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)

Anaemia during peginterferon (PEG-IFN) and ribavirin (RBV) therapy is common in human immunodeficiency virus/hepatitis C virus (HIV/HCV)-coinfected patients despite the use of lower doses of RBV than are recommended for HIV-seronegative persons. In addition, concurrent zidovudine (ZDV) may exacerbate the anaemia caused by PEG-IFN and RBV. We retrospectively analysed the incidence of anaemia, RBV dose reduction and epoetin-alpha (EPO) use among coinfected patients treated with PEG-IFN and weight-based RBV (800-1400 mg/day) who enrolled in two clinical trials and had haemoglobin (Hb) levels assessed at baseline and after 4 and/or 12 weeks of HCV treatment. Overall, 217 patients were included; pre-treatment Hb levels (mean 14.7 g/dL) were similar in all patients, including ZDV users (29% of patients). After 4 weeks of therapy, the mean Hb decline was greater among ZDV recipients (3.13 g/dL) compared with those on other anti-retroviral treatment (ART) (2.13 g/dL) or on no ART (1.47 g/dL) (P < 0.0001). RBV dose reduction and EPO use were more common in patients taking ZDV compared with those not taking ZDV (P < 0.0001). RBV dose was not associated with Hb reduction, RBV dose reduction or EPO use. Virologic response after 12 weeks of therapy and the treatment discontinuation rate did not differ by ZDV use. The use of ZDV but not weight-based RBV dosing was associated with an increased risk of anaemia, RBV dose reduction or EPO use in coinfected patients treated with PEG-IFN/RBV. However, ZDV use was not associated with higher rates of treatment discontinuation or lower early virologic response rates. HIV and hepatitis C care providers should be cognizant of these data.
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PMID:Zidovudine use but not weight-based ribavirin dosing impacts anaemia during HCV treatment in HIV-infected persons. 1697 Jun

New conjugates of triplex-forming pyrimidine oligo(2'-O-methylribonucleotides) with one or two 'head-to-head' hairpin oligo(N-methylpyrrole carboxamide) minor-groove binders (MGBs) attached to the terminal phosphate of the oligonucleotides with a oligo(ethylene glycol) linker were synthesized. It was demonstrated that, under appropriate conditions, the conjugates form stable complexes with double-stranded DNA (dsDNA) similarly to triplex-forming oligo(deoxyribonucleotide) (TFO) conjugates containing 5-methylated cytosines. Kinetic and thermodynamic parameters of the complex formation were evaluated by gel-shift assay and thermal denaturation. Higher melting temperatures (Tm), faster complex formation, and lower dissociation constants (Kd) of the triple helices (6-7 nM) were observed for complexes of MGB-oligo(2'-O-methylribonucleotide) conjugates with the target dsDNA compared to the nonconjugated individual components. Interaction of MGB moieties with the HIV proviral DNA fragment was indicated by UV/VIS absorption changes at 320 nm in the melting curves. The introduction of thymidine via a 3',3'-type 'inverted' phosphodiester linkage at the 3'-end of oligo(2'-O-methylribonucleotide) conjugates (3'-protection) had no strong influence on triplex formation, but slightly affected complex stability. At pH 6.0, when one or two hairpin MGBs were attached to the oligonucleotide, both triplex formation and minor-groove binding played important roles in complex formation. When two 'head-to-head' oligo(N-methylpyrrole) ligands were attached to the same terminal phosphate of the oligonucleotide or the linker, binding was observed at pH >7.5 and at high temperatures (up to 74 degrees). However, under these conditions, binding was retained only by the MGB part of the conjugate.
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PMID:Sequence-specific conjugates of oligo(2'-O-methylribonucleotides) and hairpin oligocarboxamide minor-groove binders: design, synthesis, and binding studies with double-stranded DNA. 1719 85

Two Zn-Pc-peptide conjugates bearing either a short linker or a long PEG-linker between the macrocycle and a bifunctional peptide containing the nucleoplasmin and HIV-1 Tat 48-60 sequences have been synthesized in order to increase the Pc cell-targeting ability and to evaluate the effect of the linker. The presence of the peptide chain increased the water solubility of the Pc macrocycle and, consequently, its fluorescence in aqueous solutions. The highest fluorescence quantum yields were observed at low pH (5.0) for both conjugates and were always higher for the conjugate bearing the short linker. Both conjugates were found to have low dark cytotoxicity toward human HEp2 cells (IC50 > 77 microM) but were highly phototoxic (IC50 < 2 microM at 1 J cm-2). The conjugate bearing the long PEG-linker accumulated the most within cells (26 times more than the unconjugated Zn-Pc), followed by the short linker conjugate (17 times more than the unconjugated Zn-Pc). Both conjugates were found to localized preferentially within the cell lysosomes.
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PMID:Synthesis and properties of cell-targeted Zn(II)-phthalocyanine-peptide conjugates. 1727 88

The ability to specifically down-regulate gene expression using the RNAi pathway in mammalian cells has tremendous potential in therapy and in basic science. However, delivery systems capable of efficient and biocompatible delivery of siRNA to target cells are not yet satisfactory. Here, we report the synthesis and in vitro characterization of ABC triblock copolymers that self-assemble with siRNA based on electrostatics and with each other by hydrophobic interactions. The ABC triblock copolymer is based on poly(ethylene glycol) (PEG), poly(propylene sulfide) (PPS), and a positively charged peptide (PEG-PPS-peptide). The diblock copolymer PEG(45)-PPS(5,10) was synthesized using anionic polymerization of propylene sulfide upon a PEG macroinitiator, and the peptide domain was coupled to the PPS terminus using a disulfide exchange reaction with an N-terminal cysteine residue on the peptide. The peptides were designed to interact electrostatically with siRNA, selecting the TAT peptide domain of HIV (RKKRRQRRR) and an oligolysine (Lys(9)). The resulting triblock copolymers were able to self-assemble with siRNA as demonstrated by dynamic light scattering and gel electrophoresis. Complex size was found to be dependent on the amount of polymer used (charge ratio) and the length of the hydrophobic PPS block, achieving sizes ranging from 171 nm to 601 nm. Cell internalization and gene expression down-regulation studies showed that the triblock copolymers are able to transport siRNA inside the cell and mediate gene expression down-regulation, with the amount of internalization and gene transfer affected by charge ratio, PPS length, and the presence of serum. The proposed triblock was able to mediate gene expression down-regulation of GAPDH, achieving up to 90.5% +/- 0.02% down-regulation.
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PMID:Synthesis and in vitro characterization of an ABC triblock copolymer for siRNA delivery. 1735 44

Peptide T (ASTTTNYT), a segment corresponding to residues 185-192 of gp120, the coat protein of HIV, has several important biological properties in vitro that have stimulated the search for simpler and possibly more active analogs. We have previously shown that pseudocyclic hexapeptide analogs containing the central residues of peptide T retain considerable chemotactic activity. We have now extended the design of this type of analogs to peptides containing different aromatic residues and/or Ser in lieu of Thr. The complex conformation-activity relationship of these analogs called for a reexamination of the basic conformational tendencies of peptide T itself. Here, we present an exhaustive NMR conformational study of peptide T in different media. Peptide T assumes a gamma-turn in aqueous mixtures of ethylene glycol, a type-IV beta-turn conformation in aqueous mixtures of DMF, and a type-II beta-turn conformation in aqueous mixtures of DMSO. The preferred conformations for the analogs were derived from modeling, starting from the preferred conformations of peptide T. The best models derived from the gamma-turn conformation of peptide T are those of peptides XII (DSNYSR), XIII (ETNYTK) and XVI (ESNYSR). The best models derived from the type-IV beta-turn conformation of peptide T are those of peptides XIV (KTTNYE) and XV (DSSNYR). No low-energy models could be derived starting from the type-II beta-turn conformation of peptide T. The analogs with the most favored conformations are also the most active in the chemotactic test.
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PMID:Conformation-activity relationship of peptide T and new pseudocyclic hexapeptide analogs. 1748 94

Despite current injecting drug users (IDUs) being the major risk group for new hepatitis C virus (HCV) infections in most countries, they constitute a small minority of study populations in almost all studies of acute HCV infection treatment. The Australian Trial in Acute Hepatitis C (ATAHC) is examining natural history and treatment efficacy among predominantly IDU-acquired acute HCV. Recruitment is through an Australian network of primary and tertiary care sites. Eligible participants are offered treatment with pegylated-interferon alpha-2a (PEG-IFN) for 24 weeks, with both treated and untreated participants followed for up to three years. Quantitative and qualitative data on injecting behaviour is collected on study participants. Participants are regularly reviewed by a multidisciplinary team that includes the treating clinician, HCV clinic nurse, outreach worker and when necessary are referred to a drug and alcohol worker, social worker, psychiatrist or other appropriate services. A contact log records all interactions between participants and the study team. In September 2006, 121 subjects had been screened, 107 were enrolled and 75 had chosen to commence a 24-week course of PEG-IFN (HIV/HCV coinfected participants are treated with PEG-IFN/ribavirin combination therapy). Eighty per cent of ATAHC participants reported IDU within the previous six months. Recruitment is planned to continue through mid-2007. Through a series of case reports, this paper describes factors that are potential barriers to recruitment, follow-up, and treatment of IDUs in the context of acute HCV infection. PEG-IFN adherence and toxicity, current substance use or mental health issues are not presenting as the only barriers to HCV treatment. Financial and transport difficulties, isolation and social support, and legal issues have been prominent and had the potential to impact on clinic attendance and treatment success. Our work suggests that by using a multidisciplinary approach, potential barriers to recruitment and follow-up of current IDUs to HCV treatment can be effectively addressed, and this highly marginalised population can be successfully engaged and treated.
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PMID:Recruitment and follow-up of injecting drug users in the setting of early hepatitis C treatment: insights from the ATAHC study. 1785 36

Over the last years there has been considerable progress in the treatment of chronic hepatitis B. Five drugs are now approved for the treatment of this virosis: interferon alpha, lamivudine, adefovir, entecavir and telbivudine. Interferons (conventional or PEG) were the first medicine used in the treatment of hepatitis being able to lead the persistent response (loss of DNA-HBV and of AgHbe) to up to one third of treated cases. A large number of nucleoside/nucleotide analogues are, at present, available to treat hepatitis B. The efficacy of lamivudine, the first nucleoside analogue used, is limited by the high rate of resistance. Adefovir has efficacy comparable to that of lamivudine, but with low resistance rate. Entecavir and tenofovir have also been particularly active in the control of hepatitis B virus replication and are associated with minimal resistance development, even during long treatment regimens. Other drugs, such as telbivudine, emtricitabine and clevudine, will become new treatment options in the near future. Individuals co-infected with HIV/HBV are particularly difficult to manage and are nowadays able to benefit from combinations of drugs of the HAART therapy, which should be effective towards both viruses. The development of more potent antiviral drugs as well as new drug combinations, together with a better understanding of hepatitis B virus resistance mechanisms are important milestones to improve treatment efficacy and to diminish, in the future, the global burden of hepatitis B virus.
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PMID:[Advances in the treatment of hepatitis B]. 1787 70

Cyanovirin-N (CV-N) is a potent inhibitor of human immunodeficiency virus and many other viruses. It has a high potential for use as a systemic compound to control viral load or in the development of microbicides to prevent primary viral infection. Due to its cyanobacterial origin it is likely to show the typical drawbacks associated with pharmaceutical use of foreign proteins such as short plasma half-life, proteolysis and immunogenicity. Several strategies were used to covalently bond poly(ethylene glycol) (PEGylate) to CV-N. Random PEGylation at lysine residues resulted in poor retention of antiviral activity. Many site-directed mutants were made to test site-specific PEGylation. One mutant, where glutamine 62 was replaced with cysteine (CV-N(Q62C)) and PEGylated with maleimide activated PEG, retained significant anti-HIV activity in vitro.
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PMID:PEGylation of cyanovirin-N, an entry inhibitor of HIV. 1788 38

Curing HIV-1 infection has remained elusive because of low and fluctuating drug levels arising from poor absorption, the development of viral reservoirs and sanctuary sites, toxicity, and patient nonadherence. The present study addresses the issue of insufficient drug exposure in macrophages. Viral reservoir sites such as macrophages are believed to be responsible for the viral rebound effect observed upon the discontinuation of anti-HIV drug therapy. In our proposed model, a drug can be covalently attached to a nanocarrier in order to facilitate the delivery of therapeutic agents to the site(s) of infection. As an initial step, we propose the covalent attachment of several copies of N-formyl-Met-Leu-Phe (fMLF), a known chemo-attractant for macrophages. In this article, one or more copies of fMLF were conjugated to multifunctional commercially available or novel, peptide-based PEG nanocarriers in which the structure was varied by appending PEGs with average molecular weights of 5, 20, and 40 kDa. U937 cell-specific binding and cellular uptake were analyzed. The results of uptake studies indicate that (i) uptake is energy dependent and mediated by a fMLF receptor, (ii) appending only 2 copies of the targeting ligand to the multifunctional nanocarrier appears sufficient for binding in vitro, and (iii) of the three configurations studied, the nanocarrier with a molecular weight of about 20 kDa, corresponding to a size of 20-60 nm, demonstrated the highest uptake. The results of the current studies demonstrate the feasibility of targeting macrophages and the suitability of using these synthetically versatile peptide--backbone PEG nanocarriers. The convenience, flexibility and possible limitations of this nanocarrier approach are discussed.
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PMID:Optimizing size and copy number for PEG-fMLF (N-formyl-methionyl-leucyl-phenylalanine) nanocarrier uptake by macrophages. 1809 43

Dimeric Hoechst 33258 molecules [dimeric bisbenzimidazoles (DBBIs)] that, upon binding, occupy one turn of the B form of DNA in the narrow groove were constructed by computer simulation. Three fluorescent DBBIs were synthesized; they consist of two bisbenzimidazole units tail-to-tail linked to phenolic hydroxy groups via penta- or heptamethylene or tri(ethylene glycol) spacers and have terminal positively charged N.N-dimethylaminopropyl carboxamide groups in the molecule. The absorption spectra of the DBBIs in the presence of different DNA concentrations showed a hypochromic effect and a small shift of the absorption band to longer wavelengths, which indicated the formation of a complex with DNA. The presence of an isobestic point in the spectrum indicates the formation of one type of DBBI-DNA complexes. The interaction of DBBIs with DNA was studied by CD using a cholesteric liquid-crystalline dispersion (CLD) of DNA. The appearance of a positive band in the absorption region of ligand chromophores in the CD spectrum of the DNA CLD indicates the formation of a DBBI-DNA complex in which ligand chromophores are arranged at an angle close to 54 degrees relative to the helix axis of DNA, which suggests the localization of the DBBI in the narrow groove of DNA. All the DBBIs were found to be in vitro inhibitors of HIV-1 DNA integrase in the 3'-processing reaction, and, of the three DBBIs, two dimers inhibit HIV-1 integrase even in submicromolar concentrations.
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PMID:[DNA sequence-specific ligands: XIII. New Dimeric Hoechst 33258 molecules, inhibitors of HIV-1 integrase in vitro]. 1817 24


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