2,172 research outputs found
HSV suppression reduces seminal HIV-1 levels in HIV-1/HSV-2 co-infected men who have sex with men.
OBJECTIVES: Suppressive herpes simplex virus (HSV) therapy can decrease plasma, cervical, and rectal HIV-1 levels in HIV-1/HSV-2 co-infected persons. We evaluated the effect of HSV-2 suppression on seminal HIV-1 levels. DESIGN: Twenty antiretroviral therapy (ART)-naive HIV-1/HSV-2 men who have sex with men (MSM) in Lima, Peru, with CD4 >200 cells/microl randomly received valacyclovir 500 mg twice daily or placebo for 8 weeks, then the alternative regimen for 8 weeks after a 2-week washout. Peripheral blood and semen specimens were collected weekly. Anogenital swab specimens for HSV DNA were self-collected daily and during clinic visits. METHODS: HIV-1 RNA was quantified in seminal and blood plasma by TaqMan real-time polymerase chain reaction (RT-PCR) or Roche Amplicor Monitor assays. HSV and seminal cytomegalovirus (CMV) were quantified by RT-PCR. Linear mixed models examined differences within participants by treatment arm. RESULTS: Median CD4 cell count of participants was 424 cells/microl. HIV-1 was detected in 71% of 231 semen specimens. HSV was detected from 29 and 4.4% of swabs on placebo and valacyclovir, respectively (P < 0.001). Valacyclovir significantly reduced the proportion of days with detectable seminal HIV-1 (63% during valacyclovir vs. 78% during placebo; P = 0.04). Seminal HIV-1 quantity was 0.25 log10 copies/ml lower [95% confidence interval (CI) -0.40 to -0.10; P = 0.001] during the valacyclovir arm compared with placebo, a 44% reduction. CD4 cell count (P = 0.32) and seminal cellular CMV quantity (P = 0.68) did not predict seminal plasma HIV-1 level. CONCLUSIONS: Suppressive valacyclovir reduced seminal HIV-1 levels in HIV-1/HSV-2 co-infected MSM not receiving ART. The significance of this finding will be evaluated in a trial with HIV-1 transmission as the outcome
Self-avoiding walks crossing a square
We study a restricted class of self-avoiding walks (SAW) which start at the
origin (0, 0), end at , and are entirely contained in the square on the square lattice . The number of distinct
walks is known to grow as . We estimate as well as obtaining strict upper and lower bounds,
We give exact results for the number of SAW of
length for and asymptotic results for .
We also consider the model in which a weight or {\em fugacity} is
associated with each step of the walk. This gives rise to a canonical model of
a phase transition. For the average length of a SAW grows as ,
while for it grows as
. Here is the growth constant of unconstrained SAW in . For we provide numerical evidence, but no proof, that the
average walk length grows as .
We also consider Hamiltonian walks under the same restriction. They are known
to grow as on the same lattice. We give
precise estimates for as well as upper and lower bounds, and prove that
Comment: 27 pages, 9 figures. Paper updated and reorganised following
refereein
Statistics of nested spiral self-avoiding loops: exact results on the square and triangular lattices
The statistics of nested spiral self-avoiding loops, which is closely related
to the partition of integers into decreasing parts, is studied on the square
and triangular lattices.Comment: Old paper, for archiving. 7 pages, 2 figures, epsf, IOP macr
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