Today’s Practice of Cardiopulmonary Medicine

Role of Humoral Mediators in Adult Respiratory Distress Syndrome

Differentiation induction as a therapeutic strategy has, so far, the greatest impact in hematopoietic malignancies, most notably leukemia. Diosgenin is a very interesting natural product because, depending on the specific dose used, its biological effect is very different in HEL (human erythroleukemia) cells. For example, at 10 μM, diosgenin induced megakaryocytic differentiation, in contrast to 40 μM diosgenin, which induced apoptosis in HEL cells previously demonstrated using sedimentation field-flow fractionation (SdFFF). The goal of this work focused on the correlation between cyclooxygenase-2 (COX-2) and thromboxane synthase (TxS) and megakaryocytic differentiation induced by diosgenin in HEL cells. Furthermore, the technique of SdFFF, having been validated in our models, was used in this new study as an analytical tool that provided us with more or less enriched differentiated cell fractions that could then be used for further analyses of enzyme protein expression and activity for the first time. In our study, we showed the implication of COX-2 and TxS in diosgenin-induced megakaryocytic differentiation in HEL cells. Furthermore, we showed that the analytical technique of SdFFF may be used as a tool to confirm our results as a function of the degree of cell differentiation.

‘Resuscitate: revive from unconsciousness or apparent death’ (Sykes, 1978).

‘Shock: a term used by clinicians to describe a condition characterized by inadequate cellular perfusion and consequent failure of function of various tissues and organs’ (Hanson, 1978).

Five patients with sepsis-induced acute organ system failure were treated by sequential plasmafilterdialysis with slow continuous hemofiltration in addition to conventional therapy. In this way, we were able to associate the possible clearance of mediators and toxic substances achieved by plasmapheresis with an improved clearance of nitrogen waste products, since we added diffusion to the convective effect of hemofiltration. The hypercatabolism was well controlled, and there was a significant improvement in cardiorespiratory parameters at the same time. These patients were retrospectively compared with four conventionally treated patients (100% mortality) and with six others treated by association of conventional therapy and continuous arteriovenous hemodialysis (50% mortality). Despite the small numbers of patients treated and the need of additional studies, our good results (all the patients survived) encourage us to use this approach as an adjunct of conventional therapeutic measures in oliguric and hypercatabolic AOSF patients.

Studies have shown that there are at least two broad categories of acute lung injuries: those that require polymorphonuclear leukocytes, and those that do not. Knowledge from animal experiments is very incomplete, and the relevance of animal models to human disease is unknown. Specific therapy appears to be a distant goal, because there is no single underlying mechanism of lung injury, and because there is no way to precisely identify what injured the lung or to make a clinical diagnosis early enough in lung injury. Many possibilities for therapy are based on interfering with inflammation, and may therefore increase susceptibility to infection. Considerable progress is being made, but there is much left to learn.