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ABSTRACT We present a new approach to calculate the particle distribution function about relativistic shocks including synchrotron losses using the method of lines with an explicit finite-difference scheme. A steady, continuous, one-dimensional plasma flow is considered to model thick (modified) shocks, leading to a calculation in three dimensions plus time, the former three being momentum, pitch angle and position. The method accurately reproduces the expected power-law behaviour in momentum at the shock for upstream flow speeds ranging from 0.1 c to 0.995 c (Γ∈ (1, 10]). It also reproduces approximate analytical results for the synchrotron cutoff shape for a non-relativistic shock, demonstrating that the loss process is accurately represented. The algorithm has been implemented as a hybrid OpenMP-MPI parallel algorithm to make efficient use of SMP cluster architectures and scales well up to many hundreds of CPUs. [ABSTRACT FROM AUTHOR]

Background  Patients with papulopustular rosacea have a higher density of Demodex folliculorum mites on their faces than normal subjects but the role, if any, of their mites in initiating inflammation is disputed. Selective antibiotics are effective in reducing the inflammatory changes of papulopustular rosacea, but their mode of action is unknown. Objectives  To investigate whether a D. folliculorum-related bacterium was capable of expressing antigens that could stimulate an inflammatory immune response in patients with rosacea. Methods  A bacterium ( Bacillus oleronius) was isolated from a D. folliculorum mite extracted from the face of a patient with papulopustular rosacea, and was investigated further. Results  This bacterium produced antigens capable of stimulating peripheral blood mononuclear cells proliferation in 16 of 22 (73%) patients with rosacea but only five of 17 (29%) control subjects ( P = 0·0105). This antigenic preparation was fractionated into 70 subfractions and the proteins in each fraction were visualized by sodium dodecyl sulphate–polyacrylamide gel electrophoresis. Western blot analysis revealed the presence of two antigenic proteins of size 62 and 83 kDa in fractions when probing with sera from patients with rosacea. No immunoreactivity to these proteins was recorded when probing with sera from control patients. Two-dimensional electrophoretic separation was used to isolate these proteins and matrix-assisted laser desorption/ionization time-of-flight analysis was employed to identify the relevant peptides. The 62-kDa immunoreactive protein shared amino acid sequence homology with an enzyme involved in carbohydrate metabolism and signal transduction while the 83-kDa protein was similar to bacterial heat shock proteins. Conclusions  Antigenic proteins related to a bacterium ( B. oleronius), isolated from a D. folliculorum mite, have the potential to stimulate an inflammatory response in patients with papulopustular rosacea. [ABSTRACT FROM AUTHOR]

Progression to AIDS in patients harboring human immunodeficiency virus type 1 (HIV-1) isolates expressing a syncytium-inducing (SI) phenotype is faster than in those in whom the virus expresses a non-SI (NSI) phenotype. Zidovudine monotherapy does not appear to alter this outcome. To examine the role of didanosine (ddl) monotherapy in phenotype expression, HIV-1 isolates from 73 patients receiving ddl for up to 72 weeks were analyzed. After 12 weeks, the number of isolates expressing an NSI phenotype was 29% higher than at the start of treatment. Patients receiving high-dose ddI (375 mg twice daily) were significantly more likely to express the NSI phenotype at 12 weeks than patients who received low-dose ddI (100 mg twice daily), even after adjustment for phenotype and CD4 cell count at baseline, suggesting that ddI may be selective against the faster-replicating virus. ddI at 375 mg twice daily significantly increases the probability of an NSI phenotype over the short term in patients with advanced HIV disease. [ABSTRACT FROM PUBLISHER]

V3 loop sequences were compared from 5 human immunodeficiency virus type 1(HIV-1)-infected patients over time. Three patients remained asymptomatic and 2 became symptomatic with large decreases in CD4 cell counts. The patient isolates were previously evaluated for phenotypic and antigenic properties and had different sensitivities to serum neutralization and changes in phenotype. This study showed a number of amino acid changes for the 2 symptomatic patients, each of whom progressed to AIDS during the study. The only amino acid substitution consistently associated with reduced CD4 cell counts, cytopathic effect, and progression to AIDS was Arg at position 11. Specific amino acid changes could not be correlated with increasing serum neutralization resistance or cytotropism changes. Increased loop charge was associated with a switch from macrophage to T cell tropism and a decrease in the number of CD4 cells. The study shows the importance of naturally occurring mutations in the V3 loop in controlling the biologic properties of HIV-1. [ABSTRACT FROM PUBLISHER]