RESUMEN
Histamine has the ability to influence the activity of immune cells including neutrophils and plays a pivotal role in inflammatory processes, which are a complex network of cellular and humoral events. One of the main functions manifested by activated neutrophils is oxidative burst, which is linked to the production of reactive oxygen species; therefore, the effects of histamine receptor agonists and antagonists on the oxidative burst of neutrophils is reviewed. A role for the well-characterized histamine H1 and H2 receptors in this process is discussed and compared to that of the recently discovered H4 receptor.
Asunto(s)
Agonistas de los Receptores Histamínicos/farmacología , Antagonistas de los Receptores Histamínicos/farmacología , Receptores Acoplados a Proteínas G/efectos de los fármacos , Receptores Histamínicos/efectos de los fármacos , Animales , Histamina/metabolismo , Humanos , Inflamación/metabolismo , Neutrófilos/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Receptores Histamínicos/metabolismo , Receptores Histamínicos H1/efectos de los fármacos , Receptores Histamínicos H1/metabolismo , Receptores Histamínicos H2/efectos de los fármacos , Receptores Histamínicos H2/metabolismo , Receptores Histamínicos H4 , Estallido Respiratorio/efectos de los fármacosRESUMEN
INTRODUCTION: The differentiation between extra- and intracellular production of reactive oxygen species (ROS) in whole blood was measured by luminol- and isoluminol-enhanced chemiluminescence (CL). METHODS: Azide (total CL inhibition), azide + horseradish peroxidase (HRP, restoring extracellular CL), superoxide dismutase + catalase (depleting extracellular ROS) and HRP (enhancing extracellular CL) were used to modulate luminol- and isoluminol-enhanced CL (10(-6) -10(-3) m luminophores) of 125× diluted whole blood which was activated by both calcium ionophore A23187 (Ca-I) and opsonized zymosan particles (OZP) separately. RESULTS: Both activators stimulated intra- and extracellular production of ROS. Luminol-enhanced CL of Ca-I-activated samples detected the intracellular ROS, and with the addition of HRP detected the extracellular CL as well. CL enhanced with isoluminol in concentrations of 10(-4) m or less was mostly extracellular. There was a mixture of intra- and extracellular CL in OZP-activated samples, probably because of the ingestion of luminophore molecules. CONCLUSION: Measurement of Ca-I-activated CL enhanced with 10(-4) m luminol is recommended for the detection of intracellular ROS. The addition of HRP leads to the detection of overall ROS production while the OZP-activated system with its addition of HRP can only be used to detect overall ROS production. Ca-I-activated CL enhanced with 10(-4) m isoluminol and with addition of HRP is recommended for the detection of extracellular CL.
Asunto(s)
Luminiscencia , Mediciones Luminiscentes/métodos , Especies Reactivas de Oxígeno/análisis , Sangre , Células Sanguíneas , Humanos , Luminol/análogos & derivadosRESUMEN
The interaction of adrenergic agonists and/or antagonists with the adrenergic receptors expressed on immunologically active cells including macrophages plays an important role in regulation of inflammatory responses. Our study investigated the effects of carvedilol, a unique vasodilating beta-adrenergic antagonist, and endogenous adrenergic agonists (adrenalin, noradrenalin, and dopamine) and/or antagonists (prazosin, atenolol) on lipopolysaccharide-stimulated nitric oxide (NO) production from murine macrophage cell line RAW 264.7. The production of NO was determined as the concentration of nitrites in cell supernatants (Griess reaction) and inducible nitric oxide synthase (iNOS) protein expression (Western blot analysis). Scavenging properties against NO were measured electrochemically. Carvedilol in a concentration range of 1, 5, 10 and 25 microM inhibited iNOS protein expression and decreased the nitrite concentration in cell supernatants. Adrenalin, noradrenalin or dopamine also inhibited the iNOS protein expression and the nitrite accumulation. Prazosine and atenolol prevented the effect of both carvedilol and adrenergic agonists on nitrite accumulation and iNOS expression in lipopolysaccharide-stimulated cells. These results, together with the absence of scavenging properties of carvedilol against NO, imply that both carvedilol and adrenergic agonists suppress the lipopolysaccharide-evoked NO production by macrophages through the activation and modulation of signaling pathways connected with adrenergic receptors.
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Agonistas Adrenérgicos/farmacología , Antagonistas Adrenérgicos beta/farmacología , Carbazoles/farmacología , Propanolaminas/farmacología , Receptores Adrenérgicos/efectos de los fármacos , Antagonistas Adrenérgicos alfa/farmacología , Antagonistas Adrenérgicos beta/administración & dosificación , Animales , Carbazoles/administración & dosificación , Carvedilol , Línea Celular , Relación Dosis-Respuesta a Droga , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Lipopolisacáridos , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo II/efectos de los fármacos , Óxido Nítrico Sintasa de Tipo II/metabolismo , Nitritos/metabolismo , Propanolaminas/administración & dosificación , Receptores Adrenérgicos/metabolismo , Transducción de Señal/efectos de los fármacosAsunto(s)
Antagonistas de los Receptores Histamínicos H1/farmacología , Fagocitos , Feniramina/farmacología , Daño por Reperfusión/metabolismo , Estallido Respiratorio , Animales , Bromofeniramina/farmacología , Clorfeniramina/farmacología , Mediciones Luminiscentes , Masculino , Fagocitos/efectos de los fármacos , Fagocitos/metabolismo , Ratas , Ratas WistarRESUMEN
The effect is described of selenium supplemented in an inorganic and organic form on the innate immune response of goats. Though the phagocytic activity (as a marker of the immune function) was found to be lower in organic-Se-treated group than in control (54.5 +/- 4.32 vs. 60.2 +/- 9.15 %), it did not generally exhibit any significant differences; similarly, no differences were found in the phagocytic index. The production of reactive oxygen species (ROS) was determined using the luminol-enhanced chemiluminescence (CL) (estimated as peak CL, integral CL and a peak time after addition of calcium ionophore A23187, opsonised zymosan (OZP) and phorbol-12-myristate-13-acetate as effectors. A significant ROS increase reflected in integral CL and a peak time was found in the inorganic-Se-treated group when OZP was used as activator; other parameters did not exhibit significant changes. The supplementation of Se in inorganic form can thus be seen to influence positively the innate immune system of kids.
Asunto(s)
Inmunidad Innata/efectos de los fármacos , Factores Inmunológicos/administración & dosificación , Selenio/administración & dosificación , Animales , Femenino , Cabras , Compuestos Inorgánicos/administración & dosificación , Masculino , Compuestos Orgánicos/administración & dosificación , Fagocitosis/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismoRESUMEN
The aim was to study the antioxidant properties of four wine polyphenols (flavonoids catechin, epicatechin, and quercetin, and hydroxystilbene resveratrol). All three flavonoids exerted significant and dose-dependent scavenging effects against peroxyl radical and nitric oxide in chemical systems. The scavenging effect of resveratrol was significantly lower. All polyphenols decreased production of reactive oxygen species (ROS) by RAW264.7 macrophages. Only quercetin quenched ROS produced by lipopolysaccharide-stimulated RAW264.7 macrophages incubated for 24 h with polyphenols. Quercetin and resveratrol decreased the release of nitric oxide by these cells in a dose-dependent manner which corresponded to a decrease in iNOS expression in the case of quercetin. In conclusion, the higher number of hydroxyl substituents is an important structural feature of flavonoids in respect to their scavenging activity against ROS and nitric oxide, while C-2,3 double bond (present in quercetin and resveratrol) might be important for inhibition of ROS and nitric oxide production by RAW 264.7 macrophages.
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Flavonoides/farmacología , Depuradores de Radicales Libres/farmacología , Macrófagos/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Fenoles/farmacología , Especies de Nitrógeno Reactivo/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Vino , Animales , Catequina/farmacología , Línea Celular , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Flavonoides/química , Depuradores de Radicales Libres/química , Lipopolisacáridos/farmacología , Macrófagos/metabolismo , Ratones , Óxido Nítrico Sintasa de Tipo II/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo II/metabolismo , Fenoles/química , Polifenoles , Quercetina/farmacología , Resveratrol , Estilbenos/farmacología , Relación Estructura-Actividad , Factores de TiempoRESUMEN
OBJECTIVE: Oxidative stress is one of the important complications occurring in haemodialysis. The aim of the study was to determine haemodialysis-induced changes in oxidative burst of phagocytes and the antioxidative properties of plasma. METHODS: Twenty-seven patients and 50 healthy controls were examined. Oxidative burst of phagocytes and plasma antioxidative potential were measured luminometrically. Concentrations of major plasma antioxidants (vitamin E, bilirubin and uric acid) were also determined. RESULTS: Phagocyte chemiluminescence was higher in patients before haemodialysis compared with that in controls and decreased after haemodialysis compared with predialysis status. A significant increase in plasma antioxidative potential and uric acid was found in patients before haemodialysis. These parameters decreased after haemodialysis compared with both predialysis and control values. CONCLUSIONS: The higher generation of phagocyte-derived oxidants and the decline in plasma antioxidative properties after haemodialysis confirm insufficient antioxidant defence in patients with chronic renal failure.
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Antioxidantes/análisis , Fallo Renal Crónico/sangre , Fallo Renal Crónico/terapia , Oxidantes/sangre , Fagocitos/metabolismo , Diálisis Renal , Adulto , Anciano , Bilirrubina/sangre , Femenino , Radicales Libres/análisis , Humanos , Mediciones Luminiscentes , Masculino , Persona de Mediana Edad , Oxidación-Reducción , Especies Reactivas de Oxígeno/efectos adversos , Valores de Referencia , Factores de Riesgo , Ácido Úrico/sangre , Vitamina E/sangreAsunto(s)
Benzotiepinas/farmacología , Antagonistas de los Receptores Histamínicos H1/farmacología , Fagocitos/efectos de los fármacos , Estallido Respiratorio/efectos de los fármacos , Animales , Leucocitos/efectos de los fármacos , Leucocitos/fisiología , Fagocitos/fisiología , Ratas , Ratas Wistar , Receptores Histamínicos H1/efectos de los fármacos , Receptores Histamínicos H1/fisiología , Estallido Respiratorio/fisiologíaRESUMEN
Open heart surgery with a cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response which significantly contributes to adverse postoperative complications. The purpose of this study was to characterize the activation of blood phagocytes during open heart surgery with CPB. Blood samples were collected during and up to 24 h after surgery. The production of reactive oxygen species (ROS) in whole blood, the expression of surface molecules by blood phagocytes and complement activity in the plasma were determined. A cDNA microarray analysis of leukocyte RNA profile of genes was performed related to the inflammatory response. Activation of the complement was already observed at the beginning of CPB. This was followed by an increase in the neutrophil number and in both spontaneous and opsonized zymosan-activated ROS production after the onset of reperfusion. The activation of blood phagocytes was affirmed by changes in surface receptors involved in the adhesion and migration of leukocytes (CD11b, CD62L and CD31). Gene arrays also confirmed the activation of leukocytes 4 h after reperfusion. In conclusion, open heart surgery with a cardiopulmonary bypass was found to be associated with a rapid and pronounced activation of blood phagocytes and complement activation which was partly independent at the onset of CPB.
Asunto(s)
Procedimientos Quirúrgicos Cardíacos/efectos adversos , Puente Cardiopulmonar/efectos adversos , Activación Neutrófila/fisiología , Síndrome de Respuesta Inflamatoria Sistémica/etiología , Anciano , Humanos , Leucocitos/metabolismo , Masculino , Persona de Mediana Edad , Neutrófilos/metabolismoRESUMEN
Carvedilol inhibits luminol-enhanced chemiluminescence of reactive oxygen metabolites in vitro. In this study it was found that, in the cell-free system, carvedilol dose-dependently decreased chemiluminescence in the following ranking order of radicals: hydroxyl radical > hydrogen peroxide > superoxide radical. The inhibition of myeloperoxidase was significant with carvedilol concentrations of 10 and 100 micromol/l and manifested in the concentration-dependent shift of chemiluminescence peaks to the right. In whole blood, carvedilol in concentrations of 10 and 100 micromol/l significantly inhibited chemiluminescence induced by both receptor-bypassing stimuli (A23187, PMA) and receptor-operating stimuli (fMLP, OpZ). Carvedilol dose-dependently inhibited chemiluminescence of isolated human polymorphonuclear leucocytes in the ranking order of stimuli: A23187 > OpZ > fMLP. In the presence of blood platelets, carvedilol did not substantially change chemiluminescence induced by fMLP and OpZ, while it was much more effective on chemiluminescence stimulated with calcium ionophore A23187. This could be the result of the supportive effect of serotonin liberated from platelets by A23187.
Asunto(s)
Células Sanguíneas/efectos de los fármacos , Carbazoles/farmacología , Propanolaminas/farmacología , Adulto , Plaquetas/efectos de los fármacos , Carvedilol , Línea Celular Tumoral , Sistema Libre de Células , Inhibidores Enzimáticos/farmacología , Humanos , Cinética , Leucocitos/efectos de los fármacos , Mediciones Luminiscentes , Masculino , Persona de Mediana Edad , Peroxidasa/antagonistas & inhibidores , Peroxidasa/metabolismo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
The purpose of this study was to follow up the changes in antioxidative adaptive mechanisms induced by various periods of small intestinal ischemia in Wistar rats. The superior mesenteric artery was occluded for 15, 30, 45, 60 and 90 min. After the respective ischemic intervals, a reperfusion was set for 120 min. Samples of the serum and intestinal mucosa were taken at the end of ischemia or at the end of reperfusion. Total radical-trapping antioxidant parameter (TRAP) of the serum and the oxidative burst of neutrophils were evaluated using luminol-enhanced chemiluminescence. Individual antioxidants in the serum and the concentration of thiobarbituric acid reactive substances (TBARs) in both serum and intestinal mucosa were measured spectrophotometrically. Increased activation of circulating neutrophils was found after the reperfusion irrespective of the duration of ischemia. TRAP of the serum was increased at the end of the ischemia lasting from 30 to 90 min. This effect was further enhanced by the subsequent reperfusion period. Ascorbate and urate contributed considerably to the TRAP value especially after reperfusion following 60 and 90 min of ischemia. On the other hand, no significant changes in albumin and bilirubin serum concentrations were observed. Contrary to the mobilized antioxidative mechanisms, increased lipid peroxidation was observed in both serum and mucosa samples.
Asunto(s)
Antioxidantes/metabolismo , Intestino Delgado/irrigación sanguínea , Intestino Delgado/metabolismo , Intestino Delgado/patología , Especies Reactivas de Oxígeno/metabolismo , Daño por Reperfusión/sangre , Daño por Reperfusión/patología , Enfermedad Aguda , Adaptación Fisiológica , Animales , Femenino , Recuento de Leucocitos , Peroxidación de Lípido , Ratas , Ratas Wistar , Estallido Respiratorio , Índice de Severidad de la EnfermedadRESUMEN
To investigate whether hemocytes of Bombyx mori (Lepidoptera) larvae produce reactive oxygen species (ROS) as part of the oxidative killing of invading pathogens, the production of ROS was measured as a luminol- and lucigenin-enhanced chemiluminescence of unstimulated or stimulated (zymosan particles, phorbol myristate acetate, calcium ionophore, rice starch or Xenorhabdus nematophila) hemolymph. No detectable ROS production was found. The spontaneous and activated ROS production measured with hemocytes, i.e. under the conditions when the antioxidative potential of hemolymph plasma was eliminated, was again undetectable. Likewise, ROS production by isolated hemocytes was observed by spectrophotometric (NBT test, cytochrome c assay) and fluorimetric (using dihydrorhodamine and hydroethidine probes) methods. Hence none of the experimental approaches used indicated the production of ROS by hemocytes of B. mori larvae as part of their immune response.
Asunto(s)
Bombyx/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Animales , Bombyx/inmunología , Mediciones LuminiscentesRESUMEN
Cytokines play a major role in the control of inflammatory responses, participate in the regulation of blood phagocyte activities and as such are used for immunomodulatory therapy. In the present study, the influence of IL-10 on human blood phagocyte activity in the presence/absence of IL-6, IL-8 and TNF-alpha was tested in vitro. Our research analyzed the effects of cytokines on the production of reactive oxygen species measured by chemiluminescence and flow cytometry, and on the expression of surface molecules (CD11b, CD15, CD62L, CD31) measured by flow cytometry. IL-10 had no inhibitory effect on reactive oxygen species production and the expression of any examined adhesion molecule by resting or stimulated blood phagocytes within 3 h of incubation. Conversely, TNF-alpha, IL-6, and IL-8 increased reactive oxygen species production and the expression of CD11b and CD15 on both neutrophils and monocytes and decreased the expression of CD62L. These priming effects of the tested pro-inflammatory cytokines were not affected by IL-10. The obtained results suggest that IL-10 does not directly control blood phagocyte activation. These results also provide better information about the contribution of IL-6, IL-8 and TNF-alpha to the regulation of blood phagocyte-mediated inflammatory processes.
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Antígenos CD/metabolismo , Interleucina-10/fisiología , Leucocitos/fisiología , Fagocitos/fisiología , Estallido Respiratorio/fisiología , Antígeno CD11b/metabolismo , Citometría de Flujo , Humanos , Interleucina-10/administración & dosificación , Interleucina-10/farmacología , Interleucina-6/administración & dosificación , Interleucina-6/farmacología , Interleucina-8/administración & dosificación , Interleucina-8/farmacología , Selectina L/metabolismo , Leucocitos/efectos de los fármacos , Leucocitos/metabolismo , Antígeno Lewis X/metabolismo , Mediciones Luminiscentes , Monocitos/efectos de los fármacos , Monocitos/metabolismo , Monocitos/fisiología , Neutrófilos/efectos de los fármacos , Neutrófilos/metabolismo , Neutrófilos/fisiología , Fagocitos/efectos de los fármacos , Fagocitos/metabolismo , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Estallido Respiratorio/efectos de los fármacos , Rodaminas/química , Acetato de Tetradecanoilforbol/farmacología , Factores de Tiempo , Factor de Necrosis Tumoral alfa/administración & dosificación , Factor de Necrosis Tumoral alfa/farmacología , Zimosan/farmacologíaRESUMEN
To predict more precisely the effect of stobadine, a pyridoindole antioxidant agent, in the whole organism, we studied its effect on opsonized zymosan-stimulated free radical generation in whole blood, on superoxide generation in the mixture of PMNL : platelets (1:50), as well as on superoxide generation and myeloperoxidase release in isolated PMNL. Without stimulation, stobadine had no effect on reactive oxygen species (ROS) generation and myeloperoxidase release. Stobadine in a concentration of 10 or 100 micromol/l significantly decreased luminol-enhanced chemiluminescence in opsonized zymosan-stimulated whole blood. In concentrations of 10 and 100 micromol/l, it reduced myeloperoxidase release from isolated neutrophils. Stobadine significantly decreased superoxide generation in isolated neutrophils in 100 micromol/l concentration. Its effect was much less pronounced in the mixture of neutrophils and platelets in the ratio close to physiological conditions (1:50). Our results suggest that stobadine might exert a beneficial effect in diseases or states where superfluous ROS generation could be deleterious.
Asunto(s)
Antioxidantes/farmacología , Plaquetas/efectos de los fármacos , Carbolinas/farmacología , Neutrófilos/efectos de los fármacos , Zimosan/farmacología , Adulto , Plaquetas/metabolismo , Humanos , Técnicas In Vitro , Masculino , Persona de Mediana Edad , Neutrófilos/metabolismo , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Estallido Respiratorio/efectos de los fármacosRESUMEN
Nitrogen oxide is a relatively stable, highly reactive radical, which develops in the organism by oxidation of the guanidine nitrogen of the amino acid L-arginine by the action of NO-synthase with the development of L-citrulline. It participates in a number of physiological and pathological processes. The difference between the physiological and pathological concentration of nitrogen oxide is very small, and for that reason we search for suitable methods of its determination and the substances influencing the level of nitrogen and thus decreasing its overproduction. Testing of scavenger activity against NO was performed by the method following Griess (spectrophotometric determination of nitrites as the oxidation products of NO), which was compared with the HPLC (high-performance liquid chromatography) method developed by the present authors. The antiradical effect of the compounds being assayed (acetylsalicylic acid, piracetam, paracetamol, serotonin, stobadin dihydrochloride, 5-hydroxy-L-tryptophan, N-acetyl-L-cysteine, L-glutathion, and N-acetyl-DL-penicillamine) against NO was compared with the so-called total antioxidant activity--TRAP (total radical-trapping antioxidant parameter), which corresponds to the capability to trap peroxyl radicals. On the basis of the obtained data, piracetam and acetylsalicylic acid show no antioxidant activity, paracetamol shows probably moderate scavenging action against nitrogen oxide, and other compounds tested (primarily 5-hydroxy-L-tryptophan, serotonin, stobadin) are strong antioxidants against both NO and peroxyl radical.
Asunto(s)
Antioxidantes/farmacología , Depuradores de Radicales Libres/farmacología , Óxido Nítrico/metabolismo , Depuradores de Radicales Libres/químicaRESUMEN
Natural bioluminescence of all recently accepted Photorhabdus species and subspecies type strains (bacterial symbionts of entomopathogenic nematodes) was measured using a commercial luminometer; optimum conditions for the measurement were described. Cultures emitted reliably measurable bioluminescence with characteristic level and kinetics for each strain. Bioluminescence of all strains was significantly higher at 37 than at 25 degrees C at the beginning of the measurement, no effect of bacterial concentration on the intensity of bioluminescence was observed. The technique can provide reliable and quick information for the determination of Photorhabdus taxons.
Asunto(s)
Photorhabdus/metabolismo , Animales , Cinética , Luminiscencia , Mediciones Luminiscentes , Photorhabdus/clasificación , Rhabditoidea/microbiología , Especificidad de la Especie , TemperaturaRESUMEN
The luminol-enhanced chemiluminiscence method was used to investigate the antioxidative activity of N-(alkoxyphenyl)-2-(2-oxo-1-aza-1-cykloalkyl) acetamides studied as potential cognitive enhancers and stobadine acylderivatives which form prodrugs with increased lipophilicity. The effect on the production of reactive oxygen metabolites by activated leukocytes was studied in vitro. Furthermore, the total radical-trapping antioxidant parameter was evaluated as the peroxyl radical-trapping capacity and the scavenging effect on the superoxide anion radical (generated by the enzymatic system hypoxanthine/xanthine oxidase) and on the hydroxyl radical (produced in Fenton reaction) were studied. The antioxidative properties of the tested substances were compared with that of stobadine dihydrochloride. Only stobadine and its butyrylderivative have been demonstrated to possess free radical scavenging activity in all systems. Cinnamoylstobadine inhibited only the leukocyte chemiluminiscence activity. The potential cognitive enhancers did not show any antioxidant activity.
Asunto(s)
Acetamidas/farmacología , Antioxidantes/farmacología , Indoles/farmacología , Leucocitos/metabolismo , Piridinas/farmacología , Acetamidas/química , Antioxidantes/química , Carbolinas/farmacología , Depuradores de Radicales Libres/farmacología , Humanos , Técnicas In Vitro , Indoles/química , Leucocitos/efectos de los fármacos , Mediciones Luminiscentes , Piridinas/químicaRESUMEN
The sequence of changes in circulating immune cells and in free radical production was studied during the small intestine reperfusion. Rat small intestine ischemia/reperfusion was induced by a 45 min superior mesenteric artery occlusion followed by a 4-hour reperfusion. Samples of peripheral blood were collected every 20 min during reperfusion. While the number of polymorphonuclear leukocytes increased significantly both in the sham-operated controls and the experimental group (about 400 per cent at the end of reperfusion), a decrease in lymphocyte counts to 60 per cent was observed in the experimental group only. Although there were no changes in the counts of total T lymphocytes, a significant reduction in B cell counts was observed. Flow-cytometrical measurements showed no changes in the Tc subpopulation, while the Th subpopulation increased in the experimental group only. Free radical generation in blood (luminometric measurements) increased gradually and reached an eight-fold level by the end of reperfusion in both groups. Thus, it has been shown that the increase in free radical production is mainly due to the increased number of polymorphonuclear leukocytes mobilized already at the initial stages of reperfusion. The reduction in B lymphocyte population is probably due to homing mechanisms