Medical Pluralism Predicts Non-ART Use among Parents in Need of ART: A Community Survey in KwaZulu-Natal, South Africa

Despite documented common use of traditional healers and efforts to scale up antiretroviral treatment (ART) in sub-Saharan Africa, evidence on whether medical pluralism predicts ART use is inconclusive and restricted to clinic settings. This study quantitatively assesses whether medical pluralism predicts ART use among parents in need of ART in South Africa. 2,477 parents or primary caregivers of children were interviewed in HIV-endemic communities of KwaZulu-Natal. Analysis used multiple logistic regression on a subsample of 435 respondents in need of ART, who reported either medical pluralism (24.6 %) or exclusive public healthcare use (75.4 %). Of 435 parents needing ART, 60.7 % reported ART use. Medical pluralism emerged as a persistent negative predictor of ART utilization among those needing it (AOR [95 % CI] = .556 [.344 - .899], p = .017). Use of traditional healthcare services by those who need ART may act as a barrier to treatment access. Effective intersectoral collaboration at community level is urgently needed

Human neutrophil phosphodiesterase

Extracts of human neutrophils were examined for phosphodiesterase activity using a radiochemical assay. As reported by other investigators, both high- and low- K m forms of the enzyme were found. Although calmodulin could be measured in these extracts, human neutrophil phosphodiesterase proved not to be calmodulin dependent. Activity of the neutrophil phosphodiesterase was also not altered by physiologic concentrations of indomethacin, p -bromophenacyl bromide, eicosatetraenoic acid, or eicosatetraynoic acid, all inhibitors of arachidonic acid metabolism. These results are relevant to stimulus-secretion coupling in neutrophils, wherein calmodulin-dependent reactions play a vital role.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44535/1/10753_2004_Article_BF00916094.pd

Antiviral innate immune response in non-myeloid cells is augmented by chloride ions via an increase in intracellular hypochlorous acid levels

Abstract Phagocytes destroy ingested microbes by producing hypochlorous acid (HOCl) from chloride ions (Cl−) and hydrogen peroxide within phagolysosomes, using the enzyme myeloperoxidase. HOCl, the active ingredient in bleach, has antibacterial/antiviral properties. As myeloperoxidase is needed for HOCl production, non-myeloid cells are considered incapable of producing HOCl. Here, we show that epithelial, fibroblast and hepatic cells have enhanced antiviral activity in the presence of increasing concentrations of sodium chloride (NaCl). Replication of enveloped/non-enveloped, DNA (herpes simplex virus-1, murine gammaherpesvirus 68) and RNA (respiratory syncytial virus, influenza A virus, human coronavirus 229E, coxsackievirus B3) viruses are inhibited in a dose-dependent manner. Whilst treatment with sodium channel inhibitors did not prevent NaCl-mediated virus inhibition, a chloride channel inhibitor reversed inhibition by NaCl, suggesting intracellular chloride is required for antiviral activity. Inhibition is also reversed in the presence of 4-aminobenzoic hydrazide, a myeloperoxidase inhibitor, suggesting epithelial cells have a peroxidase to convert Cl− to HOCl. A significant increase in intracellular HOCl production is seen early in infection. These data suggest that non-myeloid cells possess an innate antiviral mechanism dependent on the availability of Cl− to produce HOCl. Antiviral activity against a broad range of viral infections can be augmented by increasing availability of NaCl

Lactate released by inflammatory bone marrow neutrophils induces their mobilization via endothelial GPR81 signaling.

Neutrophils provide first line of host defense against bacterial infections utilizing glycolysis for their effector functions. How glycolysis and its major byproduct lactate are triggered in bone marrow (BM) neutrophils and their contribution to neutrophil mobilization in acute inflammation is not clear. Here we report that bacterial lipopolysaccharides (LPS) or Salmonella Typhimurium triggers lactate release by increasing glycolysis, NADPH-oxidase-mediated reactive oxygen species and HIF-1α levels in BM neutrophils. Increased release of BM lactate preferentially promotes neutrophil mobilization by reducing endothelial VE-Cadherin expression, increasing BM vascular permeability via endothelial lactate-receptor GPR81 signaling. GPR81-/- mice mobilize reduced levels of neutrophils in response to LPS, unless rescued by VE-Cadherin disrupting antibodies. Lactate administration also induces release of the BM neutrophil mobilizers G-CSF, CXCL1 and CXCL2, indicating that this metabolite drives neutrophil mobilization via multiple pathways. Our study reveals a metabolic crosstalk between lactate-producing neutrophils and BM endothelium, which controls neutrophil mobilization under bacterial infection

Ion channel clustering enhances weak electric field detection by neutrophils: apparent roles of SKF96365-sensitive cation channels and myeloperoxidase trafficking in cellular responses

We have tested Galvanovskis and Sandblom’s prediction that ion channel clustering enhances weak electric field detection by cells as well as how the elicited signals couple to metabolic alterations. Electric field application was timed to coincide with certain known intracellular chemical oscillators (phase-matched conditions). Polarized, but not spherical, neutrophils labeled with anti-K v 1.3, FL-DHP, and anti-TRP1, but not anti-T-type Ca 2+ channels, displayed clusters at the lamellipodium. Resonance energy transfer experiments showed that these channel pairs were in close proximity. Dose-field sensitivity studies of channel blockers suggested that K + and Ca 2+ channels participate in field detection, as judged by enhanced oscillatory NAD(P)H amplitudes. Further studies suggested that K + channel blockers act by reducing the neutrophil’s membrane potential. Mibefradil and SKF93635, which block T-type Ca 2+ channels and SOCs, respectively, affected field detection at appropriate doses. Microfluorometry and high-speed imaging of indo-1-labeled neutrophils was used to examine Ca 2+ signaling. Electric fields enhanced Ca 2+ spike amplitude and triggered formation of a second traveling Ca 2+ wave. Mibefradil blocked Ca 2+ spikes and waves. Although 10 μM SKF96365 mimicked mibefradil, 7 μM SKF96365 specifically inhibited electric field-induced Ca 2+ signals, suggesting that one SKF96365-senstive site is influenced by electric fields. Although cells remained morphologically polarized, ion channel clusters at the lamellipodium and electric field sensitivity were inhibited by methyl-β-cyclodextrin. As a result of phase-matched electric field application in the presence of ion channel clusters, myeloperoxidase (MPO) was found to traffic to the cell surface. As MPO participates in high amplitude metabolic oscillations, this suggests a link between the signaling apparatus and metabolic changes. Furthermore, electric field effects could be blocked by MPO inhibition or removal while certain electric field effects were mimicked by the addition of MPO to untreated cells. Therefore, channel clustering plays an important role in electric field detection and downstream responses of morphologically polarized neutrophils. In addition to providing new mechanistic insights concerning electric field interactions with cells, our work suggests novel methods to remotely manipulate physiological pathways.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46726/1/249_2005_Article_1.pd