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

First images on a nanometer scale of reverse transcriptases (RT) of the human immunodeficiency virus (HIV-1) and of the Moloney murine leukemia virus (MuLV) obtained by scanning tunneling microscopy (STM) are reported. The common feature of the observed molecules is a ring-type or horseshoe shape with hole diameters of approximately 30 A. The STM images are compared with high resolution transmission electron microscopy (TEM) and existing structure predictions. The similarities of the structural data obtained by STM and TEM and their agreement with the structure prediction for the RT of HIV-1 shows the principal possibility to image such biomolecules by STM.
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PMID:Direct observation of reverse transcriptases by scanning tunneling microscopy. 128 Sep 57

Scanning tunnelling microscopy (STM) has been performed on the reverse transcriptases of the human immunodeficiency virus (HIV-1) and the moloney murine leukaemia virus (MuLV). The biological molecules are adsorbed on n-type semiconducting MoTe2. The p66 (66 kD) subunit of the RT of HIV-1 is imaged by STM. Both STM and processed transmission electron microscopy (TEM) data show a spherical and horseshoe-like shape of external diameter ca. 65 A, depending on the angle of observation. The STM results show a larger diameter which is related to the curvature radius of the tip of the probing needle. The RTs of HIV-1 and MuLV exhibit a circular hole of ca. 20 A diameter in accordance with structure predictions and functioning considerations. The surface-molecule interaction is discussed in terms of the electronic properties of the semiconductor surface including the influence of small defect sites at the layered crystal surface.
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PMID:Scanning tunnelling microscopy observations of biomolecules on layered materials. 128 40

A reply is offered to an article likening the use of condoms to Russian roulette in its vaunted protection against AIDS. The Food and Drug Administration endorsed the use of nonoxynol-9 in condoms against infection with the human immunodeficiency virus (HIV) and genital herpes. 1985 research indicated that nonoxynol-9 inactivated HIV in vitro in concentrations below 0.05%. At a 1987 congress on AIDS a study was presented involving the testing of 30 condoms. 20 contained 0.9 ml of 6.6% nonoxynol-9 and 10 contained none of the substance. Each condom was placed on an empty sterilized contraception in a glass cylinder containing a 10 ml substrate of flowing synthetic tissue culture (RPMJ 1640), and 4 ml of HIV inoculum was put on top of the condoms. Anal or vaginal intercourse was simulated for 5 minutes. After each simulation 1 ml of the test material of the test material was taken out of the cylinder and from the top of the condom for HIV testing. 10 condoms without nonoxynol-9 were all HIV negative, where the test sample was taken from the outside and inside of condoms after the first simulated intercourse but before a hole was pierced into the condoms. None of the test samples taken from the inside of the condoms were HIV positive among 10 other condoms containing nonoxynol-9 with HIV inoculum. 2 of these 10 sample test taken from the outside before a hole was pierced proved to be positive among 10 condoms containing nonoxynol-9 with HIV inoculum on the outside. HIV could not be detected on the outside of any of the 20 condoms containing nonoxynol-9, even after rupture. Intact latex condoms are impervious to HIV, and those with nonoxynol-9 inactivate it in concentrations above 0.25%, even if the condom breaks.
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PMID:[Nonoxynol-9 in a perforated condom protects against HIV infection]. 184 23

The protein E-specific lysis mechanism of the Escherichia coli-specific bacteriophage PhiX174 was employed to produce Vibrio cholerae ghosts (VCG). VCG consist of both rounded and collapsed cells that have lost their cytoplasmic contents through an E-specific hole in the cell envelope. These ghosts are proposed as non-living material for immunization against cholera. A specific membrane anchor sequence was used to insert the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) fusion protein into the cell envelope of V. cholerae. The identity of the expression products was confirmed by Western blot analysis employing an RT-specific monoclonal antibody. HIV-1 RT was chosen as a model for the purpose of evaluating heterologous gene expression in V. cholerae and the carrier potential of VCG. Intraperitoneal immunization of mice was used to evaluate the immunogenic potential of VCG. Preliminary results showed significant seroconversions to intact whole-cell vibrio antigens in mice immunized with VCG or a heat-killed whole-cell vibrio preparation.
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PMID:Production of Vibrio cholerae ghosts (VCG) by expression of a cloned phage lysis gene: potential for vaccine development. 753 Aug 88

Circumcision performed using the Gomco clamp is usually quick and effective, and results in very little bleeding. However, every clinician performing circumcision occasionally has concerns or questions regarding the procedure. Some of the more common concerns regarding the use of the Gomco clamp are technique-related, including choosing the correct size of the Gomco bell and clamp for the procedure, choosing the right method of getting the foreskin properly through the hole of the Gomco base plate, and assessing how much foreskin to remove. Other concerns include poor cosmetic results, contraindications to routine circumcision, and circumcision in an infant whose mother has human immunodeficiency virus. This article reviews the technique of circumcision using the Gomco clamp and answers some of the more common questions.
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PMID:The Gomco circumcision: common problems and solutions. 1034 68

Believed to be due to unbalance between cerebrospinal fluid (CSF) production rate and its loss through the spinal dural puncture hole, post-dural puncture headache (PDPH) is often considered as a physiological syndrome, usually reversible without pathological sequelae after dural hole's closure. The clinical case here presented (incapacitating headache associated with diagnostic dural puncture in a leukaemic young female patient who underwent bone marrow transplantation) shows potentially fatal pathological sequelae following prolonged headache (untreated, due to the severe postransplant immunodeficiency and coagulopathy). The observed RMI lesions suggest interesting conclusions about the clinical indications and correct timing of autologous epidural blood patch (EBP). We also suggest the ways to preventing rebound intracranial hypertension following autologous epidural blood patch in patients suffering from incapacitating and prolonged headache.
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PMID:[Severe and prolonged post-dural puncture headache: from pathological basis to therapeutic role and correct timing for epidural blood patch]. 1177 23

The Psi-RNA packaging signal of the human immunodeficiency virus type-1 (HIV-1) genome contains a 35 nucleotide stem-loop, termed SL1, which is important for efficient genome packaging during virus assembly and for reverse transcription during infectivity. The predicted secondary structure of SL1 consists of an upper stem with a GC-rich loop that facilitates dimerization, a lower stem, and an intervening bulge (G5, A24-G25-G26) that is both strictly conserved and essential for efficient packaging of the viral genome. The structure of the upper stem in both the kissing and duplex dimer forms have been determined recently. Here, we report the structure of an engineered form of SL1 (SL1(m)) that contains a GAGA tetraloop substituted for the GC-rich loop. This construct does not aggregate and remains monomeric at concentrations up to 1mM, enabling structural studies of the intact stems and bulge. The structure was refined using 1H-13C residual dipolar couplings. The upper stem (C6-G12, C17-G23) is in close agreement with X-ray structures of kissing and duplex dimer forms of related oligoribonucleotides, and nucleotides C1-G4 and C27-G30 form the expected A-helical lower stem. Residues G5 and A24 of the predicted bulge form a G-A mismatch that stacks with the upper stem, and residues G25 and G26 stack between the G-A mismatch and the lower stem in a manner that produces a hole in the center of the bulge and a 25(+/-4) degrees bend between the upper and lower stems. SL1(m) exhibits relatively poor affinity for the HIV-1 nucleocapsid protein, suggesting that the bulge plays other roles in genome packaging.
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PMID:Structure of the intact stem and bulge of HIV-1 Psi-RNA stem-loop SL1. 1255 20

One of the most important steps in the process of viral infection is a fusion between cell membrane and virus, which is mediated by the viral envelope glycoprotein. The study of activity of the glycoprotein in the post-fusion state is important for understanding the progression of infection. Here we present a first real-time kinetic study of the activity of gp41 (the viral envelope glycoprotein of human immunodeficiency virus-HIV) and its two mutants in the post-fusion state with nanometer resolution by atomic force microscopy (AFM). Tracking the changes in the phosphatidylcholine (PC) and phosphatidylcholine-phosphatidylserine (PC:PS) membrane integrity over one hour by a set of AFM images revealed differences in the interaction of the three types of protein with zwitterionic and negatively charged membranes. A quantitative analysis of the slow kinetics of hole formation in the negatively charged lipid bilayer is presented. Specifically, analysis of the rate of roughness change for the three types of proteins suggests that they exhibit different types of kinetic behavior.
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PMID:Kinetics of interaction of HIV fusion protein (gp41) with lipid membranes studied by real-time AFM imaging. 2039 63

The purpose of this report is to discuss management of operating room personnel who have had occupational exposure to blood and other body fluids that might contain hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and human T-cell lymphotropic virus type I (HTLV-I). HBV postexposure prophylaxis includes starting hepatitis B vaccine series in any susceptible unvaccinated operating room personnel who sustain an exposure to blood or body fluid during surgery. Postexposure prophylaxis with hepatitis B immune globulin (HBIG) is an important consideration after determining the hepatitis B antigen status of the patient. Ideally, all operating room personnel should be vaccinated with hepatitis B vaccine before they pursue their career in surgery. Immune globulin and antiviral agents (eg, interferon with or without ribavirin) should not be used for postexposure prophylaxis of operating room personnel exposed to patients with HCV; rather, follow-up HCV testing should be initiated to determine if infection develops. Postexposure prophylaxis for HIV involves a basic four-week regimen of two drugs (zidovudine and lamivudine; lamivudine and stavudine; or didanosine and stavudine) for most exposures. An expanded regimen that includes a third drug must be considered for HIV exposures that pose an increased risk for transmission. When developing a postexposure prophylaxis regimen, it is helpful to contact the National Clinicians' Postexposure Prophylaxis Hotline, (888) 448-4911. Prevention should be a major consideration in postexposure prophylaxis with the use of the double-glove hole indication system by all operating room personnel.
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PMID:Postexposure prophylaxis for deadly bloodborne viral infections. 2128 94

We have developed a dual color fluorescence quantitative detection method for specific single-stranded DNA with molecular beacons (MBs) and nucleic acid dye SYBR Green I by synchronous scanning fluorescence spectrometry. It is demonstrated by a reverse-transcription oligonucleotide sequence (target DNA, 33 bases) of RNA fragment of human immunodeficiency virus (HIV) as a model system. In the absence of target DNA, the MBs are in the stem-closed state, the fluorescence of 5-carboxy-X-rhodamine (ROX) is quenched by black hole quencher-2 (BHQ-2), and the interaction between SYBR Green I and the MBs is very weak. At this time the fluorescence signals of ROX and SYBR Green I are all very weak. In the presence of target DNA, MBs hybridize with target DNA and form a double-strand structure, the fluorophore ROX is separated from the quencher BHQ-2, and the fluorescence of ROX recovers. At the same time, SYBR Green I binds to hybridized dsDNA, whose fluorescence intensity is significantly enhanced. Thus, dual color fluorescence quantitative detection for the target DNA can be realized by synchronous scanning fluorescence spectrometry. In this strategy, the fluorescence signal of SYBR Green I is far larger than that of ROX, so the quantitative analysis of target DNA with the fluorescence intensity of SYBR Green I can significantly improve the detection sensitivity. In addition, the false-positive signals of MBs do not affect the fluorescence signals of nucleic acid dye SYBR Green I. Thereby, in the analysis of complex samples, quantitative analysis of target DNA with SYBR Green I can avoid the false-positive signals of MBs and improve the detection accuracy.
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PMID:Dual color fluorescence quantitative detection of specific single-stranded DNA with molecular beacons and nucleic acid dye SYBR Green I. 2276 45


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