Swine spermatozoa trigger aggregated neutrophil extracellular traps leading to adverse effects on sperm function.

In pigs, the number of PMN in uterus lumen increases within few hours after natural or artificial AI resulting in early PMN-derived innate immune reactions. Sperm-NETs formation was recently reported to occur in various mammalian species. Aim of this study was to investigate direct interactions of boar spermatozoa with swine PMN, the release of sperm-mediated NETs, and to assess NET-derived effects on sperm functionality. Sperm-triggered NETs were visualized by SEM- and immunofluorescence analyses. Sperm-mediated NETosis was confirmed by presence of extruded DNA with global histones and NE. Largest sizes of sperm-mediated aggNETs were detected after 5 h thereby resulting in effective massive sperm entrapment. The number of aggNETs increased from 3 h onwards. Kinetic studies of swine sperm-mediated NETosis showed to be a time-dependent cellular process. In addition, number of NETs-entrapped spermatozoa increased at 3 h of exposure whilst few free spermatozoa were detected after 3 h. Anchored NETs also increased from 3 h onwards. The cytotoxicity of NETs was confirmed by diminution of the total motility and the progressive motility. Spermatozoa membrane integrity and function loss exposed to NETs was confirmed from 3 h. Experiments revealed NETs-derived damaging effects on swine spermatozoa in membrane integrity, motility and functionality. We hypothesize that swine sperm-triggered aggNETs might play a critical role in reduced fertility potential in swine reproductive technique. Thus, aggNETs formation needs to be considered in future studies about uterine environment as well as advance of sperm in the porcine female reproductive tract.

Fatty and hydroxycarboxylic acid receptors: The missing link of immune response and metabolism in cattle.

Fatty and hydroxycarboxylic acids are one of the main intermediates of energy metabolism in ruminants and critical in the milk production of cattle. High production demands on a dairy farm can induce nutritional imbalances and metabolism disorders, which have been widely associated with the onset of sterile inflammatory processes and increased susceptibility to infections. The literature suggests that short-chain fatty acids (SCFA), long-chain fatty acids (LCFA) and hydroxycarboxylic acids are relevant modulators of the host innate inflammatory response. For instance, increased SCFA and lactate levels are associated with subacute ruminal acidosis (SARA) and the activation of pro-inflammatory processes mediated by diverse leukocyte and vascular endothelial cells. As such, free LCFA and the ketone body ß-hydroxybutyrate are significantly increased in the plasma 1-2 weeks postpartum, coinciding with the time period in which cows are more susceptible to acquiring infectious diseases that the host innate immune system should actively oppose. Today, many of these pro-inflammatory responses can be related to the activation of specific G protein-coupled receptors, including GPR41/FFA3 and GPR43/FFA2 for SCFA; GPR40/FFA1 and GPR120/FFA4 for LCFA, GPR109A/HCA2 for ketone body ß-hydroxybutyrate, and GPR81/HCA1 for lactate, all expressed in different bovine tissues. The activation of these receptors modulates the release of intracellular granules [e.g., metalloproteinase-9 (MMP-9) and lactoferrin], radical oxygen species (ROS) production, chemotaxis, and the production of relevant pro-inflammatory mediators. The article aimed to review the role of natural ligands and receptors and the resulting impact on the host innate immune reaction of cattle and, further, to address the most recent evidence supporting a potential connection to metabolic disorders.

Amiloride interferes with platelet- activating factor-induced respiratory burst and MMP-9 release in bovine neutrophils independent of Na+/H+ exchanger 1.

Cytoplasmic pH homeostasis is required for an appropriate response in polymorphonuclear neutrophils (PMNs). In these cells, chemotaxis and reactive oxygen species (ROS) production are reduced by the use of Na+/H+ exchanger (NHE-1) inhibitors, but these results are mainly obtained using amiloride, a non-selective NHE-1 inhibitor. In bovine PMNs, the role of NHE-1 in functional responses has not been confirmed yet. The aim of this study was to determine the role of NHE-1 using amiloride and zoniporide in pH regulation, ROS production, matrix metalloproteinase 9 (MMP-9) release and calcium flux in bovine PMNs induced by the platelet activation factor (PAF), additionally we evaluated the presence of NHE-1 and NHE-2 mRNA Our data show the presence only of NHE-1 but not NHE-2 in bovine PMNs. Amiloride or zoniporide inhibited the intracellular alkalization induced by PAF without affecting calcium flux. Amiloride diminished ROS production and MMP-9 release, while zoniporide enhanced ROS production without change the MMP-9 release induced by PAF. Our work led us to conclude that changes in intracellular pH induced by PAF are regulated by NHE-1 in bovine neutrophils, but the effects of amiloride on ROS production and MMP-9 release induced by PAF are not NHE-1 dependent.

Saturation and stability of nonlinear photonic crystals.

We consider a one-dimensional photonic crystal made by an infinite set of nonlinear nematic films immersed in a linear dielectric medium. The thickness of each equidistant film is negligible and its refraction index depends continuously on the electric field intensity, giving rise to all the involved nonlinear terms, which joints from a starting linear index for negligible amplitudes to a final saturation index for extremely large field intensities. We show that the nonlinear exact solutions of this system form an intensity-dependent band structure which we calculate and analyze. Next, we ponder a finite version of this system; that is, we take a finite array of linear dielectric stacks of the same size separated by the same nonlinear extremely thin nematic slabs and find the reflection coefficients for this arrangement and obtain the dependence on the wave number and intensity of the incident wave. As a final step we analyze the stability of the analytical solutions of the nonlinear crystal by following the evolution of an additive amplitude to the analytical nonlinear solution we have found here. We discuss our results and state our conclusions.

Butyric acid stimulates bovine neutrophil functions and potentiates the effect of platelet activating factor.

Increased short-chain fatty acid (SCFA) production is associated with subacute ruminal acidosis (SARA) and activation of inflammatory processes. In humans and rodents, SCFAs modulate inflammatory responses in the gut via free fatty acid receptor 2 (FFA2). In bovines, butyric acid is one of the most potent FFA2 agonists. Its expression in bovine neutrophils has recently been demonstrated, suggesting a role in innate immune response in cattle. This study aimed to evaluate if butyric acid modulates oxidative and non-oxidative functions or if it can potentiate other inflammatory mediators in bovine neutrophils. Our results showed that butyric acid can activate bovine neutrophils, inducing calcium (Ca(2+)) influx and mitogen-activated protein kinase (MAPK) phosphorylation, two second messengers involved in FFA2 activation. Ca(2+) influx induced by butyric acid was dependent on the extracellular and intracellular Ca(2+) source and phospholipase C (PLC) activation. Butyric acid alone had no significant effect on reactive oxygen species (ROS) production and chemotaxis; however, a priming effect on platelet-activating factor (PAF), a potent inflammatory mediator, was observed. Butyric acid increased CD63 expression and induced the release of neutrophil granule markers matrix metalloproteinase-9 (MMP-9) and lactoferrin. Finally, we observed that butyric acid induced neutrophil extracellular trap (NET) formation without affecting cellular viability. These findings suggest that butyric acid, a component of the ruminal fermentative process, can modulate the innate immune response of ruminants.

Andrographis paniculata decreases fatigue in patients with relapsing-remitting multiple sclerosis: a 12-month double-blind placebo-controlled pilot study.

BACKGROUND: Andrographis paniculata (A. paniculata), a medicinal plant, has shown anti-inflammatory, neuroprotective and antifibrotic effects in animal models as well as clinical efficacy in different studies, including an anti-fatigue effect in autoimmune diseases such as rheumatoid arthritis. In multiple sclerosis (MS), fatigue is rated as one of the most common and disabling symptoms. In the present trial, we investigated the effect of A. paniculata on relapse rate and fatigue in relapsing-remitting MS (RRMS) patients receiving interferon beta. METHODS: A randomised double-blind placebo-controlled trial assessed the effects of 170 mg of A. paniculata dried extract tablet b.i.d. p.o. on relapse rate and fatigue using the Fatigue Severity Scores (FSS) over 12 months in RRMS patients receiving interferon. The Expanded Disability Status Scale (EDSS) score, inflammatory parameters and radiological findings were also investigated. Twenty-five patients were enrolled, and twenty-two patients were ultimately analysed and randomised to the active or placebo group. RESULTS: Patients treated with A. paniculata showed a significant reduction in their FSS score as compared to the placebo, equivalent to a 44 % reduction at 12 months. No statistically significant differences were observed for relapse rate, EDSS or inflammatory parameters, with a trend in reducing new lesions among the A. paniculata group. One patient in the A. paniculata group presented with a mild and transient skin rash, which was alleviated with anti-histamine treatment for three weeks. CONCLUSION: A. paniculata was well tolerated in patients and no changes in clinical parameters were observed. A. paniculata significantly reduces fatigue in patients with RRMS receiving interferon beta in comparison to placebo and only interferon beta treatment. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02280876 ; Trial registration date: 20.10.2014.

The acute phase response induced by Escherichia coli lipopolysaccharide modifies the pharmacokinetics and metabolism of florfenicol in rabbits.

The aim of this study was to determine the effect of Escherichia coli lipopolysaccharide (LPS)-induced acute phase response (APR) on the pharmaco-kinetics and biotransformation of florfenicol (FFC) in rabbits. Six rabbits (3.0 ± 0.08 kg body weight (bw)) were distributed through a crossover design with 4 weeks of washout period. Pairs of rabbits similar in bw and sex were assigned to experimental groups: Group 1 (LPS) was treated with three intravenous doses of 1 µg/kg bw of E. coli LPS at intervals of 6 h, and Group 2 (control) was treated with an equivalent volume of saline solution (SS) at the same intervals and frequency of Group 1. At 24 h after the first injection of LPS or SS, an intravenous bolus of 20 mg/kg bw of FFC was administered. Blood samples were collected from the auricular vein before drug administration and at different times between 0.05 and 24.0 h after treatment. FFC and florfenicol-amine (FFC-a) were extracted from the plasma, and their concentrations were determined by high-performance liquid chromatography. A noncompartmental pharmacokinetic model was used for data analysis, and data were compared using the paired Student t-test. The mean values of AUC0-∞ in the endotoxaemic rabbits (26.3 ± 2.7 µg·h/mL) were significantly higher (P < 0.05) than values observed in healthy rabbits (17.2 ± 0.97 µg·h/mL). The total mean plasma clearance (CLT ) decreased from 1228 ± 107.5 mL·h/kg in the control group to 806.4 ± 91.4 mL·h/kg in the LPS-treated rabbits. A significant increase (P < 0.05) in the half-life of elimination was observed in the endotoxaemic rabbits (5.59 ± 1.14 h) compared to the values observed in healthy animals (3.44 ± 0.57 h). In conclusion, the administration of repeated doses of 1 µg/kg E. coli LPS induced an APR in rabbits, producing significant modifications in plasma concentrations of FFC leading to increases in the AUC, terminal half-life and mean residence time (MRT), but a significant decrease in CLT of the drug. As a consequence of the APR induced by LPS, there was a reduction in the metabolic conversion of FFC to their metabolite FFC-a in the liver, suggesting that the mediators released during the APR induced significant inhibitory effects on the hepatic drug-metabolizing enzymes.

Delphinol® standardized maqui berry extract reduces postprandial blood glucose increase in individuals with impaired glucose regulation by novel mechanism of sodium glucose cotransporter inhibition.

AIM: The impetus of our study was to investigate the effects of a nutritional supplement Delphinol®, an extract of maqui berries (Aristotelia chilensis) standardised to ≥25% delphinidins and ≥35% total anthocyanins, on postprandial blood glucose and insulin levels and identify the physiologic mechanism involved. METHODS: Postprandial blood glucose and insulin were investigated in double-blind, placebo-controlled, cross-over fashion in ten volunteers with moderate glucose intolerance. Longer term effects on blood sugar levels were investigated in streptozotocin-diabetic rats over a four months period. Effects of maqui berry delphinidins on sodium-glucose symport were examined in rodent jejenum of the small intestine. RESULTS: Delphinol® intake prior to rice consumption statistical significantly lowered post prandial blood glucose and insulin as compared to placebo. We identified an inhibition of Na+-dependant glucose transport by delphinidin, the principal polyphenol to which Delphinol® is standardised. In a diabetic rat model the daily oral application of Delphinol® over a period of four months significantly lowered fasting blood glucose levels and reached values indistinguishable from healthy non-diabetic rats. CONCLUSION: Our results suggest a potential use of Delphinol® for naturally controlling post-prandial blood glucose owed to inhibition of sodium glucose co-transporter in small intestine.

Propionate induces the release of granules from bovine neutrophils.

Short-chain fatty acids (SCFA) are produced by bacterial fermentation in the rumen of cattle and are the primary energy source in ruminants. Propionate is one of the main SCFA and it can exert multiple effects on the inflammatory process and neutrophil function via calcium (Ca(2+)) release, reactive oxygen species, and intracellular pH changes. However, currently no evidence has shown whether propionate can induce granule release from bovine neutrophils. The purpose of this study was to analyze the effect of propionate on granule release and to evaluate the expression of two G-protein coupled receptors-GPR41 and GPR43-that are activated by propionate. Neutrophil degranulation was assessed by quantifying the release of the neutrophil enzymes myeloperoxidase (MPO), lactoferrin, and matrix metalloprotease-9 (MMP-9) as markers of azurophil, specific granules, and gelatinase granules, respectively. Isolated bovine neutrophils were treated with millimolar concentrations of propionate (0.3, 3 and 30mM), and the cell-free supernatants were recovered. The stimulation of neutrophils with 0.3mM propionate induced the release of lactoferrin and MMP-9 as revealed by ELISA and gelatin zymography, respectively. Propionate at 30mM induced the release of MPO as demonstrated using an enzymatic assay. The role of intracellular Ca(2+) influx and the signaling pathways that may regulate the propionate effect on granules release were also determined. Reverse transcription (RT)-PCR and real-time PCR were performed to analyze the expression of GPR41 and GPR43 mRNA in bovine neutrophils. Both mRNA were detected, whereas the expression of GPR43 was higher than that of GPR41, and the synthetic agonists for this receptor, phenylacetamides 1 and 2, caused an increase in intracellular Ca(2+), lactoferrin, and MMP-9 release. These results support that propionate-induced granule release is mediated by intracellular Ca(2+) influx and activation of extracellular signal-regulated kinase ERK 1/2. We also propose a potential role of GPR43 in propionate-induced granule release from bovine neutrophils that may be involved in regulatory effects of propionate in the innate immune response in cattle.

Mechanical behaviour and rupture of normal and pathological human ascending aortic wall.

The mechanical properties of aortic wall, both healthy and pathological, are needed in order to develop and improve diagnostic and interventional criteria, and for the development of mechanical models to assess arterial integrity. This study focuses on the mechanical behaviour and rupture conditions of the human ascending aorta and its relationship with age and pathologies. Fresh ascending aortic specimens harvested from 23 healthy donors, 12 patients with bicuspid aortic valve (BAV) and 14 with aneurysm were tensile-tested in vitro under physiological conditions. Tensile strength, stretch at failure and elbow stress were measured. The obtained results showed that age causes a major reduction in the mechanical parameters of healthy ascending aortic tissue, and that no significant differences are found between the mechanical strength of aneurysmal or BAV aortic specimens and the corresponding age-matched control group. The physiological level of the stress in the circumferential direction was also computed to assess the physiological operation range of healthy and diseased ascending aortas. The mean physiological wall stress acting on pathologic aortas was found to be far from rupture, with factors of safety (defined as the ratio of tensile strength to the mean wall stress) larger than six. In contrast, the physiological operation of pathologic vessels lays in the stiff part of the response curve, losing part of its function of damping the pressure waves from the heart.

2-Aminoethoxydiphenyl borate (2-APB) reduces alkaline phosphatase release, CD63 expression, F-actin polymerization and chemotaxis without affecting the phagocytosis activity in bovine neutrophils.

2-Aminoethoxydiphenyl borate (2-APB) interferes with the Ca(2+) influx and reduces the ROS production, gelatinase secretion and CD11b expression in bovine neutrophils. Moreover, it has been suggested that inhibition of the Ca(2+) channel involved in the store operated Ca(2+) entry (SOCE) is a potential target for the development of new anti-inflammatory drugs in cattle, however it is unknown whether 2-APB affects neutrophil functions associated with the innate immune response. This study describes the effect of 2-APB, a putative SOCE inhibitor, on alkaline phosphatase activity a marker of secretory vesicles, CD63 a marker for azurophil granules, F-actin polymerization and in vitro chemotaxis in bovine neutrophils stimulated with platelet-activating factor (PAF). Also, we evaluated the effect of 2-APB in the phagocytic activity against Escherichia coli and Staphylococcus aureus bioparticles. We observed that doses of 2-APB ≥10 µM significantly reduced alkaline phosphatase activity and in vitro chemotaxis, whereas concentrations of 2-APB ≥50 µM reduced CD63 expression and F-actin polymerization. Finally, we observed that 2-APB did not affect the phagocytic activity in neutrophils incubated with E. coli and S. aureus bioparticles. We concluded that inhibition of Ca(2+) influx could be a useful strategy to reduce inflammatory process in cattle.

2-Aminoethoxydiphenyl borate (2-APB) reduces respiratory burst, MMP-9 release and CD11b expression, and increases l-selectin shedding in bovine neutrophils.

This study describes the effect of 2-aminoethoxydiphenyl borate (2-APB), a putative store-operated calcium (Ca(2+)) entry (SOCE) inhibitor, on reactive oxygen species (ROS) production, matrix metalloproteinase 9 (MMP-9) release, CD11b and l-selectin (CD62L) expression, size changes and apoptosis in bovine neutrophils stimulated with platelet-activating factor (PAF). It was observed that doses ⩾1µM 2-APB significantly reduced ROS production, whereas 50 and 100µM 2-APB reduced MMP-9 release induced by PAF. Moreover, concentrations ⩾10µM 2-APB reduced CD11b expression and increased l-selectin shedding. PAF induced size changes in neutrophils, and this effect was inhibited by 2-APB. From this work it is possible to conclude that 2-APB at concentrations that inhibit SOCE responses was able to inhibit ROS and MMP-9 release and CD11b expression, and increase l-selectin shedding, suggesting that the Ca(2+) channel involved in SOCE is a potential target for the development of new anti-inflammatory drugs in cattle.

D-lactic acid interferes with the effects of platelet activating factor on bovine neutrophils.

D-lactic acidosis occurs in ruminants, such as cattle, with acute ruminal acidosis caused by ingestion of excessive amounts of highly fermentable carbohydrates. Affected animals show clinical signs similar to those of septic shock, as well as acute laminitis and liver abscesses. It has been proposed that the inflammatory response and susceptibility to infection could both be caused by the inhibition of phagocytic mechanisms. To determine the effects of d-lactic acid on bovine neutrophil functions, we pretreated cells with different concentrations of D-lactic acid and measured intracellular pH using 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and calcium flux using FLUO-3 AM-loaded neutrophils. Reactive oxygen species (ROS) production was measured using a luminol chemiluminescence assay, and MMP-9/gelatinase-B granule release was measured by zymography. CD11b and CD62L/l-selectin expression, changes in cell shape, superoxide anion production, phagocytosis of Escherichia coli-Texas red bioparticles, and apoptosis were all measured using flow cytometry. Our results demonstrated that D-lactic acid reduced ROS production, CD11b upregulation and MMP-9 release in bovine neutrophils treated with 100 nM platelet-activating factor (PAF). D-lactic acid induced MMP-9 release and, at higher concentrations, upregulated CD11b expression, decrease L-selectin expression, and induces late apoptosis. We concluded that D-lactic acid can interfere with neutrophil functions induced by PAF, leading to reduced innate immune responses during bacterial infections. Moreover, the increase of MMP-9 release and CD11b expression induced by 10mM D-lactic acid could promote an nonspecific neutrophil-dependent inflammatory reaction in cattle with acute ruminal acidosis.

Calcium influx, a new potential therapeutic target in the control of neutrophil-dependent inflammatory diseases in bovines.

Neutrophils are the first line of defense against pathogens in bovines; however, they are also one of the most aggressive cells during the inflammatory process, causing injury in surrounding tissues. At present, anti-inflammatory drugs are limited in acute diseases, such as pneumonia, mastitis and endometritis, because neutrophils are mostly insensitive. One of the earliest events during neutrophil activation is the increase in intracellular calcium concentration. The calcium movement is attributed to the release from intracellular stores and influx through the calcium channels in the plasma membrane, a process called store operated calcium entry (SOCE). Recently, several calcium influx blockers have been shown to have strong effects on bovine neutrophils, and this suggests that the manipulation of this pathway can be useful in the control of neutrophil functions during acute inflammatory processes. In this paper, we will review the role of calcium influx as a potential anti-inflammatory target and summarize the most recent evidences for this in bovine neutrophils.

Induction of reactive oxygen species in bovine neutrophils is CD11b, but not dectin-1-dependent.

Neutrophils play a key role in initiating an innate immune response, being the first type of immune cell arriving at the site of injury or infection. These cells are able to mount a direct anti-bactericidal response by the production of reactive oxygen or reactive nitrogen species (ROS/RNS). An important component of the host innate immune response is recognition of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs). Toll-like receptors (TLRs) are an important family of PRRs and, are a key component in activation of innate immune mechanisms. In the present study we described the presence of mRNA transcripts for TLR1, TLR2, TLR4, TLR6, TLR7 and TLR10 in bovine neutrophils. In contrast, the presence of mRNA transcripts for TLR3 varied between animals, whereas no transcripts were detected for TLR5, TLR8, TLR9 or the C-type lectin receptor dectin-1 in neutrophils isolated from bovine blood. Additionally, zymosan, a dectin-1/TLR2 ligand, induced ROS, but not RNS production in a CD11b-, but not dectin-1-dependent manner. This effect was dependent on Store Operated Calcium Entry (SOCE), and partially inhibited using monoclonal antibodies to CD11b. Taken together, our data describe the presence of specific PRRs transcripts in the mRNA isolated from bovine neutrophil and show a CD11b-/Ca(2+) dependent ROS production by these cells.

Efficacy of an Andrographis paniculata composition for the relief of rheumatoid arthritis symptoms: a prospective randomized placebo-controlled trial.

Andrographis paniculata (Burm. f.) Wall ex Nees (Acanthaceae) possesses anti-inflammatory effects, attributed to the main constituent andrographolide proposed as alternative in the treatment of autoimmune disease. A prospective, randomized, double blind, and placebo-controlled study in patients with rheumatoid arthritis (RA) was performed. Tablets (Paractin) made of an extract of A. paniculata (30% total andrographolides) were administered three times a day for 14 weeks, after a 2-week washout period to 60 patients with active RA. The primary outcomes were pain intensity measured using a horizontal visual analog pain scale (VAPS). In addition, ACR, EULAR, and SF36 clinical parameters were recorded. The intensity of joint pain decreased in the active vs placebo group at the end of treatment, although these differences were not statistically significant. A significant diminishing for week in tender joint -0.13 95% confidence interval (CI; -0.22 to 0.06; p = 0.001), number of swollen joints -0.15 95%CI (-0.29 to -0.02; p = 0.02), total grade of swollen joint -0.27 95%CI (-0.48 to -0.07; p = 0.010), number of tender joints -0.25 95%CI (-0.48 to -0.02; p = 0.033), total grade of swollen joints -0.27 95%CI (-0.48 to -0.07; p = 0.01), total grade of tender joints -0.47 95%CI (-0.77 to -0.17; p = 0.002) and HAQ -0.52 95%CI (-0.82 to -0.21; p < 0.001) and SF36 0.02 95%CI (0.01 to 0.02; p < 0.001) health questionnaires was observed within the group with the active drug. Moreover, it was associated to a reduction of rheumatoid factor, IgA, and C4. These findings suggest that A. paniculata could be a useful "natural complement" in the treatment of AR; however, a larger trial and a more extended period of treatment is necessary in order to corroborate these results.

New potential targets to modulate neutrophil function in inflammation.

The importance of neutrophils in human disease such as rheumatoid arthritis, asthma, adult respiratory distress syndrome, and COPD has prompted the search for drugs capable to slow down neutrophil-dependent inflammation, without interference with innate immune responses. In this review, we summarize new potential drugs targets against neutrophils mediated inflammatory responses.

Propionate induces pH(i) changes through calcium flux, ERK1/2, p38, and PKC in bovine neutrophils.

Propionate is a short-chain fatty acid produced under normal physiological conditions in the rumen of cattle. It is also involved in the inflammatory process and neutrophil function via calcium release, reactive oxygen species and intracellular pH (pH(i)) changes. This study examined the effect of propionate on the pH(i) of bovine neutrophils; specifically if pH(i) changes are controlled by calcium flux, and the mitogen-activated protein kinase (MAPK) pathway. Propionate caused rapid intracellular acidification and sustained alkalinization in bovine neutrophils loaded with 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM), a fluorescent indicator of pH(i). The acidification phase seems to be controlled by intracellular calcium release and p38 MAPK pathway. The pH recovery phenomenon was mediated by an amiloride-sensitive Na+/H+ exchanger and H+ channel, and was inhibited by UO126 (an ERK1/2 MAPK phosphorylation inhibitor), Gö6850 (a PKC inhibitor) and calcium chelating. Ionomycin, a calcium ionophore, induced intracellular acidification and sustained alkalinization. The intracellular acidification was strongly inhibited by BAPTA-AM (an intracellular calcium chelator) and SB203580 (a p38 MAPK inhibitor). In addition, the intracellular alkalinization was reduced by EGTA (a calcium chelator), UO126, LY294002 (a PI3K inhibitor) and Gö6850. Propionate did not increase superoxide production, however it reduced the superoxide production induced by platelet-activating factor (PAF), and increased the release of superoxide induced by ionomycin. Our results suggest that propionate-induced intracellular acidification is mediated by intracellular calcium release and p38 MAPK activation, and that pH recovery is controlled via ERK1/2 MAPK, PKC and calcium entry in bovine neutrophils.

Activation of kinin B1 receptors induces chemotaxis of human neutrophils.

Kinins are biologically active peptides that are powerful mediators of cellular inflammation. They mimic the cardinal signs of inflammation by inducing vasodilatation and by increasing vascular permeability and pain. Neutrophils are chemoattracted to sites of inflammation by several stimuli. However, the evidence concerning the chemotactic effect of kinin peptides has been contradictory. We analyzed the chemotactic effect of kinin B(1) receptor agonists on neutrophils isolated from peripheral blood of human healthy subjects. Chemotaxis was performed using the migration under agarose technique. To test the effect of B(1) receptor agonists, each assay was carried out overnight at 37 degrees C in 5% CO(2)-95% air on neutrophils primed with 1 ng/ml interleukin-1beta. Simultaneous experiments were performed using unprimed cells or cells challenged with formyl-Met-Leu-Phe (fMLP). A clear chemotactic activity was observed when primed neutrophils were challenged with Lys-des[Arg(9)]-bradykinin (LDBK) or des[Arg(9)]-bradykinin at 10(-10) M but not when unprimed cells were used. A reduction in the chemotactic response was observed after priming of cells in the presence of 0.5 mM cycloheximide and 10 mug/ml brefeldin A, suggesting that some protein biosynthesis is required. Techniques such as reverse transcriptase-polymerase chain reaction and in situ hybridization confirmed the expression of the B(1) receptor mRNA, and immunocytochemistry and autoradiography demonstrated the expression of the B(1) receptor protein. In contrast to other chemoattractants such as fMLP, cytosolic intracellular calcium did not increase in response to the B(1) receptor agonist LDBK. A generation of kinin B(1) receptor agonists during the early phase of acute inflammation may favor the recruitment of neutrophils to the inflammatory site.

American cutaneous leishmaniasis outbreak, Tartagal city, province of Salta, Argentina, 1993.

An American cutaneous leishmaniasis outbreak, with cases clustering during 1993 in Tartagal city, Salta, was reported. The outbreak involved 102 individuals, 43.1% of them with multiple ulcers. Age (mean: 33 years old) and sex distribution of cases (74.5% males), as well as working activity (70 forest-related), support the hypothesis of classical forest transmission leishmaniasis, despite the fact that the place of permanent residence was in periurban Tartagal. Moreover, during July, sandflies were only collected from one of the 'deforestation areas'. Lutzomyia intermedia was the single species of the 491 phlebotomines captured, reinforcing the vector incrimination of this species. Most infections must have been acquired during the fall (April to June), a pattern consistent with previous sandfly population dynamics data. Based on the epidemiological and entomological results, it was advised not to do any vector-targeted periurban control measures during July. Further studies should be done to assess if the high rate of multiple lesions was due to parasite factors or to infective vector density factors.