RESUMO
In a previous study, and in the present study, we have found that the baseline plasma samples of patients with asthma contain average levels of an endogenous heparin-like material (EHM) that is significantly higher than that noted in non-allergic, non-asthmatic controls. This material appears to have properties of both heparin and heparan sulfate. Three out of six patients responding to inhalational antigen challenge displayed an acute increment in EHM concentration that coincided with a fall in FEV values. The relation of EHM concentration to provoked asthma, or to asthma in general, remains to be determined.
Assuntos
Anticoagulantes/sangue , Asma/sangue , Heparina/sangue , Adulto , Antígenos/administração & dosagem , Asma/fisiopatologia , Feminino , Volume Expiratório Forçado , Heparitina Sulfato/sangue , Humanos , MasculinoRESUMO
An in vitro test for the rate of appearance of kallikrein in plasma due to contact system activation by dextran sulfate at 0 degree C was applied to plasmas of 19 atopic asthma patients and 19 age- and sex-matched controls without atopy. The average prekallikrein activation rate was markedly higher in the plasmas of the atopic patients. Mean endogenous heparin levels were also elevated.
Assuntos
Asma/sangue , Calicreínas/sangue , Pré-Calicreína/sangue , Adolescente , Adulto , Criança , Pré-Escolar , Sulfato de Dextrana , Dextranos/farmacologia , Fator XII/metabolismo , Feminino , Heparina/sangue , Heparina/farmacologia , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Purified human C1-esterase inhibitor (C1INH) infused into the circulation of rabbits caused an immediate drop in white blood cell (WBC) count and, simultaneously, a marked decrease in WBC adhesion to the endothelium in the microcirculation. Infusion of iodipamide caused a marked "carpeting" of the venous endothelium by WBC, and this condition was reversed by subsequent infusion of C1INH. The relationship of elevated C1INH to the protective effect of prednisolone on iodipamide toxicity in the rabbit is discussed.
Assuntos
Proteínas Inativadoras do Complemento 1/farmacologia , Contagem de Leucócitos , Leucócitos/fisiologia , Veias/fisiologia , Vênulas/fisiologia , Animais , Velocidade do Fluxo Sanguíneo , Adesão Celular/efeitos dos fármacos , Endotélio/fisiologia , Iodopamida/análogos & derivados , Iodopamida/farmacologia , Prednisolona/farmacologia , CoelhosRESUMO
An in vitro is described that attempts to detect patients with a potential for adverse systemic reactions to contrast material. This test involves measuring the rate of conversion of prekallikrein to kallikrein under certain standard conditions. In a preliminary retrospective study, the test could be used to identify such patients with a sensitivity of 88%, a specificity of 82%, and a predictive value of 79%.
Assuntos
Anafilaxia/diagnóstico , Meios de Contraste/efeitos adversos , Hipersensibilidade a Drogas/diagnóstico , Calicreínas/sangue , Pré-Calicreína/sangue , Anafilaxia/induzido quimicamente , Dextranos , Hipersensibilidade a Drogas/etiologia , Técnicas In Vitro , Masculino , Estudos RetrospectivosRESUMO
Rabbits pretreated with methylprednisolone acquired significant protection against an intravenous challenge of meglumine iodipamide. In comparison to controls, the pretreated rabbits showed moderate elevations of Factor XII, and rather striking elevations of C1-esterase inhibitor. Treated rabbits also showed significantly less granulocytosis. It is believed that the protective effect can be ascribed to the modulation of acute phase reactants by increased concentrations of C1-esterase inhibitor.
Assuntos
Proteínas Inativadoras do Complemento 1/sangue , Iodopamida/análogos & derivados , Metilprednisolona/farmacologia , Animais , Fator XII/metabolismo , Hematócrito , Iodopamida/intoxicação , Contagem de Leucócitos , Leucócitos/efeitos dos fármacos , Masculino , Meglumina/análogos & derivados , Meglumina/intoxicação , Metilprednisolona/uso terapêutico , CoelhosRESUMO
Both animal and human data suggest the possibility that the C1 esterase inhibitor may play an important controlling role in contrast media systemic reactions. This critical controlling protein has a major inhibitory effect on C1, kallikrein, activated factor XII of the intrinsic coagulation system, and on plasmin. In addition, it probably has other inhibitory effects not so well documented. Any circumstance that contributes to a continuing activation of the complement, coagulation, kinin, or fibrinolytic systems may result in partial consumption of the inhibitor and predispose the individual to adverse reactions to contrast challenge.
Assuntos
Proteínas Inativadoras do Complemento 1/imunologia , Meios de Contraste/efeitos adversos , Hipersensibilidade a Drogas/imunologia , Anafilaxia/induzido quimicamente , Anafilaxia/imunologia , Animais , Coagulação Sanguínea/efeitos dos fármacos , Ativação do Complemento/efeitos dos fármacos , Cães , Fibrinólise/efeitos dos fármacos , Humanos , Cininas , CoelhosRESUMO
A patient, suffering a severe anaphylactoid reaction to contrast material injected for an intravenous pyelogram, developed a consumption coagulopathy and evidence of complement activation. Precontrast complement values suggested that the patient had been processing complement via the classical pathway, perhaps as a consequence of an earlier protracted Klebsiella infection. Following contrast injection, a precipitous fall in hemolytic complement (CH50) and in the concentration of the C1 esterase inhibitor (C1INH) developed, as well as a diminution in C4 and C3 with the evolution of C3 conversion products. The possible role that these changes might play in the pathogenesis of idiosyncratic reactions to contrast media is considered.
Assuntos
Anafilaxia/induzido quimicamente , Meios de Contraste/efeitos adversos , Hipersensibilidade a Drogas/imunologia , Adulto , Anafilaxia/sangue , Transtornos da Coagulação Sanguínea/induzido quimicamente , Ativação do Complemento/efeitos dos fármacos , Proteínas Inativadoras do Complemento 1/análise , Proteínas do Sistema Complemento/análise , Feminino , Humanos , Fatores de Tempo , UrografiaRESUMO
Patients showing systemic reactions to intravascular contrast media and patients receiving contrast media without reaction have significantly different mean values (p is less than 0.05) for functionally determined serum C1-esterase inhibitor (C1 INH) and total hemolytic complement (CH50). The lower concentration of these components in reactors appears in baseline serum samples (as well as after injection), and suggests that many anaphylactoid reactions to contrast media are conditioned by earlier complement consumption, and result directly from contrast-induced activation of complement, and other activation system components in the presence of inhibitor depression.
Assuntos
Proteínas Inativadoras do Complemento 1/metabolismo , Proteínas do Sistema Complemento/metabolismo , Meios de Contraste , Hipersensibilidade/imunologia , Meios de Contraste/efeitos adversos , Hemólise , HumanosRESUMO
Earlier studies suggest that adverse reactions to injected radiographic contrast media are idiosyncratic. In an attempt to gain a better understanding of pathophysiologic events underlying these reactions, rabbit models injected with lethal dose ranges of a cholangiographic contrast material were studied. These animals showed activation of both the complement and coagulation systems. Externally applied heat potentiated complement consumption and increased mortality. Depleting complement components C3-C9 by cobra venom factor did not prevent activation of coagulation or diminish mortality. However, depleting fibrinogen diminished complement activation and markedly diminished mortality. Heparin, administered at several hourly intervals after contrast challenge, also diminished mortality. These studies suggest that the adverse effects of contrast media in this model system are mediated chiefly by the coagulation system, and that complement, if it participates deleteriously, must involve components up to, but not including, C3. A logical role for the inhibitor of C1 esterase in adverse contrast reactions is considered.
Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Ativação do Complemento/efeitos dos fármacos , Iodopamida/análogos & derivados , Ancrod/farmacologia , Animais , Testes de Coagulação Sanguínea , Proteínas Inativadoras do Complemento 1/fisiologia , Heparina/farmacologia , Temperatura Alta , Iodopamida/efeitos adversos , Masculino , Meglumina/efeitos adversos , Meglumina/análogos & derivados , Modelos Biológicos , CoelhosRESUMO
Since complement activation is sharply temperature-dependent, we have examined the effects of fever produced by a very small dose of endotoxin on contrast media lethality in rabbits. After the injection of 8.2 ml/kg of 52% methylglucamine iodipamide, a group of rabbits exhibiting an average temperature elevation of 1.5 degrees C had a 100% mortality rate. This was contrasted to a 30% mortality in control rabbits receiving contrast alone, and no mortality in rabbits receiving endotoxin alone. The rabbits with fever and increased mortality exhibited increased activation of serum complement. From this preliminary data it appears that caution should be observed in performing a contrast examination in a patient with endotoxemia and/or a fever.
Assuntos
Endotoxinas/sangue , Iodopamida/toxicidade , Meglumina/toxicidade , Sorbitol/análogos & derivados , Toxemia/mortalidade , Animais , Temperatura Corporal , Proteínas do Sistema Complemento/biossíntese , Escherichia coli , Febre/etiologia , Febre/fisiopatologia , Técnicas In Vitro , Masculino , Coelhos , Toxemia/fisiopatologiaRESUMO
Intravenous or intra-aortic injections of meglumine iothalamate in dogs indicate a slightly different tissue distribution and excretory pattern of the meglumine cation and the iothalamate anion. Differences in serum and urinary concentrations of these ions suggest some cellular penetration of the meglumine anion. In addition, there seems to be some evidence for both tubular absorption and tubular excretion of meglumine as a minor component in the renal excretion of this ion. No significant differences could be demonstrated for either urinary load or concentration when the sodium salts of iothalamate were compared to the methylglucamine salts.
Assuntos
Iotalamato de Meglumina/metabolismo , Ácido Iotalâmico/análogos & derivados , Rim/metabolismo , Urografia , Animais , Ânions , Aorta Abdominal , Cães , Feminino , Taxa de Filtração Glomerular/efeitos dos fármacos , Injeções Intra-Arteriais , Injeções Intravenosas , Iotalamato de Meglumina/administração & dosagem , Ácido Iotalâmico/administração & dosagem , Ácido Iotalâmico/metabolismo , Masculino , Fatores de TempoRESUMO
Canine peripheral venous or suprarenal aortic injections of sodium or meglumine iothalamate produced a significant swing towards an alkaline urine only in individual dogs injected with meglumine salts. When mean values were compared for the sodium or meglumine groups as a whole, however, no significant differences could be established for pH change or induced diuresis. With both salts, ATPase inhibition could play a role in urinary electrolyte excretion. Carbonic anhydrase inhibition does not seem to play a significant role in urinary pH changes induced by contrast media.