RESUMEN
Individual common carp Cyprinus carpio were screened repeatedly for risk taking (rate of exploration of a novel, potentially dangerous environment) and for competitive ability (success in gaining access to a spatially restricted food source). Marked differences in behaviour were evident, and significant consistency in individual responses across trials was found for both risk taking and competitive ability. In addition, there was a significant positive relationship between individual performance in these two contexts, with fish that explored more quickly in the novel environment tending to be among the first to gain access to restricted food. In two follow-up studies, resting metabolic rate, blood lactate and glucose and the expression of the cortisol receptor gene in the head kidney and brain were compared in fish from the two extremes of the risk-taking spectrum. Mass-specific metabolic rate was significantly higher in risk-taking than in risk-avoiding fish, while plasma lactate and glucose concentrations and expression of the cortisol receptor gene were lower. It was concluded that a behavioural syndrome based on boldness and aggression exists in C. carpio, as it does in many other animals, and that this is associated with differences in metabolic and stress physiology (down to the genomic level) similar to those described in animals with different coping strategies.
Asunto(s)
Conducta Animal , Carpas/metabolismo , Conducta Competitiva , Asunción de Riesgos , Adaptación Psicológica , Animales , Glucemia , Carpas/fisiología , Lactatos/sangre , Receptores de Glucocorticoides/metabolismo , Estrés FisiológicoRESUMEN
The alpha 7 nicotinic receptor is reportedly a key element in the cholinergic anti-inflammatory pathway. Because a prototypical ligand for this receptor is nicotine, we studied the in vivo human response to bacterial endotoxin or lipopolysaccharide (LPS) in the context of nicotine or placebo pretreatment. Twelve adult male normal subjects were studied prospectively. Six received overnight transcutaneous nicotine administration by application of a standard patch (7 mg). Six hours later, all subjects were given an intravenous dose of endotoxin (2 ng/kg) and were evaluated for an additional 24 h for circulating levels of inflammatory biomarkers, vital signs and symptoms. The nicotine subjects had elevated blood levels of the nicotine metabolite, continine, prior to and throughout the 24-h post-endotoxin exposure phase. Subjects receiving nicotine exhibited a significantly lower temperature response as well as attenuated cardiovascular responses for 2.5-6 h after LPS exposure. In addition, increased circulating interkeukin (IL)-10 and cortisol levels were also noted in nicotine subjects. These data indicate an alteration in LPS-induced systemic inflammatory responses in normal subjects exposed to transcutaneous nicotine. In this model of abbreviated inflammation, nicotine exposure attenuates the febrile response to LPS and promotes a more prominent anti-inflammatory phenotype.
Asunto(s)
Endotoxinas/farmacología , Lipopolisacáridos/farmacología , Nicotina/farmacología , Agonistas Nicotínicos/farmacología , Administración Cutánea , Adolescente , Adulto , Análisis de Varianza , Biomarcadores/sangre , Cotinina/sangre , Citocinas/sangre , Selectina E/sangre , Humanos , Hidrocortisona/sangre , Inflamación , Masculino , Estudios ProspectivosRESUMEN
Toll-like receptors (TLRs) are involved in the recognition of bacterial products and thus participate in the induction of the inflammatory cascade. However, much less is known about the evolution of leucocyte TLR expression during human inflammatory stress. We hypothesized that a decrease in leucocyte TLRs could account for the so-called tolerance or hyporesponsiveness state to subsequent stimulation with bacteria-derived products. Because of the profound monocytopenia that ensues after in vivo lipopolysaccharide (LPS) challenge, we also compared monocyte TLR expression using two different techniques of flow cytometric gating. In a first set of experiments, 17 healthy volunteers underwent LPS challenge. Blood was drawn at different time-points and analysed by flow cytometry using light scatter gating and one-colour analysis to assess the expression of the tumour necrosis factor receptor (TNFR) and TLR2 and TLR4 on both monocytes and granulocytes. In a second set of experiments, the assessment of those receptors was made using a more specific gating method that utilized light scatter and CD14 immunofluorescence in a two-colour analysis. This was performed using whole blood drawn from five healthy volunteers and incubated ex vivo for different time periods with or without LPS and in 12 volunteers who underwent LPS challenge in vivo. The pattern of expression for monocyte TNFR was similar for both types of gating. Using only the light scatter gating, an initial drop of TLR 2 and 4 was observed on monocytes. By contrast, when using light scatter x immunofluorescence gating, an up-regulation of these two receptors following both in vivo and in vitro LPS exposure was observed. LPS up-regulates the expression of TLRs on monocytes and granulocytes. Depending upon the methodology utilized, contrasting results were obtained with respect to TLR2 and TLR4 expression. The flow cytometric gating technique used is of importance in determining cellular TLR2 and TLR4 expression, especially in blood samples exhibiting significant monocytopenia.
Asunto(s)
Inflamación/sangre , Leucocitos/metabolismo , Lipopolisacáridos/toxicidad , Glicoproteínas de Membrana/sangre , Receptores de Superficie Celular/sangre , Receptores del Factor de Necrosis Tumoral/sangre , Adolescente , Adulto , Femenino , Citometría de Flujo/métodos , Técnica del Anticuerpo Fluorescente , Granulocitos/metabolismo , Humanos , Masculino , Monocitos/metabolismo , Dispersión de Radiación , Receptor Toll-Like 2 , Receptor Toll-Like 4 , Receptores Toll-Like , Regulación hacia Arriba/efectos de los fármacosRESUMEN
The prevalence of laryngeal pathology in a treatment-seeking population of southwestern Ohio underwent a 15-year reexamination. Relationships between pathology and demographic variables of age, gender, and occupation were investigated. Data were collected from 1,158 new patients seen by participating otolaryngologists between 1996 and 1998. The most frequent pathologies were reflux laryngitis, functional (including diagnoses of laryngeal myasthenia and hoarseness), vocal fold paralysis, nodules, and laryngitis. Pathologies were found to occur more often in females, with some pathologies more common to one gender. Pathologies occurred more often in the older age categories. The most common occupations found in the sample were retired persons, executives/managers, and homemakers. Comparisons were made to an earlier investigation of laryngeal pathology in the same otolaryngology practices. Differences from the previous study were noted in the prevalence of pathology and the distribution of demographic variables. Relationships between pathology and demographic variables reported by the two studies were examined for consistency.
Asunto(s)
Enfermedades de la Laringe/epidemiología , Aceptación de la Atención de Salud , Trastornos de la Voz/epidemiología , Adulto , Anciano , Demografía , Femenino , Humanos , Enfermedades de la Laringe/complicaciones , Enfermedades de la Laringe/diagnóstico , Masculino , Persona de Mediana Edad , Prevalencia , Trastornos de la Voz/diagnóstico , Trastornos de la Voz/etiología , Calidad de la VozAsunto(s)
Aniversarios y Eventos Especiales , Catolicismo , Hospitales Religiosos/normas , Cronología como Asunto , Planificación en Salud Comunitaria , Atención a la Salud/tendencias , Hospitales Religiosos/organización & administración , Objetivos Organizacionales , Responsabilidad Social , Estados UnidosRESUMEN
To determine the role of tumor necrosis factor (TNF) in endotoxin-induced changes in plasma thyroid hormone and thyroid-stimulating hormone (TSH) concentrations, 24 healthy postabsorptive humans were studied on a control study day (n = 6), after infusion of a recombinant TNF receptor IgG fusion protein (TNFR:Fc; 6 mg/m2; n = 6) after intravenous injection of endotoxin (2 ng/kg; n = 6), or after administration of endotoxin with TNFR:Fc (n = 6). Administration of TNFR:Fc alone did not affect thyroid hormone or TSH levels when compared with the control day. Endotoxin induced a transient rise in plasma TNF activity (1.5 h: 219 +/- 42 pg/ml), which was completely prevented by TNFR:Fc (P < 0.05). After endotoxin administration, plasma L-thyroxine (T4), free T4, 3,5, 3'-triiodothyronine (T3), and TSH were lower and 3,3', 5'-triiodothyronine was higher than on the control day (all P < 0. 05). Coinfusion of TNFR:Fc with endotoxin did not influence these endotoxin-induced changes. Our results suggest that endogenous TNF does not play an important role in the alterations in plasma thyroid hormone and TSH concentrations induced by mild endotoxemia in healthy humans.
Asunto(s)
Endotoxinas/farmacología , Hormonas Tiroideas/metabolismo , Factor de Necrosis Tumoral alfa/fisiología , Adulto , Síndromes del Eutiroideo Enfermo/sangre , Síndromes del Eutiroideo Enfermo/inducido químicamente , Humanos , Fragmentos Fc de Inmunoglobulinas/genética , Inmunoglobulina G/genética , Inyecciones Intravenosas , Lipopolisacáridos/farmacología , Masculino , Receptores del Factor de Necrosis Tumoral/genética , Proteínas Recombinantes de Fusión/farmacología , Tirotropina/sangre , Tiroxina/sangre , Triyodotironina/sangre , Triyodotironina Inversa/sangreRESUMEN
BACKGROUND: The responses of monocyte and neutrophil tumor necrosis factor receptor type 1 (TNFR-1) and TNFR-2 during systemic inflammation have been described previously. Several other members of the TNFR superfamily also appear to have regulatory roles in immunocyte function, including apoptosis. However, the response of these other receptor members, such as CD95, to systemic inflammation is unclear. OBJECTIVES: To compare the response of CD95 with that of TNFR during systemic inflammation and to assess the influence of the inflammatory milieu on CD95 function. SETTING: Adult clinical research center of a university hospital. SUBJECTS AND METHODS: Five healthy male subjects were administered intravenous endotoxin (2 ng/kg), and systemic response was measured by cytokine analysis and receptor expression assays during a 48-hour period. CD95 function during systemic inflammation was assessed using a Jurkat cell bioassay for degree of apoptosis. RESULTS: Monocyte and neutrophil CD95 expression exhibited changes parallel to that of TNFR following endotoxin injection. In contrast to soluble TNFR, which was transiently elevated during endotoxemia, soluble CD95 levels remained unchanged from baseline. Jurkat cells incubated in normal and post-endotoxin serum samples equally exhibited less than 10% spontaneous apoptosis. No soluble CD95 ligand was detectable in experimental human endotoxemia. CONCLUSIONS: Cell-associated CD95 exhibited changes parallel to its receptor family member TNFR following endotoxin administration. Soluble CD95 is present in human serum samples, but the levels remained unchanged following endotoxin administration. No soluble CD95 ligand activity was detectable by enzyme-linked immunosorbent assay or by functional assay. The potential protective role of soluble CD95 in human serum samples against CD95 ligand-induced apoptosis remains to be defined.
Asunto(s)
Apoptosis , Endotoxemia/inmunología , Receptor fas/fisiología , Adulto , Endotoxemia/sangre , Humanos , Masculino , Receptores del Factor de Necrosis Tumoral/fisiologíaRESUMEN
OBJECTIVE: To assess the ability of 9 clinical or biological variables to predict outcome (survival or nonsurvival) using multiple regression and classification analyses. DESIGN: Prospective, descriptive cohort study with no interventions. SETTING: Surgical intensive care unit of a tertiary care hospital and a medical school research laboratory. PATIENTS: Eighteen patients with a documented source of infection who met currently accepted criteria for sepsis syndrome or septic shock. MAIN OUTCOME MEASURES: Prediction of survival or nonsurvival based on analysis of clinical (Multiple Organ Dysfunction score, Acute Physiology and Chronic Health Evaluation III scores) and biological (plasma levels of cortisol, interleukin 6, interleukin 10, phospholipase A2, soluble tumor necrosis factor receptor p75, and monocyte membrane tumor necrosis factor receptor levels) variables, with comparison of predicted and actual outcomes. RESULTS: Plasma interleukin 6, interleukin 10, and phospholipase A2 concentrations were not significantly (P>.05) different between survivors and nonsurvivors. By standard, forward stepwise, and backward stepwise multiple regression analyses, only monocyte membrane tumor necrosis factor receptor levels measured at the onset of sepsis significantly predicted outcome in all 3 analyses. However, by both standard and backward stepwise analyses, Multiple Organ Dysfunction scores based on evaluation at the onset of sepsis and 24 hours later were also significant predictors of outcome. Classification analysis showed that assignment to outcome group was statistically significant when based on monocyte membrane tumor necrosis factor receptor levels determined at the onset of sepsis or on Multiple Organ Dysfunction scores assessed 24 hours after sepsis was diagnosed. CONCLUSION: Although these findings were based on a relatively small cohort, both multiple regression and classification analyses indicated that only monocyte membrane tumor necrosis factor receptor levels are able to discriminate survivors from nonsurvivors at the onset of sepsis.
Asunto(s)
Choque Séptico/sangre , Choque Séptico/mortalidad , Síndrome de Respuesta Inflamatoria Sistémica/sangre , Síndrome de Respuesta Inflamatoria Sistémica/mortalidad , Biomarcadores/sangre , Humanos , Análisis Multivariante , Valor Predictivo de las Pruebas , Estudios Prospectivos , Tasa de SupervivenciaRESUMEN
Venous thrombosis and bacterial infections are common complications of parenteral nutrition. To test the hypothesis that infection facilitates activation of coagulation during parenteral nutrition, healthy subjects were intravenously injected with endotoxin (2 ng/kg) after they had received either 1 week of standard parenteral nutrition (n = 7) or normal enteral feeding (n = 8). Compared with enteral feeding, parenteral nutrition was associated with a selectively enhanced activation of the coagulation system (plasma levels of thrombin-antithrombin III complexes) during endotoxemia. Activation of the fibrinolytic system (plasminogen activator activity, tissue-type plasminogen activator, plasminogen activator inhibitor type 1) proceeded similarly in both study groups. In patients receiving parenteral nutrition, one common complication (bacterial infection) may facilitate the occurrence of another common complication (venous thrombosis) by synergistic stimulation of the coagulation system.
Asunto(s)
Endotoxemia/complicaciones , Nutrición Parenteral/efectos adversos , Tromboflebitis/complicaciones , Adulto , Coagulación Sanguínea , Endotoxinas , Nutrición Enteral , Escherichia coli , Humanos , MasculinoRESUMEN
To determine the role of tumor necrosis factor (TNF) in lipopolysaccharide (LPS)-induced inflammation, 12 healthy subjects received an intravenous injection with LPS (2 ng/kg) preceded by infusion of either a recombinant human dimeric TNF receptor type II-IgG fusion protein (TNFR:Fc; 6 mg/m2; n = 6) or vehicle (n = 6) from -30 minutes to directly before LPS injection. LPS elicited a transient increase in plasma TNF activity, peaking after 1.5 hours (219 +/- 42 pg/mL; P < .05). Infusion of TNFR:Fc completely neutralized endogenous TNF activity. LPS administration was associated with an early activation of fibrinolysis (plasma concentrations of tissue-type plasminogen activator, plasminogen activator activity, and plasmin-alpha2-antiplasmin complexes), followed by inhibition (plasma plasminogen activator inhibitor type I), changes that were completely prevented by TNFR:Fc. By contrast, TNFR:Fc did not influence LPS-induced activation of coagulation (plasma levels of prothrombin fragment F1 + 2 and thrombin-antithrombin III complexes). TNFR:Fc strongly inhibited endothelial cell activation (plasma levels of soluble E-selectin), modestly reduced neutrophil responses (neutrophilia and plasma concentrations of elastase-alpha1-antitrypsin complexes and lactoferrin), but did not affect the release of secretory phospholipase A2 or lipopolysaccharide-binding protein (P > .05). Infusion of TNFR:Fc only (without LPS) in another 6 normal subjects did not induce any inflammatory response. These data indicate that TNF is involved in only some inflammatory responses to intravenous LPS in humans.
Asunto(s)
Antiinflamatorios no Esteroideos/uso terapéutico , Endotoxemia/tratamiento farmacológico , Inmunoglobulina G/metabolismo , Receptores del Factor de Necrosis Tumoral/metabolismo , Factor de Necrosis Tumoral alfa/fisiología , Adulto , Antiinflamatorios no Esteroideos/farmacología , Coagulación Sanguínea/efectos de los fármacos , Factores de Coagulación Sanguínea/análisis , Citocinas/sangre , Selectina E/sangre , Endotoxemia/sangre , Endotoxemia/complicaciones , Endotoxemia/fisiopatología , Endotoxinas/administración & dosificación , Endotoxinas/efectos adversos , Etanercept , Fibrinólisis/efectos de los fármacos , Humanos , Inmunoglobulina G/genética , Inflamación/etiología , Inflamación/prevención & control , Inyecciones Intravenosas , Recuento de Leucocitos/efectos de los fármacos , Masculino , Neutrófilos , Fosfolipasas A/sangre , Fosfolipasas A2 , Receptores del Factor de Necrosis Tumoral/genética , Factor de Necrosis Tumoral alfa/antagonistas & inhibidoresRESUMEN
To determine the effect of a physiologically relevant elevation in the plasma concentrations of epinephrine on the activation of the hemostatic mechanism during endotoxemia, 17 healthy men were studied after intravenous injection of lipopolysaccharide (LPS, 2 ng/kg), while receiving a continuous infusion of epinephrine (30 ng/kg/min) started either 3 h (n = 5) or 24 h (n = 6) before LPS injection, or an infusion of normal saline (n = 6). Activation of the coagulation system (plasma concentrations of thrombin-antithrombin III complexes and prothrombin fragment F1+2) was significantly attenuated in the groups treated with epinephrine when compared with subjects injected with LPS only (P <0.05). Epinephrine enhanced LPS-induced activation of fibrinolysis (plasma levels of tissue-type plasminogen activator and plasmin-alpha2-antiplasmin complexes; P <0.05), but did not influence inhibition of fibrinolysis (plasminogen activator inhibitor type I). In subjects infused with epinephrine, the ratio of maximal activation of coagulation and maximal activation of fibrinolysis was reduced by >50%. Hence, epinephrine exerts antithrombotic effects during endotoxemia by concurrent inhibition of coagulation, and stimulation of fibrinolysis. Epinephrine, whether endogenously produced or administered as a component of treatment, may limit the development of disseminated intravascular coagulation during systemic infection.
Asunto(s)
Anticoagulantes , Coagulación Sanguínea/efectos de los fármacos , Endotoxemia/sangre , Epinefrina/farmacología , Fibrinólisis/efectos de los fármacos , Lipopolisacáridos/toxicidad , Adulto , Epinefrina/administración & dosificación , Epinefrina/sangre , Escherichia coli , Fibrinolisina/metabolismo , Hemostasis , Humanos , Infusiones Intravenosas , Masculino , Inhibidor 1 de Activador Plasminogénico/sangre , Activador de Tejido Plasminógeno/sangre , alfa 2-Antiplasmina/metabolismoRESUMEN
Epinephrine inhibits lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF) production by increasing intracellular cAMP concentrations. Because agents that increase cAMP levels can enhance TNF receptor expression in vitro, granulocyte and monocyte TNF receptors were determined by FACS-analysis in 7 normal humans who were receiving a constant 24-h infusion of epinephrine (30 ng/kg/min), and in 15 normal subjects after intravenous injection of LPS (2 ng/kg), while they were receiving a continuous infusion of epinephrine started either 3 h (EPI-3) or 24 h (EPI-24) before LPS injection or an infusion of normal saline (LPS; n = 5 per group). Infusion of epinephrine per se did not influence TNF receptor expression. LPS induced a transient decrease in monocyte TNF receptors and a more sustained decrease in granulocyte TNF receptors (both P < 0.05). EPI-3 partly prevented LPS-induced down-modulation of monocyte TNF receptors (P < 0.05 vs. LPS only), but did not affect LPS-induced down-modulation of granulocyte TNF receptors. EPI-24 had no effect on TNF receptor expression. These data suggest that epinephrine not only influences the bioavailability of TNF by an effect on the production of this proinflammatory cytokine, but also by modulating the expression of its receptors.
Asunto(s)
Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/inmunología , Endotoxemia/inmunología , Epinefrina/farmacología , Monocitos/efectos de los fármacos , Monocitos/metabolismo , Receptores del Factor de Necrosis Tumoral/efectos de los fármacos , Adulto , Relación Dosis-Respuesta Inmunológica , Endotoxemia/etiología , Endotoxemia/metabolismo , Epinefrina/administración & dosificación , Humanos , Infusiones Intravenosas , Inyecciones Intravenosas , Lipopolisacáridos/administración & dosificación , Masculino , Receptores del Factor de Necrosis Tumoral/biosíntesisRESUMEN
Leukocytes rapidly lose their surface receptors for TNF and IL-1 upon exposure to various stimuli in vitro. We sought to determine by FACS analysis changes in the expression of TNF receptors (TNFR) and type II IL-1R on circulating monocytes and granulocytes during endotoxemia in vivo, and the role of endogenous TNF in these changes. Twelve healthy subjects received an i.v. injection with LPS (2 ng/kg), directly preceded by a 30-min infusion of either a recombinant human dimeric TNFR type II-IgG fusion protein (TNFR:Fc; 6 mg/m2; n = 6) or vehicle (n = 6). LPS administration was associated with decreases in the expression of types I and II TNFR and type II IL-1R on both monocytes and granulocytes. Treatment with TNFR:Fc completely neutralized LPS-induced TNF activity (p < 0.0001 vs LPS only), modestly blunted the decrease in monocyte TNFR (p < 0.05), but did not influence reduced expression of granulocyte TNFR or monocyte/granulocyte type II IL-1R. In separate experiments, rTNF added to whole blood reduced cellular type I and type II TNFR expression by an effect on the type I TNFR; TNF did not (monocytes) decrease or only marginally (granulocytes) decreased type II IL-1R expression. LPS induces down-modulation of monocyte and granulocyte receptors for TNF and IL-1 in humans in vivo. TNF is involved in reduced monocyte TNFR expression during endotoxemia.
Asunto(s)
Endotoxemia/metabolismo , Granulocitos/metabolismo , Monocitos/metabolismo , Receptores de Interleucina-1/metabolismo , Receptores del Factor de Necrosis Tumoral/metabolismo , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Adulto , Regulación de la Temperatura Corporal , Dimerización , Regulación hacia Abajo , Humanos , Lipopolisacáridos/farmacología , Masculino , Proteínas Recombinantes/administración & dosificación , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Plasma concentrations of soluble interleukin (IL)-1 receptor type II, IL-10, and IL-13 were measured in 42 patients with clinically defined sepsis during a 3-day follow-up and in 7 healthy humans after intravenous injection of endotoxin (2 ng/kg). Levels of soluble IL-1 receptor type II were persistently elevated in patients with sepsis than in healthy controls and higher in nonsurviving patients (n = 22) than in surviving patients (n = 20) at all time points. IL-10 was found in the circulation of 81% of patients with sepsis, while it was not detectable in normal plasma. During follow-up, IL-10 remained invariably high only in nonsurviving patients, while it significantly decreased in survivors. Endotoxin induced IL-10, while soluble IL-1 receptor type II remained unchanged. IL-13 remained undetectable in the vast majority of patients and was not induced by endotoxin. Enhanced IL-13 production does not seem to be part of an inducible host defense mechanism during sepsis.
Asunto(s)
Endotoxemia/sangre , Interleucina-10/sangre , Interleucina-13/sangre , Receptores de Interleucina-1/sangre , Sepsis/sangre , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , SolubilidadRESUMEN
Whole blood of 6 healthy subjects, who were intravenously injected with lipopolysaccharide (LPS, 2 ng/kg), was stimulated ex vivo with LPS (10 ng/mL). Three and 6 h after injection of LPS, whole blood produced less tumor necrosis factor-alpha (TNF), interleukin (IL)-1beta, IL-6, and IL-10 (all P < .05). By contrast, the production of IL-1 receptor antagonist was enhanced after LPS injection (P < .05). Plasma obtained 2 h, but not 1 h, after in vivo administration of LPS showed a dose-dependent inhibition of TNF, IL-1beta, and IL-6 production by LPS-stimulated whole blood from 6 other healthy donors not previously exposed to LPS, while the production of IL-10 and IL-1 receptor antagonist were not or were marginally influenced. LPS tolerance represents a purposeful adaptation of the host, rather than a generalized hyporesponsiveness, and is at least partly mediated by soluble factors produced within 2 h after previous exposure to LPS.
Asunto(s)
Sangre/inmunología , Tolerancia Inmunológica , Interleucina-10/biosíntesis , Interleucina-1/biosíntesis , Interleucina-6/biosíntesis , Lipopolisacáridos/farmacología , Factor de Necrosis Tumoral alfa/biosíntesis , Vacunación/métodos , Adulto , Sangre/metabolismo , Relación Dosis-Respuesta a Droga , Humanos , Lipopolisacáridos/administración & dosificación , Masculino , Receptores de Interleucina-1/antagonistas & inhibidoresRESUMEN
Hypercortisolemia directly before the administration of endotoxin (LPS) to normal humans completely prevents the release of the proinflammatory cytokine tumor necrosis factor, whereas hypercortisolemia 12 h to 7 days before the injection of LPS is associated with enhanced tumor necrosis factor release. To determine the effect of elevated cortisol levels on the secretion of the antiinflammatory cytokine interleukin-10 (IL-10), 23 healthy men were given iv LPS (lot EC-5; 2 ng/kg) alone or in combination with a continuous iv infusion of hydrocortisone (3 micrograms/kg.min) for 6 h immediately before or 6, 12, or 144 h before LPS injection. LPS induced a monophasic increase in plasma IL-10 concentrations that peaked after 2 h (162 +/- 27 pg/mL; P < 0.0001). In subjects who were infused with hydrocortisone directly before LPS administration, IL-10 concentrations were much higher (1784 +/- 331 pg/mL; P < 0.0001 vs. LPS only), whereas hypercortisolemia 6, 12, or 144 h before LPS injection did not influence LPS-induced IL-10 levels. In human whole blood in vitro, hydrocortisone caused a dose-dependent reduction of LPS-induced IL-10 levels. Further, hydrocortisone reversed the increase in IL-10 concentrations by epinephrine in LPS-stimulated whole blood. Stimulation of IL-10 release may contribute to the antiinflammatory properties of glucocorticoids.
Asunto(s)
Endotoxemia/sangre , Hidrocortisona/sangre , Interleucina-10/sangre , Adulto , Relación Dosis-Respuesta a Droga , Epinefrina/administración & dosificación , Epinefrina/farmacología , Escherichia coli , Femenino , Humanos , Hidrocortisona/administración & dosificación , Hidrocortisona/farmacología , Lipopolisacáridos , Masculino , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Microcystins were extracted from 7 l (equivalent to 313 g dry weight) of cyanobacterial scum collected from Rutland Water in Leicestershire, UK in 1989. The resulting aqueous extract was rapidly concentrated on a C18 flash chromatography cartridge and microcystins were eluted using a step gradient. Fractions were collected manually and monitored by UV spectrophotometer and analytical HPLC. Fractions containing microcystins of similar polarity were pooled to give three fractions. Simple isocratic methods for separating each fraction were developed on an analytical column and scaled up to a 15 x 7.5 cm I.D. column. Closed-loop recycling was used to maximise yield and purity of two hydrophobic microcystins.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Cromatografía/métodos , Péptidos Cíclicos/aislamiento & purificación , Secuencia de Aminoácidos , Cianobacterias/química , Inhibidores Enzimáticos/aislamiento & purificación , Microcistinas , Datos de Secuencia Molecular , Péptidos Cíclicos/química , Fosfoproteínas Fosfatasas/antagonistas & inhibidoresRESUMEN
OBJECTIVE: To assess peripheral blood monocyte tumor necrosis factor receptor (TNFR) levels and plasma soluble tumor necrosis factor receptor (sTNFR) concentrations in critically ill patients with sepsis syndrome. DESIGN: Prospective, descriptive cohort study with no interventions. SETTING: Surgical intensive care unit of a tertiary-care hospital associated with a university medical school. PATIENTS: Twenty-one patients with a documented source of infection who met currently accepted criteria for sepsis syndrome/septic shock. MAIN OUTCOME MEASURES: Plasma sTNFR p55 and p75 values were quantified by enzyme-linked immunosorbent assay, and monocyte TNFR levels were assessed by fluorescence flow cytometry after the monocytes were stained with biotinylated human recombinant TNF-alpha and streptavidin-phycoerythrin. RESULTS: Compared with healthy controls, plasma sTNFR p55 and p75 values were significantly higher (P <.01) in both surviving and nonsurviving patients with sepsis; in nonsurviving patients with sepsis, however, only sTNFR p55 values were significantly (P < .05) higher than in surviving patients with sepsis. By contrast, monocytes from the nonsurviving patients with sepsis manifested a significant (P < .01) and sustained (up to 4 days) decrease in cell surface TNFR values compared with either the normal controls or the surviving patients with sepsis. CONCLUSIONS: Assessment of monocyte surface TNFR values may provide a rapid prognostic indicator for patients with sepsis who are at increased risk of death.
Asunto(s)
Monocitos/metabolismo , Receptores del Factor de Necrosis Tumoral/metabolismo , Síndrome de Respuesta Inflamatoria Sistémica/sangre , Análisis de Varianza , Humanos , Pronóstico , Estudios Prospectivos , Factores de RiesgoRESUMEN
Short-term preexposure of mononuclear cells to epinephrine inhibits LPS-induced production of TNF, whereas preexposure for 24 h results in increased TNF production. To assess the effects of epinephrine infusions of varying duration on in vivo responses to LPS, the following experiments were performed: (a) Blood obtained from eight subjects at 4-24 h after the start of a 24-h infusion of epinephrine (30 ng/kg per min) produced less TNF after ex vivo stimulation with LPS compared with blood drawn before the start of the infusion, and (b) 17 healthy men who were receiving a continuous infusion of epinephrine (30 ng/kg per min) started either 3 h (EPI-3; n = 5) or 24 h (EPI-24; n = 6) were studied after intravenous injection of LPS (2 ng/kg, lot EC-5). EPI-3 inhibited LPS-induced in vivo TNF appearance and also increased IL-10 release (both P < 0.005 versus LPS), whereas EPI-24 only attenuated TNF secretion (P = 0.05). In separate in vitro experiments in whole blood, epinephrine increased LPS-induced IL-10 release by a combined effect on alpha and beta adrenergic receptors. Further, in LPS-stimulated blood, the increase on IL-10 levels caused by epinephrine only marginally contributed to concurrent inhibition of TNF production. Epinephrine, either endogenously produced or administered as a component of sepsis treatment, may have a net antiinflammatory effect on the cytokine network early in the course of systemic infection.
Asunto(s)
Endotoxinas , Epinefrina/farmacología , Interleucina-10/biosíntesis , Toxemia/metabolismo , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Adulto , Humanos , Infusiones Intravenosas , Masculino , Receptores Adrenérgicos alfa/metabolismo , Receptores Adrenérgicos beta/metabolismoRESUMEN
Intravenous fat emulsions are frequently given to malnourished patients who are prone to suffer from infectious complications. As injection of low dose endotoxin represents a model to study the human response to acute infection, we sought to determine the effect of lipid emulsion infusion on endotoxin-induced activation of the hemostatic mechanism in man. Ten healthy men received a bolus intravenous injection of endotoxin (lot EC-5; 20 U/kg) midway through a 4-h infusion (125 ml/h) of either dextrose 5% (n = 5) or Intralipid 20% (n = 5). Lipid infusion potentiated endotoxin-induced coagulation activation, as indicated by higher plasma levels of the prothrombin fragment F1 + 2 and of thrombin-antithrombin III complexes (both p < 0.05 for the difference between groups). However, lipid infusion did not influence the fibrinolytic response to intravenous endotoxin, as reflected by similar increases in the levels of tissue-type plasminogen activator and plasmin-alpha 2-antiplasmin complexes in both groups. Endotoxin-induced appearance of plasminogen activator inhibitor type I was enhanced by lipid infusion (p < 0.05). These data suggest that fat emulsion infusion may enhance the tendency towards thrombotic complications in patients with infections.