Levels of viraemia in subjects with serological markers of past or chronic hepatitis B virus infection

Subjects with serological markers for a past HBV infection may still have HBV DNA in their serum, but the levels of viraemia in such cases are not known. In the present study, of 63 consecutive HBsAg-negative, anti-HBc-positive serum samples with or without anti-HBs, 20 were HBV DNA-positive as analysed by a highly sensitive quantitative PCR, the Cobas Amplicor HBV Monitor test. However, all of these 20 samples had viraemia levels below 1000 copies/ml, compared with median viraemia levels of 10(8.6) and 10(4.3) copies/ml, respectively, in 98 HBeAg-positive and 124 HBeAg-negative HBsAg carriers. There was no difference in viraemia between subjects with anti-HBc alone compared with both anti-HBs and anti-HBc, nor between those with or without hepatitis C virus antibodies. The findings indicate that HBsAg-negative subjects may retain a low infectivity. Their risk for progressive liver damage is probably low, but this deserves further study.     

In vitro antiviral activity and single-dose pharmacokinetics in humans of a novel, orally bioavailable inhibitor of human rhinovirus 3C protease

(E)-(S)-4-((S)-2-{3-[(5-methyl-isoxazole-3-carbonyl)-amino]-2-oxo-2H-pyridin-1-yl}-pent-4-ynoylamino)-5-((S)-2-oxo-pyrrolidin-3-yl)-pent-2-enoic acid ethyl ester (Compound 1) is a novel, irreversible inhibitor of human rhinovirus (HRV) 3C protease {inactivation rate constant (Kobs/[I]) of 223,000 M-1s-1}. In cell-based assays, Compound 1 was active against all HRV serotypes (35 of 35), HRV clinical isolates (5 of 5), and related picornaviruses (8 of 8) tested with mean 50% effective concentration (EC50) values of 50 nM (range, 14 to 122 nM), 77 nM (range, 72 to 89 nM), and 75 nM (range, 7 to 249 nM), respectively. Compound 1 inhibited HRV 3C-mediated polyprotein processing in infected cells in a concentration-dependent manner, providing direct confirmation that the cell-based antiviral activity is due to inhibition of 3C protease. In vitro and in vivo nonclinical safety studies showed Compound 1 to be without adverse effects at maximum achievable doses. Single oral doses of Compound 1 up to 2,000 mg in healthy volunteers were found to be safe and well tolerated in a phase I-ascending, single-dose study. Compound 1 estimated free observed maximum concentration in plasma (Cmax) for 500-, 1,000-, and 2,000-mg doses were higher than the protein binding-corrected EC50 required to inhibit 80% of the HRV serotypes tested. Treatment of HRV 52-infected cells with one to five 2-h pulses of 150 nM Compound 1 (corresponding to the Cmax at the 500-mg dose) was sufficient to effect a significant reduction in viral replication. These experiments highlight Compound 1 as a potent, orally bioavailable, irreversible inhibitor of HRV 3C protease and provide data that suggest that Cmax rather than the Cmin might be the key variable predicting clinical efficacy.     

Peer counselors' role in supporting patients' adherence to ART in Ethiopia and Uganda

Our aim was to explore peer counselors' work and their role in supporting patients' adherence to antiretroviral treatment (ART) in resource-limited settings in Ethiopia and Uganda. Qualitative semi-structured interviews were conducted with 79 patients, 17 peer counselors, and 22 providers in ART facilities in urban and rural areas of Ethiopia and Uganda. Two main categories with related subcategories emerged from the analysis. The first main category, peer counselors as facilitators of adherence, describes how peer counselors played an important role by acting as role models, raising awareness, and being visible in the community. They were also recognized for being close to the patients while acting as a bridge to the health system. They provided patients with an opportunity to individually talk to someone who was also living with HIV, who had a positive and life-affirming attitude about their situation, and were willing to share personal stories of hope when educating and counseling their patients. The second main category, benefits and challenges of peer counseling, deals with how peer counselors found reward in helping others while at the same time acknowledging their limitations and need of support and remuneration. Their role and function were not clearly defined within the health system and they received negligible financial and organizational support. While peer counseling is acknowledged as an essential vehicle for treatment success in ART support in sub-Saharan Africa, a formal recognition and regulation of their role should be defined. The issue of strategies for disclosure to support adherence, while avoiding or reducing stigma, also requires specific attention. We argue that the development and implementation of support to peer counselors are crucial in existing and future ART programs, but more research is needed to further explore factors that are important to sustain and strengthen the work of peer counselors.     

A domain unique to plant RanGAP is responsible for its targeting to the plant nuclear rim

Ran is a small signaling GTPase that is involved in nucleocytoplasmic transport. Two additional functions of animal Ran in the formation of spindle asters and the reassembly of the nuclear envelope in mitotic cells have been recently reported. In contrast to Ras or Rho, Ran is not associated with membranes. Instead, the spatial sequestering of its accessory proteins, the Ran GTPase-activating protein RanGAP and the nucleotide exchange factor RCC1, appears to define the local concentration of RanGTP vs. RanGDP involved in signaling. Mammalian RanGAP is bound to the nuclear pore by a mechanism involving the attachment of small ubiquitin-related modifier protein (SUMO) to its C terminus and the subsequent binding of the SUMOylated domain to the nucleoporin Nup358. Here we show that plant RanGAP utilizes a different mechanism for nuclear envelope association, involving a novel targeting domain that appears to be unique to plants. The N-terminal WPP domain is highly conserved among plant RanGAPs and the small, plant-specific nuclear envelope-associated protein MAF1, but not present in yeast or animal RanGAP. Confocal laser scanning microscopy of green fluorescent protein (GFP) fusion proteins showed that it is necessary for RanGAP targeting and sufficient to target the heterologous protein GFP to the plant nuclear rim. The highly conserved tryptophan and proline residues of the WPP motif are necessary for its function. The 110-aa WPP domain is the first nuclear-envelope targeting domain identified in plants. Its fundamental difference to its mammalian counterpart implies that different mechanisms have evolved in plants and animals to anchor RanGAP at the nuclear surface.     

Greater reversal of CD4+ cell abnormalities and viral load reduction after initiation of antiretroviral therapy with zidovudine,lamivudine, and nelfinavir before complete HIV type 1 seroconversion

In a prospective open-label study, 41 male subjects received nelfinavir, zidovudine, and lamivudine stratified as either: early stage (ES; negative/indeterminate Western blot; n = 19) or late stage (LS; positive Western blot; n = 22) primary HIV-1 infection. Despite higher median baseline HIV-1 RNA levels and lower CD4(+) cell numbers in the ES subjects, a significantly greater decline in viral load (-3.46 vs. -2.83 log(10) copies/ml; p = 0.023) and increase in CD4(+) cell number (+85 vs. +41 cells/month increase, p = 0.01) were observed over the first 3 months of therapy such that both groups had comparable results at 1 year. The proportion with HIV-1 RNA < 50 copies/mL at 1 year was similar (9 of 19 ES subjects and 11 of 22 LS subjects by intention-to-treat analysis). Memory CD4(+) cell numbers, and activated CD4(+) percentages, were also significantly improved in ES subjects. Despite poorer prognostic markers at baseline ES subjects achieved responses similar to those of LS subjects after 1 year of treatment.     

Smoking does not alter the dose-requirements and the pharmacodynamics of rocuronium

PURPOSE: Controversial data about the effect of smoking on the dose-requirements and the pharamcodynamics of rocuronium have been reported recently. This study was conducted to evaluate the dose-requirements and the pharmacodynamics of rocuronium in smokers using target controlled infusion. METHODS: The dose-requirements of rocuronium for 60 min relaxation, using target controlled infusion, given under intravenous anaesthesia with propofol, fentanyl and nitrous oxide was studied in 37 smokers and 37 non-smokers. Initially 450 microg x kg(-1) rocuronium were administered, neuromuscular effects were quantified by recording the single twitch response of the adductor pollicis muscle after ulnar nerve stimulation using a force transducer, and the neuromuscular block was kept at 80% by target controlled infusion throughout the procedure. RESULTS: The dose-requirements for one hour relaxation were 867 +/- 116 microg x kg(-1) x hr(-1) for smokers (S) and 839 +/- 149 microg x kg(-1) x hr(-1) for non-smokers (NS). The duration to 10% and the spontaneous recovery from 25% to 75% of the control twitch response also showed no differences between S (17.2 +/- 3.4 min, 10.6 +/- 0.9 min) and NS (18.9 +/- 4.3 min, 10.9 +/- 3.2 min), as well as maximum block, onset time and infusion rate. CONCLUSION: Smoking does not alter the dose-requirements for rocuronium and no effects on the onset time, degree of block, time to maximum block, duration 10% and spontaneous recovery index were observed.     

Automated Quantitative Analysis of Hepatitis B Virus DNA by Using the Cobas Amplicor HBV Monitor Test

A highly sensitive method of quantitative analysis of hepatitis B virus (HBV) DNA in serum, the Cobas Amplicor HBV Monitor (Cobas-AM) test, was evaluated. Following a manual extraction of viral DNA, amplification, colorimetric detection, and quantitative determination are all automatically performed in the Cobas analyzer. Serially diluted samples with known HBV DNA concentrations were analyzed blindly. All samples with a virus concentration of 400 copies/ml and 83% of samples with a virus concentration of 100 copies/ml could be detected. A linear correlation between input HBV DNA and measured HBV DNA was seen in the range from 100 to 10(5) copies/ml. The mean coefficient of variation was 29.6% for all input levels and 18.9% for HBV DNA concentrations above 400 copies/ml. Samples with an HBV DNA level above 10(9) copies/ml could be reproducibly measured after predilution to 10(-4) or 10(-6) in negative serum; however, the level was underestimated if target DNA after dilution was still above the linear range of the assay. Quantitative results of the Cobas-AM test were interchangeable with measurements by the manual microwell plate version of Amplicor HBV Monitor (MWP-AM); the mean ratio for log Cobas-AM results/log MWP-AM results was 0.97 (standard error of the mean, 0.007) when serum samples from 153 chronic carriers were analyzed. The test should be of value for clinical assessment of chronic carriers and for monitoring the response to antiviral treatment. A limitation is the relatively narrow linear range of the assay, requiring predilution of high-titer (mainly hepatitis B e-antigen-positive) samples.     

Dynamic studies of positron-emitting putative tumor marker 132Cs in mice show differential tumor and regional uptake

Positron-emitting 132Cs (t1/2 = 6.47 days) was generated from stable 133CsCl via the 133Cs (p,pn) 132Cs reaction. BALB/c mice, bearing implanted MT296 mammary tumors, were given 4.6 mEq kg-1 of 132CsCl via a single intraperitoneal injection. Postinjection uptake of 132Cs into body regions was monitored in vivo with external detectors. Positron emission from the tumor region was continuously greater than that from the head, the numerical ratio of mean emission intensities being fourfold at 10 min postinjection. Tissues excised from these mice postmortem showed sequence of relative tissue cesium uptake rates to be kidney 1.8, small intestine 1.7, tumor 1.0, skin 0.75, liver 0.75, skeletal muscle 0.4, and brain 0.28. Comparative studies with multiple injections of stable cesium and rubidium showed this sequence to be ion-specific. These observations suggest that positron-emitting isotopes of cesium could provide useful markers for tumors of several tissues.