RESUMEN
Although studies of drug uptake by leukocytes use similar methods, the results reported are sometimes vastly different. To determine the possible reasons for this, we studied neutrophil uptake of [3H]-clindamycin using the most frequently used density gradient centrifugation method and the volume probes 3H2O and [3H]-polyethylene glycol. We found that the [3H]-clindamycin available to investigators had undergone radiolytic decomposition; thus, its microbiologic activity was only 20% of its original potency. By thin-layer chromatography and autoradiography, four extra label-bearing regions were observed with [3H]-clindamycin. Results of neutrophil uptake studies have shown a drop of cellular:extracellular concentration ratios from 40:1 in 1981 to 10:1 in 1982 and 1987.
Asunto(s)
Clindamicina/metabolismo , Leucocitos/metabolismo , Cromatografía en Capa Delgada , Humanos , Técnicas In Vitro , Neutrófilos/metabolismo , Tritio , Agua/metabolismoRESUMEN
The cellular/extracellular (C/E) concentration ratio of teicoplanin in polymorphonuclear leukocytes (PMNs) increased rapidly with time (C/E 60 +/- 13 at 20 min). The C/E ratio was time- and concentration-dependent. At 20 min and an initial concentration of 75 +/- 16 micrograms/ml the cellular drug concentration was 4,700 +/- 1,300 micrograms/ml. The mechanism of drug uptake was by an active process and transported (cellular) drug retained its antimicrobial activity. Washing removed 42% of cellular drug. Teicoplanin inhibited PMN chemotaxis at very high concentrations and PMN microbicidal activity at lower concentrations.
Asunto(s)
Neutrófilos/metabolismo , Transporte Biológico Activo , Quimiotaxis de Leucocito/efectos de los fármacos , Clindamicina/farmacocinética , Femenino , Glicopéptidos/farmacocinética , Glicopéptidos/farmacología , Humanos , Masculino , Neutrófilos/efectos de los fármacos , TeicoplaninaRESUMEN
We studied 46 patients who suffered from serious blunt trauma to examine the possible mechanism of their acquired neutrophil (PMN) locomotory dysfunction. Concentrations of plasma C3adesArg were higher in patients than in controls (310 +/- 190 ng/ml vs. 90 +/- 28 ng/ml, respectively; P = 3 X 10(-5)). Both resting and phagocytosing PMNs from the patients produced higher quantities of H2O2 (0.31 +/- 0.29 and 5.2 +/- 3.4 nmol/10(6) PMNs per hr, respectively). These levels resemble the H2O2 production of normal PMNs preactivated with chemotactic factor (0.85 +/- 0.03 for normal and 8.2 +/- 1.6 nmol/10(6) PMNs per hr for preactivated PMNs). Concentrations of oxidized glutathione were not significantly higher in PMNs from patients compared with PMNs from controls (0.053 +/- 0.057 vs. 0.037 +/- 0.046 nmol/10(6) PMNs, respectively; P = .5). A higher percentage of PMNs from trauma patients than from controls were capped with concanavalin A (66% +/- 11% vs. 37% +/- 14%, respectively; P = 4 X 10(-5)), a result indicating microtubular dysfunction. These findings suggest that in trauma, activation of intravascular complement results in inappropriate chemotactic stimulation and subsequent deactivation and autoxidative damage of circulating PMNs.
Asunto(s)
Quimiotaxis de Leucocito , Neutrófilos/fisiología , Heridas no Penetrantes/inmunología , Adolescente , Adulto , Anciano , Activación de Complemento , Complemento C3/análisis , Complemento C3a , Femenino , Glutatión/metabolismo , Humanos , Peróxido de Hidrógeno/metabolismo , Activación de Linfocitos , Masculino , Persona de Mediana Edad , Oxidación-ReducciónRESUMEN
We showed previously in vitro that ibuprofen, a nonsteroidal anti-inflammatory agent, at concentrations easily achievable in blood, inhibits polymorphonuclear leukocyte cell swelling and aggregation in response to chemotactic factor stimulation. To confirm this in vivo, we studied the ability of ibuprofen i.v. pretreatment to reverse the transcutaneous hypoxia induced by i.v. infusion of 1 nmol/kg of formyl-methionyl-leucyl-phenylalanine. This effect was compared with that of methylprednisolone. For ibuprofen and methylprednisolone, respectively, the maximum percentage of reversal of hypoxia was 85 and 106%; the dose required to produce 50% of maximum reversal was 2.7 and 4.6 mg/kg; and the serum drug concentration needed to achieve 50% of maximum reversal was 14 and 11 micrograms/ml. We conclude that ibuprofen could be a useful alternative to steroidal antiinflammatory agents for the prevention and treatment of complications of stimulated polymorphonuclear leukocytes.
Asunto(s)
Ibuprofeno/farmacología , Metilprednisolona/farmacología , N-Formilmetionina Leucil-Fenilalanina/antagonistas & inhibidores , Neutrófilos/efectos de los fármacos , Oxígeno/metabolismo , Piel/metabolismo , Animales , Agregación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , N-Formilmetionina Leucil-Fenilalanina/farmacología , Neutrófilos/metabolismo , Presión Parcial , Conejos , Piel/efectos de los fármacosRESUMEN
The stimulation of cell swelling, cell aggregation, polymorphonuclear leukocyte locomotion, and lysosomal enzyme release in response to chemoattractant were all inhibited by ibuprofen, a nonsteroidal anti-inflammatory agent. The dosages needed to induce 50% inhibition (ID50) were 5.9, 7.6, 60, and 95 micrograms/mL, respectively. Aside from the differences in ID50, there was also a difference in the degree of maximum inhibition (Imax) of the complement C5a-stimulated responses observed, so that at achievable serum drug concentrations of 20-50 micrograms/mL, inhibition of 67-78% for cell swelling, 69-82% for cell aggregation, 20-35% for migration response, and 17-38% for lysosomal enzyme release were demonstrated. Also observed were a minor stimulatory effect on nitroblue tetrazolium reduction and an inhibitory effect on the ability to kill Staphylococcus aureus, but only at very high concentrations (approximately 2 mg/mL).