Prostaglandin E1 and prostaglandin I2 modulation of superoxide production by human neutrophils

15(S)-15-methyl-prostaglandin E1 and prostaglandin I2 rapidly and reversibly inhibit formyl-methionyl-leucyl-phenylalanine induced superoxide production by human neutrophils. In contrast, 15(S)-15-methyl-prostaglandin E1 and prostaglandin I2 did not alter the rate or the total amount of superoxide production by human neutrophils stimulated with either phorbol myristate acetate or arachidonic acid. These data suggest that the production of superoxide anion by human neutrophils may be mediated by at least two mechanisms, one regulated by prostaglandins and intracellular cyclic adenosine monophosphate levels and a second independent of prostaglandin modulation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25188/1/0000627.pd

Oxygen metabolite detoxifying enzyme levels in bleomycin-induced fibrotic lungs

The activities of three enzymes cytosolic superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSHP), and malonylialdehyde (MDA), a by-product of lipid peroxidation, were determined in whole lungs of normal and bleomycin-treated rats. Two days after bleomycin treatment total lung SOD, CAT, and GSHP activities were significantly (p p p 2 metabolites may play an important role in the development of bleomycin-induced pulmonary fibrosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27559/1/0000603.pd

3‐Deaza‐Adenosine Inhibition of Stimulus‐Response Coupling in Human Polymorphonuclear Leukocytes

In an effort to define better the functional role of S‐adenosyl‐methionine‐mediated methylation reactions in modulating polymorphonuclear (PMN) functional responses to chemotactic stimuli, we investigated the effects of 3‐deaza‐adenosine (3‐DZA), a known inhibitor of methylation reactions in phagocytic cells, on formyl methionyl‐leucyl‐phenylalanine (FMLP)‐induced responses in human PMN leukocytes. Using the fluorescent cyanine dye 3,3’‐dipropylthiocarbocyanine (di‐S‐C3‐(5)) as an optical probe of membrane potential we observed that 3‐DZA at concentrations that inhibit FMLP‐induced O2− production does not significantly alter FMLP‐induced changes in transmembrane potential. Additional studies showed an inhibitory effect of 3‐DZA on FMLP‐induced PMN pinocytosis and to a lesser degree on FMLP‐induced degranulation. However, pretreatment of PMNs with 3‐DZA did not alter FMLP‐induced changes in Quin‐2 fluorescence, an indicator of changes in intracellular calcium levels. These findings demonstrate a dissociation between chemotactic factor‐induced cell membrane depolarization, changes in intracellular calcium, and specific neutrophil functional responses and suggest that chemotactic factor‐induced changes in transmembrane potential and intracellular calcium are independent of chemotactic factor‐induced methylation reactions. Furthermore, 3‐DZA did not alter phorbol myristate acetate induced O2− production or fluid pinocytosis indicating a stimulus specificity for the inhibitory effects of this agent on O2− production.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141044/1/jlb0121.pd

Inhibition of carrageenin-induced rat footpad edema by systemic treatment with prostaglandins of the E series

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23862/1/0000101.pd

Suppression of human polymorphonuclear function after intravenous infusion of prostaglandin E1

In two of three patients with peripheral vascular disease, systemic infusion of PGE1 inhibited chemotactic factor induced secretion of glucosaminidase from neutrophils.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24290/1/0000556.pd

Rapid purification of human peripheral blood monocytes by centrifugation through Ficoll-Hypaque and Sepracell-MN

We have developed a rapid and simple method for isolating human peripheral blood monocytes in suspension. The procedure combines two separation media and involves isolation of the mononuclear cells by centrifugation through Ficoll-Hypaque followed by purification of the monocytes using Sepracell-MN, a colloidal silica-based medium. The final cell population contained approximately 90% monocytes with good functional ability. The contaminating cells were lymphocytes. Viability was always [greater, double equals] 99% with 90% recovery of the monocytes from the mononuclear cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27265/1/0000275.pd

The role of the neutrophil and free radicals in ischemic myocardial injury

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27676/1/0000059.pd

Prostaglandin modulation of N-formylmethionylleucylphenylalanine-induced transmembrane potential changes in rat neutrophils

Prostaglandins of the E-series (PGEs) and PGI2 will inhibit formylmethionylleucylphenylalanine- (f-Met-Leu-Phe) induced lysosomal enzyme release and superoxide-anion (O-2) production by neutrophils. The inhibitory effects of PGEs and PGI2 on neutrophil functional responses have been correlated with their ability to increase intracellular cAMP. In this study we have examined the effects of PGEs and PGI2 on f-Met-Leu-Phe- and phorbol-myristate-acetate-induced rat neutrophil membrane potential changes using an optical probe of membrane potential 3,3-dipropylthiodicarbocyanine iodide. 15-(S)-15-methyl-PGE1 (15-methyl-PGE1), a stable analogue of PGE1 and PGI2 inhibited f-Met-Leu-Phe-induced transmembrane potential changes in a dose-dependent manner. This inhibition was correlated with the ability of these agents to increase intracellular cAMP levels and inhibit O-2 production and degranulation. In contrast, 15-methyl-PGE1 and PGI2, did not inhibit phorbol-myristate-acetate-induced transmembrane potential changes and O-2 production. These results suggest independent mechanisms of activation of neutrophils by phorbol myristate acetate and f-Met-Leu-Phe, and they also suggest that the inhibitory effects of prostaglandins and cAMP on f-Met-Leu-Phe-stimulated cells is at a step or steps prior to activation of those processes involved in effecting changes in transmembrane potential, which are common to both stimuli.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24755/1/0000177.pd

Myocardial glutathione depletion impairs recovery of isolated blood-perfused hearts after global ischaemia

This study was performed to determine whether depletion of myocardial glutathione would impair recovery of left ventricular function of blood-perfused, isolated hearts after reversible ischaemic injury. Cats were treated with either vehicle or buthionine sulfoximine (BSO), an inhibitor of gamma-glutamylcysteine synthetase, the rate-limiting enzyme in the synthesis of glutathione. The feline isolated hearts were perfused with the blood of normal donor cats before and after 40 min of global myocardial ischaemia. The myocardial concentration of glutathione of the BSO group, 178+/-38 ng/mg tissue, was significantly less than that of the control group, 292+/-38 ng/mg tissue (PP=0.05 vs. control). The peak left ventricular dP/dt after reperfusion, expressed as a fraction of the peak dP/dt before ischaemia, was 1.08+/-0.14 for the control group and 0.78+/-0.09 for the BSO group (P=0.05 vs. control). The myocardial creatine kinase activity of the BSO group, 1046+/-46 U/g tissue, was not significantly different from that of the control group, 1038+/-17 U/g tissue (P=0.87). Thus, depletion of myocardial glutathione resulted in impaired post-ischaemic contractile function that cannot be attributed to a greater extent of irreversible cell injury.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29775/1/0000114.pd

Human platelets mediate iron release from transferrin by adenine nucleotide-dependent and -independent mechanisms

We assessed the ability of platelet sonicates and mediators secreted by unstimulated and thrombin-stimulated platelets to facilitate the release of iron from transferrin. Platelet sonicates and platelet conditioned media potentiated the release of iron from transferrin. The rate of release of iron was dependent on the pH of the reaction and amount of platelet sample added. Conditioned media from thrombin-stimulated platelets was more effective in mediating the release of iron from transferrin than was conditioned media from unstimulated cells. The rate of iron released from transferrin following addition of ATP and ADP in amounts equivalent to that present in platelet conditioned media was significantly less than the rate of iron released following the addition of conditioned media from platelets. Depletion of ATP and ADP in platelet conditioned media by incubation with apyrase only partially inhibited their ability to enhance the rate of iron release from transferrin. These observations indicate that platelets enhance the release of iron from transferrin by adenine nucleotide-dependent and -independent mechanisms. These observations are consistent with the hypothesis that platelets promote oxidant-induced tissue injury at sights of inflammation secondary to their ability to enhance the local release of iron from transferrin.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28084/1/0000530.pd