Low pH immobilizes and kills human leukocytes and prevents transmission of cell-associated HIV in a mouse model

BACKGROUND: Both cell-associated and cell-free HIV virions are present in semen and cervical secretions of HIV-infected individuals. Thus, topical microbicides may need to inactivate both cell-associated and cell-free HIV to prevent sexual transmission of HIV/AIDS. To determine if the mild acidity of the healthy vagina and acid buffering microbicides would prevent transmission by HIV-infected leukocytes, we measured the effect of pH on leukocyte motility, viability and intracellular pH and tested the ability of an acidic buffering microbicide (BufferGel(®)) to prevent the transmission of cell-associated HIV in a HuPBL-SCID mouse model. METHODS: Human lymphocyte, monocyte, and macrophage motilities were measured as a function of time and pH using various acidifying agents. Lymphocyte and macrophage motilities were measured using video microscopy. Monocyte motility was measured using video microscopy and chemotactic chambers. Peripheral blood mononuclear cell (PBMC) viability and intracellular pH were determined as a function of time and pH using fluorescent dyes. HuPBL-SCID mice were pretreated with BufferGel, saline, or a control gel and challenged with HIV-1-infected human PBMCs. RESULTS: Progressive motility was completely abolished in all cell types between pH 5.5 and 6.0. Concomitantly, at and below pH 5.5, the intracellular pH of PBMCs dropped precipitously to match the extracellular medium and did not recover. After acidification with hydrochloric acid to pH 4.5 for 60 min, although completely immotile, 58% of PBMCs excluded ethidium homodimer-1 (dead-cell dye). In contrast, when acidified to this pH with BufferGel, a microbicide designed to maintain vaginal acidity in the presence of semen, only 4% excluded dye at 10 min and none excluded dye after 30 min. BufferGel significantly reduced transmission of HIV-1 in HuPBL-SCID mice (1 of 12 infected) compared to saline (12 of 12 infected) and a control gel (5 of 7 infected). CONCLUSION: These results suggest that physiologic or microbicide-induced acid immobilization and killing of infected white blood cells may be effective in preventing sexual transmission of cell-associated HIV

Polarised Quark Distributions in the Nucleon from Semi-Inclusive Spin Asymmetries

We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range $0.003$1 GeV$^2$. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at $Q^2$=10 GeV$^2$. The polarised $u$ valence quark distribution, $\Delta u_v(x)$, is positive and the polarisation increases with $x$. The polarised $d$ valence quark distribution, $\Delta d_v(x)$, is negative and the non-strange sea distribution, $\Delta \bar q(x)$, is consistent with zero over the measured range of $x$. We find for the first moments $\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08$, $\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09$ and $\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03$, where we assumed $\Delta \bar u(x) = \Delta \bar d(x)$. We also determine for the first time the second moments of the valence distributions $\int_0^1 x \Delta q_v(x) dx$.Comment: 17 page

Spin asymmetries A1 and structure functions g1 of the proton and the deuteron from polarized high energy muon scattering.

Adeva B, Akdogan T, Arik E, et al. Spin asymmetries A(1) and structure functions g(1) of the proton and the deuteron from polarized high energy muon scattering. Phys.Rev. D. 1998;58(11): 112001.We present the final results of the spin asymmetries A(1) and the spin structure functions g(1) of the proton and the deuteron in the kinematic range 0.0008 < x < 0.7 and 0.2 < Q(2) < 100 GeV2. For the determination of A(1), in addition to the usual method which employs inclusive scattering events and includes a large radiative background at low x, we use a new method which minimizes the radiative background by selecting events with at least one hadron as well as a muon in the final state. We find that this hadron method gives smaller errors for x < 0.02, so it is combined with the usual method to provide the optimal set of results. [S0556-2821(98)07017-9]

A NEW MEASUREMENT OF THE SPIN-DEPENDENT STRUCTURE-FUNCTION G(1)(X) OF THE DEUTERON

We present a new measurement of the spin-dependent structure function g(1)(d) of the deuteron in deep inelastic scattering of 190 GeV polarised muons on polarised deuterons, in the kinematic range 0.003<x<0.7 and IGeV2,Q(2)<60GeV(2). This structure function is found to be negative at small x. The first moment Gamma(1)(d)=integral(0)(1)g(1)(d)dx evaluated at Q(0)(2)=10GeV(2) is 0.034+/-0.009(stat.)+/-0.006(syst). This value is below the Ellis-Jaffe sum rule prediction by three standard deviations. Using our earlier determination of Gamma(1)(p), we obtain Gamma(1)(p)-Gamma(1)(n)=0.199+/-0.038 which agrees with the Bjorken sum rule

Polarization of valence and non-strange sea quarks in the nucleon from semi-inclusive spin asymmetries.

Adeva B, Arik E, Arvidson A, et al. Polarisation of valence and non-strange sea quarks in the nucleon from semi-inclusive spin asymmetries. Phys.Lett. B. 1996;369(1):93-100.We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.003 < x < 0.7. From these asymmetries and the previously published inclusive spin asymmetries we determine, for the first time, the x-dependent spin distributions for up and down valence quarks and for non-strange sea quarks. We find that the first moments of the valence quark spin distributions are Delta u(v) = 1.01 +/- 0.19 +/- 0.14 and Delta d(v) = -0.57 +/- 0.22 +/- 0.11. The spin distribution function of non-strange sea quarks is consistent with zero over the measured range of x and the first moment is Delta (u) over bar = Delta (d) over bar = -0.02 +/- 0.09 +/- 0.03

Spin structure of the proton from polarized inclusive deep-inelastic muon-proton scattering

We have measured the spin-dependent structure function g1p in inclusive deep-inelastic scattering of polarized muons off polarized protons, in the kinematic range 0.003<x<0.7 and 1GeV2<Q2<60GeV2. A next-to-leading order QCD analysis is used to evolve the measured g1p(x,Q2) to a fixed Q02. The first moment of g1p at Q02=10GeV2 is \u3931p=0.136\ub10.013 (stat) \ub10.009 (syst) \ub10.005 (evol). This result is below the prediction of the Ellis-Jaffe sum rule by more than two standard deviations. The singlet axial charge a0 is found to be 0.28\ub10.16. In the Adler-Bardeen factorization scheme, \u394g 432 is required to bring \u394\u3a3 in agreement with the quark-parton model. A combined analysis of all available proton, deuteron, and 3He data confirms the Bjorken sum rule

A line-shape analysis for spin-1 NMR signals

An analytic model of the deuteron absorption function has been developed and is compared to experimental NMR signals of deuterated butanol obtained at the SMC experiment in order to determine the deuteron polarization. The absorption function model includes dipolar broadening and a frequency-dependent treatment of the intensity factors. The high-precision TE signal data available are used to adjust the model for Q-meter distortions and dispersion effects. Once the Q-meter adjustment is made, the enhanced polarizations determined by the asymmetry and TE-calibration methods compare well within the accuracy of each method. In analyzing the NMR signals, the quadrupolar coupling constants could be determined for both the C-D and the O-D bonds of deuterated butanol

Nucl.Instrum.Meth. A

Adams D, Adeva B, Arik E, et al. A large Streamer Chamber muon tracking detector in a high-flux fixed-target application. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 1999;435(3):354-374.Arrays of limited streamer tubes of the Iarocci type were deployed in our experiment at CERN as part of a forward muon detector system with provisions for the beam to pass through the center of each panel in the array. A total of 16 4 m x 4 m panels were assembled with inductive readout strips on both sides of each panel. An active feedback system. was deployed to regulate the high voltage to the streamer tubes to insure a constant efficiency for minimum ionizing particles. The arrays were operated in this environment for over five years of data taking. Streamer tube track-reconstruction efficiencies and tube replacement rates are reported. (C) 1999 Elsevier Science B.V. All rights reserved