Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vitamin C (ascorbic acid) is required for normal host defense and functions importantly in cellular redox systems. To define the interrelationship between human immunodeficiency virus (HIV) infection and vitamin C flux at the cellular level, we analyzed vitamin C uptake and its effects on virus production and cellular proliferation in HIV-infected and uninfected human lymphoid, myeloid, and mononuclear phagocyte cell lines. Chronic or acute infection of these cell lines by HIV-1 led to increased expression of glucose transporter 1, associated with increased transport and accumulation of vitamin C. Infected cells also showed increased transport of glucose analogs. Exposure to vitamin C had a complex effect on cell proliferation and viral production. Low concentrations of vitamin C increased or decreased cell proliferation depending on the cell line and either had no effect or caused increased viral production. Exposure to high concentrations of vitamin C preferentially decreased the proliferation and survival of the HIV-infected cells and caused decreased viral production. These findings indicate that HIV infection in lymphocytic, monocytic, and myeloid cell lines leads to increased expression of glucose transporter 1 and consequent increased cellular vitamin C uptake. High concentrations of vitamin C were preferentially toxic to HIV-infected host defense cell lines in vitro.
 ...
PMID:Increased uptake and accumulation of vitamin C in human immunodeficiency virus 1-infected hematopoietic cell lines. 903 96

Ascorbic acid (ascorbate or vitamin C) has been shown to suppress the induction of HIV in latently infected T lymphocytic cells following stimulation with a tumor promoter (PMA) and inflammatory cytokine (TNF-alpha). To assess whether this inhibition was mediated via modulation of the cellular transcription factor, NF-kappa B, we carried out gel shift analysis on nuclear extracts prepared under different conditions of cell stimulation in the presence or absence of ascorbate, N-acetylcysteine (NAC), or zidovudine (AZT). Pretreatment of ACH-2 T cells by NAC followed by stimulation with PMA, TNF-alpha, or hydrogen peroxide (H2O2) resulted in strong suppression of NF-kappa B activation. In contrast, neither ascorbate nor AZT affected NF-kappa B activity under all three induction conditions in the ACH-2 cell line. Ascorbate and AZT also had no effect on NF-kappa B activation following TNF-alpha- or PMA-induced stimulation of U1 promonocytic cells. These results suggest that the molecular mechanism of HIV inhibition by ascorbate is not mediated via NF-kappa B inhibition, unlike that seen with other antioxidants.
 ...
PMID:NF-kappa B-independent suppression of HIV expression by ascorbic acid. 911 10

We measured plasma levels of all the antioxidant-micronutrients in subjects with HIV infection and controls. Plasma levels of all the carotenoids, including lutein, cryptoxanthin, lycopene, alpha-carotene and beta-carotene as well as vitamins A, C and E and cholesterol were assayed in 35 subjects with HIV infection and 38 controls. We found a significant depletion of all the carotenoids (P < 0.001) and vitamin C (P < 0.01) and cholesterol (P < 0.001) but not vitamins A or E in HIV-infected subjects. Further analysis of the HIV-infected subjects revealed that plasma levels of 4 of the groups of carotenoids and cholesterol were correlated with CD4 count but that beta-carotene and vitamins A, C and E were not. These results are reviewed in the light of the published literature and we conclude that these abnormalities of antioxidant-micronutrients are likely to reflect a metabolic phenomenon associated with HIV infection. However, an additional contribution to these deficiencies from malabsorption later in HIV disease cannot be ruled out.
 ...
PMID:Antioxidant-micronutrients and HIV infection. 911 64

The first product of ascorbate oxidation, the ascorbate free radical (AFR), acts in biological systems mainly as an oxidant, and through its role in the plasma membrane redox system exerts different effects on the cell. We have investigated the role of ascorbate, AFR and dehydroascorbate (DHA) in the activation of the NF-kappaB transcription factor in Jurkat T-cells stimulated by tumour necrosis factor-alpha (TNF-alpha). Here we show, by electrophoretic mobility shift assays, that ascorbate increases the binding of NF-kappaB to DNA in TNF-alpha-stimulated Jurkat cells. The ability of ascorbate to enhance cytoplasmic inhibitory IkBalpha protein degradation correlates completely with its capacity to induce NF-kappaB binding to DNA and to potentiate NF-kappaB-mediated transactivation of the HIV-1 long terminal repeat promoter in TNF-alpha-stimulated Jurkat cells but not in cells stimulated with PMA plus ionomycin. AFR behaves like ascorbate, while DHA and ascorbate phosphate do not affect TNF-alpha-mediated NF-kappaB activation. These results provide new evidence for a possible relationship between the activation of the electron-transport system at the plasma membrane by ascorbate or its free radical and redox-dependent gene transcription in T-cells.
 ...
PMID:Role of ascorbate in the activation of NF-kappaB by tumour necrosis factor-alpha in T-cells. 922 25

Replication of human immunodeficiency virus type 1 (HIV-1) requires specific interactions of Tat protein with the trans -activation responsive region (TAR) RNA, a 59 base stem-loop structure located at the 5'-end of all HIV transcripts. We have used an intramolecular RNA self-cleaving strategy to determine the folding of TAR RNA and its interactions with a Tat peptide. We incor-porated an EDTA analog at position 24 in the HIV-1 Tat binding site of the TAR RNA. After isolation and purification of the EDTA-TAR conjugate, RNA self-cleavage was initiated by the addition of an iron salt, ascorbate and hydrogen peroxide. Hydroxyl radicals generated from the tethered Fe(II) cleaved TAR RNA backbone in two localized regions. Sites of RNA cleavage were mapped by sequencing reactions. A Tat fragment, Tat(38-72), specifically inhibited RNA self-cleavage. To determine the structural changes caused by the Tat peptide, we performed Fe(II)-EDTA footprinting experiments on Tat-TAR complex. Our high-resolution footprinting results suggest that the inhibition of self-cleavage of EDTA-TAR is due to two effects of Tat binding: (i) Tat binds in the bulge and protects residues in the vicinity of the bulge from self-cleavage and (ii) RNA goes through a structural change where EDTA-U24 is rigidly positioned out of the helix and cannot get access to other nucleotides in the loop of TAR RNA, which are not protected by the Tat peptide. Our results demonstrate that Fe(II)-EDTA-mediated RNA self-cleavage can be applied to study RNA tertiary structures and RNA-protein interactions.
 ...
PMID:Visualizing tertiary folding of RNA and RNA-protein interactions by a tethered iron chelate: analysis ofHIV-1 Tat-TAR complex. 992 43

Comparison of immune function in athletes and nonathletes reveals that the adaptive immune system is largely unaffected by athletic endeavour. The innate immune system appears to respond differentially to the chronic stress of intensive exercise, with natural killer cell activity tending to be enhanced while neutrophil function is suppressed. However, even when significant changes in the level and functional activity of immune parameters have been observed in athletes, investigators have had little success in linking these to a higher incidence of infection and illness. Many components of the immune system exhibit change after prolonged heavy exertion. During this 'open window' of altered immunity (which may last between 3 and 72 hours, depending on the parameter measured), viruses and bacteria may gain a foothold, increasing the risk of subclinical and clinical infection. However, no serious attempt has been made by investigators to demonstrate that athletes showing the most extreme post-exercise immunosuppression are those that contract an infection during the ensuing 1 to 2 weeks. This link must be established before the 'open window' theory can be wholly accepted. The influence of nutritional supplements, primarily zinc, vitamin C, glutamin and carbohydrate, on the acute immune response to prolonged exercise has been measured in endurance athletes. Vitamin C and glutamine have received much attention, but the data thus far are inconclusive. The most impressive results have been reported in the carbohydrate supplementation studies. Carbohydrate beverage ingestion has been associated with higher plasma glucose levels, an attenuated cortisol and growth hormone response, fewer perturbations in blood immune cell counts, lower granulocyte and monocyte phagocytosis and oxidative burst activity, and a diminished pro- and anti-inflammatory cytokine response. It remains to be shown whether carbohydrate supplementation diminishes the frequency of infections in the recovery period after strenuous exercise. Studies on the influence of moderate exercise training on host protection and immune function have shown that near-daily brisk walking compared with inactivity reduced the number of sickness days by half over a 12- to 15-week period without change in resting immune function. Positive effects on immunosurveillance and host protection that come with moderate exercise training are probably related to a summation effect from acute positive changes that occur during each exercise bout. No convincing data exist that moderate exercise training is linked with improved T helper cell counts in patients with HIV, or enhanced immunity in elderly participants.
 ...
PMID:Exercise and immune function. Recent developments. 1009 Dec 72

We assessed oxidative stress in three different clinical conditions: smoking, human immunodeficiency virus (HIV) infection, and inflammatory bowel disease, using breath alkane output and other lipid peroxidation parameters such as plasma lipid peroxides (LPO) and malondialdehyde (MDA). Antioxidant micronutrients such as selenium, vitamin E, C, beta-carotene and carotenoids were also measured. Lipid peroxidation was significantly higher and antioxidant vitamins significantly lower in smokers compared to nonsmokers. Beta-carotene or vitamin E supplementation significantly reduced lipid peroxidation in that population. However, vitamin C supplementation had no effect. In HIV-infected subjects, lipid peroxidation parameters were also elevated and antioxidant vitamins reduced compared to seronegative controls. Vitamin E and C supplementation resulted in a significant decrease in lipid peroxidation with a trend toward a reduction in viral load. In patients with inflammatory bowel disease, breath alkane output was also significantly elevated when compared to healthy controls. A trial with vitamin E and C is underway. In conclusion, breath alkane output, plasma LPO and MDA are elevated in certain clinical conditions such as smoking, HIV infection, and inflammatory bowel disease. This is associated with lower levels of antioxidant micronutrients. Supplementation with antioxidant vitamins significantly reduced these lipid peroxidation parameters. The results suggest that these measures are good markers for lipid peroxidation.
 ...
PMID:Breath alkanes as a marker of oxidative stress in different clinical conditions. 1080 18

Between 1995 and 1997, 1,675 HIV-positive men and women using complementary and alternative medicine (CAM) were enrolled into the Bastyr University AIDS Research Center's Alternative Medicine Care Outcomes in AIDS (AMCOA) study. Funded by the National Institutes of Health (NIH) Office of Alternative Medicine (OAM) and National Institute of Allergy and Infectious Diseases (NIAID), the AMCOA study collected information on participant demographics, health status and use of conventional and CAM therapies. Participants from 46 states completed a baseline questionnaire, while additional clinical information (such as CD4 count and HIV-RNA viral load) was obtained from laboratory records. AMCOA participants reported using more than 1,600 different types of CAM therapies (1,210 CAM substances, 282 CAM therapeutic activities and 119 CAM provider types) for treating HIV/AIDS. Approximately two-thirds (63% n = 1,054) of the AMCOA cohort reported using antiretroviral drug therapy (ART) during the six-months previous to completing the baseline questionnaire, while 37% (n = 621) indicated they were not using ART. Of those not using ART, 104 subjects reported never having used any conventional medications for their HIV and 12 subjects used only non-prescription diarrhoea medications. The most frequently reported CAM substances were vitamin C (63%), multiple vitamin and mineral supplements (54%), vitamin E (53%) and garlic (53%). CAM provider types most commonly consulted by the AMCOA cohort were massage therapists (49%), acupuncturists (45%), nutritionists (37%) and psychotherapists (35%). CAM activities most commonly used were aerobic exercise (63%), prayer (58%), massage (53%) and meditation (46%). The choice of CAM therapies among the AMCOA cohort does not appear to be solely based on scientific evidence of efficacy of individual therapies. The majority of AMCOA subjects could be characterized as using integrated medicine, since an overwhelming proportion of the cohort consult with both conventional and CAM providers and use both conventional and CAM medications, yet few subjects reported that their conventional and CAM providers work as a team. These data and this cohort set the stage for conducting studies of health status changes associated with specific CAM therapies.
 ...
PMID:Alternative medicine use in HIV-positive men and women: demographics, utilization patterns and health status. 1130 25

Millimolar concentrations of alkaline extract of Cacao husk (polycaphenol) were more cytotoxic to human oral tumor cells (human oral squamous cell carcinoma HSC-2, human salivary gland tumor HSG), than to human gingival fibroblast (HGF), suggesting its tumor-specific action. Polycaphenol enhanced the radical intensity and cytotoxic activity of vitamin K3 more effectively than that of sodium ascorbate (vitamin C). Polycaphenol effectively scavenged the superoxide anion, produced by the hypoxanthine-xanthine oxidase reaction, indicating bimodal (prooxidant and antioxidant) action of polycaphenol. Polycaphenol inhibited the cytopathic effect of HIV (human immunodeficiency virus) infection in MT-4 cells, to a comparable extent as that achieved by lignin. Pretreatment of mice with polycaphenol protected them from lethal infection of Eschericia coli. These data suggest the medicinal efficacy of polycaphenol.
 ...
PMID:Diverse biological activity of polycaphenol. 1131 19

Diverse biological activities of moxa extracts and smoke (gas phase) were investigated. Moxa was extracted with hot water (Fr. I), or ethanol (Fr. II), or extracted with hot water after ethanol wash (Fr. III) and then lyophilized to obtain the dried powders. Moxa smoke (containing a lot of gaseous components obtained by burning Moxa) (Fr. IV) was collected into phosphate-buffered saline and quantified spectrophotometrically. These extracts and Moxa smoke showed comparable cytotoxic activity against human oral tumor cell lines (HSC-2, HSG). Human gingival fibroblasts (HGF) were more resistant to any Moxa fractions. Neither of the extracts showed anti-HIV activity. Pretreatment of mice with Fr. I significantly reduced the lethal effect of E. coli infection. All extracts produced radicals under alkaline condition, with a maximum intensity at pH 10.5, and enhanced the radical intensity of sodium ascorbate. It was unexpected that these extracts show significant O2- scavenging activities. These data suggest the medicinal efficacy of Moxa extracts and smoke.
 ...
PMID:Diverse biological activities of moxa extract and smoke. 1149 Oct 21


<< Previous 1 2 3 4 5 6 Next >>