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

A series of neoglycoproteins was synthesized by coupling of thiophosgene-activated p-aminophenyl derivatives [Biol. Cell. 47:95-110 (1983); J. Histochem. Cytochem. 32:1091-1094 (1984)] of various sugars to human serum albumin. The compounds were evaluated for their in vitro activity against human immunodeficiency virus (HIV). Neoglycoproteins with the highest sugar content were found to be the most potent inhibitors of HIV-1-induced cytopathogenicity. However, this was not due to the nature of the sugar used but, rather, was related to the extra negative charge of the neoglycoproteins. To investigate whether the antiviral activity of the neoglycoproteins exhibited sugar specificity, increased with increasing negative charge, or depended on both sugar specificity and negative charge, we synthesized albumins and neoglycoproteins with an enhanced negative charge, by treatment with formaldehyde or succinic anhydride. Succinylated human serum albumin had the most pronounced net negative charge and had an IC50 of about 1 microgram/ml. No cytotoxicity was observed at concentrations up to 1 mg/ml, implicating a selectivity index (CC50/IC50) of at least 10(3). To elucidate the mechanism of action of these anionic albumins, we investigated whether they interfered with HIV-1 adsorption to the cells, binding of anti-OKT4A monoclonal antibody (mAb) to the CD4 receptor, binding of anti-gp120 mAb to gp120, or inhibition of syncytium formation in co-cultures of HIV-1-infected HUT-78 cells with MOLT-4 cells. From these experiments, we conclude that albumins with an increased negative charge (a) are potent and nontoxic anti-HIV-1 agents, (b) cause a 50% reduction of syncytium formation in the same concentration range as their IC50 in the antiviral assay, and (c) do not bind to the OKT4A epitope of the CD4 receptor and only partly inhibit anti-gp120 mAb-gp120 interaction and virus-cell binding at concentrations that are 100 times higher than their IC50 in the antiviral assay. Therefore, we conclude that the modified albumins interfere with a post-binding event, of which one of the potential mechanisms is an interaction with the gp41 fusion protein, which is necessary for syncytium formation but is not involved in initial virus binding.
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PMID:Potent in vitro anti-human immunodeficiency virus-1 activity of modified human serum albumins. 205 94

The prevalence of the human immunodeficiency and hepatitis viruses has led to considerable concern by health care workers about safer means of examining surgical pathological specimens. The human placenta needs to be examined when there are complications during pregnancy, labor, and delivery; when the fetus is born with apparent problems; and when the delivered placenta is abnormal. Placentas are routinely immersion fixed with neutral buffered 3.7% to 4.0% formaldehyde solution before examination and without obtaining a fresh weight. This study was undertaken to determine if there was a significant change in weight between a fresh and fixed placenta. The results show a 7.67% increase in placental weight after formaldehyde fixation for 24 hours. Thus, the practice of formaldehyde fixation prior to weighing and examination can be continued and still allow for accurate estimation of fresh placental weight.
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PMID:The effect of immersion formaldehyde fixation on human placental weight. 206 35

Effects of cell fixation procedures appropriate for flow cytometric analysis on the infectivity of human T lymphoblastoid H9 cells infected with human immunodeficiency virus-1 (HIV-1) were evaluated to provide guidelines for choosing cell treatments for potentially infectious samples. H9 cells experimentally infected with HIV-1 were treated by the test fixation procedure, washed, and cocultured with equal numbers of live, uninfected H9 cells. To estimate the reduction in infectivity due to the fixation procedure, dilution series of live infected H9 cells in uninfected H9 cells were simultaneously established in culture. Cell cultures were incubated 8-10 d, harvested, and evaluated for evidence of HIV-1 infection by the presence of cell-associated HIV-1 antigens and/or by the presence of particle-associated reverse transcriptase activity in cell culture supernatants. Thirty-minute fixation with formaldehyde (1.85%), methanol (absolute), methanol:acetone (1:1), or paraformaldehyde (0.5%) reduced the infectivity of HIV-1-infected H9 cells by greater than 99.99%. To the same degree, a multi-step fixation procedure utilizing formaldehyde and ethanol was effective in reducing HIV-1 infectivity. Conversely, the erythrocyte fixative dimethylsuberimidate at 3 micrograms/ml was ineffective in reducing HIV-1 infectivity.
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PMID:Effects of cellular fixatives on human immunodeficiency virus production. 237 57

Materials commonly employed in the preparation of otologic homografts such as ethanol and formaldehyde are effective in vitro in inactivating human immunodeficiency virus (HIV). However, to our knowledge, the complete permeation of homograft materials with preservative has not been demonstrated. Ethanol and formaldehyde have not been shown to be effective in inactivating the Creutzfeldt-Jakob agent. The literature on sterilization procedures for these agents is reviewed. Standard procedures for preparation of otologic homografts are examined. It is recommended that donor HIV serologic status be determined when otologic homografts must be used. Further research is required to determine the efficacy of otologic homograft sterilization techniques against HIV and Creutzfeldt-Jakob disease.
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PMID:Can acquired immunodeficiency syndrome and Creutzfeldt-Jakob disease be transmitted via otologic homografts? 304 23

A "new" polyclonal activator of human peripheral blood B cells, formaldehyde-fixed Salmonella paratyphi B, is described. This bacterium does not stimulate cell proliferation as measured by incorporation of tritiated thymidine but does stimulate a subpopulation of B cells to secrete large amounts of IgM, IgG, and IgA in 7-day cell cultures. The immunoglobulins (Ig) produced by cells responding to S. paratyphi B are not specific antibodies against the bacterial antigens. In comparison with other B cell activators (pokeweed mitogen, Staphylococcus aureus Cowan I, and lipopolysaccharide), S. paratyphi B stimulation produced greater amounts of IgM but less IgG than pokeweed mitogen (PWM) or S. aureus Cowan I; lipopolysaccharide failed to stimulate significant Ig production on day 7 in most cases. In addition, the response to S. paratyphi apparently did not require T cell collaboration. These results suggest that the B cell subpopulation(s) responding to S. paratyphi B may be more differentiated B cells than those responding to either PWM or S. aureus Cowan I. Peripheral blood mononuclear cells from five patients with common variable immunodeficiency without evidence of abnormal suppressor T cells or monocytes failed to respond to S. paratyphi B, whereas cells from two of the same patients responded well to S. aureus Cowan I and partially to PWM. Thus, S. paratyphi B appears to be superior to other B cell activators for studies of B cell function in normal and abnormal states.
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PMID:Polyclonal activation of human peripheral blood B lymphocytes by formaldehyde-fixed Salmonella paratyphi B. I. Immunoglobulin production without DNA synthesis. 697 34

Freshly isolated, human peripheral blood T (PBT) cells are largely resistant to the apoptotic effects of anti-CD3 monoclonal antibody, ionomycin, or phorbol 12-myristate 13-acetate (PMA). We demonstrate here, however, that PBT cells, including both CD4+ and CD8+ cell populations, can be readily induced to undergo apoptosis when cocultured with either autologous or allogeneic monocytes (Mo) in PMA-containing medium. Incubation of PBT cells with Mo at a ratio of 1:1 for 18 hr resulted in maximal levels (80%) of apoptotic cell death. The mechanism whereby Mo enable PBT cells to undergo apoptosis in PMA-containing medium appeared to depend on cell-cell contact or close proximity between Mo and PBT cells rather than solely via soluble mediators. It was demonstrated that Mo acquire the ability to prime PBT cells for apoptosis after treatment with PMA and that treated Mo maintain this ability even after fixation with formaldehyde. It was also found that once PBT cells became primed for apoptosis by incubation with PMA-pretreated Mo, the primed PBT cells were susceptible to apoptosis triggered not only by PMA but also by either ionomycin or by monoclonal antibody crosslinking of T-cell surface molecules such as CD4 and CD3. Interestingly, the degree of apoptosis of CD4+ T cells by crosslinking of CD4 molecules via a combination of gp120, anti-gp120, and goat anti-mouse IgG was significantly greater for T cells primed with PMA-treated Mo than for unprimed T cells. Together, these findings reveal an important role for accessory cells in priming resting PBT cells for apoptosis and suggest a possible Mo-dependent mechanism by which T cells may become primed for apoptosis in human immunodeficiency virus-infected asymptomatic individuals.
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PMID:Monocytes are required to prime peripheral blood T cells to undergo apoptosis. 787 13

Reagents that lyse red blood cells and fix white blood cells were tested for their ability to inactivate cell-associated human immunodeficiency virus (HIV). Whole blood was spiked with cells from an HIV-positive cell line (H9), lysed, and fixed. The cell preparations were then cocultured with T cell blasts in serial ten-fold dilutions to rescue infectious virus and measure viral titer. All commercial lysing and fixing reagents tested inactivated cell-associated HIV by 3-5 logs, while ammonium chloride had little effect. Although an additional incubation with 1% formaldehyde for 30 min did not increase the effectiveness of the commercial lysing/fixing reagents, it did inactivate cell-associated HIV in blood treated with ammonium chloride.
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PMID:Inactivation of HIV-infected H9 cells in whole blood preparations by lysing/fixing reagents used in flow cytometry. 845 8

The risk of infection of investigators working on the biomechanics of human bone from a variety of modern pathogens including the human immunodeficiency virus or the hepatitis B virus has increased recently. New safety procedures are needed to reduce that risk. The procedure we follow in our laboratory employs brief (< 3 h) fixation in formaldehyde, and we report here the effects it has on some mechanical properties of bovine bone. Results in quasistatic loading tests were almost unaffected by our fixation protocol, but a significant decrease in impact strength was found. These results indicate that there may be some interaction between fixation and strain rate dependent effects and, therefore, some caution is needed when using common biomechanical measurement methods on fixed bone material.
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PMID:Effect of formaldehyde fixation on some mechanical properties of bovine bone. 858 98

It is generally agreed that middle ear reconstructive surgery performed with tympano-ossicular homografts produces superior functional results compared with prosthetic material, especially with respect to extrusion rate. The use of homografts, though, has been seriously hampered recently by the fear of transmission of human immunodeficiency virus (HIV) infection. In HIV-infected patients, the virus is primarily found in the cells of the lymphoid and monocytic lineage. The nature of the tissues in the eardrum and ossicles, mostly fibrous tissue and compact bone without marrow, suggests that little virus load should be found in homografts. Indeed, culturing minced homograft tissue from two HIV-infected donors with acquired immune deficiency syndrome (AIDS) in a sensitive culture system with PHA-stimulated lymphoblasts produced no virus. Before use, homografts undergo a fixation procedure in 5% formaldehyde and then are kept in a solution containing Cialit as a preservative. The authors therefore examined the capacity of formaldehyde and Cialit to reduce the infectivity of HIV in models of infected tissue as measured in vitro. The reduction of in vitro infectivity due to these treatments was at least 10(5)-fold and 10(2)-fold, respectively. Coupled with the low virus burden in tympano-ossicular tissue, our data suggests that the fixation procedure affords such a reduction in infectivity that the risk of HIV transmission, even from an HIV-infected donor, is vanishingly low.
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PMID:Risk of transmission of human immunodeficiency virus infection during tympano-ossicular homograft: an experimental study. 861 99

Since chemically preserved allogenic transplants have an established place in reconstructive procedures, the possibility of transferring the human immunodeficiency virus (HIV) with these transplants has been intensively discussed. In this study the authors obtained brain and spleen samples from six HIV-infected cadavers and preserved them with Merthiolate, Cialit, and formaldehyde. After preservation, the tissues were examined for proviral HIV-1 DNA (gag, pol, env) using the polymerase chain reaction. Proviral sequences were clearly demonstrated after the preservation procedure. The results of this study indicate that HIV remains in tissues that have been treated with Merthiolate, formaldehyde, or Cialit. Further investigations are necessary to determine if the virus is in an inactivated or activated form. It can be concluded that, because of the possible transmission of HIV by chemically preserved homografts, serologic screening of donors should be mandatory.
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PMID:Influence of chemical allograft preservation procedures on the human immunodeficiency virus. 862 97


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