Farm Exposures and Allergic Disease Among Children Living in a Rural Setting

OBJECTIVES

The purpose of this study was to examine the association between farm exposures and asthma and allergic disease in children while also highlighting the experiences of non-farm rural children.

METHODS

This was a cross-sectional analysis of data collected from across the province of Saskatchewan, Canada in 2014. Surveys were completed by parents of 2275 rural dwelling children (farm and non-farm) aged 0 to 17 years within 46 rural schools. Questionnaires were distributed through schools for parents to complete.

RESULTS

Asthma prevalence was 7.6%, of which 29.5% of cases were allergic. After adjustment for potential confounders, home location (farm vs non-farm) and other farm exposures were not associated with asthma and asthma phenotypes. Those who completed farm safety education were more likely to have asthma (11.7% vs. 6.7%; p = .001) compared to children without asthma. In sub-analyses among 6-12-year-old children, boys were more likely to have asthma (non-allergic) and use short-acting beta-agonists compared to girls. Doing farm work in the summer was associated with an increased risk of asthma [adjusted OR (aOR) = 1.71 (1.02-2.88); p = .041]. Doing routine chores with large animals was associated with an increased risk of asthma [aOR = 1.83 (1.07-3.15); p = .027] and allergic asthma [aOR = 2.37 (95%CI = 1.04-5.40); p = .04].

CONCLUSION

The present study showed that the prevalence of asthma and asthma phenotypes were similar between farm and non-farm rural children. There did not appear to be differential involvement in farming activities between those with and without asthma although those with asthma had more training suggesting possible attempts to mitigate harm from farm exposures.

Field Evaluations of Sulfuryl Fluoride Fumigation for Control of the Common Bed Bug (Hemiptera: Cimicidae), Using a 1.9× Dosage Factor in Motor Vehicles and Filled Cargo Trailers

This study investigated the efficacy of using Vikane gas fumigant (sulfuryl fluoride) at the 1.9× dosage rate for eliminating bed bugs (Cimex lectularius L.) in two challenging infestation situations: personal vehicles, and confined spaces densely packed with personal belongings. The vehicles used in this study were large minivans with seating that folded into the floor. The confined spaces were cargo trailers filled to 85% capacity with books, furniture, and other household items. Each van and trailer was equipped with ~90 sentinel bed bugs consisting of three groups of 9-11 bed bug eggs, 10 nymphs, and 10 adults. The Vikane Fumiguide calculator was used to determine the target dosage (g-h/m3) to apply in each replicate (e.g., one van or trailer). Sulfuryl fluoride concentrations were measured throughout the fumigation process using a Spectros SF-ReportIR. Concentration readings were input into the Fumiguide to determine when the accumulated dosage (g-h/m3) was achieved, and when aeration should be initiated. After aeration was complete, the sentinel bed bugs were removed from the replicates and bed bug nymph and adult mortality was recorded. Bed bug eggs were monitored for 23 d to determine latent mortality. Fumigated bed bug mortality for each replication was 100% regardless of life stage. Latent mortality was observed in a single bed bug egg, but the first instar never fully eclosed. This study determined that fumigation with sulfuryl fluoride at the 1.9× dosage factor is an effective method for eliminating resistant bed bugs from vehicles and personal belongings in densely packed situations.

CXCR1/CXCR2 antagonist CXCL8(3-74)K11R/G31P blocks lung inflammation in swine barn dust-instilled mice

Inhalation of agricultural occupational dusts from swine confinement facilities can result in lung inflammation. The innate immune response to organic barn dusts results in production of a number of pro-inflammatory factors in the lungs of barn workers such as cytokines, chemokines, and an influx of neutrophils. Many of these inflammatory factors are influenced by the chemokine CXCL8/IL-8 (KC or MIP-2 in mice). Previously, we have demonstrated that an endotoxin-independent component of swine barn dust extract (SBE) elevates lung chemokines in a protein kinase C (PKC)-dependent manner resulting in the significant formation of lung inflammatory cell infiltrates in a mouse model of SBE injury. In this study we test the ability of a CXCR1/CXCR2 antagonist, CXCL8(3-74)K11R/G31P (G31P) to block many of the features of lung-inflammation in response to challenge with SBE in an established mouse exposure system. Injection of G31P concurrent with SBE nasal instillation over a course of 3 weeks significantly reduced neutrophil accumulation in the lungs of barn dust exposed animals compared to those given SBE alone. There was a similar reduction in pro-inflammatory cytokines and chemokines IL-6, KC, and MIP-2 in SBE plus G31P-treated mice. In addition to excreted products, the receptors ICAM-1, CXCR1, and CXCR2, which all were elevated with SBE exposure, were also decreased with G31P treatment. SBE activation of PKCα and PKCε was reduced as well with G31P treatment. Thus, G31P was found to be highly effective at reducing several features of lung inflammation in mice exposed to barn dust extracts.

Proteinase-activated receptor-2 activation participates in allergic sensitization to house dust mite allergens in a murine model

BACKGROUND

Many aeroallergens contain proteinase activity and are able to induce allergic sensitization when presented to mucosal surfaces. Some of these allergens activate proteinase-activated receptor-2 (PAR2 ).

OBJECTIVE

To determine the role of PAR2 activation in a murine house dust mite (HDM) allergy model.

METHODS

We sensitized and challenged PAR2 -deficient mice with HDM, and examined allergic outcomes compared to wild-type animals. To focus on the role of PAR2 in allergic sensitization, we administered a PAR2 blocking antibody to wild-type animals during the sensitization phase and examined the outcomes immediately after sensitization or following subsequent allergen challenge.

RESULTS

We found PAR2 -deficient mice sensitized and challenged with HDM failed to develop airway inflammation, did not produce HDM-specific IgG1 and had less IL-4 mRNA in the lungs than wild-type animals. Prevention of PAR2 activation during sensitization in wild-type mice diminished the levels of Th2 mediators, including IL-4, IL-5 and IL-13, in the lungs. Blocking PAR2 during the sensitization phase also led to decreased manifestations of allergic disease, including airway hyperresponsiveness (AHR) and airway inflammation following subsequent allergen challenge. HDM-induced proliferation of splenocytes obtained from animals sensitized in the presence of PAR2 antibody was reduced relative to those that did not receive antibody. The effect of PAR2 blockade could be transferred to naïve mice through splenic CD4(+) T cells from sensitized mice.

CONCLUSIONS AND CLINICAL RELEVANCE

PAR2 activation plays a key role during the sensitization phase of our HDM allergy model, leading to increased lung cytokine production and augmented lung reactivity. PAR2 activation is a common mechanism for sensitization to a wide variety of allergens and is therefore a potential pharmacological target to prevent allergy.

Therapeutic induction of tolerance by IL-10-differentiated dendritic cells in a mouse model of house dust mite-asthma

BACKGROUND

It has been reported that retrovirally transduced IL-10-expressing dendritic cells can reverse the asthma phenotype in mice, but that i.v. delivery of dendritic cells differentiated with IL-10 alone (DC10) does not. We report herein DC10 can be highly effective therapeutically in experimental asthma.

METHODS

BALB/c mice were sensitized by airway exposure to house dust mite (HDM) without use of adjuvants, then treated with 10⁶ allergen-presenting DC10. We assessed the airway hyperresponsiveness (AHR) to methacholine, circulating levels of IgE and IgG1, and airway recall responses to HDM allergen, including eosinophilia and Th2 cytokines. We also asked whether the DC10 treatments induced tolerance through activation of pulmonary regulatory T cell activities.

RESULTS

In vitro, cognate-, but not irrelevant-, allergen-presenting DC10 productively engaged pulmonary Th2-phenotype CD4(+) cells magnetically sorted from HDM-asthmatic mice in Forster (or fluorescence) resonance energy transfer assays. In vivo, treatment of HDM-asthmatic mice with HDM, but not ovalbumin-presenting DC10 abrogated AHR within 4 weeks, and significantly reduced airway eosinophilia, IL-4, IL-5, and IL-13 responses, and circulating HDM-specific IgE and IgG1 levels (each, P ≤ 0.01 versus control mice). CD4(+) CD25(+) Foxp3(+) cells from the lungs of the DC10-treated mice, but not those from asthmatic animals, up-regulated expression of the activated regulatory T cell markers CTLA4 and LAG3, and passive transfer of pulmonary CD4(+) T cells from these mice induced allergen tolerance in HDM-asthmatic recipients.

CONCLUSIONS

These findings indicate that allergen-presenting DC10 treatments up-regulate T cell regulatory activities and thereby induce allergen-specific tolerance in a relevant model of human asthma.

Measured concentrations of combustion gases from the use of unvented gas fireplaces

Measurements of combustion product concentrations were taken in 30 homes where unvented gas fireplaces were used. Measurements of CO, CO(2), NO(x), NO(2) , O(2) (depletion), and water vapor were taken at 1-min interval. The analyzers were calibrated with certified calibration gases for each placement and were in operation for 3-4 days at each home. Measured concentrations were compared to published health-based standards and guidelines. The two combustion gases that exceeded published values were NO(2) and CO. For NO(2) , the Health Canada guideline of 250 ppb (1-h average) was exceeded in about 43% of the sample and the World Health Organization (WHO) guideline of 110 ppb (1-h average) was exceeded in 80% of the sample. Carbon monoxide levels exceeded the U.S. EPA 8-h average standard of 9 ppm in 20% of the sample. Moisture problems were not evident in the test homes. An analysis of the distribution of CO showed that the CO is dispersed throughout the home almost immediately upon operation of the fireplace and that the concentrations throughout the home away from the immediate vicinity of the fireplace are 70-80% of the level near the fireplace. Decay analysis of the combustion gases showed that NO was similarly stable to CO and CO(2) in the indoor environment but that both NO(2) and water vapor were removed from the air at much greater rates.

PRACTICAL IMPLICATIONS

Previous studies on unvented gas fireplaces have made assumptions of how they are operated by users. This article presents the results of field monitoring of 30 unvented gas fireplaces under normal operation, regardless of whether users follow industry recommendations regarding installation, usage patterns, and maintenance. The monitoring found that health-based standards and guidelines were exceeded for CO in 20% of homes and for NO(2) in most homes. There were no identified moisture problems in these homes. Nearly, half of the fireplaces were used at least once for longer than 2 h, counter to manufacturers' intended usage as supplemental heating. This demonstrates that given actual usage patterns and compared to current health-based thresholds, these appliances can produce indoor air concentrations considered to be unhealthy to at least sensitive or at-risk individuals.

Postnatal changes in testicular concentrations of transforming growth factors-alpha and-beta 1, 2 and 3 and serum concentrations of insulin like growth factor I in bulls

Based on work largely in laboratory animals, transforming growth factors (TGF) and insulin like growth factors (IGF) could be regulators of testicular development. The aim of this study was to see if TGF-alpha and -beta 1, 2 and 3 are present in the bovine testis and to monitor concentrations of these factors in the testis and IGF-I in serum during reproductive development. Separate groups of Hereford x Charolais calves (n = 6) were castrated every 4 weeks from 5 to 33 weeks of age and at 56 weeks of age. A week prior to castration, from 5 to 33 weeks of age, blood was collected every 15 min for 10 h. Serum IGF-I concentrations increased from 8 to 12 weeks of age, decreased from 24 to 28 weeks and increased to 32 weeks of age (p < 0.05). Testicular TGF-alpha concentrations increased from 13 to 17 weeks of age, decreased to 21 weeks and from 33 to 56 weeks of age (p < 0.05). Testicular TGF-beta 1 concentrations decreased from 17 to 21 weeks of age, increased to 25 weeks and decreased from 25 to 33 weeks of age (p < 0.05). Testicular TGF-beta 2 concentrations increased from 5 to 17 weeks of age, decreased to 21 weeks, increased to 25 weeks and decreased at 29 weeks of age (p < 0.05). Testicular TGF-beta 3 concentrations increased from 13 to 17 weeks of age, decreased to 21 weeks and from 25 to 29 weeks of age (p < 0.05). We concluded that TGF-alpha and TGF-beta 1, 2 and 3 are present in the testis of the bull calf, and changes in concentrations with age suggest a functional role in the development of the testis.

Post-natal changes in testicular concentrations of interleukin-1 alpha and beta and interleukin-6 during sexual maturation in bulls

Based on observations in laboratory animals interleukins could be regulators of testicular development. The objects of this study were to see if interleukins (IL-1 and IL-6) are present in the developing bull testis and to establish the temporal patterns of concentrations of IL-1 and IL-6 in the bovine testis during development. Separate groups of six bull calves were castrated every 4 weeks from 5 to 33 weeks of age, and at 56 weeks of age. Mean testicular IL-1 alpha concentrations decreased (p < 0.01) from 5 to 9 weeks of age and 13 to 21 weeks of age. Mean testicular IL-1 beta concentrations decreased (p < 0.01) from 13 to 17 weeks of age and from 29 to 33 weeks of age. Mean IL-1 bioactivity increased from 13 to 17 weeks of age, decreased to 21 weeks, increased to 25 weeks, decreased to 29 weeks and decreased from 33 to 56 weeks of age (p < 0.05). Mean testicular IL-6 concentrations decreased (p < 0.05) from 9 to 13 weeks of age, increased (p < 0.05) to 21 weeks, decreased (p < 0.05) to 25 weeks, increased (p < 0.05) to 29 weeks and decreased (p < 0.01) to 56 weeks of age. In conclusion, testicular IL-1 alpha, IL-1 beta and IL-6 were found in the bovine testis and concentrations were age dependent. Testicular IL-1 alpha and IL-1 beta concentrations were highest in the early post-natal period; however, IL-1 bioactivity and IL-6 concentrations were greatest in the immediate pre-pubertal period. These findings suggest a functional role for interleukins in testicular development in the bull.

Mast cells: immunologically specific effectors and potential sources of multiple cytokines during IgE-dependent responses

Mast cells are critical effectors in many IgE-dependent responses, and the numbers and phenotype of certain mast cell populations can be influenced, through IL-3 and IL-4, by the same T cells that regulate IgE production. However, IgE can interact with cells other than mast cells, and different mast cell populations express significant variation in multiple important aspects of their phenotype, including mediator content and responses to cytokines and stimuli of activation. As a result it may be difficult to define the unique contributions of mast cells to IgE-dependent reactions. One approach for analysing the roles of various mast cell populations in individual biological responses is to attempt to elicit these reactions in mice in which the presence or absence of specific mast cell populations can be regulated experimentally. We have used genetically mast cell-deficient and mast cell-reconstituted mice to demonstrate that mast cells provide essential effector function in certain IgE-dependent responses involving the skin, stomach or lungs but are not necessary for the pulmonary alterations and death associated with active anaphylaxis. Similar approaches can be used to investigate the biological significance of the production, by mast cells stimulated with IgE and specific antigen, of cytokines similar or identical to IL-1, IL-3, IL-4, IL-5, IL-6, TNF-alpha/cachectin, IFN-gamma, GM-CSF, JE, MIP-1 alpha, MIP-1 beta and TCA3.

Functional role of specific secreted and cell surface molecules in tumour cell invasion and metastasis

The invasion and metastatic spread of tumour cells are complex biological processes involving an array of cell surface and secreted protein molecules which function as specific recognition and catalytic agents in each step of the malignant cascade. In order to begin to identify these molecules and implicate them as true functioning agents, our laboratory has developed selected panels of monoclonal antibodies that have been screened for their ability to inhibit specific manifestations of the malignant phenotype in various model systems. Since monoclonal antibodies recognize only single and unique determinants, it is hypothesized that any monoclonal antibody which is specifically antifunctional will allow for the identification and isolation of relevant protein molecules.

Regular salbutamol use increases CXCL8 responses in asthma: relationship to the eosinophil response

Regular salbutamol use can exacerbate allergen-induced airway eosinophilia in asthmatics, but its effect on airway eosinophil chemokine responses is unknown. Asthmatic subjects (n=14) were treated for 10 days with placebo or salbutamol in a double-blind, cross-over study, then given same-dose allergen challenges. Their sputa were then analysed 1 and 7 h later for a panel of eosinophil-related cytokines. Eosinophils from five test and three control subjects were tested for expression of CXCL8/interleukin (IL)-8, and its receptors and responsiveness to CCL11/eotaxin and CXCL8/IL-8. Sputum CXCL8/IL-8, but not IL-5, CCL5/regulated on activation, T-cell expressed and secreted, CCL7/monocyte chemotactic protein-3, CCL11/eotaxin, granulocyte-macrophage colony-stimulating factor or tumour necrosis factor levels, were increased (42%) by the salbutamol treatments. The CXCL8/IL-8 levels correlated with the proportions of sputum eosinophils and these cells, but not other sputum cells, stained strongly for CXCL8/IL-8. The circulating eosinophils of the tested subjects (n=5) expressed CXCL8/IL-8 receptors and secreted high levels of this chemokine. Neutralisation of sputum CXCL8/IL-8 reduced eosinophil chemotactic responses to these samples by 19 +/- 5%. These data suggest that regular use of salbutamol can augment airway CXCL8/interleukin-8 responses to allergen challenge and that this CXCL8/interleukin-8 could contribute to the airway inflammatory response.

Psychosocial issues near the end of life

End-of-life care has received increasing attention in the last decade; however, the focus continues to be on the physical aspects of suffering and care to the virtual exclusion of psychosocial areas. This paper provides an overview of the literature on the intra- and interpersonal aspects of dying, including the effects that psychosocial variables have on end-of-life decision-making; common diagnosable mental disorders (e.g., clinical depression, delirium); other types of personal considerations (e.g., autonomy/control, grief); and interpersonal/environmental issues (e.g., cultural factors, financial variables). Six roles that qualified mental health professionals can play (i.e., advocate, counselor, educator, evaluator, multidisciplinary team member, and researcher) are also outlined. Because psychosocial issues are ubiquitous and can have enormous impact near the end of life, properly trained mental health professionals can play vital roles in alleviating suffering and improving the quality of life of people who are dying.

DNA array and biological characterization of the impact of the maturation status of mouse dendritic cells on their phenotype and antitumor vaccination efficacy

We systematically investigated the impact of the relative maturation levels of dendritic cells (DCs) on their cell surface phenotype, expression of cytokines and chemokines/chemokine receptors (by DNA array and RNase protection analyses), biological activities, and abilities to induce tumor immunity. Mature DCs expressed significantly heightened levels of their antigen-presenting machinery (e.g., CD54, CD80, CD86) and numerous cytokines and chemokines/chemokine receptors (i.e., Flt-3L, G-CSF, IL-1alpha and -1beta, IL-6, IL-12, CCL-2, -3, -4, -5, -17, and -22, MIP-2, and CCR7) and were significantly better at inducing effector T cell responses in vitro. Furthermore, mice vaccinated with tumor peptide-pulsed mature DCs better survived challenge with a weakly immunogenic tumor (8 of 8 survivors) than did mice vaccinated with less mature (3 of 8 survived) or immature (0 of 8 survivors) DCs. Nevertheless, intermediate-maturity DCs expressed substantial levels of Flt-3L, IGF-1, IL-1alpha and -1beta, IL-6, CCL-2, -3, -4, -9/10, -17, and -22, MIP-2, osteopontin, CCR-1, -2, -5, and -7, and CXCR-4. Taken together, our data clearly underscore the critical nature of employing DCs of full maturity for DC-based antitumor vaccination strategies.

The importance of interleukin-8 as a neutrophil chemoattractant in the lungs of cattle with pneumonic pasteurellosis

Interleukin-8 (IL-8), an in vitro and in vivo neutrophil chemoattractant, is expressed at high levels in the lesions observed in bovine pneumonic pasteurellosis. Because of the role of neutrophils in the pathogenesis of pneumonic pasteurellosis, we investigated the relative importance of IL-8 as a neutrophil chemoattractant in this disease. Bronchoalveolar lavage (BAL) fluid was harvested from calves experimentally infected with bovine herpesvirus-1 and challenged with Mannheimia haemolytica. Neutrophil chemotactic activity was measured in pneumonic BAL fluid samples treated with a neutralizing monoclonal antibody to ovine IL-8, and compared to the activity in samples treated with an isotype-matched control antibody. Bronchoalveolar lavage fluid was analyzed at a dilution which induced a half-maximal response, and the concentrations of antibody were optimized in a preliminary experiment. Following incubation of replicate samples of diluted pneumonic bovine BAL fluid with 70 microg/mL of IL-8-neutralizing antibody or control antibody, the neutrophil chemotactic activities of the samples were determined using an in vitro microchemotaxis assay. Overall, pretreatment of BAL fluid samples with neutralizing anti-IL-8 antibody reduced neutrophil chemotactic activity by 15% to 60%, compared to pretreatment with control antibody. This effect was highly significant (P < 0.001), and was present in 5 of 5 samples. These data indicate that IL-8 is an important neutrophil chemoattractant in calves with pneumonic pasteurellosis, but that mediators with actions redundant to those of IL-8 must also be present in the lesions.

Induction of pulmonary allergen-specific IgA responses or airway hyperresponsiveness in the absence of allergic lung disease following sensitization with limiting doses of ovalbumin-alum

Respiratory allergies represent a failure to generate nonpathogenic responses to innocuous foreign materials. Herein we assessed the role of the sensitizing dose of allergen in this response/nonresponse paradigm, sensitizing BALB/c mice with 5 ng-2 microg of OVA-alum and assessing their responses to repeated OVA aerosol challenge. Mice sensitized with < or = 25 ng of OVA-alum did not develop atopic antibodies, airway hyperresponsiveness (AHR), eosinophilia, or pulmonary Th2 responses, but the 25-ng group animals did develop significant IgA responses. The mice sensitized with 100 ng of OVA-alum developed AHR in the absence of detectable allergic disease, while the mice sensitized with 250 ng-2 microg of OVA/alum developed full-spectrum allergic disease (i.e., eosinophilia, IgE, IgG1, pulmonary Th2 cytokine responses, and AHR). These data indicate that limiting doses of allergen can differentially induce IgA or AHR in the absence of atopic disease in mice.

Il-8((3-73))K11R is a high affinity agonist of the neutrophil CXCR1 and CXCR2

In studies aimed at developing a high affinity IL-8 antagonist, our first objective was to generate a high-affinity IL-8 analogue. We targeted amino acids within the receptor-binding domain and found that IL-8((3-73))K11R induced significantly more neutrophil beta-glucuronidase release than either IL-8 or the alternate analogues and, in chemotaxis assays, induced 2-3-fold greater neutrophil responses than IL-8. Furthermore, in competitive radio- or biotinylated-ligand binding assays, IL-8((3-73))K11R was more effective than IL-8, IL-8((3-73)), or its T12S, H13F, and K11R/T12S/H13F analogues in blocking IL-8 binding to neutrophils; 1.8 pmol IL-8((3-73))K11R inhibited by 50% the binding of approximately 20 pmol (125)I-IL-8 to neutrophils. Both IL-8 (a CXCR1/CXCR2 ligand) and the CXCR2-specific ligand GROalpha differentially inhibited binding of (125)I-IL-8((3-73))K11R to neutrophils, albeit weakly, suggesting that IL-8((3-73))K11R is a high affinity ligand for both the CXCR1 and CXCR2. Thus IL-8((3-73))K11R is an excellent candidate for further studies aimed at generating a high affinity IL-8 antagonist.

Lymphotactin expression by engineered myeloma cells drives tumor regression: mediation by CD4+ and CD8+ T cells and neutrophils expressing XCR1 receptor

The C chemokine lymphotactin has been characterized as a T cell chemoattractant both in vitro and in vivo. To determine whether lymphotactin expression within tumors could influence tumor growth, we transfected an expression vector for lymphotactin into SP2/0 myeloma cells and tested their ability to form tumors in BALB/c and nude mice. Transfection did not alter cell growth in vitro. Whereas SP2/0 cells gave rise to a 100% tumor incidence, lymphotactin-expressing SP2/0-Lptn tumors invariably regressed in BALB/c mice and became infiltrated with CD4(+) and CD8(+) T cells and neutrophils. Regression of the SP2/0-Lptn tumors was associated with a type 1 cytokine response and dependent on both CD4(+) and CD8(+) T cells, but not NK cells. Both SP2/0 and SP2/0-Lptn tumors grew in nude mice, but growth of the latter tumors was retarded and associated with heavy neutrophil responses; this retardation of SP2/0-Lptn tumor growth was reversed by neutrophil depletion of the mice. Our data also indicate that mouse neutrophils express the lymphotactin receptor XCR1 and that lymphotactin specifically chemoattracts these cells in vitro. Thus, lymphotactin has natural adjuvant activities that may augment antitumor responses via effects on both T cells and neutrophils and thereby could be important in gene transfer immunotherapies for some cancers.

Expression of transforming growth factor beta(1), beta(3), and basic fibroblast growth factor in full-thickness skin wounds of equine limbs and thorax

OBJECTIVE

To map the expression of transforming growth factor (TGF)-beta(1), TGF-beta(3), and basic fibroblast growth factor (bFGF) in full-thickness skin wounds of the horse. To determine whether their expression differs between limbs and thorax, to understand the pathogenesis of exuberant granulation tissue.

STUDY DESIGN

Six wounds were created on one lateral metacarpal area and one midthoracic area of each horse. Sequential wound biopsies allowed comparison of the temporal expression of growth factors between limb and thoracic wounds.

ANIMALS

Four 2- to 4-year-old horses.

METHODS

Wounds were assessed grossly and histologically at 12 and 24 hours, and 2, 5, 10, and 14 days postoperatively. ELISAs were used to measure the growth factor concentrations of homogenates of wound biopsies taken at the same timepoints.

RESULTS

TGF-beta(1) peaked at 24 hours in both locations and returned to baseline in thoracic wounds by 14 days but remained elevated in limb wounds for the duration of the study. Expression kinetics of TGF-beta(3) differed from those of TGF-beta(1). TGF-beta(3) concentrations gradually increased over time, showing a trend toward an earlier and higher peak in thoracic compared with limb wounds. bFGF expression kinetics resembled those of TGF-beta(1), but no statistically significant differences existed between limb and thoracic wounds.

CONCLUSIONS

Growth factor expression is up-regulated during normal equine wound repair. TGF-beta(1) and TGF-beta(3) show a reciprocal temporal regulation. Statistically significant differences exist between limb and thoracic wounds with respect to TGF-beta(1) expression.

CLINICAL RELEVANCE

The persistence of TGF-beta(1) expression in leg wounds may be related to the development of exuberant granulation tissue in this location, because TGF-beta(1) is profibrotic.

Neutrophils and B cells express XCR1 receptor and chemotactically respond to lymphotactin

The C chemokine lymphotactin (Lptn) has been reported to act specifically on CD4(+) and CD8(+) T lymphocytes and natural killer (NK) cells, but not monocytes. However, the chemotactic effect of Lptn on other types of hematopoietic cells has not been well studied. In this study we investigated (i) the chemotactic influences of Lptn on T and B lymphocytes, neutrophils, monocytes, and dendritic cells, and (ii) the expression of the Lptn receptor (XCR1) by these cells, using RT-PCR. Our data showed that Lptn is chemotactic for B lymphocytes and neutrophils as well as T lymphocytes, but not for monocytes or dendritic cells, and that XCR1 expression is found only in association with T and B lymphocytes and neutrophils, but not monocytes or dendritic cells. Thus, this study is the first demonstration of a chemotactic effect of Lptn on neutrophils and confirms the association of this effect with expression of the XCR1 receptor on these cells. These data suggest that Lptn could potentially be an important protein in the regulation of T and B lymphocytes and neutrophil trafficking, and thereby also their roles in inflammatory and immunological responses.

Thrombin induces IL-6 but not TNFalpha secretion by mouse mast cells: threshold-level thrombin receptor and very low level FcepsilonRI signaling synergistically enhance IL-6 secretion

Mast cells become activated in multiple diseases wherein thrombin generation is often clinically apparent, but the effect of thrombin on cytokine release by mast cells remains unexplored. Thus, we examined IL-6 and TNFalpha release by thrombin-challenged mast cells. Thrombin and the protease-activated receptor (PAR)-1 peptide TRAP(14) induced these cells to secrete IL-6 in a dose-dependent fashion. Mast cells secreted > or =2800 pg IL-6/10(6) cells over 24 h, but only low levels of serotonin and no significant TNFalpha. Furthermore, at near-background levels of allergen, threshold doses of alpha-thrombin synergistically enhanced the IL-6 response (by up to 100-fold), but high-dose costimulation led to a simple additive response. Both the PI(3)- and sphingosine-kinase signaling pathways contributed importantly to the thrombin response. Our data thus clearly demonstrate that low-level thrombin and FcepsilonRI signaling can synergize to augment mast cell IL-6 responses, and that thrombin also differentially induces cytokine secretion by mast cells.

Cloning a chloride conductance mediator from the apical membrane of porcine ileal enterocytes

Attempts to attribute ileal brush-border chloride conductance to specific proteins were pursued by screening a porcine intestinal cDNA library. A 0.94-kb clone was identified on expression screening with a monoclonal antibody that inhibited enterocyte brush-border chloride conductance. Further screening approaches led to the isolation of a 3.1-kb full-length sequence called pCLCA1, consistent with the identification of a 2.9-kb transcript through Northern analysis. This sequence had significant homology to the CLCA gene family of calcium-regulated chloride channels, especially to hCLCA1. However, a strong A-kinase consensus phosphorylation site in a predicted cytoplasmic loop of the protein was a notable difference from the hCLCA1 gene product. Several porcine exocrine epithelial tissues, including ileum, trachea, and the major salivary glands express pCLCA1 mRNA. In situ hybridization studies localized the expression of pCLCA1 mRNA to the crypt and villus epithelia of porcine ileum, whereas tracheal expression was observed in both surface epithelium and submucosal glands. In situ expression of pCLCA1 in mouse 3T3 cells induces an ionomycin-dependent chloride conductance activity in these cells.

Monocyte chemoattractant peptide-1 expression during cutaneous allergic reactions in mice is mast cell dependent and largely mediates the monocyte recruitment response

BACKGROUND

Macrophages and infiltrating monocytes comprise the largest population of cells within the airways of patients with allergic asthma. Both become activated and thus contribute to the pathologic features of allergic reactions, but the mechanism by which they are recruited has not been well documented.

OBJECTIVE

Our purpose was to assess the role of the CC chemokine monocyte chemotactic peptide-1 (MCP-1) in monocyte recruitment during allergic reactions in mice.

METHOD

We used immunohistochemistry and Northern blotting to assess MCP-1 expression, selective mast cell reconstitution of mast cell-deficient W/W(v) mice to demonstrate the mast cell dependence of MCP-1 expression and monocyte recruitment and neutralizing anti-MCP-1 antibodies to block monocyte recruitment during cutaneous allergic reactions.

RESULTS

MCP-1 was expressed largely by resident dermal cells within the allergic lesions at 4 hours after challenge, followed within several hours by an influx of monocytes; at 10 hours after challenge monocytes comprised a substantial proportion of the infiltrating cells at the nidus of the response. Mast cell-reconstituted, but not mast cell-deficient W/W(v) mice expressed MCP-1 transcripts and developed monocyte infiltrates after allergen challenge. Finally, anti-MCP-1 antibody treatments reduced by approximately 63% the influx of monocytes into the reaction sites.

CONCLUSIONS

These data clearly demonstrate the mast cell dependence of the MCP-1 expression and the monocyte influx and establish a substantial, but not exclusive, causal relationship between these 2 events.

Innate resistance to experimental African trypanosomiasis: differences in cytokine (TNF-alpha, IL-6, IL-10 and IL-12) production by bone marrow-derived macrophages from resistant and susceptible mice

Resistance to African trypanosomiasis is under multigenic control. BALB/c mice are highly susceptible while C57Bl/6 mice are relatively resistant. Macrophages eliminate opsonized trypanosomes from the bloodstream and are involved in immunosuppression. We therefore investigated the production of a number of cytokines (IL-10, IL-6, TNF-alpha and IL-12) by bone marrow-derived macrophages (BMDM) from C57Bl/6 and BALB/c mice following challenge with either Trypanosoma congolense or Trypanosoma brucei. BMDM from C57Bl/6 mice, upon challenge with whole cell extracts (WCE) of T. congolense or T. brucei, produced significantly more TNF-alpha and IL-12 than those from BALB/c mice. The production of these cytokines was significantly enhanced by pretreatment of the cells with IFN-gamma. BMDM from BALB/c mice, however, produced significantly more IL-6 and IL-10 than those from C57Bl/6 mice. In contrast to LPS stimulation, simultaneous treatment of cells with WCE and IFN-gamma enhanced IL-10 synthesis by BMDM from BALB/c mice. These results indicate that cytokine genes are differentially regulated in macrophages from trypanosome-susceptible and -resistant mice and are consistent with our previous findings wherein retrovirus-immortalized macrophage cell lines from BALB/c and C57Bl/6 mice produce differential amounts of cytokines after phagocytosis of trypanosomes.

Mast cell tryptase release and asthmatic responses to allergen increase with regular use of salbutamol

BACKGROUND

Increased asthmatic responses to allergen, both early and late, have been demonstrated after regular use of beta(2)-agonists in as few as 7 days. Desensitization of beta(2)-adrenergic receptors on airway mast cells may contribute to this effect by allowing greater release of mast cell mediator on allergen-induced degranulation. Tryptase released from lung mast cells can be measured in serum 1 hour after allergen challenge and serves as a marker of mast cell degranulation.

OBJECTIVE

To examine the effect of regular treatment with salbutamol, a beta(2)-agonist, on mast cell mediator release after allergen challenge and its influence on the early asthmatic response (EAR) and the late allergic response, we measured the EAR, serum tryptase levels, the 7-hour FEV(1), and sputum tryptase levels and cell profiles.

METHODS

We conducted a placebo-controlled, double-blind, randomized cross-over comparison of treatments for 10 days with either a salbutamol metered-dose inhaler (100 microgram, 2 puffs 4 times daily) or a matched placebo inhaler with at least a 7-day washout between treatments. Atopic subjects (n = 14) with mild-to-moderate asthma performed same-dose allergen inhalation tests after both treatments 12 to 15 hours after the last dose of study inhaler. Baseline and 7-hour FEV(1) and the EAR to allergen were measured by using spirometry; venous blood was drawn at 1 hour for analysis of serum tryptase; and sputum was induced and collected at 1 and 7 hours.

RESULTS

Salbutamol treatment resulted in a significantly greater EAR (20% +/- 1.6% [SEM] vs 15% +/- 2.1%; P =.047); increased 1-hour serum tryptase levels (9.09 +/- 1.57 vs 7.52 +/- 1.12 microgram/L; P =. 011); increased proportions of eosinophils in the 7-hour sputum sample (39.1% +/- 5.1% vs 28.4% +/- 4.4%; P <.05); increased proportion of metachromatic cells in the 7-hour sputum sample (4.4% +/- 1.1% vs 2.2% +/- 0.6%; P =.032); and lower 7-hour FEV(1) (2.77 +/- 0.18 vs 2.97 +/- 0.20 L; P =.014). Baseline FEV(1) was not significantly different after salbutamol treatment compared with values after placebo treatment (2.90 +/- 0.20 vs 3.00 +/- 0.19 L; P =.11).

CONCLUSION

Regular 10-day treatment with salbutamol increases the allergen-induced release of mediator from airway mast cells, and this is reflected in an increased EAR to allergen. Late-phase responses to allergen were also enhanced, as demonstrated by decreased 7-hour FEV(1) and increased eosinophilia and percentage of metachromatic cells in the 7-hour sputum sample. Increased allergen-induced mast cell degranulation could, in part, explain the increased asthmatic responses to allergen after beta(2)-agonist treatment and could contribute to the deterioration of asthma control that is associated with regular use of beta(2)-agonist by potentiating allergic inflammation.

TGFbeta1 and TNFalpha secreted by mast cells stimulated via the FcepsilonRI activate fibroblasts for high-level production of monocyte chemoattractant protein-1 (MCP-1)

Monocytes/macrophages usually make up the largest population of cells in the airways of allergic asthma patients and, as such, contribute substantially to the pathogenesis of this and other allergic diseases. In this report we address one mechanism by which monocytes can be recruited during allergic responses. We and others have shown previously that MCP-1 is important to monocyte infiltration of the tissues during allergic responses in mice and, independently, that mast cells activate fibroblasts to express type alpha1(I)-collagen during such responses. We demonstrate herein that immunologically activated, but not quiescent mouse bone-marrow-derived mast cells release mediators which in turn activate primary cultures of embryonic dermal fibroblasts for high-level secretion of monocyte chemoattractant activities. We identify the CC chemokine MCP-1 as a major component of this activity. Anti-MCP-1 antibodies neutralized approximately 80% of the monocyte chemoattractant activities secreted by such mast-cell-activated fibroblasts. Furthermore, our data implicate mast cell TGFbeta and TNFalpha in this process. Depletion of TGFbeta, TNFalpha, or both TGFbeta and TNFalpha from the mediator pool secreted by mast cells activated via the FcepsilonRI reduced the mast-cell-driven fibroblast MCP-1 response by 80+/-15, 56+/-11, or 82+/-5%, respectively. These data thus further delineate a mechanism by which fibroblasts are recruited into and participate in the mast cell-leukocyte cytokine cascades that orchestrate allergic responses.

Transtracheal administration of interleukin-12 induces neutrophil responses in the murine lung

Although the roles of interleukin-12 (IL-12) in the immunomodulation of antigen-specific responses are well characterized, the effects of IL-12 on the respiratory tract following mucosal administration are not well defined. Therefore, we investigated changes in the murine lung shortly after intranasal (i.n.) administration of murine IL-12. We showed that IL-12 induced neutrophil influx to the murine lung in both C57BL/6 and BALB/c mice. Histologic examination revealed that intranasal administration of IL-12 with liposomes induced focal neutrophil infiltration into the alveoli and a significant increase in neutrophils in bronchoalveolar lavage fluids when compared with administration of liposomes alone. In vitro chemotaxis assays indicated that the observed pulmonary neutrophil response induced by IL-12 could have been due in part to the direct chemotactic activity of IL-12 for murine neutrophils.

Innate resistance to Trypanosoma congolense infections: differential production of nitric oxide by macrophages from susceptible BALB/c and resistant C57Bl/6 mice

BALB/c and C57B1/6 mice differ in resistance to Trypanosoma congolense infections. Evidence suggests that macrophages play a central role in the resistance to trypanosomiasis. Nitric oxide (NO) produced by macrophages in response to various stimuli or pathogens is one of the important arms of nonspecific immunity. We investigated the production of NO by the peritoneal macrophages and bone marrow-derived macrophages (BMDM) from trypanosome-resistant C57B1/6 and -susceptible BALB/c mice following stimulation with T. congolense whole cell extract (WCE) or following phagocytosis of T. congolense mediated by anti-variant surface glycoprotein (VSG) antibodies of IgM or IgG2a isotype. C57B1/6 peritoneal macrophages as well as BMDM produced significantly more NO than similar BALB/c macrophages in response to T. congolense lysate and IFN-gamma. In both BALB/c and C57B1/6 BMDM cultures, phagocytosis of T. congolense mediated by anti-VSG antibodies of IgG2a isotype in the presence of IFNgamma induced two- to ninefold more NO than phagocytosis mediated by IgM antibodies and C57B1/6 BMDM produced significantly higher amounts of NO than BALB/c BMDM under these conditions. NO produced by BMDM was found to exert trypanostatic effect on T. congolense in vitro, but was not found to influence the in vivo infectivity of these treated parasites under the conditions used in this study.

Innate resistance to experimental Trypanosoma congolense infection: differences in IL-10 synthesis by macrophage cell lines from resistant and susceptible inbred mice

BALB/c and C57Bl/6 mice differ in resistance to T. congolense infections. We investigated the production of various cytokines (IL-10, IL-6, TNF-alpha and TGF-beta) by macrophages from these mice. Macrophage cell lines (BALB.BM cells) of BALB/c mice but not (ANA-I cells)of C57BL/6 mice constitutively produced IL-10. Challenge of these cells with trypanosomes induced the production of 50-100 times more IL-10 in BALB.BM cells than in ANA-1 cells. Pre-incubation of the cell lines with IFN-gamma. prior to the trypanosome challenge, further upregulated this IL-10 production in BALB.BM but not in ANA-1 cells. Primary cultures of bone marrow-derived macrophages (BMDM) from BALB/c mice also produced more IL-10 following challenge with IFN-gamma and opsonized trypanosomes than did the C57Bl/6 BMDM. Similarly after challenge with trypanosomes, BALB.BM and BALB/c BMDM produced significantly more IL-6 than did the analogous cells from the C57Bl/6 mice following such challenges. Higher steady state levels of TNF-alpha mRNA accumulated in ANA-1 cells than in BALB.BM cells following challenge with IFN-gamma and opsonized trypanosomes. Findings of this study for the first time indicate a differential regulation of cytokines (IL-10, IL-6 and TNF-alpha) in macrophages of mice that significantly differ in their susceptibility to infections with T. congolense.

Production and functional characterization of recombinant bovine interleukin-8 as a specific neutrophil activator and chemoattractant

Interleukin-8, a member of the chemokine family of cytokines, is a potent neutrophil chemoattractant in many non-rodent species. In this study, recombinant bovine interleukin-8 (rbIL-8) was expressed in bacteria as a glutathione-S-transferase fusion protein. The fusion protein was purified by glutathione-Sepharose affinity chromatography and recombinant rbIL-8 was eluted by cleaving with thrombin. The purified rbIL-8 molecule was approximately 8 kDa and was confirmed as authentic IL-8 by Western analysis. Recombinant bovine IL-8 induced specific dose-dependent in vitro chemotaxis of neutrophils at doses as low as 1.0 ng/ml, and this activity was inhibited by pre-treatment of rbIL-8 with a monoclonal antibody to ovine IL-8. Neutrophils exposed to rbIL-8 developed pseudopodia and became elongated as determined by microscopic analysis and flow cytometry. Injection of 3.3 ng to 3.3 microg of rbIL-8 into the skin of a normal calf induced dose-dependent recruitment of neutrophils but not eosinophils. Intravascular margination of neutrophils was obvious at the injection sites from 15 to 60 min after administration of rbIL-8, and extravascular neutrophil numbers increased steadily from 1 to 18 h after injection. Neutrophils with morphologic features of apoptosis were detected in these lesions at 18 and 30 h after injection, and this correlated with reduction in the number of dermal neutrophils. These results confirm unequivocally that bovine IL-8 functions as a neutrophil, but not an eosinophil, chemoattractant in vitro and in vivo.

Cytokines and antibody responses during Trypanosoma congolense infections in two inbred mouse strains that differ in resistance

We studied IL-4, IL-10 and IFN-gamma secretion by splenocytes and the plasma levels of different isotypes of antibodies against various antigens of Trypanosoma congolense in highly susceptible BALB/c and relatively resistant C57BL/6 mice during the early course of infection with T. congolense. The patterns of appearance of cytokine spotforming cells in the spleens were essentially similar in the two mouse strains although higher numbers were detected in the spleens of BALB/c than C57BL/6 mice on some days post-infection. However, the amount of IL-4, IL-10 and IFN-gamma secreted into the culture fluids was dramatically different. From day 4 forward, splenocytes from BALB/c mice secreted very high levels of these cytokines. In contrast, splenocytes from infected C57BL/6 mice did not secrete detectable levels of IL-4 throughout the period tested. The secretion of IL-10 and IFN-gamma by C57BL/6 splenocytes only became appreciable on day 6 and was down-regulated by day 8, when the first wave of parasitaemia was being controlled. At days 6-8, splenocytes from infected C57BL/6 mice secreted two-fold higher amounts of IL-12 p40 than those from BALB/c mice. Infected BALB/c mice mounted an earlier IgM antibody response to variant surface glycoprotein (VSG), formalin-fixed T. congolense and whole T. congolense lysates than did infected C57BL/6 mice. However, they failed to make any detectable IgG3 and IgG2a antibody responses to these antigens whereas infected C57BL/6 mice made strong IgG3 and IgG2a responses. We speculate that enhanced resistance against T. congolense infections in mice may be mediated by IL-12 dependent synthesis of IgG2 antibodies to VSG and possibly also common trypanosomal antigens.

Experimental murine Trypanosoma congolense infections. II. Role of splenic adherent CD3+Thy1.2+ TCR-alpha beta- gamma delta- CD4+8- and CD3+Thy1.2+ TCR-alpha beta- gamma delta- CD4-8- cells in the production of IL-4, IL-10, and IFN-gamma and in trypanosome-elicited immunosuppression

Trypanosome-induced suppression of T and B cell responses to parasite-related and -unrelated Ags is considered a major mechanism of evasion of the host's immune defenses by the parasite. Reduced T and B cell responses have been attributed to suppressor T cells, suppressor macrophages, or both. We have previously shown that endogenously produced IL-10 and IFN-gamma mediate the suppression of T cell responses in Trypanosoma congolense-infected mice. Here, we show for the first time that splenic CD3+ Thy1.2+ alphabeta- gammadelta- CD4+ 8- and CD3+ Thy1.2+ alphabeta- gammadetla- CD4- 8- cells that copurify with plastic-, nylon wool-, or Sephadex G-10-adherent cell populations, in synergy with adherent Thy1.2- cells, are the major producers of IL-4, IL-10, and IFN-gamma in T. congolense-infected mice. We further demonstrate the involvement of these cells in the suppression of T cell proliferative responses to mitogen and in B cell responses to a parasite-unrelated Ag.

Experimental murine Trypanosoma congolense infections. I. Administration of anti-IFN-gamma antibodies alters trypanosome-susceptible mice to a resistant-like phenotype

The mechanisms regulating resistance or susceptibility to African trypanosomes have been enigmatic. In this study, we assessed the production of several cytokines (IL-4, IFN-gamma, and TNF-alpha) in vivo and in vitro using genetically susceptible (BALB/c) or resistant (C57BL/6) mice infected with cloned Trypanosoma congolense and the role of these cytokines in pathogenesis of this infection. Plasma of infected BALB/c mice contained higher levels of IL-4 and IFN-gamma than the plasma of infected C57BL/6 mice. Conversely, plasma TNF-alpha levels were elevated significantly in the resistant mice relative to the susceptible ones. Splenic IFN-gamma mRNA appeared earlier and were maintained at higher levels in infected BALB/c than in C57BL/6 mice. Both spontaneous and Con A-induced secretions of IL-4 and IFN-gamma by splenocytes from infected BALB/c mice were significantly higher than those from their C57BL/6 counterparts. Con A-induced proliferation of splenocytes from infected BALB/c mice was progressively suppressed. Nitric oxide was not involved in this suppression, but the suppression was positively correlated with IFN-gamma secretion. Addition of neutralizing Abs to IFN-gamma to cultures of Con A-stimulated spleen cells from infected BALB/c mice effectively reversed this suppression. Furthermore, administration of anti-IFN-gamma Abs to BALB/c mice early during infection dramatically shifted the phenotype of these susceptible mice to a more resistant-like phenotype, as expressed by a low and undulating parasitemia and a >300% increase in survival period. These results strongly suggest that the enhanced induction and secretion of IFN-gamma during T. congolense infections contribute to the relative susceptibility of BALB/c mice to the disease.

Immunoregulation in experimental murine Trypanosoma congolense infection: anti-IL-10 antibodies reverse trypanosome-mediated suppression of lymphocyte proliferation in vitro and moderately prolong the lifespan of genetically susceptible BALB/c mice

We infected highly susceptible BALB/c and relatively resistant C57BL/6 mice with cloned Trypanosoma congolense and followed the effects of these infections on the circulating parasite numbers, mouse mortality and cytokine expression. C57BL/6 mice controlled their parasitaemia and survived for up to 163 +/- 12 days, while BALB/c mice could not control their parasitaemia and succumbed to the infection within 8.4 +/- 0.5 days. Susceptible BALB/c mice had dramatically higher plasma levels of IL-10 than the resistant C57BL/6 mice from day 7 forward. This was preceded by an earlier and higher level induction of splenic IL-10 messenger RNA (mRNA) expression in the infected BALB/c mice. There was a strong negative correlation between the splenocyte proliferative responses to Concanavalin-A (Con-A) and their production of IL-10 in these infected BALB/c mice. Co-treatment of the Con-A-stimulated spleen cell cultures with monoclonal anti-IL-10 antibodies, but not isotype-matched control antibodies, could completely reverse this suppression of the splenocyte proliferative response. Finally, in three experiments, anti-IL-10 antibody treatment in vivo reduced the peak circulating parasitaemia of infected BALB/c mice by 43% and increased their median survival periods by 38% relative to isotype-matched control antibody-treated mice.

Expression of the neutrophil chemoattractant interleukin-8 in the lesions of bovine pneumonic pasteurellosis

We investigated the expression of interleukin-8 (IL-8) in pneumonic pasteurellosis of cattle because neutrophils are important mediators of tissue injury in this disease and because IL-8 is a major neutrophil chemoattractant in other species. We also compared IL-8 expression in bacterial and viral pneumonia, since the latter lacks the severe neutrophil exudation typical of pneumonic pasteurellosis. IL-8 expression was assessed by northern analysis, in situ hybridization, enzyme-linked immunosorbent assay, and in vivo bioassay. IL-8 mRNA expression was elevated dramatically in lesions of pneumonic pasteurellosis compared to unaffected lung from the same calves. In situ hybridization revealed intense expression of IL-8 mRNA in alveolar macrophages and neutrophils and milder expression in bronchiolar and alveolar epithelium, interstitial cells, and pleural mesothelium. Bronchoalveolar lavage fluid from lesional lung contained 16.06+/-4.00 ng/ml IL-8, whereas those from nonlesional and normal lung contained 0.34+/-0.11 and 0.01+/-0.002 ng/ml, respectively. We detected IL-8 expression at only minimal levels in bovine respiratory syncytial viral pneumonia. Lung extracts from lesions of pneumonic pasteurellosis induced vigorous neutrophil infiltration following injection into bovine skin, and 89% depletion of IL-8 from the extract reduced this neutrophil influx by 60%. These results demonstrate consistent upregulation of IL-8 expression in lesions of pneumonic pasteurellosis, implying a role for IL-8 in the ongoing recruitment of neutrophils to established lesions of pneumonic pasteurellosis. Because neutrophil-mediated tissue injury is critical to the pathogenesis of pneumonic pasteurellosis, these data suggest that neutralization of IL-8 activity could ameliorate the severe clinical signs and lesions of this disease.

Elevation in tumour necrosis factor-alpha (TNF-alpha) messenger RNA levels in the uterus of pregnant gilts after oestrogen treatment

In pigs, induction of embryonic degeneration, by exogenous oestrogens given early in gestation, has been long recognised. However, the underlying mechanisms responsible for this degeneration remain unclear. The present study was conducted to determine whether oestrogen-induced early porcine embryonic mortality was associated with changes in the levels of tumour necrosis factor-alpha (TNF-alpha) messenger RNA in the uterine endometrium. Prepubertal gilts were induced into oestrus with PG600 and artificially inseminated at their second natural oestrus and again 24 h later. After insemination, gilts were randomly assigned to treatment and given 0.5 ml intramuscular injections of either oestradiol valerate (10 mg ml-1) or corn oil on day 9 and 10 of gestation. The gilts were slaughtered on day 12, 15 or 18 of gestation. The reproductive tract was removed from each gilt and the uterine horns were flushed to check for the presence and integrity of embryos. Samples of uterine endometrial tissues were collected, snap-frozen in liquid nitrogen and stored at -80 degrees C. Total cellular RNA was isolated from frozen tissues using a guanidine isothiocyanate-cesium chloride method. The abundance of TNF-alpha messenger RNA was determined by Northern blot hybridisation analysis. Treatment of pregnant gilts with oestrogen resulted in severe fragmentation of embryos on days 15 (2/3) and 18 (2/2), confirming the embryocidal effect of exogenous oestrogen. Uterine TNF-alpha messenger RNA level was elevated in oestrogen-treated gilts compared with controls (P < 0.05). This observation of an association between increased levels of TNF-alpha mRNA in the uterus and embryonic degeneration in oestrogen-treated gilts suggests that TNF-alpha may be involved in mediating oestrogen-induced early embryonic mortality in the pig.

Relapse prevention as an interventive model for HIV risk reduction in gay and bisexual men

Despite considerable self-initiated HIV risk reduction among men who have sex with men, little is known about how to design interventions that will effectively assist individuals from this population in maintaining safer sex behaviors over time. The present study evaluated the effectiveness of a 17-session group counseling intervention that incorporated components based on a cognitive-behavioral model of relapse. Differential behavioral outcomes following treatment included an increase in the percentage of sexual activities that were protected and a decrease in unprotected oral sex. However, considerable risk reduction (e.g., increased condom use, decreased unprotected sex, and decreases in the number of male partners and in the total number of sexual acts) occurred in both treated and untreated participants. Measures of mediating attitudinal variables drawn from relapse prevention theory largely predicted behavioral changes. Over time, several of the risk reduction behaviors achieved at posttreatment were not maintained, suggesting the importance of further developing effective strategies for supporting behavior change maintenance.

Promotion of mouse fibroblast proliferation by IgE-dependent activation of mouse mast cells: role for mast cell tumor necrosis factor-alpha and transforming growth factor-beta 1

Pathologic fibroblast proliferation or tissue fibrosis develops in certain chronic allergic diseases and in a wide array of other inflammatory disorders in which mast cell activation is also a prominent feature. In this study we investigated a number of potential mechanisms by which IgE-dependent activation of mouse mast cells might influence the proliferation of mouse fibroblasts in vitro. We found that supernatants from in vitro-derived mast cells that had been activated by IgE and specific antigen (but not those from quiescent mast cells) promoted the proliferation of mouse embryonic skin or 3T3 fibroblasts, and we showed that this effect was detectable in the absence of fetal calf serum. We analyzed the kinetics with which the fibroblast-proliferative activity was secreted from bone marrow-derived cultured mast cells and found that it was released both rapidly (i.e., in 30 minutes or less) and for a more prolonged period (i.e., for more than 2 hours) after IgE-dependent mast cell activation. We then measured the levels at which the mast cells produce a number of cytokines that are known to affect fibroblasts (IL-1, IL-6, transforming growth factor-beta 1 [TGF-beta 1], and tumor necrosis factor-alpha [TNF-alpha]) and assessed their relative effects, as recombinant cytokines, on fibroblast proliferation. Our mast cells secreted high levels of TGF-beta 1 and TNF-alpha, intermediate amounts of IL-6, and low levels of IL-1. We titrated the fibroproliferative effects of each of these cytokines and determined that at a dose of 50 pg/ml their rank order of activity was TGF-beta 1 > TNF-alpha > IL-1 > IL-6, with all but IL-6 having significant effects. The ability of supernatants from activated bone marrow-derived cultured mast cells to promote fibroblast proliferation was partially diminished by absorption with neutralizing antibodies against either TNF-alpha or TGF-beta 1, and absorption of the supernatants with a combination of antibodies against TNF-alpha and TGF-beta 1 reduced their ability to induce fibroblast proliferation by approximately 50% (p < or = 0.001, n = 5). These findings show that IgE-dependent activation of mouse mast cells can result in the release of mediators that promote fibroblast proliferation in the absence of any other cell type and suggest that mast cell-derived TNF-alpha and TGF-beta 1 contribute substantially to this effect. They also suggest that these cytokines exert their effects through synergistic interactions with other mast cell mediators.

Induction of intra-articular tumour necrosis factor during acute inflammatory responses in equine arthritis

Synovial fluid (SF) was collected at 2, 12 and 26 h post racing from 5 Thoroughbred horses (6 joints) with degenerative joint disease. The effects of serial arthrocentesis on SF TNF alpha levels were controlled for by testing, in parallel, site- and time-matched samples from clinically normal horses (i.e. without arthritis). A significant induction in TNF alpha bioactivity was detected in SF from arthritic joints (compared to the control joints) over the 26 h following racing. After subtraction of values for the arthrocentesis control SF, TNF alpha and protein levels and WBC and mononuclear cell numbers each peaked at 12 h in the SF from the degenerative joints, although there were no statistically significant correlations between any of these parameters. The presence in the SF of TNF alpha, as well as immunoreactive IL-1 beta and IL-6, was confirmed through use of specific anti-human cytokine IgG antibodies in neutralisation and slot-blot radioimmunoassays. TNF beta was not detected in the SF by slot-blot radioimmunoassay. These results suggest that a significant increase in intra-articular TNF alpha occurs during acute inflammatory arthritis in horses. The lack of correlation between infiltrating inflammatory cells and SF TNF alpha levels further suggests that the source of TNF alpha may be resident cells of the joint, as opposed to infiltrating cells found within the joint fluids. SF from clinically normal and arthritic joints of racing and hospitalised horses were also screened for bioactive TNF alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

Re-engineering: a prescription for hospitals

Previously applied mostly in large, private sector corporations, "re-engineering" is fast becoming a tool that hospitals can use to break away from the old to find a new and better way of doing things. Re-engineering, however, first requires strong leadership which is committed to employee involvement and re-inventing the process design to meet the needs of the customers. Once the transition has been completed, the processes and the organization must continue to be managed differently. This article reviews the processes involved in re-engineering, and discusses the implementation of the initiative at the Sunnybrook Health Science Centre in Toronto.

Promotion of mouse fibroblast collagen gene expression by mast cells stimulated via the Fc epsilon RI. Role for mast cell-derived transforming growth factor beta and tumor necrosis factor alpha

Chronic allergic diseases and other disorders associated with mast cell activation can also be associated with tissue fibrosis, but a direct link between mast cell mediator release and fibroblast collagen gene expression has not been established. Using in situ hybridization, we show that the elicitation of an IgE-dependent passive cutaneous anaphylaxis (PCA) reaction in mice results in a transient, but marked augmentation of steady state levels of type alpha-1 (I) collagen mRNA in the dermis. While peak levels of collagen mRNA expression in the skin are observed 16-24 h after mast cell activation, substantial numbers of dermal cells are strongly positive for collagen mRNA at 1 and 2 h after antigen challenge, before circulating inflammatory cells are recruited into the tissues. Furthermore, experiments in mast cell-reconstituted or genetically mast cell-deficient WBB6F1-W/Wv mice demonstrate that the increased expression of collagen mRNA at sites of PCA reactions is entirely mast cell dependent. In vitro studies show that the supernatants of mouse serosal mast cells activated via the Fc epsilon RI markedly increase type alpha-1 (I) collagen mRNA levels in mouse embryonic skin fibroblasts, and also upregulate collagen secretion by these cells. The ability of mast cell supernatants to induce increased steady state levels of collagen mRNA in mouse skin fibroblasts is markedly diminished by absorption with antibodies specific for either of two mast cell-derived cytokines, transforming growth factor beta (TGF-beta 1) or tumor necrosis factor alpha (TNF-alpha), and is eliminated entirely by absorption with antibodies against both cytokines. Taken together, these findings demonstrate that IgE-dependent mouse mast cell activation can induce a transient and marked increase in steady state levels of type alpha-1 (I) collagen mRNA in dermal fibroblasts and that mast cell-derived TGF-beta 1 and TNF-alpha importantly contribute to this effect.

Inhibition of endogenous dopamine release in amphibian retina by L-2-amino-4-phosphonobutyric acid (L-AP4) and trans-2-aminocyclopentane-1,3-dicarboxylate (ACPD)

The metabotropic glutamate receptor agonists 2-amino-4-phosphonobutyric acid (AP4) and trans-2-aminocyclopentane-1,3-dicarboxylate (ACPD) blocked light-stimulated dopamine release from Xenopus laevis retina. ACPD suppressed release in darkness but AP4 did not. AP4 blocked release stimulated in darkness by picrotoxin, a GABA-A receptor antagonist. The data suggest that regulation of dopamine release in Xenopus retina involves subpopulations of metabotropic glutamate receptors.

Human eosinophils can express the cytokines tumor necrosis factor-alpha and macrophage inflammatory protein-1 alpha

By in situ hybridization, 44-100% of the blood eosinophils from five patients with hypereosinophilia and four normal subjects exhibited intense hybridization signals for TNF-alpha mRNA. TNF-alpha protein was detectable by immunohistochemistry in blood eosinophils of hypereosinophilic subjects, and purified blood eosinophils from three atopic donors exhibited cycloheximide-inhibitable spontaneous release of TNF-alpha in vitro. Many blood eosinophils (39-91%) from hypereosinophilic donors exhibited intense labeling for macrophage inflammatory protein-1 alpha (MIP-1 alpha) mRNA, whereas eosinophils of normal donors demonstrated only weak or undetectable hybridization signals for MIP-1 alpha mRNA. Most tissue eosinophils infiltrating nasal polyps were strongly positive for both TNF-alpha and MIP-1 alpha mRNA. By Northern blot analysis, highly enriched blood eosinophils from a patient with the idiopathic hypereosinophilic syndrome exhibited differential expression of TNF-alpha and MIP-1 alpha mRNA. These findings indicate that human eosinophils represent a potential source of TNF-alpha and MIP-1 alpha, that levels of expression of mRNA for both cytokines are high in the blood eosinophils of hypereosinophilic donors and in eosinophils infiltrating nasal polyps, that the eosinophils of normal subjects express higher levels of TNF-alpha than MIP-1 alpha mRNA, and that eosinophils purified from the blood of atopic donors can release TNF-alpha in vitro.

Mast cell cytokines in allergy and inflammation

Recent findings indicate that mast cells can influence biological responses through the production of cytokines and suggest that many allergic reactions and other biological processes may be regulated by a "mast cell-leukocyte cytokine cascade". This hypothesis proposes that certain biological responses are initiated by mast cell activation, resulting in the mast cell-dependent release of TNF-alpha and other cytokines which can promote the recruitment of eosinophils, neutrophils, and other effector cells. The recruited effectors then influence the progression of the response by providing additional sources of some cytokines which also can be elaborated by mast cells, as well as by producing other cytokines not known to be of mast cell origin.

Evaluation of dexamethasone for reduction of postsurgical sequelae of third molar removal

Sixty patients with bilaterally symmetrical impacted third molars participated in this double-blind, within-subject study to quantify the effects of 4 mg of dexamethasone on reducing postsurgical sequelae. Each patient's surgery was staged by mouth side and completed in two appointments 5 to 6 weeks apart. A preoperative dose of dexamethasone given intravenously was randomized to mouth side and surgical appointment; sterile water served as a control. Major areas assessed in this study were facial swelling, pain, and trismus. No difference in swelling and daily pain was noted. However, trismus and global pain were significantly affected by the steroid. Patients had a daily postsurgical increase in incisal opening of 4 to 6 mm over the control side during the examination period. Patients evaluated pain by choosing the least painful side. By a greater than 4:1 margin, patients chose the steroid side as the least painful side. No increase in the rate or type of complications was detected between control and steroid sides.

Analyzing mast cell development and function using mice carrying mutations at W/c-kit or Sl/MGF (SCF) loci

Mast cells have been implicated in a wide variety of biological responses, but identifying the nature and importance of the mast cell's specific contributions to these reactions has been difficult. W/Wv mice have mutations affecting the c-kit tyrosine kinase receptor which is encoded at the W locus and which is necessary for normal mast cell development. In W/Wv mice, the cells which ordinarily give rise to normal mast cell populations do not adequately respond to a major migration, survival, proliferation and maturation factor expressed in the microenvironments where mast cells ordinarily develop: the c-kit receptor ligand, SCF. As a result, W/Wv mice virtually lack tissue mast cells. However, adoptive transfer to W/Wv mice of immature mast cells derived in vitro from the bone marrow cells of the congenic normal (+/+) mice selectively repairs the mast cell deficiency of the W/Wv recipients. These "mast cell knock-in" mice can be used to analyze the expression of biological responses in tissues which differ only because they do or do not contain populations of mast cells. This approach permits identification and quantification of the specific contributions of the mast cell to biological responses expressed in the skin, gastrointestinal tract and other anatomical sites, and also greatly facilitates analysis of the mechanisms by which mast cells influence these responses.

Cytokine production by mast cells and basophils

Mast cells and/or basophils have been implicated in the expression of a wide variety of biological responses, including immediate hypersensitivity reactions, host responses to parasites and neoplasms, angiogenesis, tissue remodeling, and immunologically non-specific inflammatory and fibrotic conditions. Recent findings suggest that an important mechanism by which mast cells influence such biological responses is through the production of a broad panel of multifunctional cytokines. In contrast, the extent to which basophils can produce cytokines is uncertain.

Eosinophils from patients with blood eosinophilia express transforming growth factor beta 1

The infiltration of eosinophils into tissues during pathologic responses is often associated with extracellular matrix alterations such as fibrosis. Transforming growth factor-beta 1 (TGF-beta 1) is a well-characterized multifunctional cytokine known to exert potent effects on the extracellular matrix. In this report, we showed the production of TGF-beta 1 by human eosinophils from patients with blood eosinophilia. Northern blot analysis using RNA isolated from eosinophils purified from a patient with the idiopathic hypereosinophilic syndrome (HES) detected the 2.5-kb TGF-beta 1 transcript. In situ hybridization and immunohistochemistry of leukocytes from two patients with HES and two patients with blood eosinophilia localized TGF-beta 1 messenger RNA (mRNA) and protein to eosinophils. No other cell type contained TGF-beta 1 mRNA by in situ hybridization, whereas other leukocytes contained detectable TGF-beta 1 protein by immunohistochemistry. Eosinophils from four normal donors contained little or no detectable TGF-beta 1 protein by immunohistochemistry, whereas eosinophils from two of these four normal donors labeled weakly for TGF-beta 1 mRNA by in situ hybridization. These results show that eosinophils in the peripheral blood of patients with blood eosinophilia can express TGF-beta 1, but that eosinophils in the blood of normal donors contained little or no TGF-beta 1.