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: UMLS:C0021051 (immunodeficiency)
71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Retroviral RNA is copied into DNA by reverse transcriptase when the viral genome enters into its life cycle. In the case of human immunodeficiency virus (HIV), massive amounts of unintegrated viral DNA reportedly appear in the early phase of primary infection. However, the relationship between the accumulation of this DNA and the cytopathic effect (CPE) remains obscure. In an attempt to delineate this association, we examined the appearance of the unintegrated viral DNA by means of two experimental systems: (1) primary infection of highly susceptible MOLT-4#8 cells and (2) induction of CPE by cell-fusion of persistently infected MOLT-4#8 cells. A correlation was observed between the accumulation of unintegrated viral DNA and the appearance of CPE, both when MOLT-4#8 cells were infected with cell-free virus and when persistently infected MOLT-4#8 cells were co-cultured with uninfected cells. Persistently infected cells did not fuse spontaneously in culture, because they lack the CD4-molecule on their surfaces. However, when treated with polyethylene glycol (PEG), the cells fused, exhibited ballooning degeneration, and released fewer viruses. After PEG treatment, unintegrated viral DNA also appeared. Since such DNA is generally not detected in persistently infected cells, it is possible that some cellular mechanism exists to suppress the synthesis of viral DNA and that the fusion induced by PEG treatment cancels the suppression. Treatment of persistently infected cells with Ca2+ ionophore and Ca2+ antagonist also resulted in the accumulation of unintegrated viral DNA and inhibited virus release. These findings suggest that the induction of unintegrated HIV DNA may be an effective strategy for reducing the release of the virus.
...
PMID:Unintegrated DNA in cells infected in vitro with human immunodeficiency virus (HIV): a new approach to suppression of virus release. 169 87

The T lymphocyte surface protein CD4 is an integral membrane glycoprotein noncovalently associated with the tyrosine protein kinase p56lck. In normal T cells, surface association of CD4 molecules with other CD4 molecules or other T-cell surface proteins, such as the T-cell antigen receptor, stimulates the activity of the p56lck tyrosine kinase, resulting in the phosphorylation of various cellular proteins at tyrosine residues. Thus, the signal transduction in T cells generated through the surface engagement of CD4 is similar to that observed for the class of growth factor receptors possessing endogenous tyrosine kinase activity. As CD4 is also the cellular receptor for the human immunodeficiency virus (HIV), binding of the virus or gp120 (the virus surface protein responsible for specific CD4+ T-cell association) could mimic the types of immunological interactions that have previously been found to stimulate p56lck and trigger T-cell activation pathways. We have evaluated this possibility and report here that binding of HIV-1 or the virus glycoprotein gp120 to CD4+ human T cells fails to elicit detectable p56lck-dependent tyrosine kinase activation and signalling, alterations in the composition of cellular phosphotyrosine-containing proteins, or changes in intracellular Ca2+ concentration.
...
PMID:No T-cell tyrosine protein kinase signalling or calcium mobilization after CD4 association with HIV-1 or HIV-1 gp120. 170 Oct 34

Culture supernatants from the rabbit macrophage cell line 6083 infected with a retrovirus, human immunodeficiency virus type 1 (HIV-1), were negative for reverse transcriptase (RT) expression although the line was shown to be productively infected by all other criteria tested. Supernatants from uninfected cultures of 6083, the human monocyte line U937, and from freshly isolated peripheral human monocytes, were found to contain a monocyte-derived inhibitory factor (MDIF) which interferes with a standard assay for RT. MDIF is a heat-labile activity of approximately of 40 kD. Both substrates and products of the reverse transcriptase assay are degraded by MDIF which is not affected by reduction and alkylation of disulfide bonds. MDIF is inhibited by the addition of a particular thioated oligonucleotide (S-dG30) to the reaction mixture but this addition also inhibits RT. The optimum method to minimize MDIF interference in the RT assay is by addition of ethylene glycol bis-(beta-aminoethyl ether)N,N,N',N'-tetraacetic acid (EGTA); MDIF requires divalent cations for activity and has a strong preference for calcium which is preferentially chelated by EGTA. The potential presence of this inhibitory activity should be considered when using RT levels as a measure of retroviral infection.
...
PMID:A monocyte-derived factor interferes with detection of reverse transcriptase in HIV-1 infection. 170 43

Cell signaling events are known to affect human immunodeficiency virus type 1 (HIV-1) replication. Treatment of lymphoid CEM cells with the calcium channel blocker verapamil (25-75 microM) enhanced HIV-1 expression in acute, whole virus infection experiments, despite lowering intracellular calcium levels, ablating the acute rise in intracellular calcium normally seen with infection, and lengthening the doubling time of cell replication. Verapamil had no effect on cell surface CD4 expression. Transfection of CEM cells with plasmids containing the HIV-1 long terminal repeat linked to the chloramphenicol acetyltransferase reporter gene showed that verapamil enhanced expression of the HIV-1 long terminal repeat in a dose-dependent fashion. This effect was abolished by mutations in the binding sites for nuclear factor kappa-B. Electrophoretic mobility shift assays confirmed that verapamil induced nuclear factor kappa-B activity in CEM cells. Thus, verapamil, in high concentrations, can potentiate HIV-1 replication in lymphoid cells, and this effect may be mediated by induction of nuclear factor kappa-B.
...
PMID:Effect of the calcium channel blocker verapamil on human immunodeficiency virus type 1 replication in lymphoid cells. 171 54

In characterizing a group of independent human immunodeficiency virus (HIV-1) isolates, we noted that certain isolates had anomolously low levels of virion-associated reverse transcriptase activity. In an attempt to understand the basis of this phenomenon, we examined in detail one such isolate, HIV-1G. We found correctly processed forms of the viral reverse transcriptase in virions as well as processed forms of other viral proteins, suggesting that viral proteins are both expressed and properly processed. We have detected a nuclease activity associated with the outer face of the HIV-1G envelope. This nuclease degrades the DNA product generated during the reverse transcription assay. The nuclease activity is more sensitive to mild protein denaturation than is the viral reverse transcriptase, and it is stimulated by the presence of Ca2+. The amount of virion-associated nuclease activity relative to reverse transcriptase activity varies between virus isolates and can vary also for one isolate during virus spread through a culture. The origin of the nuclease activity is unknown but is presumed to be cellular. The variability in amount of nuclease activity may reflect variability in the interaction of the virus with different cellular components during maturation.
...
PMID:Characterization of an HIV-1 isolate displaying an apparent absence of virion-associated reverse transcriptase activity. 171 16

To elucidate the action of vitamin C on pathogenic human retroviruses, we investigated and compared the effects of noncytoxic concentrations of ascorbic acid (AA), its calcium salt (Ca-ascorbate), and two thiol-based reducing agents [glutathione (GSH) and N-acetyl-L-cysteine (NAC)] against human immunodeficiency virus (HIV)-1 replication in chronically infected T lymphocytes. Ca-ascorbate reduced extracellular HIV reverse transcriptase (RT) activity by about the same magnitude as the equivalent dose of AA. Long-term experiments showed that continuous presence of ascorbate was necessary for HIV suppression. NAC (10 mmol/L) caused less than twofold inhibition of HIV RT and conferred a synergistic effect (approximately eightfold inhibition) when tested simultaneously with AA (0.426 mmol/L). In contrast, nonesterified GSH (less than or equal to 1.838 mmol/L) had no effect on RT concentrations and did not potentiate the anti-HIV effect of AA. These results further support the potent antiviral activity of ascorbate and suggest its therapeutic value in controlling HIV infection in combination with thiols.
...
PMID:Comparative study of the anti-HIV activities of ascorbate and thiol-containing reducing agents in chronically HIV-infected cells. 172 May 98

Cases of mania associated with acquired immune deficiency syndrome (AIDS) are reviewed in an attempt to elucidate patterns that may be helpful in guiding treatment, determining prognosis, and understanding pathophysiology. Fourteen well-described cases in the English language literature were critically reviewed. Data was collected regarding chronological appearance of signs and symptoms, specific psychiatric symptoms, associated neurologic and cognitive function, objective testing of brain structure and function, and outcome. When mania or hypomania occur in the setting of a human immunodeficiency virus (HIV) infection, it frequently occurs once and does not recur. AIDS-associated manic states are adequately responsive to available antimanic agents, however, AIDS patients may be more prone to deleterious side effects. Although mania or hypomania may be the presenting complaints that lead to the discovery of human immunodeficiency virus (HIV) seropositive status, mania tends to occur in people exhibiting signs of immunodeficiency as is exemplified, in the sample, by death occurring within six months of the psychiatric presentation in nearly a quarter of the patients. It is hypothesized that AIDS-related mania and agitated psychosis may be related to increased intracellular free calcium.
...
PMID:Mania in AIDS: clinical significance and theoretical considerations. 177 29

We report a rare case of interrupted aortic arch and a right aortic arch associated with DiGeorge syndrome, in neonate. Through a median sternotomy bypass was established placing an arterial perfusion cannula both in the ascending aorta, and in the main pulmonary artery. The right and left pulmonary arteries were temporarily occluded, while this pulmonary cannula perfused the lower part of the body. The arch reconstruction was performed during profound hypothermic total circulatory arrest. The right descending aorta had an adequate length and direct anastomosis was carried out without any tension. The VSD was repaired through a right atrial approach. The patient had hypocalcemia and thymic abnormalities which was consistent with the DiGeorge syndrome. He was treated with calcium gluconate and alfacalcidol, but no serious infection due to immunodeficiency was seen after operation. Post operative catheterization revealed no pressure gradient at the site anastomosis of the aortic arch and satisfactory results.
...
PMID:[Successful complete repair of interrupted aortic arch and associated with DiGeorge syndrome in neonate]. 177 90

Erythropoietin is a glycoprotein hormone that plays a vital role in erythropoiesis. It is mainly produced in the fetal liver till the third trimester of pregnancy. At that point, the kidney interstitium takes over this function and becomes the main source of erythropoietin. Hypoxia stimulates erythropoietin production by a mechanism that may require a heme protein as a second messenger. Erythropoietin stimulates the maturation of erythroid precursors (colony-forming unit-erythroid and burst-forming unit-erythroid) via at least two types of cell surface receptors. The higher-affinity receptors appear to be more important in modulating the effects of erythropoietin in vivo. Changes in intracellular calcium may ultimately mediate the action of erythropoietin on erythroid precursors. A specific and sensitive radioimmunoassay is now available for accurately measuring erythropoietin levels. All forms of erythrocytosis except polycythemia vera are associated with elevated erythropoietin levels. Levels are also high in cord blood obtained following fetal asphyxia. Reduced levels are seen in patients with anemia due to renal diseases. The response of erythropoietin to the degree of anemia appears to be attenuated in patients with cancer, chronic diseases, and human immunodeficiency virus (HIV) infection. Erythropoietin has been successfully used for treating patients with anemia due to renal failure. Its use has also been approved for the treatment of anemia patients receiving zidovudine for HIV infection. Encouraging results have been observed when erythropoietin was used to treat anemia due to rheumatoid arthritis, hematological malignancies, and prematurity. It has also been used to increase the yield of autologous blood collected prior to an elective surgical procedure. However, it has not proved to be useful in sickle cell anemia and myelodysplastic syndromes.
...
PMID:Erythropoietin. Biology and clinical applications. 178 66

In human immunodeficiency virus-1 (HIV-1)-infected cell cultures, cell-to-cell fusion and the formation of multinucleated giant cells (syncytia) are induced as a consequence of interactions between the viral envelope glycoprotein on infected cells and cell surface CD4 molecules on uninfected cells. Although activated CD4+ T cells rapidly form syncytia when cultured with HIV-1 envelope glycoprotein expressing (env+) cells, freshly isolated, unstimulated CD4+ T cells do so more slowly. In these studies, we sought to explore the role of T cell activation in rendering CD4+ T cells susceptible to HIV-1-mediated syncytia formation. Our results indicate that within 2 h of exposure to immunologic stimuli, CD4+ T cells acquire the ability to form syncytia with HIV-1 env+ cells. Both cholera toxin, an inhibitor of protein kinase C (PKC) through its effects on inositol triphosphate and diacylglycerol production, and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride, a noncompetitive inhibitor (with respect to ATP) of PKC, prevented unstimulated but not previously stimulated CD4+ T cells from forming syncytia with HIV-1 env+ cells. 1-Oleoyl-2-acetyl glycerol, an analog of the PKC activator, diacylglycerol, enhanced syncytia formation whereas ionomycin, a calcium ionophore, had no effect. These results suggest that activation of PKC is essential for previously unstimulated CD4+ T cells to become fusogenic.
...
PMID:Early activation events render T cells susceptible to HIV-1-induced syncytia formation. Role of protein kinase C. 182 86


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

---