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)

Cholic acid (sodium cholate) exhibits a strong spermicidal and antiviral [anti-human immunodeficiency virus (HIV)-1] activity. The same effects are observed for F-5 Gel, the active mixture of a new contraceptive sponge (Protectaid), which contains sodium cholate together with low concentrations (0.5%) of nonoxynol-9 and benzalkonium chloride. Both cholic acid and the F-5 Gel exerted a dose-dependent, in-vitro inhibitory effect 1) on the activity of HIV-1 associated reverse transcriptase in an acellular system (their 50% inhibitory dose was 7.2 mM and 0.8 x 10 -3 v/v, respectively, and 2) on the potential of HIV-1 to infect human lymphocytes efficiently. In the 3 semen samples examined, sperm motility was instantaneously inhibited by the addition of a 6 mM solution of sodium cholate or of a 1:10 dilution of F-5 Gel. Both cholic acid and F-5 Gel affected in a dose-dependent manner the viability of normal peripheral blood lymphocytes (NPBL) and CEM cells. The Protectaid contraceptive sponge impregnated with F-5 Gel was given to 20 young women aged 19-25 years for a period of 1 year who had chosen this method for both contraception and against sexually transmitted diseases. All women were instructed to insert the sponge within the 12 hours preceding each sexual intercourse and to remove it 4-6 hours afterwards. During 12 months of use with at least 3 intercourse per week, the contraceptive efficacy of the Protectaid vaginal sponge was 100%. Cervical cultures at 6-month intervals showed the presence of Mycoplasma hominis and Candida albicans in 1 and 2 cases, respectively. The combined spermicidal and anti-HIV properties of cholic acid reported and used in the Protectaid sponge offer a new and modern protective method of contraception. At the end of the study, cervical cultures revealed the presence of Escherichia coli and Candida albicans in 1 case each. No slide effects were recorded, and only 1 woman complained of discomfort.
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PMID:Spermicidal and antiviral properties of cholic acid: contraceptive efficacy of a new vaginal sponge (Protectaid) containing sodium cholate. 768 80

Congestive heart failure is characterized by avid sodium retention and a blunted renal response to exogenous and endogenous atrial natriuretic peptide. Inhibition of neutral endopeptidase EC 3.4.24.11, the main enzyme that degrades natriuretic peptides, produces a natriuretic response in different models of congestive heart failure. This raises the possibility that an increase in either the expression or activity of neutral endopeptidase is responsible for these phenomena. In the present study, we examined (1) the renal effects of SQ-28,603, a neutral endopeptidase inhibitor, in rats with moderate and severe congestive heart failure induced by an aortocaval fistula compared with sham controls, and (2) neutral endopeptidase expression and activity in the lungs and kidneys of these rats. Infusion of SQ-28,603 (40 mg/kg IV) induced a significant natriuretic response in normal rats and rats with moderate congestive heart failure. This response was blunted in rats with severe congestive heart failure. Surprisingly, renal neutral endopeptidase mRNA levels, assessed by quantitative reverse transcriptase-polymerase chain reaction; protein levels, assessed by Western blotting; and activity, assessed by gelatin gels, were comparable in all groups. Pulmonary neutral endopeptidase mRNA levels decreased by 45% in rats with severe congestive heart failure but not in rats with mild congestive heart failure. In addition, pulmonary neutral endopeptidase immunoreactivity levels and activity were significantly decreased in congestive heart failure in correlation with the severity of the disorder.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pulmonary and renal neutral endopeptidase EC 3.4.24.11 in rats with experimental heart failure. 776 60

A Na+/SO4(2-)-cotransport system was recently identified from a rat kidney cortex cDNA library by expression cloning (NaSi-1;). In this work the sites of expression of NaSi-1-related mRNA and protein were determined using reverse transcriptase-polymerase chain reaction (RT-PCR) with microdissected nephron segments, and Western blot analysis on isolated tubules or purified membranes using polyclonal antibodies against the C-terminus of NaSi-1. Expression of both NaSi-1-related mRNA and protein was observed in proximal tubules and in papillary collecting ducts. Membrane separation studies indicated that in proximal tubules the NaSi-1-related protein is expressed apically. The observed distribution patterns (together with the earlier functional analysis) of NaSi-1-related mRNA and protein suggest that the NaSi-1 protein is involved in proximal tubular brush-border membrane Na+/SO4(2-)-cotransport. The functional correlation of the observed expression of the NaSi-1-related protein in collecting ducts remains to be determined.
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PMID:Nephron localization of Na/SO4(2-)-cotransport-related mRNA and protein. 789 1

Our aim was to examine whether the human glomerulus was a target for C-type natriuretic peptide (CNP) and how A, B and C receptors of natriuretic peptides (ANPR-A, ANPR-B, ANPR-C) were distributed in glomerular mesangial and epithelial cells. CNP stimulated cyclic GMP production in cultured human mesangial and epithelial cells with similar threshold concentrations (1 nM) and maximum effects (basal value x 30 at 1 microM). In contrast, atrial natriuretic peptide (ANP) was only stimulatory in epithelial cells. [125I] CNP bound specifically to mesangial cells with a Kd of 0.47 nM and Bmax of 42 fmol/mg. Equilibrium of binding was obtained after four to five hours at +4 degrees C and nonspecific binding represented 10 to 20% of total binding. HS142-1 (100 micrograms/ml), a specific inhibitor of ANPR-A and ANPR-B, suppressed 90% of CNP-dependent cyclic GMP production whereas it had little effect on [125I]-CNP binding, suggesting that C receptors were largely predominant in mesangial cells. No biological effect of CNP on mesangial cells, including change in basal or angiotensin II-induced contractility and inhibition of basal or serum-dependent proliferation, could be demonstrated. Similar results were obtained with 8-bromo-cyclic GMP and sodium nitroprusside. Intraglomerular localization of ANPR-A, ANPR-B and ANPR-C mRNA was studied using reverse transcriptase-polymerase chain reaction with amplification of their corresponding cDNA by different primers. Amplification products were identified on gel electrophoresis by their predicted sizes and sequencing. ANPR-A, ANPR-B and ANPR-C mRNA were present in epithelial cells whereas only ANPR-B and ANPR-C mRNA were detected in mesangial cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of C-type natriuretic peptide receptors in human mesangial cells. 799 93

Following massive small bowel resection, the remaining intestine adapts to compensate for lost absorptive capacity. Although the Na+/glucose cotransporter plays a critical role in nutrient, fluid, and electrolyte transport in the small intestine, its role in adaptation following resection has not been defined. To examine this, we sought to determine whether there were changes in the expression of the Na+/glucose cotransporter, SGTL1, at the messenger RNA level. Lewis rats underwent either transection or 70% small bowel resection and reanastomosis. The animals were sacrificed at intervals following operation. Jejunum proximal to the anastomosis and ileum and colon distal to the anastomosis were harvested and analyzed for Na+/glucose mRNA by reverse transcriptase-polymerase chain reaction and Southern blot. Blots were semiquantitated by 32P labeling and standardized to beta-actin. Histologic sections and analysis of DNA, RNA, and protein content revealed hyperplastic changes. Following resection, mRNA for the Na+/glucose cotransporter in the jejunum increased significantly (P < 0.05) by 1 week and remained elevated. In the ileum, an almost fivefold increase occurred at 6 hr and persisted throughout the study (P < 0.05). The early response was greater in the ileum, distal to the reanastomosis, than that in the jejunum (P < 0.05). In contrast, there was no change in the small amount of transporter mRNA detected in the colon. These results suggest that, in addition to mucosal hyperplasia, the intestinal response to resection involves upregulation of transporter mRNA by the individual enterocyte. This transcriptional increase in the Na+/glucose cotransporter appears to be an early response by the intestine and may be important in maintaining overall intestinal transport capacity following resection.
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PMID:Adaptation of the Na+/glucose cotransporter following intestinal resection. 804 Nov 42

The alpha T3-1 cell line, an immortalized gonadotroph cell line, expresses high levels of the gonadotrophin-releasing hormone (GnRH) receptor. Sustained exposure of these cells to the GnRH receptor agonist des-Gly10-[D-Ala6]luteinizing hormone-releasing hormone ethylamide resulted in a substantial down-regulation of cellular levels of a combination of the alpha subunits of the phospholipase C-beta 1-linked G proteins Gq and G11, as assessed by immunoblotting with an antiserum able to identify these two proteins equally. This effect was dependent upon the concentration of agonist used (EC50 = 4 nM) and on the time of the treatment (t1/2 = 6 hr) when a maximally effective concentration of agonist (1 microM) was used. Comparison of agonist regulation of inositol phosphate generation and Gq alpha/G11 alpha down-regulation demonstrated that effects on inositol phosphate production were approximately 3-fold more potent. In contrast to Gq alpha/G11 alpha, membrane-associated levels of Gs alpha and G12 alpha, the G proteins that transduce stimulatory and inhibitory regulation, respectively, of adenylyl cyclase, were not altered by agonist treatment. Analysis of mRNA by reverse transcriptase/polymerase chain reaction indicated the coexpression by alpha T3-1 cells of mRNA corresponding to both Gq alpha and G11 alpha. Immunoblotting with antisera selective for either Gq alpha or G11 alpha confirmed their coexpression. Resolution of membranes from untreated and agonist-treated alpha T3-1 cells under sodium dodecyl sulfate-polyacrylamide gel electrophoresis conditions able to separate Gq alpha from G11 alpha indicated that G11 alpha was more prevalent than Gq alpha at steady state but that agonist treatment regulated cellular levels of both of these G proteins in a nonselective manner. Sustained activation of protein kinase C with phorbol myristate acetate was unable to mimic agonist regulation of cellular Gq alpha/G11 alpha levels, as was treatment of alpha T3-1 cells with the selective protein kinase C inhibitor chelerythrine. These data suggest that the GnRH receptor is able to interact functionally with both Gq alpha and G11 alpha in alpha T3-1 cells and that sustained exposure to a GnRH receptor agonist selectively regulates the cellular levels of the G proteins that interact with the receptor.
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PMID:The gonadotrophin-releasing hormone receptor of alpha T3-1 pituitary cells regulates cellular levels of both of the phosphoinositidase C-linked G proteins, Gq alpha and G11 alpha, equally. 805 44

Two-phase extraction in a system composed of dextran and polyethylene glycol was used to purify simian immunodeficiency virus, SIVMAC251 (32H isolate) from 25 l of culture supernatant. The virus partitioned to the interphase with 80% recovery of gag peptide p27 and reverse transcriptase and an about 25% recovery of the external env glycoprotein, gp148. The virus was treated with octylglycoside and its subcomponents separated. Two gag-p27 containing fractions were obtained; gag-1, which also contained reverse transcriptase and nucleopeptides, and gag-2, which contained the major portion of the p27. The env gp148 was purified by chromatography through a series of lectin columns. The prepared materials are characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and immuno- and lectin blotting.
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PMID:Purification of simian immunodeficiency virus, SIVMAC251, and of its external envelope glycoprotein, gp148. 808 61

As the sole renal Na,K-ATPase isozyme, the alpha 1 Na,K-ATPase accounts for all active transport of Na+ throughout the nephron. This role in renal Na+ reabsorption and the primacy of the kidney in hypertension pathogenesis make it a logical candidate gene for salt-sensitive genetic hypertension. An adenine (A)1079-->thymine (T) transversion, resulting in the substitution of glutamine276 with leucine and associated with decreased net 86Rb+ (K+) influx, was identified in Dahl salt-sensitive/JR rat kidney alpha 1 Na,K-ATPase cDNA. However, because a Taq polymerase chain reaction amplification-based reanalysis did not detect the mutant T1079 but rather only the wild-type A1079 alpha 1 Na,K-ATPase allele in Dahl salt-sensitive rat genomic DNA, we reexamined alpha 1 Na,K-ATPase sequences using Taq polymerase error-independent amplification-based analyses of genomic DNA (by polymerase allele-specific amplification and ligase chain reaction analysis) and kidney RNA (by mRNA-specific thermostable reverse transcriptase-polymerase chain reaction analysis). We also performed modified 3' mismatched correction analysis of genomic DNA using an exonuclease-positive thermostable DNA polymerase. All the confirmatory test results were concordant, confirming the A1079-->T transversion in the Dahl salt-sensitive alpha 1 Na,K-ATPase allele and its transcript, as well as the wild-type A1079 sequence in the Dahl salt-resistant alpha 1 Na,K-ATPase allele and its transcript. Documentation of a consistent Taq polymerase error that selectively substituted A at T1079 (sense strand) was obtained from Taq polymerase chain reaction amplification and subsequent cycle sequencing of reconfirmed known Dahl salt-sensitive/JR rat mutant T1079 alpha 1 cDNA M13 subclones. This Taq polymerase error results in the reversion of mutant sequence back to the wild-type alpha 1 Na,K-ATPase sequence. This identifies a site- and nucleotide-specific Taq polymerase misincorporation, suggesting that a structural basis might underlie a predisposition to nonrandom Taq polymerase errors.
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PMID:Confirmation of mutant alpha 1 Na,K-ATPase gene and transcript in Dahl salt-sensitive/JR rats. 808 31

The role of cell-surface proteoglycans in human immunodeficiency virus (HIV) infection of T-cell lines was investigated. HIV-1-susceptible lymphoblastic T-cell lines, MT-4 and H9, were analyzed for proteoglycan synthesis and found to make heparan sulfate (HS) and chondroitin sulfate proteoglycans. Enzymatic treatment of these cells with heparitinase, but not chondroitinase, significantly prevented HIV-1(IIIB) infection as measured by inhibition of cytopathicity, reverse transcriptase production, and syncytia formation. Sulfation of glycosaminoglycans HS chains was critical to viral entry as shown by inhibition of viral infection with sodium chlorate and its specific reversal with exogenous sulfate addition. Quantitation of direct virus binding to cells showed that treatment of cells with heparitinase inhibited HIV-1 binding to the T-cell surface. Exogenous HS added to cultures inhibited virus infection in a manner analogous to dextran sulfate, further supporting a functional role for HS in HIV-1 binding. These results provide evidence for participation of cell-surface HS proteoglycans in HIV-cell attachment and virus entry.
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PMID:Cell-surface heparan sulfate proteoglycan mediates HIV-1 infection of T-cell lines. 809 45

The expression and extracellular release of transferrin receptor (TR) was investigated by in vitro model system of erythroid differentiation. Human peripheral blood mononuclear cells were cultured with interleukin-3 (IL-3) for 7 days, and with erythropoietin (EPO) for an additional 8 days. After EPO stimulation, IL-3-stimulated blastic cells were serially differentiated into mature erythrocytes. [3H]-thymidine incorporation of cultured cells increased linearly from day 0 to 5, followed by a decrease. Flow cytometric analysis showed an increase of TR expression from day 0 to 5, followed by a slight decrease. By metabolic labeling with [35S]methionine and immunoprecipitation, the cell lysate exhibited a 95-kD band corresponding to the intact TR on sodium dodecyl sulfate-polyacrylamide gel electrophoresis/autoradiography at day 5, when polychromatic erythroblasts had their peak. The culture supernatant solubilized by tween-20 exhibited a 95-kD and an 85-kD band on days 5 and 8, which corresponded to the intact and the truncated forms of TR, respectively. The 95-kD band was more intense at day 5 than at day 8. The reverse transcriptase-polymerase chain reaction assay showed that the receptor-mRNA expression was parallel to receptor synthesis. Thus, the synthesis and expression of TR on erythrocytes is associated mainly with cell proliferation in the early phase, and with both cell proliferation and hemoglobin production in the middle to late phases of maturation. Concomitantly, the extracellular release of TR from erythrocytes occurs in the middle to late phases of maturation. These data suggest that polychromatic erythroblasts release soluble TR as both intact and truncated forms and may be an important source of serum TR implicated as an index for erythropoietic activity in the marrow.
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PMID:Expression and extracellular release of transferrin receptors during peripheral erythroid progenitor cell differentiation in liquid culture. 811 25


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