Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
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 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.
 ...
PMID:[The in vitro effect of recombinant human growth hormone on lymphocyte and granulocyte function in healthy and uremic children]. 972 79

A primary cell culture of human gastric mucous cells was developed using enzymatic treatment of surgically obtained gastric mucosal specimens. Preferential attachment of gastric mucous cells during a preincubation step resulted in the enrichment of mucous cells [over 90% stained with periodic acid-Schiff (PAS) and mucin-type lectins] in the primary cell culture. Gastric mucous cells could be maintained in culture for 10 days. DNA synthesis peaked during the first 2 days in culture (8+/-1% bromodeoxyuridine-positive cells). During the entire culture period gastric mucous cells released high-molecular-weight glycoproteins into the medium, as determined by gel chromatography on a Sepharose CL-4B column and by metabolic labelling with [14C]-N-acetylglucosamine. Gastric mucin was verified by gas chromatographic analysis of the carbohydrate composition and fractionation of the void-volume fraction by density gradient centrifugation. Determination of the terminal glycosylation of the secreted glycoproteins by a lectin-ELISA revealed that there was a high quantity of alpha-l-fucose. Prostaglandin E2 significantly stimulated glycoprotein secretion during the entire cultivation period by 29-60%. Analysis of mucin-encoding MUC mRNA expression by reverse transcriptase polymerase chain reaction revealed that gastric mucous cells predominantly express MUC1 and MUC5AC, and to a lesser extent MUC6, which reflects the expression pattern obtained following analysis of biopsied samples of gastric mucosa. This primary cell culture model enables the regulation of mucin secretion and mucin gene expression in man to be investigated.
 ...
PMID:Morphological and molecular characterization of human gastric mucous cells in long-term primary culture. 979 1

Periodontitis is the inflammatory response in periodontal tissues elicited by bacterial colonization in periodontal pockets. In this response, pocket epithelial cells are the first cells to come into contact with bacteria. To elucidate this mechanism, we determined the adherence of the periodontopathic bacterium Eikenella corrodens 1073, which has a GalNAc-sensitive lectin-like adhesin (EcLS), to a human oral epithelial carcinoma cell line (KB) and the induction of proinflammatory cytokine production in the cells following exposure to this bacterium in vitro. In the adherence assay, EcLS played a role as the adhesin of this bacterium in adherence to KB cells. In a reverse transcriptase PCR, significant interleukin-8 (IL-8) and IL-6 mRNA levels were induced in response to exposure to this bacterium. In an enzyme-linked immunosorbent assay after an 8-h bacterial exposure, the IL-8 and IL-6 protein levels were 13.5- and 8.3-fold higher than those in the nonexposed controls, respectively. These protein responses were time dependent. Interestingly, when E. corrodens was separated from KB cells by cell culture inserts, a slight stimulation of the IL-6 and IL-8 mRNA and secreted protein levels was seen. These results imply that the direct contact of E. corrodens 1073 with oral epithelial cells is not necessarily required for the stimulation of IL-6 and IL-8 secretion. We suggest that E. corrodens induces the epithelial cells to secrete proinflammatory cytokines which serve as an early signaling system to host immune and inflammatory cells in underlying connective tissues.
 ...
PMID:Interleukin-6 (IL-6) and IL-8 are induced in human oral epithelial cells in response to exposure to periodontopathic Eikenella corrodens. 986 40

Sexually active women represent the fastest growing HIV/AIDS (human immunodeficiency virus/acquired immunodeficiency syndrome) risk group. In an effort to develop a vaginal microbicidal contraceptive potentially capable of preventing HIV transmission as well as providing fertility control, we have synthesized novel non-nucleoside inhibitors (NNIs) of HIV-1 reverse transcriptase (RT) and examined them for dual-function anti-HIV and spermicidal activity. Structure-based drug design by use of a computer docking procedure for the NNI binding pocket generated from nine RT-NNI crystal structures led to the synthesis of three novel NNIs: N-[2-(2, 5-dimethoxyphenethyl)]-N'-[2-(5-bromopyridyl)]-thiourea (D-PBT); N-[2-(2-fluorophenethyl)]-N'-[2-(5-bromopyridyl)]-thiourea (F-PBT); and 5-isopropyl-2-[(methylthiomethyl)thio]-6-(benzyl)-pyrimidin-4-(1H)-on e (S-DABO). The anti-HIV activity of these NNIs was compared with that of trovirdine and virucidal/spermicide, nonoxynol-9 (N-9), by measuring viral RT activity and p24 antigen production as markers of viral replication using HTLVIIIB-infected human peripheral blood mononuclear cells (PBMCs). The effects on sperm motion kinematics and sperm membrane integrity were examined by computer-assisted sperm analysis and by confocal laser scanning microscopy (CLSM), respectively. The growth-inhibitory effects of NNI versus N-9 against normal human ectocervical and endocervical epithelial cells were tested using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay. All three NNIs were potent inhibitors of purified recombinant HIV RT and abrogated HIV replication in PBMCs at nanomolar concentrations (IC50 < 1 nM) when compared with N-9 or trovirdine (IC50 values of 2.2 microM and 0.007 microM, respectively). Two NNIs, F-PBT and S-DABO, also exhibited concentration- and time-dependent spermicidal activity. The drug concentration required to inhibit sperm motility by 50% (EC50 values) for the lead compound F-PBT versus N-9 was 147 microM and 81 microM, respectively. Sperm-immobilizing activity induced by F-PBT and S-DABO was rapid (t1/2 = 7-13 min) and irreversible. Unlike that of N-9, spermicidal activity of F-PBT and S-DABO was not accompanied by loss of acrosomal membrane as detected by fluorescent-lectin binding assay and CLSM. Whereas N-9 was cytotoxic to normal human ectocervical and endocervical cells at spermicidal doses, both F-PBT and S-DABO were selectively spermicidal. We conclude that as potent anti-HIV agents with spermicidal activity and reduced cytotoxicity, F-PBT and S-DABO show unique clinical potential to become the active ingredients of a vaginal contraceptive for women who are at high risk for acquiring HIV by heterosexual vaginal transmission.
 ...
PMID:Novel derivatives of phenethyl-5-bromopyridylthiourea and dihydroalkoxybenzyloxopyrimidine are dual-function spermicides with potent anti-human immunodeficiency virus activity. 1033 Jan 1

Induction of proinflammatory cytokines has been proposed to be a link between prenatal maternal intrauterine infection and neonatal brain damage. It is known that the endotoxin, lipopolysaccharide (LPS), released during bacterial infection crosses the placenta. Cytokine induction in the fetal rat brain after maternal administration of LPS was determined by reverse transcriptase-polymerase chain reaction method. LPS suspension in pyrogen-free saline was administered (i.p.) to pregnant rats at 18 d of gestation. The control group was treated with pyrogen-free saline. Expression of the proinflammatory cytokines, tumor necrosis factor-alpha and IL-1beta mRNA, in the fetal rat brain was increased in a dose-dependent manner at 1 h after LPS administration. The great increase in expression of IL-1beta mRNA was only observed at 1 h after injection of LPS (4 mg/kg), whereas the increased expression of tumor necrosis factor-alpha was still detectable from 4 to 24 h after LPS administration. Brain injuries were examined by immunohistochemistry in 8-d-old rat pups born to the dams that were consecutively treated with LPS (500 microg/kg) or pyrogen-free saline on gestation d 18 and 19. No apparent necrotic tissue damage was found in either the LPS group or the control group. Myelin basic protein staining, as a marker of myelin, was clearly observed in the internal capsule and the fimbria hippocampus in the rat brain from the control group. Myelin basic protein staining was much less and weaker in the brains of the LPS-treated group. Glial fibrillary acidic protein-positive astrocytes were observed in both the control and the LPS-treated groups. The LPS-treated group appeared to have more glial fibrillary acidic protein-positive astrocytes in the hippocampal and the cortex areas of the brain than the control group. Immunoblotting data showed that glial fibrillary acidic protein content in the cortex or the hippocampus of the LPS-treated rat brain was higher than in the control group. OX-42-positive staining (a marker of the type 3 complement receptors) of microglial cells was greatly reduced in the 8-d-old rat brain after maternal LPS administration. However, histochemistry with tomato lectin showed that staining of both amoeboid and ramified microglial cells in the LPS-treated rat brain was similar to that in the control group. The overall results indicate that maternal LPS administration induces an increased expression of IL-1beta and tumor necrosis factor-alpha mRNA in the fetal brain. Maternal LPS administration also increases glial fibrillary acidic protein-positive astrocytes, decreases myelin basic protein and alters immunoreactivity of microglia in the brain of offspring. Although results from the current study do not provide direct evidence linking LPS-induced cytokines with the abnormalities in the neonatal rat brain, our animal model may be appropriate for exploring the mechanisms involved in the effects of maternal infection on glial cells in the brains of offspring.
 ...
PMID:Cytokine induction in fetal rat brains and brain injury in neonatal rats after maternal lipopolysaccharide administration. 1062 84

The cysteine-rich region of the 170-kDa subunit galactose-adherence lectin (Gal-lectin) of Entamoeba histolytica is a subunit vaccine candidate and a protective antigen in the gerbil model of amebiasis. Macrophage-mediated immunity is important for protection against E. histolytica and is activated by Th1 cytokines. As Th1 differentiation is promoted by IL-12, we investigated what portion of the Gal-lectin could stimulate IL-12 in human THP-1 macrophages. Native Gal-lactin stimulated IL-12 p40 / p35 mRNA expression in a dose- and time-dependent manner as measured by reverse transcriptase-PCR. Human immune serum and Gal-lectin mAb inhibition studies identified amino acids (aa) 596 - 998 as immunogenic and containing the IL-12 inducing domain. IFN-gamma priming augmented Gal-lectin-induced IL-12 mRNA expression independent of TNF-alpha and IL-1beta, and was required for IL-12 p70 protein production from macrophages and human peripheral blood mononuclear cells. Gal-lectin plus IFN-gamma stimulated IL-12 p40 and p35 gene transcription with stable mRNA transcripts and a differential requirement for protein synthesis. These results suggest that aa 596 - 998 of the Gal-lectin can confer Th1-mediated protection against amebiasis through IL-12 induction.
 ...
PMID:A subunit vaccine candidate region of the Entamoeba histolytica galactose-adherence lectin promotes interleukin-12 gene transcription and protein production in human macrophages. 1067 Nov 97

Natural killer (NK)-cell recognition of target cells and cytolytic function are controlled by multiple receptor-ligand interactions. These receptors can transmit either positive or negative signals and belong to the lectin superfamily or immunoglobulin superfamily (IgSF). One member of the IgSF, 2B4, is expressed on the surface of all mouse and human NK cells and the subset of T cells that mediate NK-like killing. In both mouse and human, 2B4 is a transmembrane protein and is the counter-receptor for CD48. Northern blot analysis had indicated the existence of 2B4-related genes. Here we report the cloning of novel cDNAs (r2B4R) closely related to the rat 2B4. Unlike 2B4, rat NK cells express mRNA corresponding to both transmembrane (r2B4R-tm) and soluble (r2B4R-se) forms of r2B4R. r2B4R-tm contains an open reading frame encoding a polypeptide of 311 amino acid residues. The encoded protein has characteristics of type I transmembrane proteins with a 20-amino acid leader sequence, a 203-amino acid extracellular domain, a 23-amino acid transmembrane domain, and a 65-amino acid cytoplasmic domain. r2B4R-se encodes a protein of 205 amino acid residues without a putative transmembrane domain. Northern blot analysis and reverse transcriptase-PCR analysis revealed that both transmembrane and soluble forms of r2B4R are expressed in interleukin-2-activated NK cells.
 ...
PMID:Molecular cloning of transmembrane and soluble forms of a novel rat natural killer cell receptor related to 2B4. 1080 43

A large variety of natural products have been described as anti-HIV agents, and for a portion thereof the target of interaction has been identified. Cyanovirin-N, a 11-kDa protein from Cyanobacterium (blue-green alga) irreversibly inactivates HIV and also aborts cell-to-cell fusion and transmission of HIV, due to its high-affinity interaction with gp120. Various sulfated polysaccharides extracted from seaweeds (i.e., Nothogenia fastigiata, Aghardhiella tenera) inhibit the virus adsorption process. Ingenol derivatives may inhibit virus adsorption at least in part through down-regulation of CD4 molecules on the host cells. Inhibition of virus adsorption by flavanoids such as (-)epicatechin and its 3-O-gallate has been attributed to an irreversible interaction with gp120 (although these compounds are also known as reverse transcriptase inhibitors). For the triterpene glycyrrhizin (extracted from the licorice root Glycyrrhiza radix) the mode of anti-HIV action may at least in part be attributed to interference with virus-cell binding. The mannose-specific plant lectins from Galanthus, Hippeastrum, Narcissus, Epipac tis helleborine, and Listera ovata, and the N-acetylgl ucosamine-specific lectin from Urtica dioica would primarily be targeted at the virus-cell fusion process. Various other natural products seem to qualify as HIV-cell fusion inhibitors: the siamycins [siamycin I (BMY-29304), siamycin II (RP 71955, BMY 29303), and NP-06 (FR901724)] which are tricyclic 21-amino-acid peptides isolated from Streptomyces spp that differ from one another only at position 4 or 17 (valine or isoleucine in each case); the betulinic acid derivative RPR 103611, and the peptides tachyplesin and polyphemusin which are highly abundant in hemocyte debris of the horseshoe crabs Tachypleus tridentatus and Limulus polyphemus, i.e., the 18-amino-acid peptide T22 from which T134 has been derived. Both T22 and T134 have been shown to block T-tropic X4 HIV-1 strains through a specific antagonism with the HIV corecept or CXCR4. A number of natural products have been reported to interact with the reverse transcriptase, i.e., baicalin, avarol, avarone, psychotrine, phloroglucinol derivatives, and, in particular, calanolides (from the tropical rainforest tree, Calophyllum lanigerum) and inophyllums (from the Malaysian tree, Calophyllum inophyllum). The natural marine substance illimaquinone would be targeted at the RNase H function of the reverse transcriptase. Curcumin (diferuloylmethane, from turmeric, the roots/rhizomes of Curcuma spp), dicaffeoylquinic and dicaffeoylt artaric acids, L-chicoric acid, and a number of fungal metabolites (equisetin, phomasetin, oteromycin, and integric acid) have all been proposed as HIV-1 integrase inhibitors. Yet, we have recently shown that L-c hicoric acid owes its anti-HIV activity to a specific interaction with the viral envelope gp120 rather than integrase. A number of compounds would be able to inhibit HIV-1 gene expression at the transcription level: the flavonoid chrysin (through inhibition of casein kinase II, the antibacter ial peptides melittin (from bee venom) and cecropin, and EM2487, a novel substance produced by Streptomyces. (ABSTRACT TRUNCATED)
 ...
PMID:Current lead natural products for the chemotherapy of human immunodeficiency virus (HIV) infection. 1093 47

Dystroglycans (DGs) bind laminin matrix proteins in skeletal and cardiac muscle and are expressed in other nonmuscle tissues. However, their expression in airway epithelial cells has not been demonstrated. We examined expression of DGs in the human airway epithelial cell line 1HAEo(-), and in human primary airway epithelial cells. Expression of the common gene for alpha- and beta-DG was demonstrated by reverse transcriptase/ polymerase chain reaction in 1HAEo(-) cells. Protein expression of beta-DG was demonstrated by both Western blot and flow cytometry in cultured cells. Localization of alpha-DG, using both a monoclonal antibody and the alpha-DG binding lectin wheat-germ agglutinin (WGA), was to the cell membrane and nucleus. We then examined the function of DGs in modulating wound repair over laminin matrix. Blocking alpha-DG binding to laminin in 1HAEo(-) monolayers using either glycosyaminoglycans or WGA attenuated cell migration and spreading after mechanical injury. alpha-DG was not expressed in epithelial cells at the wound edge immediately after wound creation, but localized to the cell membrane in these cells within 12 h of injury. These data demonstrate the presence of DGs in airway epithelium. alpha-DG is dynamically expressed and serves as a lectin to bind laminin during airway epithelial cell repair.
 ...
PMID:Airway epithelial cell wound repair mediated by alpha-dystroglycan. 1115 52

Pulmonary delivery of peptidomimetic antibiotics is frequently used for local drug therapy in pulmonary infections. Identification of transport pathways into airway epithelia can lead to new strategies of therapy. Here we describe the distribution of the beta-lactam-transporting high-affinity proton-coupled peptide transporter PEPT2 in mammalian lungs. Using reverse transcriptase-polymerase chain reaction and Northern blot analysis, PEPT2-mRNA was detected in lung extracts. The expression of PEPT2-mRNA and protein was localized to alveolar type II pneumocytes, bronchial epithelium, and endothelium of small arteries of rat lung by nonisotopic in situ hybridization and immunohistochemistry. In addition, transport studies using murine whole-organ preparations revealed transporter-mediated uptake of a fluorophore-conjugated dipeptide derivative into bronchial epithelial cells and type II pneumocytes. This transport was competitively inhibited by cephalosporins and dipeptides that are reported as PEPT2-carried substrates. Cell specificity of the PEPT2-mediated uptake pattern was confirmed by double labeling with Lycopersicon esculentum lectin. Together these data suggest that PEPT2 is the molecular basis for the transport of peptides and peptidomimetics in pulmonary epithelial cells. In conclusion PEPT2 may be an interesting target for pulmonary delivery of peptides and peptidomimetics.
 ...
PMID:Localization of the peptide transporter PEPT2 in the lung: implications for pulmonary oligopeptide uptake. 1115 8


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