Time post-lung transplant correlates with increasing peripheral blood T cell granzyme B and proinflammatory cytokines

Immunosuppression therapy following lung transplant fails to prevent chronic rejection/bronchiolitis obliterans syndrome, which we have shown is associated with lack of suppression of peripheral blood T cell granzyme B, interferon (IFN)-γ and tumour necrosis factor (TNF)-α. We hypothesized that these proinflammatory mediators may increase with time post-transplant in otherwise stable patients before clinical signs of declining lung function, and patients experiencing declining lung function would show a further increase in these mediators. Intracellular cytokine profiles and granzyme B were investigated in T cells in whole blood and airways from lung transplant patients using flow cytometry. There was a significant negative correlation between forced expiratory volume in 1 s (FEV(1) ), drug dose and time post-transplant. A significant correlation between increased granzyme B, IFN-γ, interleukin (IL)-2 and TNF-α and time post-transplant was noted in peripheral blood T cells but not lung T cells from stable patients. Patients with similar drug dose but experiencing declining FEV(1) showed a further increase in peripheral blood T cell IFN-γ, IL-2 and TNF-α. Time post-lung transplant correlates with increasing peripheral blood T cell granzyme B and proinflammatory cytokines. Declining FEV(1) is associated with a further increase in these proinflammatory mediators. Drugs that reduce these inflammatory mediators effectively may reduce the incidence of chronic graft rejection.

Conditional facilitation of an aphid vector, Acyrthosiphon pisum, by the plant pathogen, pea enation mosaic virus

Plant pathogens can induce symptoms that affect the performance of insect herbivores utilizing the same host plant. Previous studies examining the effects of infection of tic bean, Vicia faba L. (Fabales: Fabaceae), by pea enation mosaic virus (PEMV), an important disease of legume crops, indicated there were no changes in the growth and reproductive rate of its primary vector the pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae). Here, we report the results of laboratory experiments investigating how A. pisum responded to PEMV infection of a different host plant, Pisum sativum L., at different stages of symptom development. Aphid growth rate was negatively related to the age of the host plant, but when they were introduced onto older plants with well-developed PEMV symptoms they exhibited a higher growth rate compared to those developing on uninfected plants of the same age. In choice tests using leaf discs A. pisum showed a strong preference for discs from PEMV-infected peas, probably in response to visual cues from the yellowed and mottled infected leaves. When adults were crowded onto leaves using clip-cages they produced more winged progeny on PEMV-infected plants. The results indicate that PEMV produces symptoms in the host plant that can enhance the performance of A. pisum as a vector, modify the production of winged progeny and affect their spatial distribution. The findings provide further evidence that some insect vector/plant pathogen interactions could be regarded as mutualistic rather than commensal when certain conditions regarding the age, stage of infection and species of host plant are met.

The RAP1 gene confers effective, race-specific resistance to the pea aphid in Medicago truncatula independent of the hypersensitive reaction

Plant resistance to pathogens is commonly associated with a hypersensitive response (HR), but the degree to which the HR is responsible for incompatibility is subject to debate. Resistance to aphids is likely to share features with resistance to pathogens but is less well understood. Here, we report effective resistance to the pea aphid Acyrthosiphon pisum in Medicago truncatula. Aphids lost weight and died rapidly (within two days) on the resistant genotype Jemalong, which developed necrotic lesions following infestation. Lesions were induced by nonvascular intracellular stylet punctures by aphids, remained localized to the site of stylet entry, stained for the presence of reactive oxygen species, and were similar to the HR induced by the bacterial pathogen Pseudomonas syringae pv. phaseolicola. The implication that aphid-induced lesions confer resistance was tested by quantitative trait loci analysis using recombinant inbred lines derived from a cross between Jemalong and the susceptible genotype DZA315.16. One major locus, RAP1, was identified that was sufficient to confer race-specific resistance against the pea aphid and was mapped to the middle of chromosome 3. Surprisingly, a separate locus, mapping to the top of chromosome 3, governed aphid-induced HR, indicating that the HR-like lesions are not required for RAP1-mediated aphid resistance.

Posttransplant bronchiolitis obliterans syndrome is associated with bronchial epithelial to mesenchymal transition

Bronchiolitis obliterans syndrome (BOS) compromises lung transplant outcomes and is characterised by airway epithelial damage and fibrosis. The process whereby the normal epithelial configuration is replaced by fibroblastic scar tissue is poorly understood, but recent studies have implicated epithelial mesenchymal transition (EMT). The primary aim of this study was to assess the utility of flow cytometry in detecting and quantifying EMT in bronchial epithelial cells. Large airway brushings were obtained at 33 bronchoscopies in 16 BOS-free and 6 BOS grade 1-3 patients at 2-120 months posttransplant. Flow cytometry was used to assess expression of the mesenchymal markers alphaSMA, S100A4 and ED-A FN and HLA-DR. TGF beta 1 and HGF were measured in Bronchoalveolar lavage (BAL). Expression of all three mesenchymal markers was increased in BOS, as was HLA-DR. BAL HGF, but not TGF beta 1 was increased in BOS. Longitudinal investigation of one patient revealed a 100% increase in EMT markers concurrent with a 6-fold increase in BAL TGF beta 1 and the diagnosis of BOS at 17 months posttransplant. Flow cytometric evaluation of bronchial epithelium may provide a novel and rapid means to assess lung allografts at risk of BOS.

Do plant viruses facilitate their aphid vectors by inducing symptoms that alter behavior and performance?

Aphids can respond both positively and negatively to virus-induced modifications of the shared host plant. It can be speculated that viruses dependent on aphids for their transmission might evolve to induce changes in the host plant that attract aphids and improve their performance, subsequently enhancing the success of the pathogen itself. We studied how pea aphids [Acyrthosiphon pisum (Harris)] responded to infection of tic beans (Vicia faba L.) by three viruses with varying degrees of dependence on this aphid for their transmission: pea enation mosaic virus (PEMV), bean yellow mosaic virus (BYMV), and broad bean mottle virus (BBMV). BYMV has a nonpersistent mode of transmission by aphids, whereas PEMV is transmitted in a circulative-persistent manner. BBMV is not aphid transmitted. When reared on plants infected by PEMV, no changes in aphid survival, growth, or reproductive performance were observed, whereas infection of beans by the other aphid-dependent virus, BYMV, actually caused a reduction in aphid survival in some assays. None of the viruses induced A. pisum to increase production of winged progeny, and aphids settled preferentially on leaf tissue from plants infected by all three viruses, the likely mechanism being visual responses to yellowing of foliage. Thus, in this system, the attractiveness of an infected host plant and its quality in terms of aphid growth and reproduction were not related to the pathogen's dependence on the aphid for transmission to new hosts.

Reading between the lines: the experiences of taking part in a community reading project

Despite the popularity of reading groups, and the increased number of general-practitioner-referred bibliotherapy schemes in the UK, there has been relatively little research on the effects of reading works of literature on the well-being and health of readers. This paper reports the findings of a study set up to explore people's experiences of taking part in community reading groups run by the Get into Reading Project in Wirral, Merseyside, UK. A qualitative approach was adopted, using three methods. These were participant observation with five reading groups, a key stakeholder interview and, with a sixth group, a single case study that consisted of observation and interviews with group members. The fieldwork conducted with the six groups took place in a variety of settings, including libraries, a residential drug rehabilitation unit and a hostel for homeless men. The research participants were all over 18 years of age, and all were members or facilitators of Get into Reading reading groups. The data were analysed thematically using NVivo qualitative analysis software. The findings show that the groups do not have a specific, targeted, therapeutic function, their primary purpose being more broadly literary, with literature itself trusted both to serve a coalescing social purpose and to offer non-specified but individual therapeutic benefits. Further work should be undertaken to explore the social and therapeutic benefits of reading literature in community settings.

Increased intracellular T helper 1 proinflammatory cytokine production in peripheral blood, bronchoalveolar lavage and intraepithelial T cells of COPD subjects

The role of T cells in the pathophysiology of chronic obstructive pulmonary disease (COPD) is not yet certain, although varying reports have shown increases in T helper 1 (Th1) and/or Th2 cytokines in peripheral blood and bronchoalveolar lavage (BAL). No studies have examined cytokine production by intraepithelial T cells obtained by bronchial brushing (BB). Intracellular cytokine analysis of T cell subsets from peripheral blood, BAL and BB from smoker and ex-smoker COPD patients, COPD patients receiving inhaled corticosteroids and smoker and non-smoker control subjects was studied using multi-parameter flow cytometry. CD4 : CD8 inversion was noted in the peripheral blood of smoker and ex-smoker COPD groups, in BAL and BB from smoker controls and BAL of COPD smokers. There was an increase in intracellular CD8(+) T cell Th1 proinflammatory cytokines in some COPD groups in the peripheral blood and in CD8(+) T cell tumour necrosis factor (TNF)-alpha in some COPD groups and smoker controls in BAL and BB. There was an increase in proinflammatory cytokines in COPD smokers compared with ex-smokers and a decrease in COPD smokers receiving inhaled corticosteroids in the airways. There was a negative correlation between forced expiratory volume in 1 s (FEV(1)) and the percentage of BAL and intraepithelial CD8(+) T cells producing TNF-alpha. COPD patients exhibit systemic inflammation as evidenced by increased intracellular Th1 proinflammatory cytokines in blood, BAL and intraepithelial CD8(+) T cells, whereas smoker controls showed localized Th1 response in the lung only. Systemic therapeutic targeting of TNF-alpha production by CD8(+) T cells may improve morbidity in COPD patients while targeting of TNF-alpha in the lung may prevent smokers progressing to COPD.

Airway infection in stable lung transplant patients is associated with decreased intracellular T-helper type 1 pro-inflammatory cytokines in bronchoalveolar lavage T-cell subsets

Current immunosuppression protocols to prevent lung transplant rejection reduce pro-inflammatory and T-helper type 1 (Th1) cytokines. However, Th1 T-cell pro-inflammatory cytokine production is important in host defense against bacterial infection in the lungs. Excessive immunosuppression of Th1 T-cell pro-inflammatory cytokines leaves patients susceptible to infection. To investigate whether pulmonary infection in lung transplant recipients is associated with reduced Th1 T-cell pro-inflammatory cytokines, whole blood and bronchoalveolar lavage (BAL) fluid from 13 stable lung transplant patients with 'culture-negative' BAL and 13 patients with 'culture-positive' BAL was stimulated in vitro, and cytokine production by CD8+ and CD4+ T-cell subsets was determined using multiparameter flow cytometry. In BAL samples, there was a significant decrease in interleukin-2 (IL2) in CD3+ T cells and tumor necrosis factor-alpha (TNF-alpha) in CD8+ T cells (but not CD4+) in 'culture-positive' compared with 'culture-negative' transplant patients. There was no difference in blood Th1 T-cell cytokines between 'culture-positive' compared with 'culture-negative' transplant patients. A decrease in Th1 cytokines IL-2 and TNF-alpha in BAL T-cell subsets is associated with isolation of potentially pathogenic organisms in the lungs in stable lung transplant patients. Excessive immunosuppression of these Th1 T-cell pro-inflammatory cytokines in stable transplant patients may leave them susceptible to infection. Modifying immunosuppression by monitoring intracellular Th1 pro-inflammatory cytokines in BAL T cells may help to improve morbidity and infection rates in stable lung transplant patients.

Compartmentalization of intracellular proinflammatory cytokines in bronchial intraepithelial T cells of stable lung transplant patients

Allograft rejection remains a major cause of morbidity and mortality following lung transplantation and is associated with an increased expression of T cell proinflammatory cytokines. We have shown that CD4(+) T cell proinflammatory cytokine production was significantly reduced in peripheral blood and bronchoalveolar lavage (BAL) of stable lung transplant patients, consistent with immunosuppression therapy. However, analysis of inflammatory cytokine profiles of intraepithelial T cells in bronchial brushing (BB) may be more relevant than peripheral blood or BAL T cells for assessing immune graft status. To investigate the immunomodulatory effects of currently used immunosuppressive regimens on bronchial intraepithelial T cell cytokine production, whole blood, BAL and BB from stable lung transplant patients and control volunteers were stimulated in vitro and cytokine production by CD8(+) and CD4(+) T cell subsets determined using multi-parameter flow cytometry. In bronchial intraepithelial T cell subsets in control subjects and transplant patients there was compartmentalization of interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha production, a decrease in interleukin (IL)-2 production by CD4(+) T cells and CD4 : CD8 inversion compared with blood and BAL. Although there was a decrease in T cell proinflammatory cytokine production in blood of transplant patients, this was not found in BAL or bronchial intraepithelial CD8 T cell subsets, suggesting that the same level of immunosuppression may not occur in the lung of transplant recipients. Drugs that effectively reduce CD8 T cell proinflammatory cytokine production in the lung compartment may improve current protocols for reducing graft rejection in these patients.

Azithromycin increases phagocytosis of apoptotic bronchial epithelial cells by alveolar macrophages

Chronic obstructive pulmonary disease (COPD) is associated with increased apoptosis and defective phagocytosis in the airway. As uncleared cells can undergo secondary necrosis and perpetuate inflammation, strategies to improve clearance would have therapeutic significance. There is evidence that the 15-member macrolide antibiotic azithromycin has anti-inflammatory properties. Its effects may be increased in the lung due to its ability to reach high concentrations in alveolar macrophages (AMs). The present study investigated the effects of low-dose (500 ng x mL(-1)) azithromycin on the phagocytosis of apoptotic bronchial epithelial cells and neutrophils by AMs. Flow cytometry was applied to measure phagocytosis and receptors involved in AM recognition of apoptotic cells. Cytokines were investigated using cytometric bead array. Baseline phagocytosis was reduced in COPD subjects compared with controls. Azithromycin significantly improved the phagocytosis of epithelial cells or neutrophils by AMs from COPD subjects by 68 and 38%, respectively, often up to levels comparable with controls. The increase in phagocytosis was partially inhibited by phosphatidylserine, implicating the phosphatidylserine pathway in the pro-phagocytic effects of azithromycin. Azithromycin had no effect on other recognition molecules (granulocyte-macrophage colony-stimulating factor, CD44, CD31, CD36, CD91, alphavbeta3 integrin). At higher doses, azithromycin decreased levels of pro-inflammatory cytokines. Thus, low-dose azithromycin therapy could provide an adjunct therapeutic option in chronic obstructive pulmonary disease.

Effect of blood storage conditions on leucocyte intracellular cytokine production

Intracytoplasmic detection of leucocyte cytokines has become a powerful tool for the characterisation of cytokine-producing cells in heterogeneous cell populations, however the effect of specimen storage conditions is unknown. The aim of this study was to determine the effect of whole blood stored at room temperature (RT) or 4 degrees C, on intracellular cytokine production by T cells and monocytes. In cell cultures stored at RT or 4 degrees C for 24h, significant changes in several leucocyte cytokines/chemokines were shown compared to blood cultures stimulated at time=0. There was a significant decrease in IL-2, IL-4 and TNFalpha production by CD4+ T cells in blood cultures stored at RT but an increase in IL-2 in cultures at 4 degrees C. There was a significant decrease in TGFbeta production by CD4+ and CD8+ T cells in cultures kept at RT or 4 degrees C. There was a significant increase in MCP-1 and MCP-3 production by monocytes in blood cultures kept at RT or 4 degrees C. There was a decrease in IL-12 production by monocytes in cultures kept at 4 degrees C, whereas IL-10 production was decreased at RT and increased in cultures kept at 4 degrees C. Blood stored at 4 degrees C showed less immunomodulatory changes than blood kept at RT although overall a possible Th1 bias at 4 degrees C.

Application of DL-beta-aminobutyric acid (BABA) as a root drench to legumes inhibits the growth and reproduction of the pea aphid Acyrthosiphon pisum (Hemiptera: Aphididae)

DL-beta-aminobutyric acid (BABA) is a non-protein amino acid that is an effective inducer of resistance against a variety of plant pathogens. However, examples of BABA-induced resistance against insect herbivores have not been reported. We applied BABA as a soil drench to legumes and monitored its effects on the pea aphid Acyrthosiphon pisum (Harris). On tic bean (Vicia faba var. minor), BABA increased aphid mortality, caused a reduction in the mean relative growth rate of individual insects and lessened the intrinsic rate of population increase (rm). BABA also caused significant reductions in the growth rate of A. pisum on pea (Pisum sativa), broad bean (Vicia faba var. major), runner bean (Phaseolus coccineus), red clover (Trifolium pratense) and alfalfa (Medicago sativa). No direct toxic effects of BABA against A. pisum were found, and no phytotoxic effects that may have caused a reduction in aphid performance were detected. Possible mechanisms behind this BABA-induced inhibition of aphid performance are discussed.

Increased airway epithelial and T-cell apoptosis in COPD remains despite smoking cessation

There is heterogeneity in the propensity of smokers to develop chronic obstructive pulmonary disease (COPD), and improved treatment strategies are hindered by limited understanding of COPD pathogenesis, especially as distinct from the effects of smoking per se. Although apoptosis is essential for tissue homeostasis, increased apoptosis may cause tissue damage and inflammation. This study addressed whether airway T-lymphocytes and airway epithelial cells (AEC) show an increased likelihood of undergoing apoptosis in COPD and if this was related to smoking. Apoptosis (7-amino-actinomycin D, Annexin, single-stranded DNA and caspase), Bcl-2, Bax and p53 were assessed in cells obtained from bronchial bushing and bronchoalveolar lavage from ex- and continuing smokers with COPD, and nonsmoking controls, using flow cytometry. A mean 87% increase in apoptosis of AEC and a 103% increase in T-lymphocyte apoptosis were found in COPD. There were no significant differences in apoptosis of AEC between current and ex-smokers with COPD. Apoptosis may contribute to chronic obstructive pulmonary disease pathogenesis, and continued excess apoptosis after smoking cessation may offer a new target for therapeutic interventions. Whether the persistence of increased apoptosis after smoking cessation results from changes in the pulmonary milleau after years of noxious insult, or whether some individuals have a natural predisposition toward increased apoptosis and possible development of chronic obstructive pulmonary disease remains to be determined.

Intracellular cytokines in blood T cells in lung transplant patients--a more relevant indicator of immunosuppression than drug levels

Allograft rejection remains a major cause of morbidity and mortality following lung transplantation and is associated with an increase in T-cell pro-inflammatory cytokine expression. Systemic levels of immunosuppressive drugs used to reduce pro-inflammatory cytokine expression are closely monitored to their 'therapeutic range'. However, it is currently unknown if levels of these drugs correlate with pro-inflammatory cytokine expression in peripheral blood T cells. To investigate the immunomodulatory effects of currently used immunosuppressive regimes on peripheral blood T-cell cytokine production, whole blood from stable lung transplant patients and control volunteers were stimulated in vitro and cytokine production by CD8+ and CD4+ T-cell subsets determined using multiparameter flow cytometry. T-cell IL-2 and TNFalpha production was significantly reduced from lung transplant patients compared to controls. CD4+ T-cell production of IFNgamma was also significantly reduced from lung transplant patients but production of IFNgamma by CD8+ T cells remained unchanged. There was an excellent correlation between the percentage of CD8+ T cells and the percentage of CD8+ T cells producing IFNgamma from transplant patients. T-cell IL-4 and CD8+ T-cell production of TGFbeta was significantly increased from lung transplant patients. We now provide evidence that current immunosuppression protocols have limited effect on peripheral blood IFNgamma production by CD8+ T-cells but do up-regulate T-cell anti-inflammatory cytokines. Drugs that effectively reduce IFNgamma production by CD8+ T cells may improve current protocols for reducing graft rejection in these patients. Intracellular cytokine analysis using flow cytometry may be a more appropriate indicator of immunosuppression than drug levels in these patients. This technique may prove useful in optimizing therapy for individual patients.

Rapid simultaneous measurement of multiple cytokines using 100 microl sample volumes--association with neonatal sepsis

Early diagnosis of neonatal infection has proved problematic due to the inadequacy of currently available laboratory tests. Neonatal sepsis is associated with an increase in plasma-derived cytokine levels, but an increase of a single cytokine cannot identify neonatal sepsis specifically and multiple cytokine levels are required. The time constraints and relatively large volume of plasma required to measure multiple cytokines from newborn infants by conventional enzyme-linked immunosorbent assay (ELISA) techniques is prohibitive. We therefore applied cytometric bead array (CBA) technology for simultaneous measurement of multiple cytokines from a group of 18 term neonates with infection confirmed by culture and a control group. 'Normal' ranges were established for each cytokine from 1-7-, 8-14- and 15-21-day-old newborns. There was no significant change in the levels of cytokines from infants in different control age groups, suggesting that basal cytokine levels are unchanged in the first 3 weeks of life. In the patient groups, however, there was a significant difference in several cytokines between the different age groups. Interleukin (IL)-6, IL-10 and IL-12 were increased significantly in the 1-7-day-old patient group compared to either the 8-14 and 15-21 age group, suggesting that infection in utero is associated with increased levels of these cytokines compared to infection acquired following birth. When individual patient cytokine levels were compared to normal control reference ranges, two patients failed to show significant elevation of any cytokine tested. All other patients showed elevated levels of between one and nine cytokines tested (mean of 4.6). There was no correlation between elevated cytokine levels and types of infective organism or patient age. In conclusion, neonatal sepsis is associated with the elevation of multiple plasma cytokines. The use of CBA kits is a rapid, easy, low sample volume and sensitive method to measure multiple plasma cytokines.

Multiple leucocyte activation markers to detect neonatal infection

Diagnosis of congenital or neonatal infection is often based on clinical signs. However, clinical symptoms of infections may not be specific, and for this reason early diagnosis is often determined on results of laboratory tests, which may not currently be adequate. A more reliable method of detection of infection may be the demonstration of activated lymphocytes, which can be conducted rapidly and before the isolation of the infected organism. We have shown that detection of up-regulation of CD45RO, an activated/memory isoform of CD45 present on T cells, provides a reasonably sensitive screening test for neonatal infection. We also showed that dual expression of CD45RA/CD45RO was up-regulated early during the infective process in neonates with documented infection. However, other leucocytes are also activated during the infective process. To improve the sensitivity of the neonatal infection screening test and to identify the types of leucocytes involved in the immune response to the infective organism, we studied further the up-regulation of a comprehensive range of surface activation markers on T cells, monocytes and natural killer (NK) cells from a group of 17 newborn patients with positive culture, a group of 40 possibly infected patients based on clinical signs and a control group. 'Normal' ranges were established for each activation marker for each leucocyte subset from 1 to 7 and 7-14-day-old newborns <35 weeks' gestation and 35-40 weeks' gestation. There was a significant increase in the percentage of T cells expressing CD25 in the peripheral blood from infants at 2 weeks of age. Expression of HLA-DR on T cells, CD25 and CD69 on monocytes and HLA-DR on NK cells was also increased significantly in the peripheral blood from infants at 2 weeks of age and may reflect a maturation of these functional surface molecules. Up-regulation of CD69 on NK cells was the most sensitive marker for neonatal sepsis (positive in 13/16 patients). CD69 and CD25 expression was increased significantly on T cells in 11/17 and 10/17 patients, respectively. A combination of CD45RA/CD45RO and CD45RO identified 11/16 infected patients. Measurement of CD69 expression on NK cells with CD45RA, CD45RO, CD25 and CD69 expression on T cells resulted in a significant increase in at least two leucocyte activation markers from infected patients. In conclusion, this is the first report of the up-regulation of CD69 on NK cells as a sensitive marker of neonatal infection. A combination of this marker with CD45RA, CD45RO, CD25 and CD69 expression on peripheral blood derived T cells is the most sensitive and specific for neonatal infection.

Strong founder effect in Drosophila pseudoobscura colonizing New Zealand from North America

The North American native species Drosophila pseudoobscura was first identified in New Zealand in the last few decades. Here, we have studied the genetic consequences of its spread across the Pacific Ocean. Using 10 microsatellites that are highly variable in North American populations, we found that the New Zealand population has substantially fewer alleles, a much lower average heterozygosity, and significantly different allele frequencies at these loci. We have discussed the relative sensitivity of these parameters for detecting the founding event. X-linked loci were more strongly differentiated between continents than autosomal loci, as reflected by larger changes in allele frequencies and greater reductions in numbers of alleles and average heterozygosity. The severity of the genetic diversity loss supports a scenario of a few D. pseudoobscura females being introduced to New Zealand from North America.

Observation of radiation-specific damage in human cells exposed to depleted uranium: dicentric frequency and neoplastic transformation as endpoints

Depleted uranium (DU) is a dense heavy metal used primarily in military applications. Published data from our laboratory have demonstrated that DU exposure in vitro to immortalised human osteoblast cells (HOS) is both neoplastically transforming and genotoxic. DU possesses both a radiological (alpha-particle) and chemical (metal) component. Since DU has a low specific activity in comparison to natural uranium, it is not considered to be a significant radiological hazard. The potential contribution of radiation to DU-induced biological effects is unknown and the involvement of radiation in DU-induced biological effects could have significant implications for current risk estimates for internalised DU exposure. Two approaches were used to address this question. The frequency of dicentrics was measured in HOS cells following DU exposure in vitro. Data demonstrated that DU exposure (50 microM, 24 h) induced a significant elevation in dicentric frequency in vitro in contrast to incubation with the heavy metals, nickel and tungsten which did not increase dicentric frequency above background levels. Using the same concentration (50 microM) of three uranyl nitrate compounds that have different uranium isotopic concentrations and therefore, different specific activities, the effect on neoplastic transformation in vitro was examined. HOS cells were exposed to one of three-uranyl nitrate compounds (238U-uranyl nitrate, specific activity 0.33 microCi.g-1; DU-uranyl nitrate, specific activity 0.44 microCi.g-1; and 235U-uranyl nitrate, specific activity 2.2 microCi.g-1) delivered at a concentration of 50 microM for 24 h. Results showed, at equal uranium concentration, there was a specific activity dependent increase in neoplastic transformation frequency. Taken together these data suggest that radiation can play a role in DU-induced biological effects in vitro.

Interleukin-4 and tumour necrosis factor-alpha inhibit transforming growth factor-beta production in a human bronchial epithelial cell line: possible relevance to inflammatory mechanisms in chronic obstructive pulmonary disease

OBJECTIVE

Human bronchial epithelial cells are known to secrete an array of inflammatory cytokines including tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-4, which may play a role in immune responses in lung diseases such as chronic obstructive pulmonary disease (COPD). However, the regulatory mechanisms governing cytokine production in bronchial epithelia in COPD are largely unknown. Transforming growth factor-beta (TGF-beta) is an anti-inflammatory cytokine and is involved in airway repair. The purpose of this study was to study the effect of TNF-alpha and IL-4 (pro-inflammatory cytokines known to be up-regulated in COPD), on the production of TGF-beta (a negative regulator of inflammation) by epithelial cells.

METHODOLOGY

A bronchial epithelial cell line was used as an in vitro culture model (16HBE). Cell cultures were stimulated with various combinations of TNF-alpha and IL-4 (20 ng/mL) for 24 h. Transforming growth factor-beta production was measured by flow cytometry, enzyme-linked immunosorbent assay and immunohistochemistry.

RESULTS

Exposure to TNF-alpha significantly up-regulated production of IL-4 from cultured epithelial cells. Unstimulated cells spontaneously released TGF-beta. Exposure to TNF-alpha and IL-4 significantly inhibited production of TGF-beta. The inhibitory effects of TNF-alpha and IL-4 on TGF-beta synthesis were summative.

CONCLUSIONS

The inhibitory effect of IL-4 and TNF-alpha on production of the regulatory cytokine TGF-beta in a bronchial epithelial cell line suggests that such mechanisms may contribute to the progression of the inflammatory response and compromise repair processes in inflammatory lung diseases such as COPD.

Muscle learning therapy--efficacy of a biofeedback based protocol in treating work-related upper extremity disorders

Work-related upper extremity disorders (WRUEDs) continue to present significant treatment and financial challenges to providers, employers, and insurers. This retrospective study reviews outcomes for 309 subjects who, between 1995 and 1999, were referred through the workers' compensation system for treatment of computer keyboard- and mouse-related WRUED injuries. The mean length of time from the recorded date of injury to the date of intake was 12.9 months. Subjects were offered a 12-visit course in muscle learning therapy (MLT). MLT is an operant conditioning program which uses surface electromyography (sEMG) to train injured workers to control their muscles during work activities. Patient response to therapy was obtained by a therapist-administered questionnaire during Visit 8 of 12. A group of 309 subjects, who had failed to respond to a previous course of therapy (typically physical therapy), reported significant improvements of pain in the neck, thorax, and upper extremities. Ninety six percent reported that they felt "more in control," 86% reported feeling "better overall," and 81% reported either "working the same and feeling better" or "working and accomplishing more." This study provides preliminary support for this approach and provides justification for controlled clinical trials in the future.

Dynamic analyses of the expression of the HISTONE::YFP fusion protein in arabidopsis show that syncytial endosperm is divided in mitotic domains

During early seed development, nuclear divisions in the endosperm are not followed by cell division, leading to the development of a syncytium. The simple organization of the Arabidopsis endosperm provides a model in which to study the regulation of the cell cycle in relation to development. To monitor nuclear divisions, we constructed a HISTONE 2B::YELLOW FLUORESCENT PROTEIN gene fusion (H2B::YFP). To validate its use as a vital marker for chromatin in plants, H2B::YFP was expressed constitutively in Arabidopsis. This enabled the observation of mitoses in living root meristems. H2B::YFP was expressed specifically in Arabidopsis syncytial endosperm by using GAL4 transactivation. Monitoring mitotic activity in living syncytial endosperm showed that the syncytium was organized into three domains in which nuclei divide simultaneously with a specific time course. Each mitotic domain has a distinct spatiotemporal pattern of mitotic CYCLIN B1;1 accumulation. The polar spatial organization of the three mitotic domains suggests interactions between developmental mechanisms and the regulation of the cell cycle.

Dynamic analyses of the expression of the HISTONE::YFP fusion protein in arabidopsis show that syncytial endosperm is divided in mitotic domains

During early seed development, nuclear divisions in the endosperm are not followed by cell division, leading to the development of a syncytium. The simple organization of the Arabidopsis endosperm provides a model in which to study the regulation of the cell cycle in relation to development. To monitor nuclear divisions, we constructed a HISTONE 2B::YELLOW FLUORESCENT PROTEIN gene fusion (H2B::YFP). To validate its use as a vital marker for chromatin in plants, H2B::YFP was expressed constitutively in Arabidopsis. This enabled the observation of mitoses in living root meristems. H2B::YFP was expressed specifically in Arabidopsis syncytial endosperm by using GAL4 transactivation. Monitoring mitotic activity in living syncytial endosperm showed that the syncytium was organized into three domains in which nuclei divide simultaneously with a specific time course. Each mitotic domain has a distinct spatiotemporal pattern of mitotic CYCLIN B1;1 accumulation. The polar spatial organization of the three mitotic domains suggests interactions between developmental mechanisms and the regulation of the cell cycle.

Cord blood leucocyte expression of functionally significant molecules involved in the regulation of cellular immunity

The cellular immune system of the newborn infant is immature and hypo-responsive when compared with adults. The extent to which immaturity of the leucocyte function underlies hyporesponsiveness in the newborn is incompletely understood. In this study flow cytometric techniques were applied to investigate the concurrent expression of a range of surface and intracellular leucocyte functional molecules and cytokines in resting and stimulated cord and adult blood. Production of interleukin (IL)-2 and expression of the components of its receptor, IL-2R alpha/beta/gamma, were investigated. No differences in the proportion of leucocytes producing IL-2R alpha and IL-2R gamma were observed for newborns and adults. A lower proportion of T cells and natural killer (NK) cells from newborns expressed IL-2R beta and upregulation of expression was slower. We hypothesize that reduced IL-2R beta may curtail early autocrine IL-2 activation of immune responses in the newborn. This hypothesis was supported by the observation that an increased proportion of stimulated T cells from newborns produced IL-2 at 4 h poststimulation, but at 24 h the proportion was lower than for adult T cells. The very low levels of interferon (IFN)-gamma produced by neonatal T cells and NK cells may also be partly explained by a curtailment of early autocrine activation of T cells. Expression and kinetics of upregulation for other functional molecules were studied. CD71, HLA-DR, tissue factor and CD152 levels were not significantly different for adults and newborns, suggesting that cord blood leucocytes, in some respects, may demonstrate functional maturity. IL-6 secretion by stimulated monocytes was also comparable in cord and adult blood. However, IL-1 alpha and IL-1 beta were produced by a lower proportion of monocytes from newborns than adults. Similarly, tumour necrosis factor (TNF)-alpha production for monocytes and T cells was lower in cord blood. The mean fluorescence intensity for IL-1 alpha, IL-1 beta and TNF-alpha was also lower for leucocytes from cord blood. These findings are significant in relation to the inability of newborn infants to mount a febrile response to infection. The findings of lower expression of IL-2R beta and lower production of inflammatory cytokines IL-1 alpha, IL-1 beta and TNF-alpha is a basis for improved understanding of the immunological immaturity of leucocytes in the newborn.

Increased levels of apoptosis of leukocyte subsets in cultured PBMCs compared to whole blood as shown by Annexin V binding: relevance to cytokine production

Most of the investigatory studies of cytokine production by cells have been performed on purified cells or cell lines by measuring the secreted cytokine levels in the bulk culture supernatant. However, results of cytokine production from isolated peripheral blood mononuclear cells (PBMCs) cultivated in synthetic media, have been reported to be inaccurate and of low reproducibility. Isolation procedures have been shown to be toxic to certain cells. We hypothesised that purified cell culture techniques may result in increased levels of apoptosis of cells compared with whole blood culture techniques. To compare the effects on cell viability between PBMCs and whole blood techniques, an Annexin V binding assay was utilised. The effect of different cell concentration and serum/plasma concentrations on apoptosis levels in the various leukocyte subsets in PBMC and whole blood cultures following stimulation was investigated. There were significantly increased levels of apoptosis of cells in PBMC compared to whole culture at similar plasma concentrations, suggesting that cell viability was plasma concentration-dependent. There were significantly increased levels of apoptosis in PBMC cultures at the same cell concentration to whole blood techniques, suggesting that interaction between all cellular elements (as in whole blood techniques) is important in maintaining cell viability. These results suggest that whole blood culture techniques provide the best conditions for study of leukocyte cytokine production. If PBMC culture is performed, similar plasma and cell concentration to whole blood will best preserve cell viability.

An evaluation of Lycosa hilaris as a bioindicator of organophosphate insecticide contamination

The potential of Lycosa hilaris as a bioindicator of organophosphate contamination was assessed experimentally in a crop of beans (Phaseolus vulgaris) in Canterbury New Zealand Although the numbers of L hilaris caught in pitfall traps fluctuated significantly as the crop aged there were no differences (P>005) in L hilaris abundance in plots sprayed with diazinon or chlorpyrifos compared with plots of beans sprayed with water The abundances of other beneficial arthropod predators (linyphiid spiders harvestmen centipedes) were also not affected by insecticide application (P>005) Although L hilaris may not represent a good bioindicator the use of this species as a laboratory bioassay organism should be further investigated especially with respect to sublethal physiological responses

Surface and intracellular interleukin-2 receptor expression on various resting and activated populations involved in cell-mediated immunity in human peripheral blood

The kinetics of assembly of the high-affinity interleukin-2 receptor (IL-2R)alpha/beta/gamma were investigated by studying intracellular and surface expression of IL-2Ralpha, beta and gamma by T cells, monocytes and natural killer (NK) cells. IL-2Ralpha and IL-2Rgamma were expressed by small numbers of resting T cells. These numbers increased following stimulation, to maximal expression at 48 h and 72 h, respectively. This observation was consistent with de novo synthesis of the receptor protein in response to the stimulus. The proportion of T cells producing IL-2Rbeta was smaller and up-regulated later than the proportion of cells producing IL-2Ralpha or IL-2Rgamma. IL-2Rbeta may therefore slow the assembly of the high-affinity IL-2R on T cells. A small number of resting NK cells expressed IL-2Ralpha, both on the cell surface and intracellularly, but this increased over 72 h on stimulated NK cells. IL-2Rbeta was constitutively expressed, both on the cell surface and intracellularly, by monocytes and NK cells. An increased proportion of NK cells and monocytes produced IL-2Rbeta, 24 h and 4 h post-stimulation, respectively. Maximal or plateau expression occurred at 72 h and 24 h post-stimulation, for NK cells and monocytes, respectively. The early up-regulation of intracellular IL-2Rbeta for monocytes may facilitate the up-regulation of surface IL-2Rbeta, and early assembly of the high-affinity IL-2R, accelerating monocyte activation and function. High constitutive intracellular IL-2Rgamma expression (> 80%) in all types of leucocyte investigated, decreased over the 72 h following stimulation with a concurrent increase in surface expression. IL-2Rgamma was expressed by increased proportions of T cells, monocytes and NK cells, 4 h following stimulation. The intracellular storage of IL-2Rgamma may accelerate translocation to the cell surface after stimulation. The early translocation of IL-2Rgamma may reflect its usage as a signal transduction molecule by other cytokine receptors - IL-4, IL-7, IL-9 and IL-15. This study delineated the potential expression of the high-affinity IL-2Ralpha/beta/gamma on various stimulated leucocytes. The differential kinetics of assembly of the high-affinity IL-2Ralpha/beta/gamma on different leucocyte subsets suggests that IL-2 may regulate the inflammatory cellular responses in a sequential manner, paralleling the timed expression of IL-2Ralpha/beta/gamma on the monocytes, NK cells and T cells.

Postinoculation PMPA treatment, but not preinoculation immunomodulatory therapy, protects against development of acute disease induced by the unique simian immunodeficiency virus SIVsmmPBj

The fatal disease induced by SIVsmmPBj4 clinically resembles endotoxic shock, with the development of severe gastrointestinal disease. While the exact mechanism of disease induction has not been fully elucidated, aspects of virus biology suggest that immune activation contributes to pathogenesis. These biological characteristics include induction of peripheral blood mononuclear cell (PBMC) proliferation, upregulation of activation markers and Fas ligand expression, and increased levels of apoptosis. To investigate the role of immune activation and viral replication on disease induction, animals infected with SIVsmmPBj14 were treated with one of two drugs: FK-506, a potent immunosuppressive agent, or PMPA, a potent antiretroviral agent. While PBMC proliferation was blocked in vitro with FK-506, pig-tailed macaques treated preinoculation with FK-506 were not protected from acutely lethal disease. However, these animals did show some evidence of modulation of immune activation, including reduced levels of CD25 antigen and FasL expression, as well as lower tissue viral loads. In contrast, macaques treated postinoculation with PMPA were completely protected from the development of acutely lethal disease. Treatment with PMPA beginning as late as 5 days postinfection was able to prevent the PBj syndrome. Plasma and cellular viral loads in PMPA-treated animals were significantly lower than those in untreated controls. Although PMPA-treated animals showed acute lymphopenia due to SIVsmmPBj14 infection, cell subset levels subsequently recovered and returned to normal. Based upon subsequent CD4(+) cell counts, the results suggest that very early treatment following retroviral infection can have a significant effect on modifying the subsequent course of disease. These results also suggest that viral replication is an important factor involved in PBJ-induced disease. These studies reinforce the idea that the SIVsmmPBj model system is useful for therapy and vaccine testing.

Functional lymphocyte immunophenotypes observed in thalassaemia and haemophilia patients receiving current blood product preparations

Immune abnormalities have been reported in recipients of cellular and plasma blood products. To document the effect of current transfusion practices, we performed ex vivo lymphocyte immunophenotypic studies on patients with thalassaemia major who had received multiple (leucocyte-depleted) transfusions and patients with haemophilia A and B who had received heat viral-inactivated factor concentrates. Patients with thalassaemia major showed a significant lymphocytosis, with mainly B-cell changes consistent with ongoing B-cell stimulation associated with chronic exposure to red cell antigens. Reduced T-cell IL-2Ralpha expression would be consistent with inhibition by desferrioxamine chelation therapy. In contrast, patients with haemophilia showed predominantly T-cell changes. Patients with haemophilia A showed significantly elevated activated CD8+ cytotoxic T lymphocytes whereas those with haemophilia B showed an increase in CD8+CD11adim and CD4+CD45RA+ suppressor T cells. Several of the immune abnormalities found may be due to the presence of cytokines not removed by leucocyte filtration or destroyed by factor concentrate production (e.g. TGF-beta) causing a T-helper-2-like response. The extensive lymphocyte characterization in this study has not previously been performed and has enabled a closer examination of the functional lymphocyte immunophenotypes seen in patients treated according to current transfusion practices.

Methyl-prednisolone up-regulates monocyte interleukin-10 production in stimulated whole blood

Glucocorticosteroids (GCS) have been used successfully in the treatment of inflammatory conditions such as asthma and acute graft-vs-host disease, but their mode of action remains unclear. There have been numerous reports of the in-vitro suppression of cytokine production by GCS based on quantitation of cytokines by ELISA on bulk supernatants from isolated cell culture systems. We report the use of a whole-blood intracellular cytokine assay which is more representative of an in-vivo environment. We examined the effects of GCS, prednisolone and dexamethasone, on cytokine production by individual cells (monocytes, T lymphocytes and natural killer or NK cells) in heterogenous cell populations. Cells in whole blood were activated with various stimuli: phorbol ester and calcium ionophore for T cells, Escherichia coli lipopolysaccharide (LPS) for monocytes, and phytohaemagglutinin (PHA) plus interleukin (IL)-12 for NK cells. Brefeldin A was used as an intracellular transport inhibitor to enhance the detection of intracellular cytokine production. The effects of various concentrations (10-5, 10-7, 10-9 and 10-11 m) of GCS on cytokine production were studied using multiparameter flow cytometry. After surface staining with fluorescently-conjugated monoclonal antibodies (MoAbs) to identify cell type, cells were fixed and permeabilised. Intracellular cytokines interferon (IFN)-gamma, IL-10, IL-1alpha and beta, IL-2, tumour necrosis factor (TNF)-alpha, and IL-12 were stained with their respective conjugated MoAbs. The GCS both caused a dose-dependent modulation of cytokine production by T cells, monocytes and NK cells. After 4 h, a decrease in the MFI (amount of cytokine produced per cell) was noted for all cell types. After 24 h a decrease in both MFI and the percentage of cells producing cytokine was observed for all cell types. The exception was monocyte production of IL-10 which was enhanced at low concentrations of GCS (10-9 and 10-11 m). Our findings thus suggest that one anti-inflammatory mechanism of GCS action may be through inhibition of the release of pro-inflammatory cytokines IL-1alpha and beta, IL-2, IFN-gamma and TNF-alpha, and up-regulation of the anti-inflammatory cytokine IL-10.

Induction of fas ligand expression by an acutely lethal simian immunodeficiency virus, SIVsmmPBj14

Simian immunodeficiency virus strain PBj14, SIVsmmPBj14, is unique among primate lentiviruses in its ability to trigger the proliferation of resting simian lymphocytes and to cause the rapid death of experimentally inoculated pigtailed macaques. Severe enteropathy, immune activation, and extensive apoptosis, particularly within gut-associated lymphoid tissue, characterize the acute disease syndrome associated with SIVsmmPBj14 infection. In the present study, we examined whether the ability of this virus to cause widespread apoptosis might be linked to the up-regulation of Fas ligand (CD95L) expression in virally infected cells. In vitro studies revealed that expression of the viral Nef protein, in the absence of any other viral gene product, was sufficient to up-regulate the transcriptional activity of the CD95L promoter and to cause cell surface expression of Fas ligand. This up-regulation was NFAT dependent (inhibited by cyclosporin A) and did not occur in cells that expressed a mutated derivative of the viral Nef protein, lacking a previously defined immunoreceptor tyrosine-based activation motif. These findings were corroborated by analysis of tissue sections from virally infected macaques. Immunohistochemical staining revealed that Fas ligand expression was efficiently up-regulated in the GALT of animals that had been experimentally infected with wild-type SIVsmmPBj14 but not in animals that were infected with a nonacutely pathogenic viral mutant lacking the Nef ITAM. Taken together, these results suggest that the ability of SIVsmmPBj14 to cause acutely lethal disease and to up-regulate FasL expression may be linked. Additional studies will be required to determine whether the induction of FasL expression is in itself important for acute disease pathogenesis.

Endogenous tumor necrosis factor-alpha contributes to lymphoproliferation induced by simian immunodeficiency virus variant, SIVsmmPBj14

The simian immunodeficiency virus (SIV) isolate, SIVsmmPBj14, contains an immunoreceptor tyrosine-based activation motif (ITAM) within its nef gene product and triggers efficient lymphoproliferation in vitro. In experimentally inoculated macaque monkeys, this virus causes acutely lethal enteropathy, which is accompanied by high levels of pro-inflammatory cytokines, including tumor necrosis factor (TNF)-alpha. Since TNF-alpha has been shown to possess weak comitogenic activity for antigen- or mitogen-induced human T-cell proliferation, experiments were conducted to examine whether TNF-alpha might also contribute to SIVsmmPBj14-induced lymphoproliferation. Addition of a dimeric soluble human TNF receptor (sTNFR):Fc fusion protein to SIVsmmPBj14-infected simian peripheral blood mononuclear cells (PBMC) resulted in a partial (> 50%) inhibition of virally-induced lymphoproliferation, but had no effect on the strong T-cell activation signal provided by phytohemagglutinin and interleukin-2. Finally, the addition of exogenous human TNF-alpha to simian PBMC infected with a non-mitogenic variant of SIVsmmPBj14 failed to result in detectable lymphoproliferation, suggesting that TNF-alpha alone is not sufficient to cause the proliferation of SIV infected T-cells. Taken together, the data suggest that endogenous TNF-alpha enhances SIVsmmPBj14-induced lymphoproliferation in simian PBMC cultures.

Surface activation markers of T lymphocytes: role in the detection of infection in neonates

Diagnosis of perinatal infection in the newborn is difficult; there may be few clinical signs and current tests are slow or non-specific. Detection of organisms, antigen or specific antibody to common pathogens often requires repeat samples and does not give immediate results. Haematological parameters, although relied upon frequently to diagnose infection in the neonate prior to a positive bacterial isolation, are unreliable and insensitive. Indicators such as an increase in neutrophil band cell counts are highly variable between morphologists. Infection induces the expression of a number of T lymphocyte surface markers, including CD45RA/CD45RO and CD45RO. The use of changed expression of surface markers as a laboratory test for detection of infection in neonates was evaluated. We used multiparameter flow cytometry to detect expression of early (CD45RA/CD45RO) and late (CD45RO) activation markers. In the respective groups of 50 full term (including 25 normal vaginal deliveries and 25 caesarean deliveries) and 30 premature, i.e. < 36 weeks gestation (born by either normal vaginal delivery or caesarean delivery) the CD45RA isoform was brightly expressed on newborn 'naive' CD4+ T cells, whereas the CD45RO isoform (including both 'bright' and 'dim' populations) was present on < 19% of CD4+ T cells from these newborn infants. In a group of 37 infants, tested to evaluate possible effects of non-infective parameters such as respiratory distress and iso-immunization, no significant changes in surface marker expression were found and specificity of the test was confirmed. In 14 neonates with documented sepsis, up-regulation of dual staining CD45RA/CD45RO isoforms on CD4+ T cells was detected early in the infection. In addition, we found that CD45RO expression persisted for several weeks after bacterial infection, and up to several months in viral infection. In conclusion, detection of T cell activation by flow cytometry for the early diagnosis of neonatal infection is an easy test to carry out on small volumes of blood, is inexpensive, and may be a specific indicator of infection.