Kinetics of CD4+ T cell repopulation of lymphoid tissues after treatment of HIV-1 infection

Potent combinations of antiretroviral drugs diminish the turnover of CD4+ T lymphocytes productively infected with HIV-1 and reduce the large pool of virions deposited in lymphoid tissue (LT). To determine to what extent suppression of viral replication and reduction in viral antigens in LT might lead correspondingly to repopulation of the immune system, we characterized CD4+ T lymphocyte populations in LT in which we previously had quantitated viral load and turnover of infected cells before and after treatment. We directly measured by quantitative image analysis changes in total CD4+ T cell counts, the CD45RA+ subset, and fractions of proliferating or apoptotic CD4+ T cells. Compared with normal controls, we documented decreased numbers of CD4+ T cells and increased proliferation and apoptosis. After treatment, proliferation returned to normal levels, and total CD4+ T and CD45RA+ cells increased. We discuss the effects of HIV-1 on this subset based on the concept that renewal mechanisms in the adult are operating at full capacity before infection and cannot meet the additional demand imposed by the loss of productively infected cells. The slow increases in the CD45RA+ CD4+ T cells are consistent with the optimistic conclusions that (i) renewal mechanisms have not been damaged irreparably even at relatively advanced stages of infection and (ii) CD4+ T cell populations can be partially restored by control of active replication without eradication of HIV-1.     

A social relations model of observed family negativity and positivity using a genetically informative sample.

The goal of this study was to investigate individual and relationship influences on expressions of negativity and positivity in families. Parents and adolescents were observed in a round-robin design in a sample of 687 families. Data were analyzed using a multilevel social relations model. In addition, genetic contributions were estimated for actor effects. Children showed higher mean levels of negativity and lower mean levels of positivity as actors than did parents. Mothers were found to express and elicit higher mean levels of positivity and negativity than fathers. Actor effects were much stronger than partner effects, accounting for between 18%–39% of the variance depending on the actor and the outcome. Genetic (35%) and shared environmental (19%) influences explained a substantial proportion of the actor effect variance for negativity. Dyadic reciprocities were lowest in dyads with a high power differential (i.e., parent–child dyads) and highest for dyads with equal power (sibling and marital dyads). (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Factors Influencing the Response of Silver Iodide Emulsions

Contrary to the conclusions of previous authors, it is shown that silver iodide emulsions may be sulphur sensitized. Additional large increases of speed for exposures at moderate and low intensity may be achieved by bathing in water, solutions of halogen acceptors, or silver nitrate before exposure, or by coating at low pAg. In agreement with the observations of some authors, a silver iodide emulsion can form an internal image. In conformity with this capacity to form an internal image. the emulsion exhibits solarization.     

Munitions Propellants Residue Deposition Rates On Military Training Ranges

Training with live munitions is an integral component of preparing the modern military for warfare. Energetic compounds, such as propellants and explosives, are consumed during the use of these munitions. These compounds are never fully consumed, however, and the deposition and accumulation of energetic residue on training ranges is the result. This paper summarizes 10 years of research into propellant deposition rates for common military munitions used in the USA and Canada. Research indicates that the firing of howitzers and tanks leave very little residue, the firing of mortars can result in moderate deposition of propellant residue, small‐arms firing positions have the potential for significant residue accumulation, and training with shoulder‐fired rockets and 40 mm machine guns can result in dangerous quantities of unburned propellants. Residue rates vary widely for the weapon systems tested, from 10⁻⁶ % for large rocket systems to over 70 % for shoulder‐fired rockets.     

Concentrations, distribution, and persistence of perfluoroalkylates in sludge-applied soils near Decatur, Alabama, USA

Sludges generated at a wastewater treatment plant (WWTP) in Decatur, Alabama have been applied to agricultural fields for more than a decade. Waste-stream sources to this WWTP during this period included industries that work with fluorotelomer compounds, and sludges from this facility have been found to be elevated in perfluoroalkylates (PFAs). With this knowledge, the U.S. Environmental Protection Agency collected soil samples from sludge-applied fields as well as nearby "background" fields for PFA analysis. Samples from the sludge-applied fields had PFAs at much higher concentrations than in the background fields; generally the highest concentrations were perfluorodecanoic acid (≤ 990 ng/g), perfluorododecanoic acid (≤ 530 ng/g), perfluorooctanoic acid (≤ 320 ng/g), and perfluorooctane sulfonate (≤ 410 ng/g). Contrasts in PFA concentration between surface and deeper soil samples tended to be more pronounced in long-chain congeners than shorter chains, perhaps reflecting relatively lower environmental mobilities for longer chains. Several PFAs were correlated with secondary fluorotelomer alcohols (sec-FTOHs) suggesting that PFAs are being formed by degradation of sec-FTOHs. Calculated PFA disappearance half-lives for C6 through C11 alkylates ranged from about 1 to 3 years and increase with increasing chain-length, again perhaps reflecting lower mobility of the longer-chained compounds.