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)

The aim of this study was to investigate whether the Kir2.1 gene is expressed by the human placenta throughout pregnancy and in cytotrophoblast cells at different stages of differentiation in culture. RNA was extracted from cytotrophoblast cells isolated from term placentas and maintained in culture for 18, 66 and 114 h and from first, second and third trimester placentas. Using the reverse transcriptase-polymerase chain reaction (RT-PCR) with gene-specific primers, a cDNA product of 1.2 kb, as expected for Kir2.1 gene expression, was detected in all the RNA samples from cytotrophoblast cells and from placentas. The RT-PCR products were verified by sequencing and by detection of the expected transcript size for the Kir2.1 mRNA at 5.6-5.7 kb on Northern blots, using the 1.2 kb cDNA generated by RT-PCR. Northern blot quantification, using a control 28S rRNA probe, showed no significant difference in Kir2.1 mRNA expression between any of the three stages of cytotrophoblast cell differentiation studied (ANOVA; n = 3 RNA samples from each stage). These data demonstrate that the Kir2.1 gene is expressed by the human placenta and, specifically, by cytotrophoblast cells, at all stages of development and differentiation.
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PMID:Expression of the Kir2.1 (inwardly rectifying potassium channel) gene in the human placenta and in cultured cytotrophoblast cells at different stages of differentiation. 954 79

The aim of the study was to establish the effect of GH on immune functions in 22 healthy and in 11 uremic children, in vitro. Oxydative burst of granulocyte in the presence of GH measured by chemiluminescence and lymphoblast proliferation to GH and lectin stimuli were studied. Gene expression of GH receptor was analyzed with reverse transcriptase polymerase chain reaction (RT-PCR) method. The metabolic burst of granulocytes individually differed, specially in the chronic renal failure (CRF) group (60%) showed rather dose and time-dependent increase, the GH had only a priming effect. In 59% of the healthy children the GH stimulated the lympho-proliferative response itself or interaction with the lectin (ANOVA-test) and increased the spontaneous lymphoproliferation in 45% of the uremic patients. The GH receptor mRNA expression differed in the childrens lymphocytes, showing no correlation with the effect of GH on lymphoproliferation. The GH has a cytokine-like role in the regulation of the human immune system, and the GH treatment in uremic children is rather stimulating on immune functions.
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PMID:[The in vitro effect of recombinant human growth hormone on lymphocyte and granulocyte function in healthy and uremic children]. 972 79

Recent demonstrations of no changes in hypothalamic gonadotropin releasing hormone (GnRH) gene expression and GnRH levels detected at the pituitary gland in diestrous and lactating rats, indicate that lactational hypogonadotropism in this species is not associated with inhibition of hypothalamic GnRH synthesis and secretion. Hypothalamic galanin potentiates GnRH effects on luteinizing hormone (LH) secretion in male and cycling rats. To explore the interaction between GnRH and galanin during lactation, we studied in vitro the effects of pulsatile stimulation with those peptides upon LH synthesis and secretion from rat pituitaries on diestrous 1 or day 10 of lactation. Hemipituitaries were separately incubated in 1 ml Dulbecco's Minimal Essential Medium supplemented with 1% penicillin-streptomycin and fetal calf serum, at 37 degrees C in 5% CO2-air. The hemipituitaries were stimulated during 12 h with hourly pulses, 6 min each, of (a) gonadotropin releasing hormone (GnRH 25 ng/pulse), (b) rat galanin (600 ng/pulse), (c) GnRH plus galanin, or (d) saline. Medium was collected before each pulse to determine LH by radioimmunoassay. After the 12 h pulsatile regime total RNA was extracted and both actin and beta-LH mRNA were determined by reverse transcriptase polymerase chain reaction. There was a significant stimulation of LH secretion by GnRH (ANOVA, p < 0.001) without significant differences between diestrous and lactation pituitaries. Galanin alone did not modify LH secretion but it potentiated the effect of GnRH upon pituitaries from diestrous (p = 0.036) but not lactating rats. Neither peptide alone or its combination modified pituitary beta-LH mRNA levels. Results show that galanin regulates differently the secretion and synthesis of LH at the pituitary level. The disappearance of galanin-induced potentiation of GnRH effects upon LH secretion during lactation might contribute to the hypogonadotropism of lactation in the rat.
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PMID:Lactation inhibits the potentiating effect of galanin upon the GnRH-induced LH release observed in diestrous-1 rat. 1002 99

Experiments were performed in the normal rat knee joint to investigate the role of different isoforms of cyclooxygenase (COX) in the regulation of basal joint blood flow. Laser Doppler imaging (LDI) was used to measure articular perfusion, and reverse transcriptase polymerase chain reaction (RT-PCR) for the detection of COX-1 and COX-2 mRNA in joint tissue. Intravenous infusion of indomethacin (a non-selective inhibitor of COX; 0.34 nmol min(-1)) over 40 min produced a time dependent increase in articular vascular resistance (maximum 22.5 % at 40 min; P < 0.0001, one-way ANOVA) whereas vehicle over a similar time period had no effect in a control group. An equimolar concentration of a highly selective inhibitor for COX-2, SC-236, was administered in a further group of rats but this did not increase articular vascular resistance. While there was no significant difference between the response to vehicle and SC-236 (two-way ANOVA; P = 0.686, n = 6) the response to indomethacin was significantly greater than vehicle or SC-236 (two-way Anova; P < 0.0001, n = 6). COX-1, but not COX-2, was detectable by RT-PCR in all joint tissue samples examined (n = 4). The results of this study indicate that prostaglandins (PGs) play an important role in the maintenance of basal perfusion in the rat knee joint, with COX-1 being the physiologically relevant isoform. Experimental Physiology (2001) 86.2, 191-197.
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PMID:Expression of constitutive but not inducible cyclooxygenase maintains articular perfusion in the rat knee. 1142 34

Atopic dermatitis is a common inflammatory skin disease of humans and dogs. Human atopic dermatitis is associated with T-helper (Th) 2 type responses, although Th1 cytokines are present in chronic lesions. This study used semi-quantitative reverse transcriptase polymerase chain reactions to determine the expression of gene transcripts for immunosuppressive cytokines (transforming growth factor beta [TGFbeta] and interleukin [IL]-10), Th2 type cytokines (IL-4 and IL-6) and Th1 type cytokines (interferon gamma [IFNgamma], tumour necrosis factor alpha [TNFalpha], IL-2 and IL-12) in lesional atopic, non-lesional atopic and healthy canine skin. Canine atopic dermatitis was associated with over-expression of IL-4 mRNA and reduced transcription of TGFbeta compared to healthy skin (ANOVA, p<0.05). Higher levels of IFNgamma, TNFalpha and IL-2 mRNA were seen in lesional compared to non-lesional and healthy skin (p<0.05). There were no significant differences in IL-10, IL-6 or IL-12 transcription. This is the first report to demonstrate that canine atopic dermatitis is associated with over-production of IL-4 and under expression of TGFbeta.
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PMID:T-helper 1, T-helper 2 and immunosuppressive cytokines in canine atopic dermatitis. 1207 61

Human heparanase has been shown to function in tumor progression, metastatic spread, and tumor angiogenesis. The aim of the present study was to assess heparanase expression in endometrial cancer in correlation with neovascularization and clinicopathological factors. Forty endometrial cancers were obtained from previously untreated patients (median age 55.5, range 33-78 years). The expression of heparanase mRNA was evaluated using a semiquantitative reverse transcriptase-polymerase chain reaction. Tumor angiogenesis was assessed using microvessel counting. The Mann-Whitney U test, one-factor ANOVA test, and Spearman's test were used to determine the relationship between heparanase expression, microvessel density, and clinicopathological parameters. The expression of heparanase mRNA was detected in 20 of 40 (50%) endometrial cancers, and was significantly correlated with FIGO stage IIIc (p=0.0075), the presence of lymph-vascular space involvement (p=0.0041), lymph node metastasis (p=0.0049), and histological tumor grade (p=0.0030). Microvessel density was also associated with FIGO stage IIIc (p=0.027), the presence of lymph-vascular space involvement (p=0.001), lymph node metastasis (p=0.038), ovarian metastasis (p=0.030) and histological tumor grade (p=0.0030). Moreover, we found a strong positive correlation between heparanase expression and microvessel density (r2=0.475, p=0.0001). These results suggest that the expression of heparanase may influence different malignant behaviors in endometrial cancer.
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PMID:Heparanase expression and angiogenesis in endometrial cancer. 1290 90

The early pathogenesis of Marek's disease virus (MDV) infection is characterized by a lytic infection followed by the induction of latency. Genetically resistant N2a and susceptible P2a chickens were infected with the less virulent JM-16 or the very virulent plus (vv+) RK-1 MDV strains to examine the relationship between virulence and resistance on virus replication during 1-10 days postinfection (dpi) using real-time quantitative polymerase chain reaction (qPCR) and quantitative reverse transcriptase (qRT)-PCR assays. The numbers of copies of the viral DNA or transcripts amplified by these assays were normalized relative to cellular controls and subjected to three-way ANOVA. Viral DNA but not RNA was present in spleens at 1-3 dpi in decreasing quantities, and at 4 dpi, viral DNA started to increase concomitant with the initiation of viral transcription independently of virus strain and genetic resistance. At 6 dpi, JM-16 became latent in resistant N2a and susceptible P2a chickens with low levels of viral transcripts, but transcriptional activity increased in susceptible P2a chickens at 9 and 10 dpi. In contrast, infection with vv+ RK-1 never went into latency in both chicken lines. Viral transcripts were present from 4 to 10 dpi showing a higher and more persistent viral activity that may lead to severe damage to the lymphoid organs resulting in increased immunosuppression and increased incidence of MD. The use of qPCR and qRT-PCR to determine viral DNA load and transcriptional activity may offer an alternative to the current system of pathotyping to characterize new MDV isolates.
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PMID:Association between rate of viral genome replication and virulence of Marek's disease herpesvirus strains. 1538 Mar 65

Antiretroviral therapy for the human immunodeficiency virus-1 (HIV-1) typically includes two nucleoside reverse transcriptase inhibitors (NRTIs). 3'-Azido-3'-deoxythymidine (AZT, Zidovudine) plus 2'-deoxy-3'-thiacytidine (3TC, Lamivudine) is a combination that is used frequently. The NRTIs are mutagenic nucleoside analogs that become incorporated into DNA and terminate replication. We therefore hypothesized that exposure to this class of drug may alter cell cycle parameters. We used flow cytometry to examine the cell cycle in human epithelioid carcinoma (HeLa) cells exposed to AZT and 3TC alone, as well as a series of AZT/3TC dose combinations: (A) 125.0 microM AZT/12.5 microM 3TC; (B) 250.0 microM AZT/25.0 microM 3TC; and (C) 500 microM AZT/50 microM 3TC. At 24 h, at all doses, there was a good cell viability (>/=68%), and incorporation of AZT into nuclear DNA. Using flow cytometry, a dose-related increase in the percentage of cells in S phase, from 9.5% with no drug, to 36.0% with dose C, was observed in cells exposed for 24 h (P = 0.001, ANOVA). A concomitant decrease in the percentage of cells in G(1) phase, from 82.6% with no drug to 58.5% with dose C, was observed in cells exposed for 24 h (P = 0.017, ANOVA). A similar S phase arrest was seen in cells exposed to 125, 250 and 500 microM AZT alone, but there was no S phase alteration with 50 microM 3TC alone, suggesting that AZT is responsible for the accumulation of cells in S phase. To elucidate the accumulation of cells in S phase and explore the cell cycle gene expression changes induced by AZT and 3TC, we used c-DNA microarray, Cell Cycle Super Array and real-time PCR. There was a strong upregulation of the DNA damage-inducible transcript 3 (DDIT3 or GADD153) in NRTI-exposed cells. In addition, AZT induced an upregulation of cyclin D1 accompanied by a downregulation of the cyclin D1-associated inhibitors P18 and P57, and the G(1)-S check point gene P21, the net effect of which would be to foster a cell progression into S phase. Cyclin A2 was down-regulated in cells exposed to AZT, suggesting a block in S-G(2)-M progression that would also be consistent with the accumulation of cells in S phase. Overall, the study demonstrates that AZT, but not 3TC, causes an arrest of cells in S phase with a consistent alteration in the expression of several cell cycle genes.
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PMID:Zidovudine induces S-phase arrest and cell cycle gene expression changes in human cells. 1578 90

Traumatic brain injury (TBI) is a major cause of disability in the pediatric population and can result in abnormal development. Experimental studies conducted in animals have revealed impaired plasticity following developmental TBI, even in the absence of significant anatomical damage. The N-methyl-D-aspartate receptor (NMDAR) is clearly involved in both normal development and in the pathophysiology of TBI. Following lateral fluid percussion injury in postnatal day (PND) 19 rats, we tested the hypothesis that TBI sustained at an early age would result in impaired NMDAR expression. Using immunoblotting and reverse transcriptase-polymerase chain reaction (RT-PCR), protein and RNA levels of NMDAR subunits were measured in the cerebral cortex and hippocampus on post-injury days (PID) 1, 2, 4, and 7 (though the PID7 analysis was only for protein) and compared with age-matched shams. Significant effects of hemisphere (analysis of variance [ANOVA], p<0.01), and interactions between hemisphere and injury (ANOVA, p<0.05) and hemisphere and PID (ANOVA, p<0.05) were found for synaptic protein levels of the NR2A subunit in hippocampus. Specifically, within the ipsilateral hippocampus, NR2A was reduced by 9.9%, 47.9%, 40.8%, and 6.3% on PID1, PID2, PID4, and PID7, respectively. Within the cortex, there was a significant effect of injury (ANOVA, p<0.05) without any hemispheric differences. These bilateral cortical reductions measured 30.5%, 3.2%, 5.7%, and 13.4% at the same timepoints after injury. Injury had no significant main effect on NR1 or NR2B protein levels. RT-PCR analysis showed no significant changes in NR1, NR2A, or NR2B gene expression; however, as a positive control, hsp70 was induced more than twofold in ipsilateral cortex and hippocampus on PID1. It is known that NR2A expression levels increase during normal development, and in response to environmental stimuli. Our data suggest that injury-induced reduction in the expression of NR2A is one likely mechanism for the impaired experience-dependent neuroplasticity seen following traumatic injury to the immature brain.
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PMID:N-methyl-D-aspartate receptor subunit changes after traumatic injury to the developing brain. 1677 79

The thiophene ethyl thiourea (TET) compound N'-[2-(2-thiophene)ethyl]-N'-[2-(5-bromopyridyl)]-thiourea (HI-443) is a potent non-nucleoside reverse transcriptase inhibitor (NNRTI). The pharmacokinetics of 17 different novel oral formulations of HI-443 were compared in an attempt to identify the most suitable dosage form for clinical use in HIV-infected persons. Plasma concentrations of HI-443 were monitored in mice after administration of the drug using these 17 different formulations at three time points. Two-way ANOVA showed highly significant formulation (p < 0.0001), time (p < 0.0001) and formulation*time interaction effects (p = 0.0003). Planned linear contrasts were performed to identify which formulations showed the highest bioavailability at 10, 30, 60 min and at all time points relative to DMSO alone. A significant positive regression was observed comparing bioavailibility of HI-443 at 10 min and hydrophilic-lipophilic balance (HLB) values of the formulations (R2 = 26%, p < 0.0001). The results showed that formulations that were hydrophilic, containing PEG400 and propylene glycol, gave the highest overall drug concentrations over the 60-min time period. The lead oral formulation of HI-443 exhibited a very favorable toxicity profile in BALB/c mice.
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PMID:In vivo pharmacokinetics and toxicity of a novel hydrophilic oral formulation of the potent non-nucleoside reverse transcriptase inhibitor compound N'-[2-(2-thiophene)ethyl]-N'-[2-(5-bromopyridyl)]-thiourea (HI-443). 1751 92


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