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

Reverse transcriptase (RT) was first discovered as an essential catalyst in the biological cycle of retroviruses. However, in the past years evidence has accumulated showing that RTs are involved in a surprisingly large number of RNA-mediated transpositional events that include both viral and nonviral genetic entities. Although it is probable that some RT-bearing genetic elements like the different types of AIDS viruses and the mammalian LINE family have arisen in recent geological times, the possibility that reverse transcription first took place in the early Archean is supported by (1) the hypothesis that RNA preceded DNA as cellular genetic material; (2) the existence of homologous regions of the subunit tau of the E. coli DNA polymerase III with the simian immunodeficiency virus RT, the hepatitis B virus RT, and the beta' subunit of the E. coli RNA polymerase (McHenry et al. 1988); (3) the presence of several conserved motifs, including a 14-amino-acid segment that consists of an Asp-Asp pair flanked by hydrophobic amino acids, which are found in all RTs and in most cellular and viral RNA polymerases. However, whether extant RTs descend from the primitive polymerase involved in the RNA-to-DNA transition remains unproven. Substrate specificity of the AMV and HIV-1 RTs can be modified in the presence of Mn2+, a cation which allows them to add ribonucleotides to an oligo (dG) primer in a template-dependent reaction. This change in specificity is comparable to that observed under similar conditions in other nucleic acid polymerases. This experimentally induced change in RT substrate specificity may explain previous observations on the misincorporation of ribonucleotides by the Maloney murine sarcoma virus RT in the minus and plus DNA of this retrovirus (Chen and Temin 1980). Our results also suggest that HIV-infected macrophages and T-cell cells may contain mixed polynucleotides containing both ribo- and deoxyribonucleotides. The evolutionary significance of these changes in substrate specificities of nucleic acid polymerases is also discussed.
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PMID:On the early emergence of reverse transcription: theoretical basis and experimental evidence. 128 61

The human immunodeficiency virus (HIV) proteins gp120 and gp41 are the principal immune target in HIV infection. One of the most important trends in the study of AIDS is linked to the mapping of sites involving in the binding to the cell receptor CD4 and in the induction of virus-neutralizing antibodies (VNA). Recent studies have revealed that gp120 as the major domain contains inducing type-specific BNA (PND) and a binding region with CD4 (CD4-BR). PND is located in the hypervariable loop of gp120 (residues 301-336 for a BRU strain), and CD4-BR is in the conservation area (residues 410-450). By using the synthetic fragments from these areas (BRU and MN strains) and HIV-infected persons' sera, the authors established that the immune response to PND and CD4-BR is somewhat interrelated: there is a synchronized response of HIV antibodies to peptides from the two regions in ELISA (r = 0.82). For analysis of this phenomenon, experiments with cross-linked immunoreactivity of rabbit antisera to peptides from PND and CD4-BR with homologous and heterologous peptides were performed by applying three control peptides from HIV and hepatitis B virus. It has been found that there is a cross reactivity between rabbit anti-PND (MN, BRU) and anti-CD4-BR abs. Peptide homological analysis revealed common structural elements for PND and CD4-BR despite significant differences in their proposed functions. There is a large amount of positively charged aa within both PND and CD4-BR which may be involved in gp120-CD4 interaction. Acetylation of Lys residues resulted in complete loss of peptide reactivity.
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PMID:[Peptides from the principal neutralizing and CD4-binding domain: similar immunoreactive properties and structure pattern]. 128 21

Catechin derivatives including (-)-epicatechin gallate (ECG), (-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin (EGC) and green tea extract (GTE) were found to inhibit the activities of cloned human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT), duck hepatitis B virus replication complexes reverse transcriptase (DHBV RCs RT), herpes simplex virus 1 DNA polymerase (HSV-1 DNAP) and cow thymus DNA polymerase alpha (CT DNAP alpha). EGCG and ECG were shown to be very potent inhibitors of HIV-1 RT. According to the IC50 values for HIV-1 RT, these compounds can be ordered as EGCG 0.0066 mumol/L > ECG 0.084 mumol/L > GTE 0.1 microgram/ml > EGC 7.2 mumol/L. DHBV RCs RT was the least sensitive to these compounds. Kinetic study showed that EGCG exerts a mixed inhibition with respect to external template inducer poly (rA).oligo (dT) 12-18 and a noncompetitive inhibition with respect to substrate dTTP for HIV-1 RT. Bovine serum albumin significantly reduced the inhibitory effects of catechin analogues and GTE on HIV-1 RT. In tissue culture GTE inhibited the cytopathic effect of coxsackie B3 virus, but did not inhibit the cytopathic effects of HSV-1, HSV-2, influenza A or influenza B viruses.
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PMID:[The inhibitory effects of catechin derivatives on the activities of human immunodeficiency virus reverse transcriptase and DNA polymerases]. 128 89

Two hundred and fifty attendees at two London genitourinary medicine clinics were asked to complete an anonymous self-administered questionnaire, enquiring about sexual behaviour whilst abroad. Two hundred and forty-three questionnaires were evaluable. In the study group there were 116 women, and 127 men (62 heterosexuals and 65 homosexuals). Ninety women, 53 heterosexual men and 53 homosexual men had travelled abroad over the preceding 6 months. Of these 18 (20%) of women, 26 (51%) of heterosexual men and 19 (36%) of homosexual men had sex with a local foreign contact on holiday. Although both heterosexual and homosexual men were statistically more likely to have sex abroad with a local inhabitant, women were more likely to have unprotected sexual intercourse with a local partner. This has important implications for the spread of sexually transmitted disease including hepatitis B and HIV.
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PMID:Sexual behaviour amongst travellers: a study of genitourinary medicine clinic attenders. 128 21

The prevalence of persistent hepatitis delta (HD) antigenaemia and associated factors in patients with chronic infection with the hepatitis delta virus (HDV) were investigated. Among 157 consecutive patients known to be carriers of hepatitis B surface antigen (HBsAg), 36 (23%) had one serum marker of HDV infection (anti-HD and/or HDAg). Nine of the patients with an HDV marker were HDAg positive, including three who were anti-HD negative. A follow-up over a mean period of 13 months showed that five of five patients had a persistent HD antigenaemia. This serological profile was associated with the presence of antibody to the human immunodeficiency virus (anti-HIV) (P < 0.01), serum HIV antigen (HIVAg) (P < 0.2), and the female sex (P < 0.05). Persistent HD antigenaemia could be the consequence of the suppression of T cell cytotoxic activity against hepatocytes expressing HDAg, a lower humoral response, and/or hormonal factors.
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PMID:Persistent delta antigenaemia in chronic delta hepatitis and its relation with human immunodeficiency virus infection. 128 32

Hepatitis B virus (HBV) markers were determined in 80 children under 5 years of age with HIV symptomatic infection. Because of high carrier rate of hepatitis B virus in Romania we investigated as control a group of age matched 36 HIV negative children offsprings of HBsAg carrier mothers. Serological and epidemiological investigations in families of HIV infected children support horizontal nosocomial and not vertical transmission for HIV in contrast with HBV whose perinatal transmission can not be excluded. Concerning the probable route of HBV infection both groups of children seem to have a comparable risk for parenteral, contact-associated or maternal-neonatal transmission. HBsAg was detected in 76.25% HIV positive subjects and in 13.9% of control (P = 0.05). From all serum samples tested, only 12, all from the control group, did not present any markers of past or current HBV infection. Two serum markers have been used as an index of active HBV replication: HBe antigen detection and HBs antigen quantification in one or paired serum specimens. HBeAg was detectable in 20% of HIV infected children and only in 2.8% controls (P = 0.05). Almost all HBeAg positive patients have higher values for HBs antigenemia. HBsAg concentrations well above the assay cut off value (sample/cut off ratio > 15) were generally representative for HIV infected children (54% versus 5.6% in controls). The prevalence of hepatitis Delta markers and anti-HCV antibodies was not significantly higher in HIV infected children in spite of the fact that they are potentially exposed to a wider range of antigens.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The evolution of hepatitis B virus infection in children with symptomatic AIDS. 128 42

This paper reviews orthodontic care in patients who are in nontraditional categories. Specific orthodontic management of a patient who had severe hemophilia, seropositivity for anti-HIV Ab, and Hepatitis B surface antigen is reviewed. The importance of defining acceptable treatment goals in these patients is of paramount importance.
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PMID:Modified orthodontic treatment goals in a patient with multiple complicating factors. 130 24

Intravenous drug users are frequently exposed to parenterally transmitted viral infections, and these infections can spread to the general population through sexual activity. We investigated the prevalence of serologic markers for human immunodeficiency virus type 1 (HIV-1), human T-cell lymphotropic virus type I/II (HTLV-I/II), hepatitis B virus (HBV), and hepatitis C virus (HCV) in intravenous drug users and their sexual contacts. Of 585 drug users from northern California tested for these serologic markers, 72% were reactive for the antibody to HCV, 71% for the antibody to hepatitis B core antigen, 12% for HTLV-I/II antibodies, and 1% for the HIV-1 antibody. The prevalence of serologic markers for these four viruses correlated with the duration of intravenous drug use, the ethnic group, and the drug of choice. More than 85% of subjects infected with either HCV or HBV were coinfected with the other virus. All persons reactive to HTLV-I/II antibodies had antibodies for either HBV or HCV. Of 81 sexual contacts tested, 17% had evidence of HBV infection while only 6% were reactive for HTLV-I/II antibodies and 4% for the antibody to HCV. None of this group was infected with HIV-1. We conclude that HTLV-I/II and HCV are inefficiently transmitted to sexual contacts while HBV is spread more readily. Programs designed to discourage the sharing of drug paraphernalia, such as needle and syringe exchanges, should decrease the risk of parenterally spread viral infections in intravenous drug users and thus slow the spread of these infections to the general population.
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PMID:Seroepidemiology of viral infections among intravenous drug users in northern California. 131 Mar 62

This review has focused on a select group of viruses that can be sexually transmitted. The viruses include the herpesviruses, hepatitis A virus, hepatitis B virus, delta virus, non-A, non-B hepatitis virus(es), and molluscum contagiosum. Their impact on the population alone or in association with HIV disease necessitates a clear understanding of their ability to cause infection and of the manifestations of these infections. Characterization of these particular pathogens and treatment have been discussed with respect to the most current data available. Despite the growing sophistication in the field, we are still limited in our endeavors to identify and manage many viral infections. Therefore, measures to prevent transmission are continually being evaluated in an attempt to minimize exposure to these pathogens.
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PMID:Sexually transmitted viruses other than HIV and papillomavirus. 131 May 46

A multicenter prospective study was carried out to evaluate whether a vapor-heated factor VIII concentrate transmitted blood-borne viral infections over a surveillance period of 15 months. Thirty-five patients with hemophilia and von Willebrand disease who had never received any blood components were treated. Twenty-eight were analyzed and found not to have non-A, non-B hepatitis. Sera from 20 of these 28 patients were also tested for the antibody to the hepatitis C virus. None had sero-converted during the follow-up period. None of the patients analyzed developed markers of the hepatitis B virus (n = 17) or the human immunodeficiency virus (n = 31). This vapor-heated factor VIII concentrate carries a low risk of transmitting hepatitis and human immunodeficiency virus infection.
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PMID:Low risk of viral infection after administration of vapor-heated factor VIII concentrate. International Investigator Group. 131 76


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