Kenneth P. Jones

Time course of changes in immuneoendocrine markers following an international rugby game.

Intense exercise is known to cause temporary impairments in immune function. Few studies, however, have investigated the effects of intense competitive exercise on immunoendocrine variables in elite team sport athletes. The aim of this study was to evaluate the time course of changes in selected immunoendocrine and inflammatory markers following an international rugby union game. Blood samples were taken from players (nxa0=xa010) on camp entry, the morning of the game (pre), immediately after (post) and 14 and 38xa0h into a passive recovery period. Players lost 1.4xa0±xa00.2xa0kg of body mass during the game (ambient conditions, 11°C, 45% RH). An acute phase inflammatory response was observed as reflected through immediate increases in serum cortisol and IL-6 (post) followed by delayed increases in serum creatine kinase (CK; 14xa0h) activity and C-reactive protein (CRP; 38xa0h); Pxa0<xa00.05. Decreases in the number of circulating T lympocytes, NK cells and bacteria-stimulated neutrophil degranulation were also observed post-exercise (Pxa0<xa00.05), indicative of decreased host immune protection. Following a large decrease in serum testosterone to cortisol (T/C) ratio immediately post and 14xa0h after exercise, T/C values then increased above those observed at camp entry 38xa0h into recovery (Pxa0<xa00.05). This rebound anabolic stimulus may represent a physiological requirement for recovery following intense tissue damage resulting from game collisions. The findings also suggest that a game of international rugby elicits disturbances in host immunity, which last up 38xa0h into the recovery period.

Surfactant lipids regulate LPS-induced interleukin-8 production in A549 lung epithelial cells by inhibiting translocation of TLR4 into lipid raft domains

In addition to providing mechanical stability, growing evidence suggests that surfactant lipid components can modulate inflammatory responses in the lung. However, little is known of the molecular mechanisms involved in the immunomodulatory action of surfactant lipids. This study investigates the effect of the lipid-rich surfactant preparations Survanta®, Curosurf®, and the major surfactant phospholipid dipalmitoylphosphatidylcholine (DPPC) on interleukin-8 (IL-8) gene and protein expression in human A549 lung epithelial cells using immunoassay and PCR techniques. To examine potential mechanisms of the surfactant lipid effects, Toll-like receptor 4 (TLR4) expression was analyzed by flow cytometry, and membrane lipid raft domains were separated by density gradient ultracentrifugation and analyzed by immunoblotting with anti-TLR4 antibody. The lipid-rich surfactant preparations Survanta®, Curosurf®, and DPPC, at physiological concentrations, significantly downregulated lipopolysaccharide (LPS)-induced IL-8 expression in A549 cells both at the mRNA and protein levels. The surfactant preparations did not affect the cell surface expression of TLR4 or the binding of LPS to the cells. However, LPS treatment induced translocation of TLR4 into membrane lipid raft microdomains, and this translocation was inhibited by incubation of the cells with the surfactant lipid. This study provides important mechanistic details of the immune-modulating action of pulmonary surfactant lipids.

Dipalmitoylphosphatidylcholine modulates inflammatory functions of monocytic cells independently of mitogen activated protein kinases

Phosphatidylcholine (PC) is the major phospholipid of pulmonary surfactant and it is hypothesized that PC and its subspecies modulate the functions of alveolar macrophages. The most abundant of these subspecies is dipalmitoylphosphatidylcholine (DPPC). This study was undertaken to determine the effect of PC on monocyte function using a human monocytic cell line, MonoMac‐6 (MM6). This study showed that preincubation of MM6 cells with DPPC at 125u2003μg/ml for 2u2003h inhibited the oxidative response to either zymosan or phorbol‐12‐myristate‐13‐acetate (PMA) by 30% (Pu2003<u20030·001). This inhibition with DPPC was independent of LPS priming. When DPPC was replaced with 1‐palmitoyl‐2‐arachidonoyl phosphatidylcholine (PAPC) there was no inhibition and in contrast a significant increase in oxidant production was observed. We also demonstrated that total PC (tPC; a heterogeneous species of PC from egg) and DPPC but not PAPC significantly inhibited the release of TNF‐α from MM6 cells (Pu2003<u20030·05). DPPC did not inhibit phosphorylation of the mitogen activated protein kinases (MAPKs) p44/p42 or p38 in stimulated cells. Measurements of membrane fluidity with spin label EPR spectroscopy indicate that DPPC incorporation significantly alters the membrane fluidity of MM6 cells. These results suggest that DPPC, the major component of pulmonary surfactant, may play a role in modulating leucocyte inflammatory responses in the lung. This may in part be related to membrane effects but does not include alterations in p44/p42 or p38 MAPK signalling.

Workers' exposure to dust, endotoxin and β-(1-3) glucan at four large-scale composting facilities.

OBJECTIVESnTo characterise compost workers exposure to dust, endotoxin and β-(1-3) glucan during various operational practices and investigate whether dust concentrations are a useful indicator of endotoxin exposure in compost workers.nnnMETHODSnThis study assessed inhalable dust fractions, bacterial endotoxin and β-(1-3) glucan in 117 personal samples and 88 ambient samples from four large-scale composting facilities.nnnRESULTSnEmployees exposures to inhalable dust, endotoxin and β-(1-3) glucan exhibited a large range. Inhalable dust was found to be generally low (GM 0.99 mg/m(3), GSD 2.99 mg/m(3)). Analysis of the biological component of the dust showed that employees exposures to endotoxin were elevated (GM 35.10 EU/m(3), GSD 9.97 EU/m(3)). Employees exposure to β-(1-3) glucan was low (GM 0.98 ng/m(3), GSD 13.39 ng/m(3)). Dust levels were elevated during manual sorting and screening of waste and high levels of endotoxin and β-(1-3) glucan were observed during all practices involving the movement of waste. A significant correlation was observed between the personal dust levels and personal endotoxin concentrations (r=0.783, p<0.05) and that personal inhalable dust concentration may be a valuable predictor for personal endotoxin concentration in the sites studied.nnnCONCLUSIONSnWorkers at composting sites are exposed to high levels of bacterial endotoxin consistent with adverse respiratory outcomes even though in most cases, their personal dust exposure is below the suggested regulatory levels. Dose-response data for the biological components present in the dust encountered at composting sites are not well established at this time and site operators should adopt precautionary measures when assessing and managing these potential risks.

Human leucocyte antigen polymorphisms in nut-allergic patients in South Wales

Background Peanuts and tree nuts are among the most common foods provoking severe allergic reactions including fatal anaphylaxis. However, little is known of the underlying genetic and immunological mechanisms involved.

Regulation of platelet-activating factor synthesis in human monocytes by dipalmitoyl phosphatidylcholine

Platelet‐activating factor (PAF) has a major role in inflammatory responses within the lung. This study investigates the effect of pulmonary surfactant on the synthesis of PAF in human monocytic cells. The pulmonary surfactant preparation Curosurf® significantly inhibited lipopolysaccharide (LPS)‐stimulated PAF biosynthesis (P<0.01) in a human monocytic cell line, Mono mac‐6 (MM6), as determined by 3H PAF scintillation‐proximity assay. The inhibitory properties of surfactant were determined to be associated, at least in part, with the 1,2‐dipalmitoyl phosphatidylcholine (DPPC) component of surfactant. DPPC alone also inhibited LPS‐stimulated PAF biosynthesis in human peripheral blood monocytes. DPPC treatment did not affect LPS‐stimulated phospholipase A2 activity in MM6 cell lysates. However, DPPC significantly inhibited LPS‐stimulated coenzyme A (CoA)‐independent transacylase and acetyl CoA:lyso‐PAF acetyltransferase activity. DPPC treatment of MM6 cells decreased plasma membrane fluidity as demonstrated by electron paramagnetic resonance spectroscopy coupled with spin labeling. Taken together, these findings indicate that pulmonary surfactant, particularly the DPPC component, can inhibit LPS‐stimulated PAF production via perturbation of the cell membrane, which inhibits the activity of specific membrane‐associated enzymes involved in PAF biosynthesis.

DPPC regulates COX-2 expression in monocytes via phosphorylation of CREB

The major phospholipid in pulmonary surfactant dipalmitoyl phosphatidylcholine (DPPC) has been shown to modulate inflammatory responses. Using human monocytes, this study demonstrates that DPPC significantly increased PGE(2) (P<0.05) production by 2.5-fold when compared to untreated monocyte controls. Mechanistically, this effect was concomitant with an increase in COX-2 expression which was abrogated in the presence of a COX-2 inhibitor. The regulation of COX-2 expression was independent of NF-kappaB activity. Further, DPPC increased the phosphorylation of the cyclic AMP response element binding protein (CREB; an important nuclear transcription factor important in regulating COX-2 expression). In addition, we also show that changing the fatty acid groups of PC (e.g. using l-alpha-phosphatidylcholine beta-arachidonoyl-gamma-palmitoyl (PAPC)) has a profound effect on the regulation of COX-2 expression and CREB activation. This study provides new evidence for the anti-inflammatory activity of DPPC and that this activity is at least in part mediated via CREB activation of COX-2.

An analysis of employee exposure to organic dust at large-scale composting facilities.

The occupational health implications from exposure to dust, endotoxin and 1-3 β Glucan at commercial composting sites are uncertain. This study aims to establish employee exposure levels to inhalable and respirable dust, endotoxin and 1-3 β Glucan during various operational practices in the composting process. Personal samples were collected and the inhalable and respirable dust fractions were determined by gravimetric analysis. Endotoxin concentrations were determined using a Limulus Amebocyte Lysate assay (LAL). 1-3 β Glucan levels were estimated using a specific blocking agent to establish the contribution that these compounds gave to the original endotoxin assay. Employees exposure to dust was found to be generally lower than the levels stipulated in the Control of Substances Hazardous to Health Regulations (COSHH) 2002 (as amended), (median inhalable fraction 1.08 mg/m3, min 0.25 mg/m3 max 10.80 mg/m3, median respirable fraction 0.05 mg/m3, min 0.02 mg/m3, max 1.49 mg/m3). Determination of the biological component of the dust showed that employees exposures to endotoxin were elevated (median 31.5 EU/m3, min 2.00 EU/m3, max 1741.78 EU/m3), particularly when waste was agitated (median 175.0 EU/m3, min 2.03 EU/m3, max 1741.78 EU/m3). Eight out of 32 (25%) of the personal exposure data for endotoxin exceeded the 200 EU/m3 temporary legal limit adopted in the Netherlands and thirteen out of 32 (40.6%) exceeded the suggested 50 EU/m3 guidance level suggested to protect workers from respiratory health effects. A significant correlation was observed between employee inhalable dust exposure and personal endotoxin concentration (r = 0.728, p<0.05) and also personal endotoxin exposure and 1-3 β Glucan concentration (r = 0.817, p<0.05). Further work is needed to explore the possibility of using inhalable dust concentration as a predictor for personal endotoxin exposure. The general dust levels stipulated in the COSHH Regulations 2002 (as amended) are inadequate for managing the potential health risks associated with endotoxin exposure at composting sites. Employee exposure levels and dose-response disease mechanisms are not well understood at this present time. Consequently, in light of this uncertainty, it is recommended that a precautionary approach be adopted in managing the potential health risks associated with inhalation of organic dusts at composting sites.

The allergenicity of feather bedding material.

This article was published in Allergy on 21 March 2002, availble at nhttp://dx.doi.org/10.1034/j.1398-9995.2002.1n3451.x

Phospholipid modulation of monocyte oxidative activity measured by luminol-enhanced chemiluminescence.

The lung is susceptible to inflammatory and oxidative injury leading to tissue damage and decreased function. Infiltrating neutrophils and monocytes and resident macrophages are a likely source of the damaging molecules. It is hypothesized that pulmonary surfactant rich in phospholipid may modulate the cytotoxic and inflammatory function of alveolar macrophages. Changes in membrane lipid composition may alter the immunological responses of monocytes to infection, including endotoxin (lipopolysacclharide, LPS). The present study was undertaken to determine the role of phospholipids in the modulation of monocyte respiratory burst activity. Materials and methods. Human monocyte-derived cell line (MonoMac 6) was from the German Cell and Tissue Culture Collection, Braunsweig, Germany. Phospholipid species luminol and LPS were from Sigma Chemical Co. (Poole, United Kingdom). Phospholipids (10-500 gg/mL) were dissolved in RPMI 1640 medium and added to 1 x 106/mL MonoMac 6 cells with or without 100 ng/mL LPS for 12 h at 37°C. The cells were then washed three times, and the respiratory burst was triggered by the additkm of zymosan in the presence of luminol. The production of reactive oxygen species was measured by chemiluminescence using an automated luminometer. Cells not preincubated with LPS to prime them produced little superoxide and acted as controls. Results. The phospholipid species investigated all had effects on the priming of monocytes for superoxide production in the respiratory burst. At the concentrations used (10-500 mg/mL), they had no direct effect on the triggering of the respiratory burst with zymosan or phorbol 12,myristate 13,acetate. Therefore the phospholipids altered the monocyte responses to LPS, resulting in a primed state for enhanced superoxide generation. Mixed lipid species of phosphatidylcholine inhibited the LPS-induced priming of the monocyte respiratory burst in a dose-dependent manner from 100-500 ~tg/mL. However, dipalmitoylphosphatidylcholine, the major phospholipid species in pulmonary surfactant, was stimulatory at 100-500 ~tg/mL but was inhibitory at concentrations below this. Mixed species of phosphatidylethanolamine had a suppressive effect on the respiratory burst in a dose-dependent manner up to 100 pg/mL, whereas at high concentrations (250-500 gg/mL) sphingomyelin had a stimulatory effect. The effects of other molecular species of the phospholipids are currently being investigated. Conclusions. This study shows that phospholipids can modulate the respiratory burst in monocytes and that this is at the level of monocyte priming. The effect of the phospholipids was dependent both on the lipid acyl composition and on the polar headgroup composition. These results suggest that phospholipid species may regulate monocyte and macrophage oxidative responses in vivo, and alterations in cellular phospholipid content and composition may affect the host responses to infection. Manipulation of the extracellular lipid content may be a novel strategy in the treatment of inflammatory lung diseases.