Polymorphonuclear leukocytes as secretory organs of inflammation

The Selective Polymorphonuclear Neutrophils (PMN) Degranulation as the Probable Additional Mechanism of the Hemodialysis (HD)-induced Complement Activation

The intracellular lysozyme and beta-glucuronidase contents were estimated in PMN isolated from peripheral blood before HD and those from the first portion of full blood leaving the dialyser. The lysozyme estimations were done by the use of the turbidimetric method and beta-glucouronidase was assayed by measuring the release of phenolphtalein from its beta-glucuronate. The cells leaving the cellophane dialyser showed the significantly decreased lysozyme contents while the estimated intracellular activity of beta-glucuronidase was practically equal in both evaluated samples.

The results seem to indicate that the HD-associated complement activation may result not only from the simple plasma-cellophane ineteraction. The direct cleavage of the inactive C5 complement component by products released from the PMN specific granules seems to play an important role too.

For several years it has been known that the hemodialysis (HD)-induced granulopenia is the result of the pulmonary polymorphonuclear neutrophils (PMN) sequestration (Toren et al., 1970). Recent studies have established that this phenomenon is the consequence of complement activation leading to PMN aggregation with subsequent pulmonary vascular embolization and/or PMN adherence to endothelial surface (Craddock et al. 1977a, Craddock et al., 1979). It was also observed that the contact of patients plasma or plasma obtained from experimental animals with dialyser cellophane results, both in vitro and during HD, in the appearance of the activities: inducing the PMN aggregation, chemotactic and augmenting the PMN adherence (Craddock et al. 1977b, Wysocki et al. 1980). At least the two first are identified as related to the presence of the C5a complement component (Craddock et al., 1977b, O'Flaherty et al., 1979).

Similarly, the disseminated complement activation appears to be the main reason of granulopenia accompanying the filtration leukapheresis (FL), the procedure suitable for PMN collection from donors peripheral blood (Hammerschmidt et al., 1978). The PMN are there sequestered in nylon wool layer and subsequently eluted for transfusion purposes. The exposition of blood to artificial surface leads there, like during HD, to the complement (C5) activation. Although, as reported by Wright et al.) 1978b), when plasma and leukocyte enriched blood were diverted by a cell separator before passage through nylon wool filters during FL, complement activation was evident only in plasma from blood containing leukocytes, indicating that extracorporeal complement activation during FL is dependent in large part upon the interaction of leukocytes with nylon wool. The more precise studies of these authors (Wright et al., 1978a) may imply, that the PMN granule constituents released after the previous adherence of cells to nylon fibers are responsible for the FL-associated complement activation.

The following studies were done in order to evaluate if the PMN degranulation may take part also in complement activation during hemodialysis carried out with the use of cellophane equipment.

Ultraviolet radiation and skin aging: roles of reactive oxygen species, inflammation and protease activation, and strategies for prevention of inflammation-induced matrix degradation - a review

Inflammation and the resulting accumulation of reactive oxygen species (ROS) play an important role in the intrinsic and photoaging of human skin in vivo. Environmental insults such as ultraviolet (UV) rays from sun, cigarette smoke exposure and pollutants, and the natural process of aging contribute to the generation of free radicals and ROS that stimulate the inflammatory process in the skin. UV irradiation initiates and activates a complex cascade of biochemical reactions in human skin. In short, UV causes depletion of cellular antioxidants and antioxidant enzymes (SOD, catalase), initiates DNA damage leading to the formation of thymidine dimmers, activates the neuroendocrine system leading to immunosuppression and release of neuroendocrine mediators, and causes increased synthesis and release of pro-inflammatory mediators from a variety of skin cells. The pro-inflammatory mediators increase the permeability of capillaries leading to infiltration and activation of neutrophils and other phagocytic cells into the skin. The net result of all these effects is inflammation and free radical generation (both reactive oxygen and nitrogen species). Furthermore, elastsases and other proteases (cathepsin G) released from neutrophils cause further inflammation, and activation of matrix metalloproteases. The inflammation further activates the transcription of various matrixes degrading metalloproteases, leading to abnormal matrix degradation and accumulation of non-functional matrix components. In addition, the inflammation and ROS cause oxidative damage to cellular proteins, lipids and carbohydrates, which accumulates in the dermal and epidermal compartments, contributing to the aetiology of photoaging. Strategies to prevent photodamage caused by this cascade of reactions initiated by UV include: prevention of UV penetration into skin by physical and chemical sunscreens, prevention/reduction of inflammation using anti-inflammatory compounds (e.g. cyclooxygenase inhibitors, inhibitors of cytokine generation); scavenging and quenching of ROS by antioxidants; inhibition of neutrophil elastase activity to prevent extracellular matrix damage and activation of matrix metalloproteases (MMPs), and inhibition of MMP expression (e.g. by retinoids) and activity (e.g. by natural and synthetic inhibitors).

Effect of Nicotine-Induced Corticosterone Elevation on Nitric Oxide Production in the Passive Skin Arthus Reaction in Rats

To elucidate the anti-inflammatory action of nicotine-induced corticosterone elevation on the passive skin Arthus reaction (PSAR), we investigated the inflammatory process in the PSAR. The polymorphonuclear leukocyte (PMNs) infiltration was observed just before as well as after elicitation by measuring extractable myeloperoxidase. The plasma exudation was significantly inhibited by anti-rat tumor necrosis factor (TNF)-alpha antibody (5 microg/site, i.d.) at the time of sensitization or by superoxide dismutase (52500 units/kg, i.p.) 1 h before elicitation or N(G)-nitro-L-arginine-methyl ester (100 mg/kg, i.v.) just at elicitation. Pretreatment with a single injection of nicotine (0.8 mg/kg, i.p.) 30 min before elicitation suppressed the plasma exudation but not the PMNs infiltration. This nicotine-induced decreasing effect was abolished in animals supplemented with L-arginine (300 mg/kg, i.v.) just at elicitation. The production of nitric oxide (NO) in peritoneal PMNs derived from an animal injected peritoneally with oyster glycogen was significantly suppressed by pretreatment with nicotine (0.8 mg/kg, i.v.) 30 min prior to harvesting. This inhibitory action of nicotine was abolished in animals pretreated with mifepristone (30 mg/kg, s.c.), a glucocorticoid receptor antagonist. These findings indicate that a single systematic administration of nicotine may attenuate the plasma exudation in the PSAR by suppressing the production of NO in the PMNs primed with TNF-alpha via nicotine-induced endogenous glucocorticoid.

The role of hydroxyurea in the management of sickle cell disease

Sickle cell disease (SCD) is one of the most common genetic diseases with some 250,000 new births each year. Most patients suffer intermittent pain crises and life-threatening events while life expectancy is considerably reduced. Until the last decade management was purely preventative or supportive aimed at symptom control. Apart from stem cell transplant, there is no cure but the oral chemotherapeutic drug hydroxyurea (HU) has now established a role in ameliorating the disease and improving life expectancy for most patients. There are side effects and risks of HU treatment in SCD but for moderate and severely affected patients, the benefits can be significant.

In vitro release of elastase from human blood and gingival crevicular neutrophils

Peripheral PMNs were collected from blood, and crevicular PMNs separated by filtration from gingival washings in 13 patients, aged 22-75 y, who had varying degrees of gingivitis and periodontitis. After pre-incubation with cytochalasin B, the same number of crevicular and peripheral cells were incubated either in PBS (with Ca2+ and Mg2+) (spontaneous release) or in the same buffer containing increasing concentrations of FMLP (stimulated release); elastase activity was measured in the supernatant by a fluorometric technique. There was a higher spontaneous release of enzyme from crevicular than from peripheral neutrophils. The average elastase activity in the supernatant of 1 x 10(4) crevicular cells was more than five times higher than that obtained from the same number of peripheral cells. However, stimulated crevicular PMNs liberated smaller amounts of enzyme than did stimulated peripheral PMNs. These results suggest that crevicular PMNs are already releasing elastase, and are consistent with the possibility that lysosomal enzymes contribute to tissue damage during gingivitis and periodontitis.

Inflammatory components in uterine fluid from mares with experimentally induced bacterial endometritis

Exudate and uterine flushings were collected at either 30, 60, 120 or 240 mins after intrauterine infusions of Streptococcus zooepidemicus in genitally normal mares during oestrus. Uteri were also flushed without prior induction of endometritis. Protein concentrations in exudate and flushings increased with time and exudate pH decreased with time; the pH of flushings did not alter. Lysozyme and lactate dehydrogenase were present in flushings from non-infected uteri, but concentrations increased with time after infection. Immunoreactive prostaglandin E2 was undetectable before infection, but concentrations rose after infection. No neutrophils were present in non-infected flushings but, by 30 mins, there were significant (P less than 0.01) neutrophil numbers in exudate and flushings; thereafter numbers increased, particularly in exudate. Acute endometritis resembled acute inflammation at other sites in the horse and a significant response had occurred by 30 mins after experimental infection.

Hyposmolarity stimulates myeloperoxidase exocytosis from human polymorphonuclear leukocytes

Medium hyposmolarity induced in human polymorphonuclear leukocytes treated with cytochalasin B a rapid exocytosis of the lysosomal enzyme, myeloperoxidase (MPO), which was linearly proportional to the degree of hyposmolarity between a 5 and 30% decrease (r = 0.92, p less than 0.001). Cell viability was unaffected by the hyposmolarity. The kinetics of MPO exocytosis induced by opsonized zymosan (OZ) and hyposmolarity were indistinguishable; the combination of hyposmolarity and OZ was additive. Since hyposmolarity similarly stimulates a burst of hormone secretion by perifused adenohypophyseal and pancreatic islet cells, the authors suggest that hyposmolarity-induced exocytosis is a general cellular phenomenon.

Effects of sera from patients with obstructive jaundice on the generation of oxygen intermediates by normal polymorphonuclear leukocytes

Recently it has been suggested that oxygen intermediates play an important role in the pathogenesis of tissue damage. The effect of sera from patients with obstructive jaundice on the generation of oxygen intermediates by normal polymorphonuclear leukocytes (PMNs) was investigated. Sera from patients with obstructive jaundice increased superoxide anion (O2-), hydrogen peroxide (H2O2) and hydroxol radical (OH.) generation compared with sera from healthy individuals or patients with biliary tract stones and/or tumors of the biliary tract or pancreas (without obstructive jaundice). In particular, the hydroxyl radical, which is one of the most potent oxidants capable of causing tissue damage, was produced in large quantities. Sera from patients with obstructive jaundice have a strong capacity to induce production of oxygen intermediates from PMNs, and oxygen intermediates may play a role in the pathogenesis of hepatic and other organ injury in obstructive jaundice.

Differential control of azurophilic and specific granule exocytosis in Sendai-virus-permeabilized rabbit neutrophils

1. Rabbit neutrophils were permeabilized by treatment with Sendai virus. This was monitored by fluorescence measurement of the formation of the adduct of deoxyribonucleic acid (DNA) with ethidium bromide. 2. On addition of Ca2+, buffered (with EGTA) in the micromolar concentration range to the permeabilized cells, secretion of beta-glucuronidase (marker of azurophilic granules) and lysozyme (marker of specific granules) occurs. Lactate dehydrogenase (cytosol marker) is retained. Half-maximal secretion of beta-glucuronidase occurs at approximately pCa 6.3; lysozyme secretion occurs at approximately pCa 6.6. 3. Secretion is dependent on the provision of nucleoside triphosphates to the permeabilized cells. There is an absolute requirement for adenosine 5'-triphosphate (ATP) for the secretion of lysozyme, but beta-glucuronidase secretion can be partly supported by other nucleoside triphosphates in the order guanosine 5'-triphosphate (GTP) greater than uridine 5'-triphosphate (UTP) = xanthosine 5'-triphosphate (XTP) greater than cytidine 5'-triphosphate (CTP). 4. Secretion from both granules is complete within 10 min of adding Ca2+ to the permeabilized cells. There is a delay before commencement of beta-glucuronidase secretion of approximately half a minute; the secretion of lysozyme has no measurable delay.

Changes in the rate of epithelial proliferation of rat oral mucosa in response to acute inflammation induced by turpentine

Inflammatory lesions were produced in the buccal mucosa by a subepithelial injection of turpentine; animals were killed 24 h later, 1 h after an intravenous injection of tritiated thymidine ( [3H]-Tdr). Control rats were given [3H]-Tdr but no turpentine. Lesions comprised a turpentine pool surrounded by a dense layer of inflammatory cells, beyond which the tissues were more diffusely inflamed. The labelling index (L.I.) for mitotic activity in overlying epithelium was determined in a region (C) close to the layer of dense infiltration and in a region (D) more distant. The L.I. in region D was over four times greater than in region C, and nearly four times greater than that of the contralateral, uninjected cheek. The L.I. in the uninjected cheek was significantly lower than that in controls, which may indicate a systemic depression of proliferative activity in the experimental animals, probably due to stress. Thus mild inflammatory injury stimulates epithelial proliferation, whereas more severe inflammation depresses it, perhaps due to more extensive progenitor-cell damage.

Function of exudative neutrophilic granulocytes in patients with Crohn's disease or ulcerative colitis

Chemotactic, phagocytic, and oxidative metabolic activity of exudative leukocytes was measured in patients with Crohn's disease (n = 20) and with ulcerative colitis (n = 20). Unstimulated and casein-stimulated migration in Boyden chambers did not differ from that of healthy controls (n = 21). Patients with Crohn's disease had reduced serum-independent phagocytosis compared with healthy controls (p less than 0.01) and patients with ulcerative colitis (p less than 0.01). Serum-dependent phagocytosis by leukocytes from patients with Crohn's disease did not differ from that in controls but was slightly increased in patients with ulcerative colitis (p less than 0.02). Unstimulated leukocytes showed increased oxidative metabolic activity in both patient groups compared with controls (p less than 0.01), which was negatively correlated with the disease activity in Crohn's disease (p less than 0.02). The study shows that mobilized leukocytes from patients with Crohn's disease differ from those mobilized in ulcerative colitis and supports the concept of an abnormal inflammatory reaction in Crohn's disease.

Basis and current scope of rational anti-inflammatory therapy

With the increased understanding of inflammation today, it is clear that those therapeutic agents that control noxious effects of inflammation without blocking the protective aspects are more desirable. In the past 30 years, numerous new classes of anti-inflammatory agents have emerged, having first passed stringent clinical pharmacologic testing. Of the available nonsteroidal anti-inflammatory agents, most act through blockade of the cyclo-oxygenase pathway, and some through specific effects on the lipoxygenase pathway. Each of the major categories of nonsteroidal anti-inflammatory agents is discussed briefly with regard to these actions and their clinical effects. The use of nonsteroidal anti-inflammatory agents is also discussed in the context of the elderly patient in whom physiologic aspects of aging must be considered.

Antiadhesive properties of biological surfaces are protective against stimulated granulocytes

Despite the fact that a series of endogenous and exogenous inflammatory mediators are potent activators of circulating granulocytes, damage of vascular endothelium, a primary target tissue, is a rather unusual event in systemic inflammatory states. Since mediator-induced neutrophil hyperadhesiveness on plastic tissue culture dishes is invariably accompanied by intense release of lysosomal granule constituents and respiratory burst activation, thus representing a powerful model to investigate neutrophil cytotoxic states, comparative studies with neutrophils suspended in autologous plasma in the presence or absence of N-formyl-Met-Leu-Phe (2.5 microM), the most potent adhesion inducer, were performed on different biologic surfaces. On optimally adherent closed monolayers of cultured endothelial cells or fibroblasts we observed poor stimulation of adhesion as well as minimal granule release and hexose monophosphate pathway activation. Functional behavior of neutrophils on single molecular components of basal laminas such as fibronectin and collagen (type IV) coats was intermediate, with positive adhesion promotion but markedly reduced metabolic activation. When tested on endothelial cell-derived extracellular matrices, neutrophils again showed functional nonresponsiveness to N-formyl-Met-Leu-Phe. Scanning electron microscopy revealed an impressive congruency between the degree of cellular spreading and metabolic activation in the presence of N-formyl-Met-Leu-Phe, with maximally flattened neutrophils on plastic vs. nonspread, polarized cells on monolayers. Identical results were obtained by using other adhesion inducers such as complement-activated plasma or endotoxin. Lack of cell injury by N-formyl-Met-Leu-Phe-exposed neutrophils was corroborated by the absence of tracer release from [111In]tropolonate-labeled endothelium. These results indicate that biologic surfaces possess antiadhesive properties that protect them from cytotoxic damage by stimulated angry phagocytes.

The immunophysiological basis for vaccinating ruminants against mastitis

The roles of humoral and cellular defence mechanisms in protection of the mammary gland against bacterial infection are reviewed. Effective protection depends on opsonisation of pathogens and subsequent phagocytosis by neutrophils. A concomitant requirement for protection is the rapid infiltration of neutrophils into the infected gland. Immunological studies have shown the need to prime animals against antigens expressed by bacteria when they grow in vivo. Vaccination procedures which promote these mammary defence mechanisms are discussed.

Gingival wound healing in the presence of plaque-induced inflammation

An accelerated loss of connective tissue attachment has been reported following surgery in plaque-infected dentitions. It was the purpose of the present study to evaluate histologically the healing of incisional wounds in the gingival supracrestal region in the presence and absence of bacterially induced inflammation. In the experimental group, marginal periodontitis was induced around the teeth by tying plaque-retentive ligatures at the gingival margins and 10 weeks later an incisional wound was made from within the gingival sulcus to the crest of the bone. In the control group, similar incisional wounds were made in normal gingiva. In each group, three specimens were available for histologic and histometric analysis 1, 3, 7 and 21 days after wounding. In the control group, the wound healing sequence in the supracrestal region was similar to that reported following incisional cutaneous wounds. In the experimental group, epithelial continuity across the wound was re-established earlier, and marked invagination of epithelium occurred into the incision. This invagination was significantly greater than in control specimens at all time points. In addition, within the experimental group a second significant epithelial migration into the wound occurred between 7 and 21 days. The epithelial invagination extended through the major portion of the supracrestal area and terminated near the cementum surface. It is conceivable that marked epithelial invagination into a supracrestal wound may predispose to an accelerated loss of connective tissue attachment.

Synergistic inhibition of complement induced granulocyte margination by BW755C and calcium channel blockers

Intravenous infusion of granulocyte (PMNL) chemotactic factors including C5ades Arg present in zymosan activated plasma (ZAP), induces granulocytopenia due to PMNL margination. Since some PMNL responses are dependent on Ca++ ions and lipoxygenation of arachidonic acid, we evaluated the effects of a lipoxygenase (and cyclooxygenase) inhibitor, BW755C and Ca++ channel blocking agents, verapamil and nifedipine, on chemotactic factor induced granulocytopenia and margination in rabbits. BW755C (20 mg/kg i.v.) treatment significantly attenuated ZAP induced granulocytopenia. Verapamil or nifedipine alone were without effect. However, combined treatment with BW755C and verapamil or nifedipine (250 micrograms/kg) completely prevented ZAP-induced granulocytopenia. Ibuprofen, a cyclooxygenase inhibitor, was without effect either by itself or in combination with the calcium channel blockers. In striking contrast to the effect on ZAP-induced granulocytopenia, BW755C plus verapamil or nifedipine had virtually no effect on f-met-leu-phe, platelet activating factor or leukotriene B4 induced granulocytopenia. PMNL aggregation in vitro in response to all of the above chemotactic factors was inhibited by BW775C to similar degrees (56-75%) and was not influenced by simultaneous treatment with verapamil. We conclude that: (a) inhibitors of the lipoxygenase pathway may synergize with Ca++ channel blocking agents in inhibiting PMNL responses to complement derived chemotactic factors in vivo; (b) that in vivo PMNL margination to other chemotactic factors may be less dependent on endogenous lipoxygenation and/or Ca++ fluxes; and (c) there is a poor correlation between pharmacological inhibition of PMNL aggregation in vitro and PMNL margination in vivo in this system.

Immunofluorescence localization of calmodulin in human polymorphonuclear leukocytes

Human polymorphonuclear leukocytes (PMNs) were purified (approximately equal to 99%) from peripheral blood of normal, adult volunteers. The indirect immunofluorescence technique was used to investigate the presence and the localization of calmodulin in human PMNs. The cellular distribution of calmodulin has been evaluated using an affinity chromatography-purified sheep IgG anti-calmodulin and fluorescein-conjugated rabbit anti-sheep IgG. The anti-calmodulin immunofluorescence pattern suggests that calmodulin is evenly distributed throughout the cytoplasm of human PMNs.

Perturbations of granulocyte counts induced by procedural, chemical and physiological events occurring during filtration leukapheresis in rats

During filtration leukapheresis a factor(s) is produced, released or extracted into rat blood which causes a transient granulocytosis in pheresed animals and in recipients of homologous plasma from these animals. To identify which factors contribute to this granulocytosis, the procedural steps involved in filtration leukapheresis as well as a number of chemical agents which are potentially extracted from of produced by the procedure, were tested for their ability to stimulate granulocytosis. Procedural steps tested included the depth of anesthesia, effect of the anticoagulant and possible interactions of blood cells with the plastic tubing in the system (sham-pheresis). Chemical agents tested included common mediators of inflammation and proteinases released by polymorphonuclear leukocytes (PMNs), extracts of nylon fibers and Tygon tubing, nylon monomers and solvents used in the manufacture of nylon, oxidized and decomplemented plasma and lysates of PMNs or microorganisms. Our findings demonstrate that several of these agents contribute to the granulocytosis seen during filtration leukapheresis of rats.

Effects of psoriatic sera on the generation of oxygen intermediates by normal polymorphonuclear leucocytes

The effects of psoriatic sera were investigated on the generation of oxygen intermediates (OIs) by normal polymorphonuclear leucocytes (PMNs). Although increased superoxide generation was noted, a further respiratory burst of the PMns was significantly suppressed. Since superoxide dismutase (SOD) and catalase activities of the sera assayed in the xanthine-xanthine oxidase system were comparable to the controls, it still remains obscure why this dissociation occurs. It is suggested that increased generation of superoxide anion from the PMNs may be another facet of PMN activation which plays an important role in the psoriatic process.

Influence of lithium and fluoride on degranulation from human neutrophils in vitro

We have demonstrated that degranulation from normal human neutrophils in whole blood was stimulated by low concentrations of lithium salts and was produced by noncytolytic means. Significant amounts of beta-glucuronidase could be released from the primary granules, in addition to vitamin B12- binding protein from the secondary granules, by 10 mM lithium. Release was almost totally inhibited by 1 mM fluoride, under the same conditions. There was no release of lactate dehydrogenase and no loss of viability of cells incubated in either lithium or fluoride at the concentrations used. Lithium was also observed to have no effect on reactive oxygen production by phagocytic stimulation of isolated neutrophils. In addition, lithium and fluoride were shown to manipulate the intracellular levels of cAMP. The results demonstrated a direct effect of lithium on release of inflammatory mediators from neutrophils in vitro. The methods used also provide a simple and effective test to study an important function of neutrophil activity and can be used to evaluate degranulation in a number of clinical conditions.

Effect of nonsteroidal anti-inflammatory agents on immune complex- and chemotactic factor-induced inflammation

Previously we reported that indomethacin and acetylsalicylic acid (ASA) inhibited leukocyte infiltration, blood flow, and vascular permeability during E. coli-induced inflammation in rabbit skin. Here we report the kinetics of these responses and the effects of these drugs on them, when a phagocytic stimulus, such as the immune complexes in the reverse Arthus reaction, or a nonphagocytic stimulus, such as the chemotactic factor in zymosan-activated plasma (ZAP, C5a des Arg), initiate inflammation. Both reactions causes infiltration of 51Cr-labeled leukocytes, an increase in blood flow, measured with 86RbC1, and in vascular permeability, measured with 125I-albumin. In both reactions, all three of these parameters were simultaneously inhibited by indomethacin or ASA. The local injection of prostaglandin E2 (0.5 microgram) at doses which, in control (uninflamed) skin increased only the blood flow, reversed all three inhibitory effects of the drugs. These results indicate that the drug-induced inhibition of leukocyte infiltration was secondary to the inhibition of the vascular responses. Furthermore, the vascular responses in both types of lesions were probably mediated, in large part, by vasodilatory prostaglandins. The magnitude and course of the vascular responses and their sensitivity to the prostaglandin synthetase inhibitors was similar in the Arthus (phagocytic) and in the ZAP (nonphagocytic) lesions. These results suggest that phagocytosis may not be a prerequisite for the generation of prostaglandins and the vascular responses during polymorphonuclear leukocyte-mediated inflammation in vivo.

The biologic significance of neutrophil regulatory mechanisms

Self-regulation of feedback control are essential features of most complex biological systems. Neutrophil leukocytes possess potent oxidative and lysomal products for the killing of invading microbes. These toxic products are also capable of causing auto-oxidative injury and tissue damage. Indeed, neutrophils have been implicated as mediators of tissue injury in a number of autoimmune and inflammatory disorders. It is proposed that a sophisticated and complex regulatory mechanism for neutrophil function is operative in healthy individuals. Much of the evidence for this is tentative and fragmentary, but a logical framework is beginning to emerge.

Increased hydroxyl radical generation by normal polymorphonuclear leukocytes incubated in sera from patients with leukocytoclastic vasculitis

The effect of sera from patients with untreated leukocytoclastic vasculitis was investigated on the generation of oxygen intermediates by normal polymorphonuclear leukocytes. Sera from untreated patients induced increased hydroxyl radical generation, which is one of the most potent oxidants capable of causing tissue damage. It is suggested that vascular injury may be mediated in part by enhanced production of hydroxyl radical by polymorphonuclear leukocytes. Circulating immune complexes in the sera of the patients are considered to be one of the factors responsible for enhanced generation of hydroxyl radical.

Improved method for neutrophil hexose-monophosphate shunt assay using serum

The addition of serum into the hexose-monophosphate shunt assay results in the reduction of neutrophil resting metabolic activity. This results in a higher stimulation index and consistent values.

Noncorticosteroidal anti-inflammatory agents in Ophthalmology

Efforts have been made to develop noncorticosteroidal anti-inflammatory therapy. The goals of such therapy have been to eradicate the primary cause, prevent the initial tissue injury, moderate inflammatory response, and enhance tissue repair while minimizing and eliminating the undesirable aspects of the therapy.