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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infectious disease specialists have proposed guidelines on diagnostic evaluation of HIV infected patients with diarrhea. They are based on using clues from a careful history, physical examination, and evaluation of known laboratory data. Early on, clinicians must differentiate between small and large bowel diarrhea to properly evaluate any patient with diarrhea. If available, they should use the patient's absolute CD4 count, duration of diarrhea, frequency and characteristics of stools, degree of weight loss, and exposure history (e.g., residence and water supply). When conducting the patient history, clinicians should ask about recent antibiotic or antiretroviral use, previous opportunistic infections, and other illnesses or hospitalizations. The physical exam should include height and weight, orthostatic blood pressure, and degree of wasting. Abnormalities of skin and mucous membrane may indicate nutrient deficiencies (e.g., vitamin B deficiency = stomatitis). The disease specialists provide us with an algorithm to the diagnostic evaluation of HIV infected patients with diarrhea using the CD4 cell count and the type of diarrhea (small or large bowel) as the defining factors. For example, clinicians should request stool cultures for Salmonella, Campylobacter, and Yersinia and examination with saline and iodine for the presence of ova and parasites for patients with CD4 counts greater than 200 cells x 1 million/l and small bowel diarrhea. If the patient also has a fever, blood cultures should be done to test for Salmonella. If all these tests are negative and the patient still has symptoms, modified acid-fast staining should be done to look for cryptosporidium oocysts. If this test is negative and symptoms continue, upper endoscopy with biopsy is warranted. This strategy should result in a less time-consuming and more directed diagnostic strategy that may improve quality of life.
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PMID:Diagnostic strategies in HIV-infected patients with diarrhea. 766 16

One of the hallmarks of human immunodeficiency virus type 1 (HIV-1) infection is the decline in CD4+ T lymphocytes which precedes the progression from an asymptomatic state to AIDS. Apoptosis (programmed cell death) is one of the mechanisms proposed to mediate this depletion. Infectious and inactivated preparations of HIV-1LAI were compared for their potential to induce apoptosis. Analysis with fluorescence-activated cell sorting using the DNA intercalative compound propidium iodide demonstrated that apoptosis occurred only with infectious HIV-1, implying that cell surface binding and signalling by the virus alone were insufficient to trigger apoptosis. Apoptosis was further confirmed by the presence of characteristic digestion of host cell DNA and morphologically by nuclear condensation observed by transmission electron microscopy. HIV infection of CD4+ T cell lines generated an accumulation of the cells in G2/M phase of the cell cycle and cells undergoing apoptosis appeared to originate from the pool of cells in the G1 phase. Inhibitors of HIV replication were used to identify the point in the virus replicative cycle at which apoptosis is induced. The reverse transcriptase inhibitor, ddI, or the HIV protease inhibitor, RO31-8959 (Saquinavir), were added either 2 h before or 6 h after HIV inoculation. Only ddI inhibited HIV-induced apoptosis when added before inoculation; however, neither treatment was effective in preventing HIV-induced apoptosis when applied 6 h after inoculation. These data indicate that apoptosis requires a single round of reverse transcription and the expression of virion proteins, but not the maturation of progeny virions. Two agents which compete with HIV for binding to CD4+ T cells, dextran sulphate and the anti-CD4 MAb Leu3a, were effective at preventing apoptosis when added 6 h after infection, implying that a subsequent gp120-CD4 interaction at the surface of an infected cell was required to complete the apoptotic process.
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PMID:Productive infection and subsequent interaction of CD4-gp120 at the cellular membrane is required for HIV-induced apoptosis of CD4+ T cells. 789 56

Recent evidence suggests that T cell apoptosis could be involved in the pathogenesis of HIV-1 infection. As the progression of HIV-2 associated disease appears to be slower than that of HIV-1, we investigated whether there were differences in the degree of T cell death and apoptosis in peripheral blood mononuclear cell (PBMC) cultures from patients with HIV-1 or HIV-2 infection. PBMC from healthy controls (n = 28) and patients infected with HIV-1 (n = 26: asymptomatic (ASY)/persistent generalized lymphadenopathy (PGL), n = 16; and AIDS-related complex (ARC)/AIDS n = 10) or HIV-2 (n = 30: ASY/PGL, n = 16; ARC/AIDS, n = 14) were cultured in the absence or presence of mitogens (PHA, PWM) or superantigen (SEB). After 48 h, cell death (CD) was assessed by trypan blue exclusion and in some patients programmed cell death (PCD) was quantified in flow cytometry by measuring the percentage of hypodiploid nuclei corresponding to fragmented DNA, after treating the cells with a propidium iodide hypotonic solution. HIV-1 and HIV-2 ARC/AIDS patients and ASY/PGL HIV-1+ patients had significant increases in cell death percentages compared with controls, both in unstimulated and stimulated lymphocyte cultures. However, HIV-2+ ASY/PGL patients did not exhibit significant increases of cell death in unstimulated cultures. In addition, the comparison between HIV-1 and HIV-2 infected subjects in similar stages of disease, showed no significant differences in CD in the ARC/AIDS patients, although ASY/PGL HIV-2 infected subjects had lower levels of CD than the HIV-1+ ASY/PGL (3.4% +/- 0.6 s.e.m. versus 6.8% +/- 1.1 s.e.m., P < 0.01). PCD was significantly increased both in ASY/PGL (14.3% +/- 2.2 s.e.m., n = 8, P < 0.005) and in ARC/AIDS (25.3% +/- 4.5 s.e.m., n = 9, P < 0.001) HIV-1+ patients compared with healthy controls (5.8% +/- 1.7 s.e.m., n = 11). This contrasts with HIV-2 infected subjects where the ASY/PGL patients (10.0% +/- 2.8 s.e.m., n = 6) did not differ significantly from healthy controls, although ARC/AIDS patients (27.2% +/- 4.2 s.e.m., n = 9, P < 0.001) had significantly increased levels of PCD. In conclusion, this is the first report describing the occurrence of spontaneous and activation-induced lymphocyte death by apoptosis in HIV-1 infected subjects.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Analysis of lymphocyte cell death and apoptosis in HIV-2-infected patients. 795 20

The 51Cr release assay has been the method of choice in analyzing natural killer cell (NK) function. Previous FCM cytotoxicity assays of NK activity have had numerous disadvantages that discouraged clinicians from attempting to evaluate NK function by flow cytometry. We demonstrate the effectiveness of using PKH-26, a stable membrane dye, to label the K562 target cells and propidium iodide intercalation into killed target cell DNA to determine the percentage of target cells killed by effector NK cells from the peripheral blood or bone marrow. This method compares favorably with the 51Cr release assay and is quicker and easier to perform. The percentage of cytotoxicity of NK cells (CD3- CD56+ and/or CD16+) from 10 normal subjects and 10 HIV-infected children are reported to demonstrate the feasibility of studying NK function in clinical populations by FCM. The potentiation of cytolysis by alpha-interferon and interleukin 2 in vitro was also compared between these two study groups. In addition, a patient whose leukemic blasts expressed CD56+ was also studied for NK activity using this flow cytometric assay. The benefits of using this flow cytometric approach to clinically assess NK function are discussed.
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PMID:Flow cytometric analysis of natural killer cell function as a clinical assay. 803 35

In May 1993 in France, Doctors without Borders, Epicentre, and INSERM met to develop a practical protocol for treatment of severely malnourished children in refugee camps and to discuss use of WHO's oral rehydration solution (ORS) for treating the children who may be dehydrated. The suggested treatment formula for catch-up growth for severely malnourished children is 80 gm dried skimmed milk; 50 gm sugar; and 60 gm oil, minerals, and vitamins per liter of feed (energy density; 1 kcal/ml). Adequate potassium, magnesium, zinc, copper, selenium, iodine, and each of the vitamins must be part of this diet. (Concentrations adequate for repletion and rapid recovery of malnourished children ingesting 100-200 ml/kg/day are tabulated in the article.) The various vitamins and minerals must be packaged separately to assure stability. During the early treatment stages, refugee workers should give this formula, diluted 3:1, either orally or through a nasogastric tube. They should administer 100 ml/kg/day of the formula (133 ml with water) during the first few days. Once the children regain their appetite, refugee workers should increase the undiluted feed to about 200 ml/kg/day. Refrigeration or lactobacillus fermentation prevent pathogenic contamination of the formula. Fermentation reduces the pH and the risk of lactose intolerance and generates antibacterial products. The potassium concentration of WHO-ORS is too low and the sodium concentration too high for severely malnourished children, especially those with kwashiorkor and marasmic-kwashiorkor. Further, it does not contain the minerals needed to stop diarrhea. Refugee workers can mix 1 WHO-ORS packet, 1 sachet of each mineral used in making the formula, and 50 gm sugar in 2 l of water to make an isotonic rehydration solution. A field trial in refugee camps in Ethiopia showed that this formula and modified WHO-ORS are practical and acceptable. Participants also suggested administering broad-spectrum antibiotic treatment, parenteral vitamin A, and measles vaccine to all children, regardless of HIV status.
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PMID:Treatment of malnutrition in refugee camps. 810 95

A tri-functional in vitro evaluation has been utilized to analyze peripheral blood mononuclear cells (BMNC) from HIV-infected patients, which allows for the classification of these individuals into convenient stages, according to the number of in vitro parameters affected. The classifying functional parameters are: the mitochondrial metabolic activity of freshly isolated BMNC, measured by an MTT reduction assay, the detection of apoptosis in 72 hour cultures of these cells assessed by propidium iodide staining and dual parametric flow cytometric analysis, and their proliferative response to pokeweed mitogen. Our results indicate that HIV-infected patients at different stages of their clinical disease, can present dysfunctions in one, two or three of the above-mentioned parameters. Based on these results, patients can be classified into four newly-described stages which are Stage 0, including uninfected controls and all patients with unaffected parameters, and Stages 1, 2 and 3, including patients having one, two or all three parameters affected, respectively. This type of immunological evaluation and classification of HIV-infected patients has the potential of becoming a predictive tool in the longitudinal follow-up of their HIV infection.
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PMID:Multifunctional immunological monitoring of HIV positive patients: a novel staging system. 814 Feb 7

The nucleocapsid protein NCp7 of the human immunodeficiency virus type I (HIV-1) is a 72 amino acid peptide containing two zinc fingers of the type CX2CX4HX4C linked by a short basic sequence 29RAPRKKG35. NCp7 was shown to activate in vitro both viral RNA dimerization and replication primer tRNA(Lys,3) annealing to the initiation site of reverse transcription. In order to clarify the possible structural role of the zinc fingers in the various functions of NCp7, complete sequence specific 1H NMR assignment of the entire protein was achieved by two-dimensional NMR experiments. Moreover, to characterize the role of the peptide linker in NCp7 folding, a synthetic analogue with an inversion of Pro31 configuration was studied by NMR and fluorescence techniques. Several long range NOEs implying amino acid protons from the folded zinc fingers and the spacer, such as Ala25 and Trp37, Phe16 and Trp37, Arg32 and Trp37, Lys33 and Trp37, Cys18 and Lys33 disappeared in the D-Pro31 (12-53)NCp7, confirming the spatial proximity of the two CCHC boxes observed in the (13-51)NCp7. This was also confirmed by iodide fluorescence quenching experiments. The N and C-terminal parts of NCp7 displayed a large flexibility except for two short sequences Tyr56 to Gly58 and Tyr64 to Gly66, which seemed to oscillate between random-coil and helical conformations. The biological relevance of the structural characteristics of NCp7 was studied in vitro and in vivo. Substitution of Pro31 by D-Pro31 in the active (13-64)NCp7 peptide led to a severe reduction of dimerization in vitro. Moreover, site-directed mutagenesis substituting Leu for Pro31 resulted in the formation of non-infectious and immature viral particles. These results suggest that the spatial proximity of the zinc fingers induced by the peptide linker, plays a critical role in encapsidation of genomic RNA and morphogenesis of HIV-1 infectious particles.
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PMID:Conformational behaviour of the active and inactive forms of the nucleocapsid NCp7 of HIV-1 studied by 1H NMR. 828 49

The development of commercial multichannel air-cooled laser flow cytometers which allow measurement of one or more characteristic parameters of particles or cells has been furthered due to advances in probes and fluorochromes. FITC-conjugated antibodies specific for selected cell surface molecules or for viral antigen expression in infected cells, fluorescein diacetate for labeling cells as a parameter of viability and propidium iodide as a DNA stain are generally used. Flow cytometric assays have been developed in virology to study the interactions of viruses with the immune system (Hantan Virus), to evaluate the diagnosis of secondary immunodeficiency syndromes (HIV), to analyze the protein and DNA content of virally infected cells during the cell cycle (SV40), to detect immediate early, early or late antigens in HCMV-infected cells, to assess the HCMV persistence in mononuclear cells, for use as a model for studying virus attachment to cellular receptors (EBV-echovirus), to screen and evaluate antiviral agents (Influenza C, HCMV, HSV, HIV) and to quantify antigens or antibodies simultaneously against various viruses (HCMV and HSV) or against different antigenic glycoproteins (HIV). This technology has thus become an important tool for the clinical virology and microbial serology laboratories.
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PMID:[Contribution of flow cytometry in virology]. 833 51

The typing of lymphocyte subsets may be influenced by a variety of technical influences including the duration and temperature of sample storage and the method used for staining samples. We have extended a previous study examining the effect of storage conditions on the baseline values of a number of lymphocyte subsets. EDTA-anticoagulated samples from 13 HIV-1-positive and 15 healthy laboratory controls were analyzed for a number of lymphocyte subsets (CD3+, CD4+/CD3+, and CD8+/CD3+ T cells and CD19+ B cells) (whole blood lysis method, Becton-Dickinson FACScan flow cytometer and reagents) at 0, 24, 48, 72, and 96 h after storage at 4 degrees C, 17 degrees C or 21 degrees C. During storage at both 4 degrees C and 21 degrees C, there were significant changes in baseline values of the majority of lymphocyte subsets and some of these were related to the HIV status of the donor. The optimum temperature for storage in our system appeared to be around 17 degrees C in both our study groups. We have also used propidium iodide in order to discriminate between viable and non-viable cells during flow cytometry of lymphocytes from eight HIV-1-positive and five control subjects. The results show that for both HIV-positive and control samples stored at 4 degrees C, and for control subjects at 21 degrees C, the changes in baseline values of lymphocyte subsets observed were not due to selective loss of particular subsets arising from cell death during storage. However, there was substantial loss of cells from all three subsets in HIV-positive subjects during storage at 21 degrees C, with loss of CD8+ and CD3+ T cells being more significant than loss of CD4+ T cells.
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PMID:Technical influences on immunophenotyping by flow cytometry. The effect of time and temperature of storage on the viability of lymphocyte subsets. 837 Sep 32

Glucose oxidase and peroxidase (lactoperoxidase or myeloperoxidase) are virucidal to human immunodeficiency virus type 1 (HIV-1) in the presence of sodium iodide, as assessed by the loss of viral replication in a syncytium-forming assay or by the inhibition of cytopathic effects on infected cells. In the presence of low concentrations of sodium iodide, five HIV-1 isolates were equally susceptible to this virucidal system at enzyme concentrations of a few milliunits. The loss of viral replication was linearly related to the time of incubation in the enzyme solutions, with an inactivation rate of 1 log unit every 30 min. These enzymes and this halide were also cytotoxic to chronically infected, but not to uninfected, cultured CEM cells. Protein conjugates were prepared by using the enzymes and murine antibody 105.34, which recognized the V3 loop of HIV-1 LAI isolate surface glycoprotein, or recombinant human CD4. The protein conjugates inactivated free virus at rates similar to those of the free enzymes and were more effective than antibody or recombinant CD4 alone. These in vitro findings demonstrate that the peroxidase-H2O2-halide system provides potent virucidal activity against HIV-1.
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PMID:Virucidal effects of glucose oxidase and peroxidase or their protein conjugates on human immunodeficiency virus type 1. 838 38


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