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

Mycoplasma fermentans and Mycoplasma pirum have been recovered from human immunodeficiency virus (HIV)-positive persons. M. fermentans has been isolated with much higher frequency from HIV-positive than from HIV-negative persons. Mycoplasma genitalium has been detected by polymerase chain reaction in the blood of a patient with AIDS. Little is known about the biology of these mycoplasmas, especially their physiology, biochemistry, and growth response to inhibitors of essential metabolic loci or transport. Metabolically, they resemble other Mycoplasma species. Those studied lack cytochromes, the tricarboxylic acid cycle, and portions of the hexose monophosphate shunt. According to limited data, they fix CO2, use ATP to phosphorylate fructose-6-phosphate, have substrate phosphorylation and transaminase(s), and interconvert most purines and pyrimidines. The synthesis of thymidine may be limited. They may require a variety of essential small molecules for optimal growth (e.g., pyridoxal phosphate, ribose-1-phosphate). Their pathogenic potential and cultural lability may involve the production of the superoxide anion and the hydroxyl radical. We hypothesize that the mycoplasmas generate toxic oxygenated products that damage the host cell, probably membrane, permitting the mycoplasmas to gain easier access to the interior of the cell. The mycoplasma-damaged host cell membrane may also effect the maturation or release of HIV particles from the cell.
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PMID:The metabolism of AIDS-associated mycoplasmas. 839 28

Mannose binding protein (MBP) is a serum lectin which, upon binding to a carbohydrate extremity, acquires the ability to activate the classical complement pathway. MBP binds human immunodeficiency virus (HIV) in vitro via glycans on gp120 and thus, it may play a defensive role in HIV infection and contribute to virus clearance through the activation of complement associated with this condition. We measured serum MBP and activation indices of the classical complement pathway (plasma C4d and C3d) in HIV-seropositive patients at different stages of disease severity, and in normal subjects. MBP was higher in HIV patients as a whole and in each Centers for Disease Control (CDC) group than controls (P<0.01). MBP was not significantly different between CDC groups and and did not significantly correlate either with CD4-positive lymphocytes, neopterin or beta2-microglobulin or with C4d and C3d. The possibility that MBP plays a defensive role in HIV infection cannot be excluded, but, it it is, it does not appear to act by recruiting complement for vital elimination.
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PMID:Circulating levels of mannose binding protein in human immunodeficiency virus infection. 866 45

During the last decade there were extensive investigations in clinical and molecular andrology with emphasis on assisted reproduction, micromanipulation techniques of gametes, sperm/egg interaction, male contraception, diabetes mellitus, varicocele, andropause versus menopause, sexual dysfunction, associated hypertension/stress, prostatic carcinoma and molecular parameters of male reproduction. Sperm hyperactivation is a required step in capacitation sequence. Sperm motility is measured by videotape to evaluate the Straight Line Velocity (microm/s) (VSLI). Fertilization/embryonic development results from single sperm transfer (S-MIST) and multiple sperm transfer. Fertilization/embryo development is achieved by injection of immotile sperm into the perivitelline space. To assess sperm viability, a supravital stain suitable for use in combination with immunofluorescent assay, Hoeschst 33258, is used. The dye fluoresces with an intense blue when bound to DNA. To assess sperm plasma membrane integrity, a hypo-osmotic swelling test (HOST) is performed, using fluoresceinated D-mannose enriched albumin (FITC-DMA). The ability of sperm to swell under hypo-osmotic conditions indicates an intact membrane. A human protein, C-peptide, thought to be a useless byproduct of insulin may protect against devastating heart and nerve damage that diabetes causes. Human diabetics may benefit from the substance. Over 15 million Americans have diabetes, in which blood sugar levels rise out of control. There are two types of diabetics: Type I diabetics produce no insulin, the hormone that regulates blood sugar. Type II diabetics are unable to use their insulin properly. Diabetics are at great risk of heart disease and nerve damage, as arteries throughout the body leak and nerve-cell impulses fail. C-peptide is a byproduct of insulin production; it can be produced by the body or synthetically. Production of this protein is not induced by insulin, so diabetics who take insulin do not get C-peptide with it. Varicocele occurs unilaterally on the left side in 78% to 93% of men. Typically the presence of a varicocele is associated with an abnormal semen analysis (sperm density and morphology) and a decreased testicular volume on the affected side. Impaired sperm motility occurs in 89.5% of all varicocele patients. Varicocele ligation improves semen parameters in two thirds of patients. A few studies on andropause included sexual dysfunction, hormonal changes, medical/psychological correlates of impotence, ostenopenia/osteoporosis and bone loss; indices of bone remodeling, testosterone supplementation, androgen, negative feedback and hypothalamo-pituitary-testicular axis. Prostatic cancer is the second leading cause of cancer death for men between the ages of 60 and 80. Early detection involves a simple blood test for prostate specific antigen (PSA). Regular screening and early detection are essential. This is an important test because a high antigen count can be the only symptom. Since no screening is 100% accurate, physicians recommend both a PSA blood test and a physical examination. Although heredity plays a major role in whether a man will develop prostate cancer, men who lead healthy lives can dramatically reduce their chances of cancer: low-fat diet, eating plenty of fruits and vegetables and not smoking. Recent advances in molecular andrology include peptide hormone binding proteins; gonadotropin-releasing hormone (GnRH) agonists/antagonists analog; gonadotropins/their receptors; growth factors/reproduction; peptides as intratesticular regulators; molecular cloning of reproductive proteins/peptides. Gene cloning is applied for characterization/expression of genes coding. The interaction of gp120 with CD4 receptor plays a role in syncytium formation, apoptosis and CD4 cell deletion in human immunodeficiency virus (HIV) infection. The recombinant V3 peptide of fragment 307-330 of HIV-1 can induce sperm head agglutination. The generation process of react
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PMID:Recent advances in clinical/molecular andrology. 958 57

Mannose-binding protein (MBP; mannose-binding lectin) forms part of the innate immune system. By binding directly to carbohydrates on the surfaces of potential microbial pathogens, MBP and MBP-associated serine proteases (MASPs) can replace antibodies and complement components C1q, C1r, and C1s of the classical complement pathway. In order to investigate the mechanisms of MASP activation by MBP, the cDNAs of rat MASP-1 and -2 have been isolated, and portions encompassing the N-terminal CUB and epidermal growth factor-like domains have been expressed and purified. Biophysical characterization of the purified proteins indicates that each truncated MASP is a Ca(2+)-independent homodimer in solution, in which the interacting modules include the N-terminal two domains. Binding studies reveal that both MASPs associate independently with rat MBP in a Ca(2+)-dependent manner through interactions involving the N-terminal three domains. The biophysical properties of the truncated MASPs indicate that the interactions with MBP leading to complement activation differ significantly from those between components C1q, C1r, and C1s of the classical pathway. Analysis of MASP binding by rat MBP containing naturally occurring mutations equivalent to those associated with human immunodeficiency indicates that binding to both truncated MASP-1 and MASP-2 proteins is defective in such mutants.
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PMID:Interaction of mannose-binding protein with associated serine proteases: effects of naturally occurring mutations. 1091 41

In many patients with human immunodeficiency virus (HIV) treated with HIV protease inhibitors, a complication develops that resembles abdominal obesity syndrome, with insulin resistance and glucose intolerance that, in some cases, progresses to diabetes. In this study, we tested the hypothesis that indinavir, an HIV-protease inhibitor, directly induces insulin resistance of glucose transport in skeletal muscle. Rat epitrochlearis muscles were incubated with a maximally effective insulin concentration (12 nmol/l) and 0, 1, 5, 20, or 40 micromol/l indinavir for 4 h. In control muscles, insulin increased 3-O-[(3)H]methyl-D-glucose (3MG) transport from 0.15 +/- 0.03 to 1.10 +/- 0.05 micromol. ml(-)(1). 10 min(-)(1). Incubation of muscles with 5 micromol/l indinavir reduced the insulin-stimulated increase in 3MG transport by 40%, whereas 20 micromol/l indinavir reduced the insulin-stimulated increase in 3MG transport by 58%. Indinavir induced a similar reduction in maximally insulin-stimulated 3MG transport in the soleus muscle. The increase in glucose transport activity induced by stimulating epitrochlearis muscles to contract was also markedly reduced by indinavir. The insulin-stimulated increase in cell-surface GLUT4, assessed using the 2-N-4-(1-azi-2,2,2-trifluoroethyl)benzoyl-1,3-bis-[2-(3)H] (D-mannose-4-yloxy)-2-propylamine exofacial photolabeling technique, was reduced by approximately 70% in the presence of 20 micromol/l indinavir. Insulin stimulation of phosphatidylinositol 3-kinase activity and phosphorylation of protein kinase B were not decreased by indinavir. These results provide evidence that indinavir inhibits the translocation or intrinsic activity of GLUT4 rather than insulin signaling.
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PMID:The HIV protease inhibitor indinavir decreases insulin- and contraction-stimulated glucose transport in skeletal muscle. 1137 41

The human immunodeficiency virus (HIV) is an enveloped virus whose surface glycoprotein gp120 binds CD4 on target cell membranes to initiate infection. About half of the carbohydrates on gp120 are terminally mannosylated, a pattern common to many pathogens. We have examined the ability of macrophage mannose receptor (MMR) on primary monocyte-derived macrophages to bind HIV and facilitate its transmission to T cells. We adapted the tyramide signal amplification system for fluorescence detection of HIV bound to macrophages. Our data show that approximately 60% of the initial association of HIV with macrophages that lack expression of DC-SIGN (a dendritic cell-specific ICAM-3 receptor/HIV-1-binding protein) is MMR mediated, as evidenced by inhibition with mannan, D-mannose, EDTA, and soluble mannose-binding lectin, but not by D-galactose. This inhibition is not seen in cells that lack MMR. Macrophages are able to mediate transmission of bound HIV to co-cultured T cells, and this transmission is blocked up to 80% by inhibitors of MMR binding. Unlike virus bound to DC-SIGN, macrophage-bound HIV has a slightly lower half-life compared to free virus, with no transmission in co-culture observed beyond 24 h after virus binding to macrophages. Results obtained with endocytosis inhibitors indicate that this decrease in viral longevity is due to rapid internalization of macrophage-bound HIV. Together, these results suggest a substantial role for MMR in the binding and transmission of HIV-1 by macrophages.
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PMID:Involvement of macrophage mannose receptor in the binding and transmission of HIV by macrophages. 1264 47

DC-SIGN, a specific C-type lectin expressed on dendritic cells, binds and transmits multiple strains of primate immunodeficiency viruses to susceptible cells. Here, we report that human DC-SIGN also captures feline immunodeficiency virus via high-affinity (1 nM), Ca(2+)-dependent, D-mannose-inhibited binding to the major envelope glycoprotein, gp95.
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PMID:Specific interaction of feline immunodeficiency virus surface glycoprotein with human DC-SIGN. 1496 64

DC-SIGN is a C-type lectin that binds to endogenous adhesion molecules ICAM-2 and ICAM-3 as well as the viral envelope glycoprotein human immunodeficiency virus, type 1, glycoprotein (gp) 120. We wished to determine whether DC-SIGN binds differently to its endogenous ligands ICAM-2 and ICAM-3 versus HIV-1 gp120. We found that recombinant soluble DC-SIGN bound to gp120-Fc more than 100- and 50-fold better than ICAM-2-Fc and ICAM-3-Fc, respectively. This relative difference was maintained using DC-SIGN expressed on three different CD4-negative cell lines. Although the cell surface affinity for gp120 varied by up to 4-fold on the cell lines examined, the affinity for gp120 was not a correlate of the ability of the cell line to transfer virus. Monosaccharides with equatorial 4-OH groups competed as well as D-mannose for gp120 binding to DC-SIGN, regardless of how the other hydroxyl groups were positioned. Disaccharide competitors and glycan chip analysis showed that DC-SIGN has a preference for oligosaccharides linked in an alpha-anomeric configuration. Alanine-scanning mutagenesis of DC-SIGN revealed that highly conserved residues that coordinate calcium (Asp-366) and/or are involved in both calcium and specific carbohydrate interactions (Glu-347, Asn-349, Glu-354, and Asp-355) significantly compromised binding to all three ligands. Mutating non-conserved residues (Asn-311, Arg-345, Val-351, Gly-352, Glu-353, Ser-360, Gly-361, and Asn-362) minimally affected binding except for the Asp-367 mutant, which enhanced gp120 binding but diminished ICAM-2 and ICAM-3 binding. Conversely, mutating the moderately conserved residue (Gly-346) abrogated gp120 binding but enhanced ICAM-2 and ICAM-3 binding. Thus, DC-SIGN appears to bind in a distinct but overlapping manner to gp120 when compared with ICAM-2 and ICAM-3.
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PMID:DC-SIGN binds to HIV-1 glycoprotein 120 in a distinct but overlapping fashion compared with ICAM-2 and ICAM-3. 1497 Feb 26

Mannose-binding proteins derived from several plants (i.e. Hippeastrum hybrid and Galanthus nivalis agglutinin) or prokaryotes (i.e. cyanovirin-N) inhibit human immunodeficiency virus (HIV) replication and select for drug-resistant viruses that show profound deletion of N-glycosylation sites in the GP120 envelope (Balzarini, J., Van Laethem, K., Hatse, S., Vermeire, K., De Clercq, E., Peumans, W., Van Damme, E., Vandamme, A.-M., Bolmstedt, A., and Schols, D. (2004) J. Virol. 78, 10617-10627; Balzarini, J., Van Laethem, K., Hatse, S., Froeyen, M., Van Damme, E., Bolmstedt, A., Peumans, W., De Clercq, E., and Schols, D. (2005) Mol. Pharmacol. 67, 1556-1565). Here we demonstrated that the N-acetylglucosamine-binding protein from Urtica dioica (UDA) prevents HIV entry and eventually selects for viruses in which conserved N-glycosylation sites in GP120 were deleted. In contrast to the mannose-binding proteins, which have a 50-100-fold decreased antiviral activity against the UDA-exposed mutant viruses, UDA has decreased anti-HIV activity to a very limited extent, even against those mutant virus strains that lack at least 9 of 22 ( approximately 40%) glycosylation sites in their GP120 envelope. Therefore, UDA represents the prototype of a new conceptual class of carbohydrate-binding agents with an unusually specific and targeted drug resistance profile. It forces HIV to escape drug pressure by deleting the indispensable glycans on its GP120, thereby obligatorily exposing previously hidden immunogenic epitopes on its envelope.
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PMID:Carbohydrate-binding agents cause deletions of highly conserved glycosylation sites in HIV GP120: a new therapeutic concept to hit the achilles heel of HIV. 1618 48

An integrated metabolic model for the production of acetate by Escherichia coli growing on glucose under aerobic conditions was presented previously (Ko et al., 1993). The resulting model equations can be used to explain phenomena often observed with industrial fermentations, i.e., increased acetate production which follows from high glucose uptake rate, a low dissolved oxygen concentration, a high specific growth rate, or a combination of these conditions. However, several questions still need to be addressed. First, cell composition is growth rate and media dependent. Second, the macromolecular composition varied between E. coli strains. And finally, a model that represents the carbon fluxes between the Embden-Meyerhof-Parnas (EMP) and the hexose monophosphate (HMP) pathways when cells are subject to internal and/or external stresses is still not well defined. In the present work, we have made an effort to account for these effects, and the resulting model equations show good agreement for wild-type and recombinant E. coli experimental data for the acetate concentration, the onset of acetate secretion, and cell yield based on glucose. These results are useful for optimizing aerobic E. coli fermentation processes. More specifically, we have determined the EMP pathway carbon flux profiles required by the integrated metabolic model for an accurate fit of the acetic acid profile data from a wild-type E. coli strain ML308. These EMP carbon flux profiles were correlated with a dimensionless measurement of biomass and then used to predict the acetic acid profiles for E. coli strain F-122 expressing human immunodeficiency virus-(HIV(528)) beta-galactosidase fusion protein. The effect of different macromolecular compositions and growth rates between these two E. coli strains required a constant scaling factor for improved quantitative predictions.
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PMID:A metabolic model of cellular energetics and carbon flux during aerobic Escherichia coli fermentation. 1861 77


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