Effects of anti-inflammatory and other compounds on the release of lysosomal enzymes from macrophages

Ultrastructural evidence of thyroid damage in amiodarone-induced thyrotoxicosis

Amiodarone-induced thyrotoxicosis occurs in 2-12.1% of patients on chronic amiodarone treatment. In most cases its pathogenesis is related to iodine overload in the presence of preexisting thyroid abnormalities, such as multinodular or diffuse goiter or autonomous nodule. A minority of patients show apparently normal glands or pictures of non-autoimmune thyroiditis. However, there is recent evidence of a direct toxic effect of amiodarone, with consequent release of iodothyronines into the circulation. We report a patient with amiodarone-induced thyrotoxicosis with toxic thyroid effects demonstrated by electron microscopy in a fine-needle aspiration biopsy. There were three main pathologic findings: multilamellar lysosomal inclusions, intramitchondrial glycogen inclusions--both ultrastructural findings indicating thyroid cell damage--and a microscopic morphological pattern of thyroid cell hyperfunction. No inflammatory changes were found. Plasma thyroglobulin levels were high. The patient proved to be a non responder to simultaneous administration of methimazole (starting dose 30 mg/day) and potassium perchlorate (1000 mg/day for 40 days), while still taking amiodarone, thus providing evidence against a possible pathogenetic role of iodine overload. Dexamethasone (starting dose 3 mg/day) was added to methimazole. After three months euthyroidism had been restored and plasma thyroglobulin level substantially decreased. Subsequent subclinical hypothyroidism developed, which persisted after stopping antithyroid treatment and required substitution treatment with levothyroxine. In view of the primary role of lysosome function in the proteolysis of thyroglobulin molecules and of the energy-requiring carrier-mediated transport of monoiodotyrosine across the lysosomal membrane for iodine salvage and reutilization, we suggest that the pathological lysosomal and mitochondrial changes observed could be an ultrastructural marker for subsequent hypothyroidism in amiodarone-induced thyrotoxicosis. Our observations suggest the usefulness of ultrastructural thyroid evaluation and serial plasma thyroglobulin determinations to thoroughly evaluate the underlying pathogenetic mechanisms in amiodarone-associated thyrotoxicosis with apparently normal thyroid glands. Moreover, more knowledge of its pathogenesis could improve both prognostic stratification and treatment guides.

RP 54745, a potential antirheumatic compound. I. Inhibitor of macrophage stimulation and interleukin-1 production

RP 54745 is an amino-dithiole-one compound found to be active at micromolar concentration on the metabolism of stimulated macrophages, for example, the hexose monophosphate pathway (HMP) and the exocytosis of lysosomal enzymes. LPS-induced interleukin-1 (IL-1) production by murine peritoneal macrophages was also diminished by this compound in vitro as well as in vivo. This effect was confirmed at the mRNA level; at the concentration of 3 x 10(-6) M, the IL-1 alpha and beta mRNA signals were inhibited, whereas the TNF alpha mRNA signal was only slightly lessened. These observations were confirmed in vivo, with a dose of RP 54745 of 25 mg kg-1. These results led us to consider that RP 54745 might influence certain cells and cytokines implicated in the regulation of the immune system, the disfunctioning of which can lead to inflammatory disorders or autoimmune pathologies.

Phospholipases A2 and C of human lung; subcellular distribution and substrate selectivity

The phospholipase activities of cell-free extracts of human lung were studied using sn-2-arachidonoyl phospholipids. Samples of human lung obtained during surgery were homogenized and separated by centrifugation into three fractions: P1, containing mitochondrial and lysosomal marker enzymes; P2, with microsomal enzymes; and S2, with cytosolic enzymes. The highest phospholipase activities were in the microsomal fraction, using any of the three substrates, [14C]arachidonoylphosphatidylcholine (PC), [14C]arachidonoylphosphatidylethanolamine (PE) and [14C]arachidonoylphosphatidylinositol (PI). From PC and PE, only free arachidonic acid was formed, suggesting the presence of a phospholipase A2 (PLA2)-like activity. From PI, two metabolites were produced, diacylglycerol and arachidonic acid, suggesting the presence of a PI-specific PLC activity. Rates of hydrolysis were highest for PI, followed by PE and then PC. Hydrolysis of [14C]arachidonoyl-PC was compared to that of [14C]oleoyl-PC and found to be similarly distributed and of comparable velocity. The distribution and relative activities of phospholipases in rat lung homogenates were very similar to those in human lung.

The effect of oral terfenadine alone and in combination with flurbiprofen on the bronchoconstrictor response to inhaled adenosine 5'-monophosphate in nonatopic asthma

Inhaled adenosine and adenosine 5'-monophosphate (AMP) cause bronchoconstriction in atopic and nonatopic asthmatics by a mechanism believed to involve histamine release from airway mast cells and an interaction with neural reflexes. In the present study, we have investigated the effect of oral terfenadine 180 mg, flurbiprofen 100 mg, and the drug combination on AMP-induced bronchoconstriction in eight nonatopic asthmatic subjects with a mean age of 53.8 +/- 5.6 yr. The provocation concentrations of histamine and AMP required to produce a 20% decrease in FEV1 (PC20) were determined to be 2.5 (range, 0.2 to 16.3) and 50.1 (range, 1.5 to 841) mg/ml, respectively, representing a potency difference of 17.8-fold on a molar basis. In subsequent time-course studies, the bronchoconstrictor response to inhalation of the PC20 histamine was suppressed completely by terfenadine and the drug combination, but unaffected by flurbiprofen. Terfenadine alone and flurbiprofen alone inhibited bronchoconstriction provoked by the PC20 AMP by 49.8 +/- 5.5% (p less than 0.01) and 31.9 +/- 7.9% (p less than 0.01), respectively, when areas under the FEV1 time curves were compared with placebo, the difference between the two treatments not being significant (p = 0.06). The drug combination inhibited the response to AMP by 60.0 +/- 8.3% (p less than 0.01), this being significantly greater than with flurbiprofen (p less than 0.01), but not with terfenadine alone. These data implicate both histamine and cyclooxygenase products in the bronchoconstrictor response to AMP.

Rapid effectiveness of prednisone and thionamides combined therapy in severe amiodarone iodine-induced thyrotoxicosis. Comparison of two groups of patients with apparently normal thyroid glands

Treatment of amiodarone iodine-induced thyrotoxicosis is often unsuccessful. Nevertheless, severe forms require a rapidly efficient therapy. Twelve patients with severe amiodarone iodine-induced thyrotoxicosis, as demonstrated on clinical and biological findings, were studied. After amiodarone withdrawal, 6 patients (group A) were treated with thionamides alone (carbimazole 60 mg daily and benzylthiouracile 1.5 g daily), and 6 patients (group B) received in addition to the same antithyroid drugs prednisone, 0.50 to 1.25 mg/kg/day for 40 days; in group A, T4 levels did not change over the study period of 40 days; T3 levels decreased only after 30 days; clinical status did not improve. In group B: T3 and T4 levels decreased dramatically at 10 days of treatment, to values significantly lower than in group A; clinical improvement occurred mainly in patients treated with high doses of prednisone; elevated thyroglobulin levels diminished rapidly. Improvement was maintained after cessation of prednisone. The rapid effect of prednisone suggests an impairement of proteolysis of thyroglobulin possibly due to a lysosomal action.

A novel method for the sampling of synovial fluid in mice. Assay of a synovial lysosomal enzyme in zymosan-induced arthritis

A novel and very useful technique was developed to assay a lysosomal enzyme released into the joint synovial fluid during zymosan-induced arthritis in mice. This beta-glucuronidase activity correlated with histomorphological changes observed in the joint: vasculitis, synovitis and pannus formation. The antiarthritic drug triamcinolone acetonide improved both biochemical and histological parameters.

Comparative studies on the effects of erythromycin A and azithromycin upon extracellular release of lysosomal enzymes in inflammatory processes

In the present studies the in vivo and in vitro effects of erythromycin A and azithromycin, a new type of macrolide (Fig. 2.), were investigated upon extracellular release of lysosomal enzymes, beta-glucuronidase (beta-Gluc) and beta-N-acetylglucosaminidase (beta-Glm) by using two experimental model systems: in vivo-adjuvant-induced arthritis in rats and in vitro- human polymorphonuclear leucocytes (PMNL) exposed to bovine serum albumin/anti-bovine serum albumin (BSA/anti-BSA), immune complex. Administrations of erythromycin A or azithromycin at doses of 5, 10 and 15 mg/kg into rats one day prior and 2, 4, 6, 8 and 10 days after a single subplantar injection of Freund's complete adjuvant significantly (p less than 0.01) inhibited extracellular release of lysosomal enzymes tested in the synovial fluid of injected left hind paw. These effects were dose-dependent. Further, erythromycin A and azithromycin at concentrations of 10(-7) M, 10(-6) M and 10(-5) M significantly (p less than 0.01) reduced excocytosis of both lysosomal enzymes, beta-Gluc and beta-Glm from human PMNL initiated by BSA/anti-BSA in a dose-related fashion. However, azithromycin was by far more effective (p less than 0.01) in decreasing extracellular release of beta-Gluc and beta-Glm either in the in vivo or in vitro experiments in comparison with erythromycin A. Appropriate control experiments excluded the possibilities that erythromycin A or azithromycin interfered with activities of lysosomal enzymes or with test reagents. Also, in no instances was there enhanced release of a cytoplasmic enzyme LDH.(ABSTRACT TRUNCATED AT 250 WORDS)

Release of lysosomal enzymes is not correlated with superoxide and prostaglandin production by stimulated rat Kupffer cells in primary culture

A substantial production of prostaglandin E2 (PGE2) was induced in primary cultures of rat Kupffer cells by zymosan, calcium ionophore A23187, phorbol ester and arachidonic acid, whereas contact with latex particles, glucan or immunocomplexes led to a minor PGE2 release only. Superoxide generation, on the other hand, was observed after administration of zymosan, glucan and the phorbol ester but not after treatment with the calcium ionophore, arachidonate, latex particles or immunocomplexes. Lysosomal enzymes like beta-glucuronidase and N-acetyl-beta-D-glucosaminidase were detected in the medium of rat Kupffer cells in primary culture after contact with zymosan or calcium ionophore A23187. Other particulate matter, e.g., latex particles, glucan and immunocomplexes, lipopolysaccharides or soluble agents such as phorbol ester, arachidonic acid and gamma-interferon did not provoke the release of lysosomal enzymes. The activities of beta-glucuronidase and N-acetyl-beta-D-glucosaminidase found following prolonged exposure to zymosan or to A23187 were accompanied by the appearance of typical cytosolic enzymes like lactate dehydrogenase and glucose-6-phosphate dehydrogenase in similar proportions and with the same time course. The release of lysosomal enzymes seen after administration of zymosan or calcium ionophore is thought to be the result of unspecific leakage rather than a specific response of elicited Kupffer cells.

Decrease of cellular ATP by dihexanoylglycerol may limit responses to protein kinase C activation

1,2-sn-Dihexanoylglycerol (HHG) reduced the ATP content of HL-60 cells. This concentration-related (10-100 microM) effect reached a maximum of over 90%, was enantiomerically specific and not accompanied by release of lactate dehydrogenase. Oleoylacetylglycerols (3-100 microM) had no effect on ATP levels while phorbol dibutyrate (PDBu, 0.01-1 microM) decreased ATP content of HL-60 cells by up to 40%. Responses stimulated by HHG became limited as the concentration was increased above 10 microM, this being manifest as either a low maximum response compared to PDBu (superoxide release) or a bell-shaped concentration-effect curve (degranulation). HHG (30-100 microM) inhibited PDBu-stimulated superoxide release, this inhibition being enantiomerically specific. It is probable that the effect of HHG on ATP content impairs cellular responses mediated through protein kinase C activation.

Glucocorticoid receptors and corticosensitivity in the human monocytic cell line CM-S: changes during phorbol ester-induced differentiation

CM-S is a line of human precursor mononuclear phagocytes inducible to macrophage differentiation in response to the tumor promoter phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). Untreated CM-S cells expressed a single class of high-affinity (KD = 4.5 +/- 2.3 nM) glucocorticoid receptor sites (GCr) (27,530 +/- 3752 sites/cell) as measured by a whole-cell assay at 37 degrees C using [3H]triamcinolone acetonide as tracer, while CM-S cells induced to macrophage differentiation by 10(-7) M TPA showed reduced levels of GCr (10,729 +/- 2135 sites/cell). Kinetic studies indicated that this reduction was progressive, reaching about 34% of the original value 96 hr after TPA addition. The GCr in untreated and TPA-induced cells were similar in their specificity for corticosteroids. In the precursor cell population dexamethasone enhanced both the rate of protein synthesis and the production of autostimulatory growth factor(s), while in TPA-induced cells it inhibited the rate of protein synthesis in a dose-dependent manner. Our data with the CM-S cell line thus suggest that in the monocytic cell line lineage both the number of GCr and the cell response to glucocorticoids depend on the degree of cell maturation.

European experience with flurbiprofen. A new analgesic/anti-inflammatory agent

Numerous European clinical trials begun more than 12 years ago have clearly demonstrated flurbiprofen's safety and efficacy as an analgesic, anti-inflammatory, and antipyretic agent. In preclinical studies, flurbiprofen was at least as potent as indomethacin, and approximately 200 times more potent than aspirin. For patients with rheumatoid arthritis, a review of several trials found flurbiprofen often superior to aspirin and naproxen, and equivalent to indomethacin and ibuprofen in efficacy. Acetaminophen appeared no more effective than placebo for patients with rheumatoid arthritis. For patients with ankylosing spondylitis, flurbiprofen was also shown to be equivalent or superior to indomethacin and phenylbutazone. For patients with osteoarthritis of the peripheral joints, spine, hip, and knee, flurbiprofen was again found equal to ibuprofen, diclofenac, indomethacin, and naproxen. Side effects with flurbiprofen were few and predominantly related to the gastrointestinal tract.

Effects of anti-inflammatory and anti-rheumatic drugs on the activities of purified and membrane-bound Na+/K+ adenosine triphosphatase

We have examined the effects of anti-inflammatory and anti-rheumatic drugs on membrane-bound and purified Na+/K+-ATPase activity in vitro. Only the gold-containing compounds (gold sodium thiomalate and auranofin) were found to inhibit the enzyme activity in a dose-dependent manner. Sodium thiomalate and triethylphosphine, the ligand compounds for gold sodium thiomalate and auranofin, respectively, had no effect on ATPase activity. The antagonistic properties was abolished by preincubation of the gold compounds with dithiothreitol. Lineweaver-Burke analysis of the inhibitions of purified ATPase by the gold compounds was found to follow uncompetitive kinetics. Inhibition of ATPase by gold may cause disruption of transmembrane cation transport and thus result in impairment of several metabolic processes and cellular functions.

Drug influences on rat hepatic macrophage enzyme production and release in vitro

Drug influences on hepatic macrophage enzyme release have been investigated using a rat model of macrophage recruitment and activation. N-acetyl-glucosaminidase (NAG), a lysosomal enzyme, and plasminogen activator (PA), a cytosolic enzyme, have been measured in both cell lysates and supernatants after 24 h in culture. 6-mercaptopurine (6-MP) and azathioprine significantly decreased (P less than 0.03) the enhanced production of NAG by recruited macrophages following stimulation in vitro (total NAG activity, nmol substrate hydrolysed/microgram cell protein; recruited macrophages exposed to endotoxin, no drug exposure 0.63 +/- 0.08, azathioprine 0.44 +/- 0.08, 6MP 0.36 +/- 0.06). Prednisolone, azathioprine and 6MP significantly reduced (P less than 0.05) the supernatant release of PA in response to endotoxin exposure in vitro by both cell types (supernatant PA values after 24 h in culture, recruited macrophages exposed to endotoxin, no drug 26.0 +/- 2.9 units, prednisolone 18.5 +/- 1.7 units, levamisole 27.3 +/- 4.7 units, azathioprine 18.1 +/- 2.3 units, 6MP 17.3 +/- 1.5 units). The results from this study indicate that certain drugs used in human liver disease are able to modify the secretory activity of rat hepatic macrophages.

Comparison of the effects of some compounds on human neutrophil degranulation and leukotriene B4 and thromboxane B2 synthesis

The effects of aspirin, indomethacin, phenylbutazone, eicosatetraynoic acid (ETYA), nordihydroguaiaretic acid (NDGA) and 3-amino-1-[3-(trifluoromethyl)-phenyl]-2-pyrazoline (BW755C) on human neutrophil degranulation induced by A23187 and F-Met-Leu-Phe (FMLP) have been studied. These effects have been compared with those on A23187 induced leukotriene B4 (LTB4) and thromboxane B2 (TXB2) synthesis by these cells to elucidate the relationship between LTB4 formation and degranulation. All compounds inhibited TXB2 synthesis by 50% at concentrations between 0.0016 and 50 microM. The synthesis of LTB4 was inhibited by 50% by ETYA (1.9 microM) and by NDGA (0.52 microM). Degranulation induced by A23187 and FMLP was inhibited by 50% by ETYA (16 and 11 microM respectively) and by NDGA (1.5 and 6.5 microM respectively). In the case of ETYA the concentrations required to inhibit degranulation were significantly higher than those required to inhibit LTB4 synthesis. In contrast, BW755C inhibited LTB4 synthesis by 50% at 2.8 microM but did not affect A23187-induced degranulation and was only a weak inhibitor of FMLP-induced degranulation (50% inhibition at 89 microM). The effects of the above compounds on the omega-oxidation of LTB4 by human neutrophils has also been studied to investigate the mechanism of action of these compounds. None of the above compounds affected the metabolism of LTB4 by these cells suggesting that their actions are not as non-specific anti-oxidants. These data indicate that human neutrophil degranulation induced by FMLP and A23187 is independent of LTB4 synthesis.

Stimulation and inhibition of secretion by phorbol myristate acetate in different cell types

In washed human platelets and in HL60 granulocytes phorbol myristate acetate (PMA, 1-2000nM) synergised with threshold concentrations of secretogogues to induce a sustained maximum secretory response. Likewise, superoxide production from HL60 cells maintained a maximal response at PMA concentrations between 30-300nM. At concentrations up to 10nM PMA also augmented calcium ionophore, A23187, stimulated histamine release from rat peritoneal mast cells. However, in the mast cell PMA concentrations above 10nM reduced maximum histamine release in a dose-dependent manner.

Influence of fever temperatures and of some cytoactive drugs on in vitro lysozyme release from monocytes and granulocytes

The selective in vitro release of lysozyme from human monocytes and granulocytes was not greatly influenced by temperatures above 37 degrees C and up to 40 degrees C. The release was markedly inhibited by preincubation with phenylbutazone, oxyphenylbutazone, colchicine and vincristine. A water-soluble hydrocortisone complex also inhibited lysozyme release, but at high concentrations, lysis of the cells occurred. Although methotrexate had a weak inhibiting effect, no appreciable influence on release was observed with cyclophosphamide or cytarabine. Thus, release of lysozyme from blood leukocytes is likely to be dependent on cellular functions involving the stability of both microtubules and membranes.

Biosynthesis and biological activity of leukotriene B5

Several studies indicate that increased intake of eicosapentaenoic acid (EPA) in the diet may lead to decreased incidence of thrombotic events. Most investigators agree that this is achieved by competitively inhibiting the conversion of arachidonic acid (AA) to thromboxane A2 in the platelets. The effect of high EPA-intake on the formation of prostacyclin is less clear. However, EPA is a good substrate for lipoxygenase enzymes which results in formation of hydroperoxy- and hydroxy-acids, and, in some cases, leukotrienes. The biological activities of the leukotrienes derived from arachidonic acid suggest that they mediate or modulate some symptoms associated with inflammatory and hypersensitivity reactions. In order to clarify the possible effect of dietary manipulation on inflammatory processes, leukotriene B5 (LTB5) was prepared and its biological activities assessed. LTB5 was biosynthesized by incubation EPA with glycogen-elicited polymorphonuclear neutrophils (PMN) from rabbits in the presence of the divalent cation ionophore, A23187. The LTB5 was extracted from the incubate using mini-reverse phase extraction columns (Sep-pak) and purified by reverse-phase high pressure liquid chromatography (RP-HPLC). The purity of the product assessed by repeat RP-HPLC and straight phase (SP) HPLC was greater than 95%. Ultra-violet spectrophotometry of the product confirmed its purity and also provided assessment of the yield. The biological activity of LTB5 was assessed and compared with that of LTB4 in the following tests: aggregation of rat neutrophils, chemokinesis of human PMN, lysosomal enzyme release from human PMN and potentiation of bradykinin-induced plasma exudation. In all these tests, LTB5 was considerably less active (at least 30 times) than LTB4.

Glucocorticoid receptors and cortico-sensitivity in a human clonal monocytic cell line, CM-SM

CM-SM is a clonal line of human precursor mononuclear phagocytes inducible to macrophage differentiation in response to the tumor promoter phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Untreated CM-SM cells contain single class, high-affinity (KD = 4.0 X 10(-9) M) glucocorticoid-specific receptor sites (approximately 60,000 per cell), as measured by a whole cell assay, at 37 degrees C, using [3H]triamcinolone acetonide (TA). Exposure of CM-SM to dexamethasone (DEX) produced a progressive, dose- and time-related series of changes in CM-SM cell growth, saturation density, morphology, and functional properties, with half-maximal effects at about 10(-9) M for DEX. TA-receptor sites rapidly decreased (about 70%) after DEX treatment, without any apparent change in steroid specificity and affinity. After 5 days in culture with a saturating concentration (3.6 X 10(-8) M) of hormone, the cells reached a saturation density of about 9.0 X 10(6) viable cells/ml (about 4.0 X 10(6) viable cells/ml in the controls), while the modal volume of the resulting cell population was approximately 60%, as compared to the volume of untreated cells. DEX-treated cells appeared less differentiated than controls, as assessed by combined morphologic, antigenic, and cytoenzymatic analyses. DEX almost completely inhibited TPA activation of the following macrophage functions: adherency to the culture plate, expression of lysosomal enzymes, Fc and C3 receptors, and stimulation of phagocytosis. After removal of DEX, the cells, within a few passages, returned to a state apparently identical to the untreated controls and could be induced to macrophage differentiation in response to TPA.

Regulation of plasminogen activator secretion, interferon induction and proliferation in murine macrophages

The purpose of this work was to study the interrelationship of proliferation and secretion of plasminogen activator (PA) and interferon (IFN) by murine macrophages. For induction of macrophage proliferation and secretion of PA, concanavalin A (Con A) was used. Secretion of IFN was induced by polyinosinic polycytidylic acid complex. The glucocorticoid dexamethasone acetate (DA) (10(-6)-10(9) M) inhibited Con A-stimulated secretion of PA and synthesis of DNA as evaluated by incorporation of [3H]thymidine. DA did not inhibit IFN induction. Preincubating macrophages with DA for 45 h reduced basal proliferation and secretion of PA but did not reduce responsiveness to Con A. Also retinoic acid, a modulator of carcinogenesis was used in inhibition studies because of its known antagonistic effects on lymphocyte mitogenesis. In macrophages a biphasic effect of retinoic acid (1 X 10(-5) - 5 X 10(-5)M) was found: (a) inhibition of DNA synthesis and secretion of PA during the first 45 h of incubation, and (b) enhancement of DNA synthesis (but not PA secretion) after 72 h. Secretion of IFN was not affected. It is suggested that secretion of PA but not IFN is linked to cell cycle traverse of macrophages.

Modulatory effects of heat-labile serum components on the inhibition of phagocytosis by dexamethasone in peritoneal macrophage cultures

This investigation examined the effects of heat-labile serum substances on the suppression of yeast phagocytosis in dexamethasone-treated cultures of murine resident peritoneal macrophages. When 4-6 day old untreated control cultures were supplemented with either heat-inactivated (56 degrees C, 30 min) or intact (non-heat-inactivated) fetal bovine serum, more than 90% of the macrophage population ingested at least 1 yeast particle during 15 min phagocytosis assays. In cultures treated with 10(-6) M dexamethasone, approximately 30% of the macrophages were phagocytic. In contrast, approximately 70% of the steroid-treated population consisted of phagocytes in cultures supplemented with intact serum. Medium shift experiments demonstrated that the type of serum present during the 15 min yeast phagocytosis assays, but not the 4-6 day incubation periods, determined the size of the phagocytic subpopulations in the treated cultures. Whereas the majority of control phagocytes ingested more than 8 yeast particles, most dexamethasone-treated phagocytes ingested far fewer than 8 particles regardless of the size of the phagocytic subpopulations. In contrast to yeast, the ingestion of latex particles was inhibited to the same extent in dexamethasone-treated cultures that contained either heat-inactivated or intact serum. Thus, dexamethasone action impairs the ability of macrophages to accumulate yeast particles even though the phagocytic subpopulation is larger in treated cultures containing intact serum. This larger subpopulation may result from the activation of the alternative complement pathway by yeast during phagocytosis.

A study of the effects of nabumetone (BRL 14777), a novel anti-inflammatory drug, on cell infiltration into sterile cotton pellets implanted in rats

Nabumetone a new non-steroidal anti-inflammatory drug is active in reducing the DNA content of implanted cotton pellets in rats on various dosing regimens. The effect of nabumetone can be seen during the early and late phases of the cellular reaction to the implant implicating effects upon polymorphonuclear leucocytes and monocytes. The levels of two lysosomal enzymes are reduced in the exudate by the drug treatment.

The transport of chloroquine across human erythrocyte membranes is mediated by a simple symmetric carrier

The kinetic properties of the mediated transport of chloroquine in human erythrocytes are investigated. The high rates of translocation across the cell membrane and high adsorbance properties to glass surfaces have led to the development of new techniques for measuring initial rates of transport. Three different methodological procedures are used to accomplish a complete kinetic characterization of the system. All measurements were done at 25 degrees C. Under zero-trans conditions the system displays complete symmetry, the Michaelis constants being 39.2 +/- 2.4 microM for influx and 36.6 +/- 5.6 microM for efflux. The respective maximal velocities are 206.4 +/- 36.0 microM . min-1 and 190.0 +/- 7.8 microM . min-1. Under equilibrium-exchange conditions the Michaelis constant is 108.6 +/- 15.6 microM and the maximal velocity is 630.3 +/- 50.4 microM . min-1. This 3-fold increase in both K and V over the zero-trans values indicates that the rate-limiting step in the transport of chloroquine is the movement of the unloaded carrier. The kinetic data are consistent with the prediction of a simple carrier model.

Short-term treatment of osteoarthritis: a comparison of sodium meclofenamate and ibuprofen

A double-blind crossover study compared sodium meclofenamate (300 mg daily) and ibuprofen (900 mg daily) in thirty patients with osteoarthritis. Each treatment period was of 3 weeks duration. Both drugs were effective in reducing the severity of joint symptoms and in improving the range of motion, with the exception of spine movement which did not show any changes from the baseline. Tolerance was good.

Inhibition of yeast phagocytosis and cell spreading by glucocorticoids in cultures of resident murine peritoneal macrophages

This study was initiated to determine whether the inhibition of phagocytosis and cell spreading in cortisol-treated cultures of resident murine peritoneal macrophages are glucocorticoid-directed responses. Phagocytosis of heat-killed Saccharomyces cerevisiae and cell spreading were measured in control and steroid-treated macrophage cultures over 6 days. When the cultures were exposed to testosterone, progesterone, or epicortisol, phagocytosis and cell spreading were similar to controls. In contrast, both macrophage functions were inhibited significantly in cultures treated with cortisol, methylprednisolone, dexamethasone, and triamcinolone acetonide. In addition, the rate of phagocytosis was retarded and phagocytic indices (i.e., yeast particle number/cell) were reduced in glucocorticoid-treated cultures. Dose-response studies with dexamethasone demonstrated that the ED50 for the inhibitory effect on phagocytosis was 20 nM. These results indicate that the inhibition of yeast phagocytosis and cell spreading in the steroid-treated cultures are specific glucocorticoid-directed responses.

Induction of cell infiltration and acid hydrolase release into the peritoneal cavity of mice

An injection of thioglycollate into the peritoneal cavity of mice produced a peak of exudate at 4 h, a peak of total leukocytes at 24 h when the predominant cell was the polymorphonuclear neutrophil, and a secondard macrophage phase beginning 2--3 days after thioglycollate. The release of N-acetylglucosaminidase (EC 3.2.1.30) into the peritoneal fluid paralleled the macrophage phase. The amount of enzyme released was related to the dose of thioglycollate. Neither zymosan (400 micrograms) nor endotoxin (30 micrograms) produced a marked inflammatory response when injected into the peritoneal cavity.

The effect of steroidal and non-steroidal antiinflammatory drugs on chronic muscle inflammation

Zymosan (400 microgram) and thioglycollate medium (0.1 ml of 2.4% w/v) have each been shown to induce a chronic inflammation when injected into the hamstring muscle of the mouse. The inflammation is characterized by an increase in muscle weight and N-acetylglycosaminidase concentrations. The response is not inhibited by oral treatment with hydrocortisone, dexamethasone or naproxen, but is inhibited by the local injection of methylprednisolone. The relevance of this model to polymyositis and fibrositis is discussed.

Mechanisms of tissue injury in desquamative interstitial pneumonitis

To evaluate a contribution of immunologic factors to the pathogenesis of desquamative interstitial pneumonitis (DIP), lung biopsy specimens from four patients were studied for immunoglobulin deposits in tissue and cellular characteristics by immunologic, ultrastructural and histochemical methods. Accumulations of large cells with vacuolated cytoplasm within the distal air spaces and marked increase in the numbers of type II pneumocytes lining pulmonary alveoli were observed in all cases. The cells in air spaces were identified as macrophages containing intracellular lysozyme and alpha-naphthyl acetate esterase. Deposits of immunoglobulin G(IgG) and the third component of complement were found in distal air spaces and on the surfaces of the accumulated macrophages. The interstitial fibrosis was not a significant feature in out patients. Circulating immune complexes and a decreased IgG level were detected in serum during the acute phase of the disease. IgG levels returned to normal and were no longer detectable during convalescence in one patient followed sequentially. The formation and deposition of complement-fixing antibody and/or immune complexes may be responsible for the local accumulation and activation of macrophages and for tissue damages. Release of lysosomal enzymes by alveolar macrophages phagocytosing the complexes could also contribute to the alveolar injury, whereas the proliferation of type II pneumocytes may be a reparative tissue reaction to immunologically-mediated injury.

Biochemical and morphological characterization of the killing of human monocytes by a leukotoxin derived from Actinobacillus actinomycetemcomitans

A potent, heat-labile leukotoxic material was extracted from Actinobacillus actinomycetemcomitans (strain Y4), an anaerobic gram-negative microorganism originally isolated from subgingival plaque in a patient with juvenile periodontitis. The cytopathic effects of Y4 toxin on purified monocytes were studied by the extracellular release of radioactive cytoplasmic markers and cell enzymes and by time-lapse microcinematography. Y4 toxin rapidly bound to the cells, producing dose- and time-dependent alterations culminating in cell death and release of intracellular constituents into the culture medium. The evidence to be presented suggests that the cell membrane of the monocyte may be the primary target in the development of these phenomena. Previous studies have shown that Y4 toxin also kills human polymorphonuclear leukocytes but not other cell types. It is conceivable that disruption of polymorphonuclear leukocytes and monocytes by Y4 toxin in the gingival crevice area may be relevant in the pathogenesis of juvenile periodontitis.

Action of gold salts in some inflammatory and immunological models

Several gold salts were compared in kaolin-induced rat paw oedema, u.v. erythema in guinea pigs, delayed type hypersensitivity and humoral immunity in mice, and adjuvant-induced arthritis in the rat. In the latter the additional parameters of serum gold and copper levels and lysosomal enzyme activity were determined. In addition, the in vitro inhibition of several lysosomal enzymes derived from mouse macrophages was studied. The gold compounds examined were aurothiomalate, aurothioglucose, triethylphosphine gold chloride (SK & F 36914) and its glucopyranoside derivative (SK & F D-39162), triphenylphosphine gold chloride and sodium gold chloride dihydrate. SK & F 36914 and SK & F D-39162 has significant activity after oral dosage upon paw kaolin and u.v. erythema in rats and guinea pigs, respectively. Gastric swelling also occurred. In Wistar rats, adjuvant arthritis was little affected by the gold salts but in the Lewis rats there was suppression. In both strains there was less elevation in serum copper levels with treatment by SK & F 36914 and SK & F D-39162, but not by aurothiomalate. None of the compounds had any measurable effect on delayed hypersensitivity or humoral antibody levels in mice. The in vitro activities of cathepsin B1 and cathepsin D were inhibited by all the gold compounds. Reactivity of gold compounds with glutathione and cysteine in vitro was dependent on compound solubility and the nature of the gold ligand. Considerable differences exist between the profiles of activity for the different gold salts evaluated. These observations indicate that some gold salts do possess anti-inflammatory activity with a potency similar to that of indomethacin.

Release of cartilage proteoglycan degrading enzyme activity by thioglycollate stimulated mouse peritoneal macrophages in culture

Media from cultured mouse peritoneal macrophages were tested for cartilage proteoglycan degrading activity using S35-labelled rabbit ear cartilage. Media samples collected at 2-day intervals contained increasing amounts of activity between days two and six. This activity was activated by trypsin and antagonized by chelating agents. The macrophage products induced release of the proteoglycan component of cartilage as determined by biochemical and histological methods without affecting the collagen component. Media from cells incubated with hydrocortisone were devoid of proteoglycan degrading activity.

Comparative effects of drugs on four paw oedema models in the rat

The development of novel anti-inflammatory drugs (AID) has been claimed to be dependent on the discovery of models of inflammation that differ from those currently used for drug screening, e.g. carrageenen paw oedema and u.v. erythema. We have thus evaluated the effect of a variety of drugs in a number of novel models of inflammation in the rat produced in the hind paw. We have utilized kaolin, zymosan, anti-rat IgG (anti-IgG) and the Reversed Passive Arthus (RPA) reaction to produce these oedema models. We found that the non-steroidal AID's, e.g. aspirin, flufenamic acid, indomethacin, naproxen, and phenylbutazone, were active in all four tests. Of the nine novel AID examined, levamisole and tetramisole demonstrated considerable activity in all four tests and dapsone was especially active in the anti-IgG and RPA tests. In contrast, the anti-rheumatic d-penicillamine was inactive in all four models. Each of the ten compounds tested which has been claimed to influence complement function, was active in the RPA but not in the kaolin model. These results are discussed in the context of the aetiology of each oedema and the suspected mode of action of the various drugs.

The anti-inflammatory profile of dapsone in animal models of inflammation

Dapsone has been shown to possess anti-inflammatory activity in a variety of animal models. It possesses oral anti-oedema activity especially pronounced in novel models of acute inflammation, viz. anti-IgG and reversed passive Arthus oedemas. However, it is not very active in the guinea pig u.v. erythema model. It is effective in chronic models such as adjuvant arthritis and the cotton pellet granuloma although multiple administration may also produce cyanosis. Antipyretic and analgesic effects for dapsone have been demonstrated and are similar to those produced by phenylbutazone. It inhibits zymosan-induced beta-glucuronidase release from cultured macrophages and also the activity of this enzyme. Dapsone does not appear to be ulcerogenic in the rat.

Acid hydrolases in monocytes from patients with inflammatory bowel disease, chronic liver disease, and rheumatoid arthritis

A sensitive technique was used to estimate two acid hydrolases--N-acetyl-beta-glucosaminidase (N.A.G.) and beta-glucuronidase (B.G.)--produced by peripheral-blood monocytes. Enzyme levels were measured after in-vitro incubation of monocytes with or without stimulation by zymosan and endotoxin. Compared with controls, enzyme production and release in inflammatory bowel disease, chronic liver disease, and rheumatoid arthritis were markedly raised. It is suggested that various stimuli, including immunological ones, may be responsible for the release of such enzymes from monocytes and that such release may be a factor in the production of the chronic inflammation seen in these disorders.