied to peripheral blood samples of patients with cancer, a result consistent with the variable expression of Ber-EP4 antigen that we found by immunohistochemistry in prostate adenocarcinomas and hepatocellular carcinomas.
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PMID:Efficiency of Ber-EP4 antibody for isolating circulating epithelial tumor cells before RT-PCR detection. 1043 96

Among sex steroids, especially estrogen metabolism has been considered to play a role in the function and pathology of human veins. We investigated the expression and activity of the estrogen-producing enzyme aromatase and estrogen receptor (ER) in human vena cava to assess possible in situ biosynthesis of estrogens and their modes of action. We first examined aromatase expression by immunohistochemistry in human inferior vena cava obtained from 29 autopsy cases (11 males, 18 females, 63.6 +/- 3.0 years old). We then semiquantitated the level of aromatase mRNA by reverse transcriptase-polymerase chain reaction in 24 cases and aromatase activity by 3H-water assay in 15 cases to examine whether or not and in which cell types aromatase was expressed. We also studied alternative use of multiple exon 1s of its gene and immunolocalization of 17beta-hydroxysteroid dehydrogenase type I (17beta-HSD I), which converts estrone produced by aromatase to estradiol, a biologically active estrogen and ER. Aromatase and 17beta-HSD I immunoreactivity were both detected in smooth muscle cells (SMC) of the media in all the cases and in endothelial cells (EC) in 20 and 22 cases, respectively. ER immunoreactivity was detected in SMC of vena cava in 21 cases. The amount of aromatase mRNA was significantly greater in the cases utilizing 1c (I.3) or 1d (P.II) of exon 1 (9 cases, 191.1 +/- 26.3 attomol/ng total RNA) than those utilizing 1b (I.4) as the promoter (14 cases, 50.6 +/- 13.0 attomol/ng total RNA) (p < 0.01). Significant correlation (p < 0.05) was observed between the amount of aromatase mRNA and aromatase activity in 15 cases examined. No significant correlation was detected between the amount of aromatase mRNA or aromatase labeling index and the ER status. These results suggest that estrone and estradiol are produced in the human vena cava and that their production is mediated by aromatase and 17beta-HSD I, respectively but not all of these locally synthesized estrogens may not work directly in situ.
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PMID:Aromatase and sex steroid receptors in human vena cava. 1046 7


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