In a porcine model of hyperdynamic endotoxemia, we studied the numerical expression of L-selectin and beta 2-integrins on circulating polymorphonuclear leukocytes (PMN). Functional changes of beta 2-integrins were determined by the adhesion of PMN to C3-coated zymosan particles. Anesthesized pigs received a continuous infusion of Salmonella abortus-equi endotoxin (5 micrograms.kg body wt-1.h-1) for 270 min (endotoxin group; n = 7). A control group received 0.9% NaCl (n = 6). L-selectin had decreased 30 min after the induction of endotoxemia [59.1 +/- 11.9 vs. 91.6 +/- 15.5 relative fluorescence units (RFU) at baseline; P < 0.05], reaching minimal values after 150 min (23.9 +/- 3.9 RFU in endotoxin group vs. 95.2 +/- 30.4 RFU in control group; P < 0.05). PMN adhesion to C3-coated zymosan increased at 30 min (41.3 +/- 9.9% in endotoxin group vs. 2.4 +/- 1.1% in control group; P < 0.05) and remained significantly elevated thereafter. In contrast to the rapid shedding of L-selectin and functional upregulation of beta 2-integrins, the numerical expression of beta 2-integrins remained unchanged until 60 min (44.8 +/- 2.8 vs. 32.2 +/- 1.7 RFU at baseline; P < 0.05); compared with the control group, significantly elevated values were observed 150 min after the start of endotoxin (48.9 +/- 2.4 RFU in endotoxin group vs. 36.5 +/- 2.7 RFU in control group; P < 0.05). We conclude that numerical and functional expressions of beta 2-integrins are dissociated during endotoxemia. Although upregulation of beta 2-integrins might render PMN more adhesive to the vascular endothelium, the presence of activated PMN in the circulation suggests that low expression of L-selectin might impede adhesion.
Infusion of adenosine might be useful to improve flow-dependent oxygen delivery and tissue oxygenation during endotoxic shock without the induction of adverse cardiopulmonary side effects. The beneficial hemodynamic effects of adenosine appear not to be mediated by the inhibition of the release of tumor necrosis factor-alpha.
Endotoxin-activated polymorphonuclear leukocytes (PMNL) adhere to the vascular endothelium and cause damage by the release of toxic superoxide anions (O2-). Because adenosine is a potent inhibitor of PMNL in vitro, the present study investigates the effects of this nucleoside on the functions of circulating PMNL in a standardized porcine model of hyperdynamic endotoxemia. Ten anesthesized pigs received an intravenous (i.v.) 330-min infusion of endotoxin (5 microg/kg of body weight per h). Another 10 pigs were also infused with endotoxin plus adenosine (150 microg/kg/min [i.v.]); this treatment was begun 30 min prior to the beginning of endotoxin treatment. Control groups (five animals per group) received either adenosine or physiological saline. Infusion of endotoxin caused severe neutropenia, shedding of L-selectin, upregulation of beta2-integrins, increased binding of C3-coated zymosan particles, and subsequent phagocytosis by PMNL. While phagocytosis-induced production of oxygen radicals appeared to decrease, extracellular release of superoxide anions was strongly enhanced. Infusion of adenosine during endotoxemia had no effect on neutropenia, expression of adhesion molecules, C3-induced adhesion, phagocytosis, or intracellular production of oxygen radicals, whereas extracellular release of O2- was strongly inhibited. Thus, i.v. infusion of adenosine during endotoxemia could be useful in protecting from O2(-)-mediated tissue injury without compromising the bactericidal mechanisms of PMNL.
Abstract:Mucormycosis is an uncommon fungal infection caused by Mucorales. It frequently occurs in patients with neutropenia, diabetes, malignancy and on corticoid therapy. However, it is rare in patients with AIDS. Clinical disease can be manifested in several forms. The case reported illustrates the rare occurrence of chromoblastomycosis and mucormycosis in an immunosuppressed patient with multibacillary leprosy, under prolonged corticosteroid and thalidomide therapy to control leprosy type 2 reaction. Neutrophil dysfunction, thalidomide therapy and work activities are some of the risk factors in this case. Chromoblastomycosis was treated by surgical excision and mucormycosis with amphotericin B. Although the prognosis of mucormycosis is generally poor, in the reported case the patient recovered successfully. This case should alert dermatologists to possible opportunistic infections in immunosuppressed patients. Keywords: Chromoblastomycosis; Immunocompromised host; Leprosy; Mucormycosis Resumo: Mucormicose é uma infecção fúngica incomum causada por Mucorales. Ocorre frequentemente em pacientes com neutropenia, diabetes, corticoterapia e condições malignas. Porém, é rara em pacientes com AIDS. A doença pode apresentar-se em diferentes formas. Este caso ilustra a rara ocorrência de mucormicose e cromoblastomicose em um paciente com hanseníase multibacilar, que estava sendo tratado com prednisona e talidomida devido a eritema nodoso (reação hansênica tipo II). Disfunção de neutrófilos, uso de talidomida e atividades profissionais são alguns fatores de risco neste caso. A cromoblastomicose foi tratada por excisão cirúrgica e a mucormicose com anfotericina B. Embora o prognóstico da mucormicose seja ruim, neste caso o tratamento foi bem sucedido. Este caso alerta dermatologistas para a possibilidade de infecções oportunistas em pacientes imunossuprimidos.
Os autores relatam três casos de pacientes portadores de psoríase que utilizaram inadvertidamente doses elevadas de metotrexato e apresentaram ulceração das lesões cutâneas de psoríase. Os efeitos adversos cutâneos do metotrexato são raros, algumas vezes dose-dependentes, outras idiossincrásicos ou relacionados com alteração de metabolização da droga, ou, ainda, interações medicamentosas
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