Evidence for a role of iron-catalyzed oxidants in functional and metabolic stunning in the canine heart.

Brief (15-minute) coronary occlusion and subsequent reperfusion lead to prolonged functional and metabolic abnormalities (stunned myocardium). Previous work suggests that one factor responsible for this phenomenon is oxygen-derived free radicals. The formation of the highly reactive hydroxyl radical requires the presence of metal ions, most importantly iron.

Respiratory syncytial virus infection in immunocompromised adults.

Respiratory syncytial virus disease was documented in 11 immunocompromised adults, aged 21 to 50. Underlying conditions included bone marrow transplant (6 patients), renal transplant (3 patients), renal and pancreas transplants (1 patient), and T-cell lymphoma (1 patient). Diagnosis of infection was based on specimens from bronchoalveolar lavage, sputum, throat, sinus aspirate, and lung biopsy.

Pentoxifylline inhibits granulocyte and platelet function, including granulocyte priming by platelet activating factor.

Pentoxifylline has been claimed to work a beneficial effect in arterial insufficiency by improving erythrocyte deformability and thus improving blood flow. A number of observations, including the drug concentrations required to work the red cell effect, suggested that this was not likely to be a complete explanation. We therefore examined the effect of pentoxifylline on several granulocyte and platelet functions.

Measurement of intracellular calcium concentration in intact monolayers of human endothelial cells.

Intracellular calcium ([Ca++]i) plays an important role in signal transduction and cell activation. The measurement of [Ca++]i in intact monolayers of human umbilical vein endothelial cells with the fluorescent calcium-sensitive probe fura 2 has been evaluated. Monolayers provide a more physiologic cell preparation than suspensions and allow a greater variety of experimental manipulation.

Platelet-activating factor primes neutrophil responses to agonists: role in promoting neutrophil-mediated endothelial damage.

During inflammation polymorphonuclear cells (PMNs) are exposed to agonistic stimuli including activated complement, kallikrein, arachidonic acid metabolites, monokines, and platelet-activating factor (PAF). We report that PAF not only directly activates PMNs but in miniscule quantities (10(-12) mol/L) "primes" them as well, that is, permits PMNs to respond to subsequent stimuli that would be otherwise ineffectual. PAF priming of responses including superoxide generation, elastase release, and aggregation is time dependent and is maximal within five minutes.

Endothelial cell heterogeneity: antioxidant profiles determine vulnerability to oxidant injury.

Human umbilical vein endothelial cells were more sensitive to hydrogen peroxide lysis than cow pulmonary artery endothelial cells. Conversely, activated neutrophils which utilize hydrogen peroxide-mediated cell cytotoxicity cell mechanisms were more toxic to the cow pulmonary artery cells. This discordance was not related to neutrophil adhesion to either cell type or cell passage number.

Pulmonary hypertension and edema induced by platelet-activating factor in isolated, perfused rat lungs are blocked by BN52021.

The experimental intravenous administration of platelet activating factor (PAF) induces pulmonary hypertension and directly or indirectly increases capillary permeability. Selective PAF antagonists BN52021 and L652-731 have been shown to inhibit the action of PAF in vitro and in vivo. Using a unique isolated perfused rat lung model, we measured the effect of these PAF antagonists on PAF-induced pulmonary hypertension and edema.

Limitation of complement activation by perfluorocarbon emulsions: superiority of lecithin-emulsified preparations.

A considerable body of evidence suggests that complement and granulocyte activation may be important in the occasional adverse reactions which occur on the administration of perfluorocarbon emulsions to patients. In an attempt to develop an emulsion which was less prone to activate complement than was the first product clinically tested, we devised an in-vitro protocol for the testing of an emulsion's ability to activate complement: emulsions were serially diluted, and were incubated with minimally-heparinized plasmas from each of several donors; the generation of C3a was assessed by commercial immunoassay. In such a system, F-Adamantane emulsions prepared with highly-purified lecithin as the emulsifier were consistently less complement-activating than comparable emulsions prepared with Pluronic F-68 as the emulsifier.

Excessive vulnerability of herpes-infected endothelium to lymphokine-activated lymphocytes: a possible role in lethal viral pneumonitis following bone marrow transplantation.

1. Lymphokine-activated killer cells are cytotoxic to human umbilical vein endothelial cells in vitro. 2.

Potentiated adherence of sickle erythrocytes to endothelium infected by virus.

Systemic viral infection is a known precipitant of vasocclusive crisis in sickle patients, but the mechanism underlying this clinical observation is unknown. In the present studies, human umbilical vein endothelial cells were infected with Herpes simplex virus type 1 (HSV) to model systemic viral disease. The already abnormal adherence of sickle erythrocytes to control endothelium is enhanced 1.

Therapy of chronic myelogenous leukemia with allogeneic bone marrow transplantation.

From December 1982 to January 1986, 57 patients received allogeneic bone marrow transplantation as therapy for Philadelphia chromosome (Ph') positive chronic myelogenous leukemia (CML). All patients were prepared for transplantation with cyclophosphamide 60 mg/kg (day -6, -5) and fractionated total body irradiation, 165 cGy twice daily (day -4, -3, -2, -1) and received major histocompatibility (MHC) matched donor marrow (day 0). All patients received graft-v-host disease (GVHD) prophylaxis with methotrexate, prednisone, and either antithymocyte globulin (ATG) (55 patients) or OKT3 infusion (two patients).

Pluronic F-68 reduces the endothelial adherence and improves the rheology of liganded sickle erythrocytes.

A perfluorochemical blood substitute emulsified with Pluronic F-68 has been shown to improve the filterability of deoxygenated sickle red cells. We questioned whether some of the effect was independent of oxygen loading and studied the influence of Fluosol DA (Green Cross, Osaka, Japan) and Pluronic on the rheology and adhesion of sickle red cells saturated with oxygen and carbon monoxide. A 5-vol/vol% concentration of Fluosol or equivalent concentration of Pluronic was equally effective at improving the filtration of washed sickle cells through 5-micron-diameter pores at wall shear stresses approximating 1,000 dyne/cm2.

Granulocytes as mediators of tissue injury in shock: therapeutic implications.

In summary, over the last twenty years, we have gained a substantially improved understanding of the ways in which granulocytes can damage host tissues. Most recently, there has been a great deal of interest in the intravascular behavior of granulocytes, and the possibility that such behavior might contribute to complications of extracorporeal circulations, bacteremic infections and shock. These insights give us several ideas about possible therapeutic interventions: corticosteroids or other drugs might be used to blunt granulocyte responsiveness; iron chelation might be used to limit the production of toxic hydroxyl radical; competitive inhibition of oxidant damage might be possible using such simple compounds as methionine; protease inhibitors might blunt endothelial cell delamination.

Lymphokine activated killer (LAK) cell-mediated endothelial injury: a mechanism for capillary leak syndrome in patients treated with LAK cells and interleukin-2.

We have investigated the possible etiology of a severe clinical syndrome seen in cancer patients treated with a new form of cancer-specific therapy, referred to as adoptive immunotherapy. This syndrome, apparently characterized by diffuse capillary injury, results in the leakage of intravascular fluid into interstitial tissues, with consequent organ dysfunction that limits the applicability of this form of therapy. We have demonstrated, using an in vitro model of cultured human endothelial cell injury, that LAK cells--lymphocytes stimulated in vitro by IL-2--appear to be potent mediators of endothelial injury.

Granulocyte oxygen radicals as potential suppressors of hemopoiesis: potentiating roles of lactoferrin and elastase; inhibitory role of oxygen radical scavengers.

In vitro studies suggest intact endothelial cells and their released growth factors are required for optimal growth and differentiation of hematopoietic cells in culture. Conversely, processes that damage endothelium might, therefore, suppress hematopoiesis. We have studied mechanisms by which stimulated inflammatory cells, particularly granulocytes, damage endothelium and suggest these studies may provide new insights into the hematopoietic suppression of inflammatory diseases.

Neutrophil oxidants inactivate alpha-1-protease inhibitor and promote PMN-mediated detachment of cultured endothelium. Protection by free methionine.

Activated granulocytes have been implicated in mediating pulmonary endothelial damage in the Adult Respiratory Distress Syndrome. In another lung disease, emphysema, pulmonary granulocytes (PMNs) are thought to be doubly responsible for lung dissolution: they release potent proteolytic enzymes including elastase, and they generate reactive oxygen species that oxidize a reactive site methionine group in alpha-1-protease inhibitor (alpha-1-PI) rendering it, in turn, impotent as an anti-elastase. This suggested an analogous scenario for pulmonary vascular damage: namely, undefended PMN elastase might also mediate endothelial injury.

Sodium morrhuate stimulates granulocytes and damages erythrocytes and endothelial cells: probable mechanism of an adverse reaction during sclerotherapy.

Stimulated by a patient with dyspnea, thrombocytopenia, and leukopenia after sodium morrhuate sclerotherapy, we studied the effect of this agent on the plasma coagulation and complement systems, the formed elements of the blood, and cultured human endothelial cells. The addition of sodium morrhuate to citrated plasma did not cause clotting or shorten the prothrombin time or partial thromboplastin time. Incubation of a 1:100 dilution of the clinical sodium morrhuate preparation in heparinized plasma led to a modest rise in [C3a].

Oxygen radical-induced erythrocyte hemolysis by neutrophils. Critical role of iron and lactoferrin.

Human neutrophils (PMN), when stimulated with such chemotaxins as phorbol myristate acetate (PMA), destroy erythrocytes and other targets. Cytotoxicity depends on PMN-generated reactive oxygen metabolites, yet the exact toxic specie and its mode of production is a matter of some dispute. Using 51Cr-labeled erythrocytes as targets, we compared various reactive-O2 generating systems for their abilities to lyse erythrocytes as well as to oxidize hemoglobin to methemoglobin.

Extracellular matrix proteins (fibronectin, laminin, and type IV collagen) bind and aggregate bacteria.

The normal microbial colonization of sites in the body's tissues by certain bacteria requires that the bacteria first bind to extracellular secreted constituents, cell-surface membranes, or cell matrixes. This study examines two interactions of a variety of bacteria with the cell matrix noncollagenous proteins fibronectin and laminin and with basement membrane (Type IV) collagen. Adherence of bacteria to matrix proteins coated on tissue culture wells was examined with the use of radiolabeled bacteria.

A histopathologic study of gastric and small intestinal graft-versus-host disease following allogeneic bone marrow transplantation.

Twenty-two stomach and 14 small intestinal biopsy specimens from 24 allogeneic bone marrow transplant recipients were reviewed to evaluate the histopathologic changes of graft-versus-host disease (GVHD) in these organs. Associations between these results and clinical symptoms and other biopsy results were sought. In both organs, single epithelial cell necrosis was found to correlate with GVHD.

Bronchiolitis obliterans after bone marrow transplantation.

Bronchiolitis obliterans occurred in the setting of chronic graft-versus-host disease 1 year after allogeneic bone marrow transplantation for chronic myelogenous leukemia. The severe obstructive pulmonary disease followed an episode of interstitial pneumonitis. The etiology and possible relationship to graft-versus-host disease of this rare pulmonary lesion following bone marrow transplantation are discussed.

Protection against lethal hyperoxia by tracheal insufflation of erythrocytes: role of red cell glutathione.

Intact erythrocytes placed into the tracheobronchial tree of hyperoxic rats dramatically improved their chances for survival. Over 70 percent of the animals so treated survived more than 12 days during continuous exposure to 95 percent oxygen, whereas all of the control animals died within 96 hours. Lungs from erythrocyte-protected rats showed almost none of the morphologic damage suffered by untreated animals.