The antinflammatory effects of glucocorticosteroids. A brief review of the literature

Consensus and controversies in the science of endophthalmitis management: Basic research and clinical perspectives

Infectious endophthalmitis is a severe intraocular infection caused by bacteria, or less commonly by fungi. It can occur after penetrating eye procedures, trauma, or the spread of infection from contiguous structures or via emboli from distant organs. Because of the time-critical nature of the treatment, endophthalmitis is treated with the clinical diagnosis and modified by the microbiological report of the intraocular contents. The current strategy for managing endophthalmitis relies on pre-clinical literature, case series, and one large multi-center randomized clinical trial on post-cataract surgery endophthalmitis. Culture-susceptibility of the microorganisms from undiluted vitreous guides the definitive treatment in non-responsive cases. Strategies to reduce the incidence of endophthalmitis after penetrating eye procedures have been developed concurrently with refined means of treatment. Despite these advances, outcomes remain poor for many patients. Although consensus articles have been published on managing endophthalmitis, treatment patterns vary, and controversies remain. These include (1) the use of newer methods for early and precise microbiological diagnosis; (2) the choice of intravitreal antibiotics; (3) the need for systemic therapy; (4) early and complete vitrectomy. Here, we review the current consensus and address controversies in diagnosing and managing endophthalmitis. This review is intended to familiarize physicians and ophthalmologists with different aspects of endophthalmitis management to make informed decisions.

Topical Ocular Therapeutics in Small Animals

This article reviews the administration of common topical ophthalmic medications, in relation to factors influencing absorption including composition of topical ophthalmic preparations, and potential systemic effects. Commonly prescribed, commercially available topical ophthalmic medications are discussed with respect to pharmacology, their indications for use, and adverse effects. Knowledge of topical ocular pharmacokinetics is essential for the management of veterinary ophthalmic disease.

Successful Additional Corticosteroid Treatment in a Patient with Mycoplasma pneumoniae Pneumonia in whom a Monobacterial Infection was Confirmed by a Molecular Method Using Bronchoalveolar Lavage Fluid

A 23-year-old Japanese woman was admitted to A hospital due to pneumonia. IgM for Mycoplasma pneumoniae was positive, and the patient was treated with imipenem/cilastatin, clindamycin, pazufloxacin and minocycline. However, both the chest radiological findings and the symptoms became exacerbated, and she was therefore transferred to our hospital. The bronchoalveolar lavage fluid was obtained, and a 16S rRNA gene sequencing analysis revealed a monobacterial infection of Mycoplasma pneumoniae. Therefore, corticosteroid treatment in addition to minocycline was administered, and the patients symptoms, laboratory data and chest radiographs improved. Corticosteroid therapy may therefore be considered for patients with refractory M. pneumoniae pneumonia.

Immunomodulators, immunostimulants, and immunotherapies in small animal veterinary medicine

Immunomodulators, immunostimulants, and immunotherapies are important tools used by veterinary practitioners and researchers to control and direct the immune system of small animals. This article is an overview and summary of some of the most common immunomodulatory agents used in companion animals emphasizing steroidal and nonsteroidal agents, T-cell inhibitors, cytotoxic drugs, immunostimulators and biologic response modifying agents, and neoplasia chemotherapeutic agents.

Severe acute lung injury caused by Mycoplasma pneumoniae: potential role for steroid pulses in treatment

Published evidence of pathogenetic mechanisms of acute respiratory distress syndrome (ARDS) in mycoplasmal lung infections suggests that the pulmonary injury is related to a cell-mediated immune response. Therefore, steroids may play a role in the treatment of severe cases. We describe a patient who had Mycoplasma pneumoniae pneumonia that progressed to severe ARDS requiring mechanical ventilation and who had improvement with prednisolone pulses.

Effect of low-dose prednisone in vivo on the ability of complement receptor to mediate an oxidative burst in rat neutrophils

Glucocorticoids have been used in the treatment of a variety of inflammatory processes including autoimmune diseases. However, the influence of low-dose glucocorticoids on the respiratory burst activity of neutrophils has not been studied. The aim of this work was to study the effect of treatment with low-dose prednisone on the oxidative burst of rat peripheral blood neutrophils. Wistar male rats were treated with prednisone by gavage (28, 87 or 257 microg/animal/day) for 7 or 15 days. These doses are equivalent to 10, 30 or 90 mg/adult human ( approximately 70 kg)/day, respectively. Sera from normal rats were used to opsonize zymosan (opZy). Neutrophils (1x10(5)) were stimulated by opZy and the oxidative burst of control or treated rat cells was measured by luminol-dependent chemiluminescence (CL). Prednisone did not affect the CL of rat neutrophils for either period of treatment, or any studied doses, when compared with controls. These results suggest that the low-dose prednisone has no effect on the oxidative burst mediated by complement receptors during the rat neutrophil phagocytosis of complement-opZy.

Retrospective evaluation of postoperative intralesional steroid injections on wound healing

Steroids have been implicated as an etiology in delayed wound healing. Although there is much documentation in the literature that steroids delay wound healing, most studies are in vitro or use high systemic doses. No studies have used a one-time, postoperative, intralesional steroid injection and evaluated wound healing. This study retrospectively reviewed 73 patients with 115 foot and ankle surgeries over 12 years. Seventy-two patients had steroid injections and 43 did not. The average healing time for the steroid group was 17.1 +/- 10.5 days, and for the non-steroid group 17.3 +/- 8.75 days. There were two infections in the non-steroid group, and one infection in the steroid group. There were five dehiscences in each group. The patients were further subdivided into groups based on age, gender, number of procedures, type of surgery, health status, steroid type, and steroid dose. The healing time increased in patients > 60 years old, and in immunocompromised patients. The patients who had more complex surgery had increased healing time. The males had a longer healing time than the females. Overall, there was not a statistically significant difference between the steroid groups and the non-steroid group. Therefore, one-time postoperative intralesional steroid injections were not found to delay wound healing.

Perioperative management of the rheumatoid patient

Rheumatoid arthritis is a systemic disease that can affect multiple organ systems of the body. It is a symmetrical polyarthropathy which leads to destruction of cartilage and bone. Before undertaking surgery on the rheumatoid patient, several issues need to be addressed. A thorough evaluation by a multidisciplinary team is essential to decrease any operative risks involved. This is a review of some of the systemic manifestations of rheumatoid arthritis with an emphasis on anesthesiology, and radiological consultation, and perioperative surgical management of rheumatoid drug therapy.

Pasteurella multocida septicemia and subsequent Pasteurella dagmatis septicemia in a diabetic patient

Pasteurella species may cause zoonotic infections of humans. Serious systemic infections with these organisms are unusual, but they may occur in individuals with predisposing underlying illnesses. Occurrences of bacteremia due to P. multocida are infrequent, and P. dagmatis bacteremia is even rarer. We report independent occurrences of P. multocida and P. dagmatis septicemia in the same diabetic patient after contact with two pet dogs. We review the history of Pasteurella species and discuss the biochemical and clinical features of its association with zoonosis.

The effects of intravitreal triamcinolone acetonide on experimental pre-retinal neovascularization

Corticosteroids, alone or in combination with other drugs, have been shown to inhibit angiogenesis. The purpose of this study was to evaluate the efficacy of triamcinolone acetonide in a new model of preretinal neovascularization. Rabbit eyes were treated with intravitreal triamcinolone acetonide 24 h before partial liquefaction of the posterior vitreous with hyaluronidase and injection of 250,000 homologous tissue-cultured dermal fibroblasts. Triamcinolone acetonide effectively inhibited new vessel growth in treated eyes. Only 14% of the treated eyes developed new blood vessels compared to 100% of sham-injected control eyes (P < 0.001). These results suggest that intravitreal triamcinolone acetonide might be effective in inhibiting new vessel growth in patients with inflammatory retinal neovascularization, such as that associated with sarcoidosis or other uveitic syndromes.

The lack of an effect of intraocular steroids on irradiated fibroblasts in experimental proliferative vitreoretinopathy

Contraction of intraocular membranes is an important event in the development of proliferative vitreoretinopathy (PVR). When sufficient numbers of cells are present in the vitreous cavity, the retina usually detaches as a result of the contractive force generated by these cells. Steroids reduce the occurrence of retinal detachments in rabbit models of PVR by inhibiting the proliferation of injected fibroblasts. In this study, we used non-proliferative, irradiated cells to determine a possible effect of steroids on preretinal membrane contraction in PVR. We found no clinical difference between steroid treated eyes and sham-treated control eyes. Surgical reduction of the contractile tissue and medical therapy to prevent reproliferation are necessary in order to treat PVR effectively.

Pharmacology of the pyrroloimidazole, SK&F 105809--I. Inhibition of inflammatory cytokine production and of 5-lipoxygenase- and cyclooxygenase-mediated metabolism of arachidonic acid

SK&F 105809 [2-(4- methylsulfinylphenyl)-3-(4-pyridyl)-6,7-dihydro-[5H]-pyrrolo[1,2- a] imidazole] was determined to be a prodrug for the sulfide metabolite SK&F 105561 [2-(4- methylthiophenyl)-3-(4-pyridyl)-6,7-dihydro-[5H]-pyrrolo[1,2-a] imidazole] which inhibited interleukin-1 (IL-1) production in vitro and both 5-lipoxygenase (5-LO) and prostaglandin H (PGH) synthase activities in vitro and ex vivo. SK&F 105561 inhibited partially purified 5-LO with a half-maximal concentration (IC50) of 3 microM. This inhibition was reversible, independent of preincubation time, and dependent on the concentration of the substrate arachidonic acid. SK&F 105561 also inhibited purified PGH synthase with the potency dependent on the level of peroxidase activity. The IC50 was 100 microM in the absence of peroxidase activity, whereas an IC50 of 3 microM was observed in the presence of peroxidase activity. Using human monocytes, SK&F 105561 inhibited A23187-stimulated prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) production with IC50 values of 0.1 and 2 microM, respectively. In addition, IL-1 production by lipopolysaccharide-stimulated human monocytes was also inhibited (IC50 2 microM). Oral administration of SK&F 105809 to rats resulted in a dose-related generation of SK&F 105561 and in the inhibition of thromboxane B2 and LTB4 production ex vivo with a half-maximal dose (ED50) of 15 and 60 mg/kg, respectively. SK&F 105561 showed weak inhibitory activity on 12-lipoxygenase with an IC50 of greater than 200 microM. Neither SK&F 105561 nor SK&F 105809 inhibited the stimulated-turnover of arachidonic acid-containing phospholipids in human monocytes or the activity of cell-free phospholipases A2 and C. Moreover, neither SK&F 105561 nor SK&F 105809 antagonized the binding of LTB4 or leukotriene D4 to membrane receptors. From these results, SK&F 105561, the active principle of SK&F 105809, acts as an inhibitor of both inflammatory cytokine and eicosanoid production.

Effects of dexamethasone on macrophages in fetal and neonatal rat lung

The effects of injecting dexamethasone to pregnant and newborn rats on the subsequent production of macrophages in the lung and on their phagocytic activity and lysosomal enzyme content were evaluated from late gestation to postnatal day 10 using an organ culture system to collect macrophages. Pieces of lung tissue cultured 6 days on cover glasses produced a halo of macrophages adherent to the glass around the explants. Thymidine labeling showed that the macrophages were derived from dividing precursors in the pulmonary interstitium. DNA synthesis was reduced after steroid treatment, and fewer cells were obtained on cover glasses, particularly just after birth when the macrophage number usually increases. Phagocytic function was also diminished in cells collected after dexamethasone injection, particularly when derived from neonatal animals. In contrast, intracellular levels of non-specific esterase and glucosaminidase were increased, probably indicative of lower phagolysosome formation and lower enzyme secretion. These results demonstrate that steroid administration to fetal or newborn animals subsequently reduces the number and phagocytic activity of macrophages in the lungs. This could reduce the defense mechanisms of the neonate and increase susceptibility to infection.

Search for drugs that may reduce the load of neutrophil azurophilic granule enzymes in the lungs of patients with emphysema

Neutrophil elastase and myeloperoxidase probably play an important role in the development of pulmonary emphysema. We have analyzed drugs from the major classes of agents that alter neutrophil function to determine if there are drugs in use today that can reduce the load of neutrophil elastase or myeloperoxidase in the lungs of smokers. Eleven representative drugs were tested for their ability to inhibit chemotaxis and degranulation. None of the drugs inhibited chemotaxis in a dose-response fashion at concentrations achievable in human plasma. Sulfinpyrazone, phenylbutazone, and auranofin completely inhibited the release of azurophilic granules (myeloperoxidase) and tertiary granules (beta-D-glucuronidase) when formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) was used as the stimulant, and inhibited azurophilic granule release by 69%, 19%, and 64% respectively, but not tertiary granule release when macrophage-conditioned media was used as the stimulus. In conclusion, none of the drugs tested are inhibitors of chemotaxis; however, three are excellent inhibitors of azurophilic granule enzyme release. Of these three, sulfinpyrazone, a drug that is not currently used clinically for its antiinflammatory effects, is the least toxic and should be considered as a potential drug to reduce the elastase and myeloperoxidase load in the lungs of smokers who are developing emphysema.

Microbial keratitis complicating penetrating keratoplasty

A retrospective review of 68 consecutive episodes of microbial keratitis complicating 66 penetrating keratoplasties (PKs) showed major risk associations: suture-related problems (50%), contact lens wear (26%), previous herpes simplex infection (15%), graft failure (15%), and persistent epithelial defects (15%). Topical steroid (85%) and antibiotic (59%) usage were common iatrogenic factors. Half the infections occurred more than 1 year after grafting. Bacterial infections involving gram-positive organisms (59%) predominated, except for patients with extended-wear hydrophilic contact lenses, which usually involved gram-negative bacilli. The incidence of fungal infections (6%) was relatively low. Recommendations to minimize microbial keratitis include prompt attention to exposed, broken, or loose sutures, and preventive and therapeutic management of epithelial defects. The inadequacy of low-dose antibiotics in precluding microbial infection in many cases and the propensity to develop infections with resistant organisms suggest that guidelines for using postoperative and prophylactic topical antibiotics require reevaluation.

Corticosteroids attenuate sensitization-induced membrane changes in airway smooth muscle cells

Serum from immunized guinea pigs or highly purified IgG1 induces specific changes in electrical and contractile characteristics of airway smooth muscle (ASM) cells. In this study, the effect of hydrocortisone and prednisolone pre-treatment on the events caused by a passive in vitro sensitization of ASM cells was investigated. ASM preparations isolated from male guinea pigs were exposed to immunized serum (1:10 dilution) together with different concentrations of hydrocortisone or prednisolone administered simultaneously or 30, 120 or 240 min before addition of immunized serum. During sensitization as well as during consecutive specific antigen challenges (1 mg/ml ovalbumin), both the resting membrane potential (Em) and isometric force developed by airway smooth muscle preparations were determined. Em was determined with glass microelectrodes and isometric force was simultaneously measured with a copper-berylium strain gauge. Pretreatment with both hydrocortisone and prednisolone (in the range of 10(-8)-10(-4) M) attenuated sensitization-induced transient depolarization and steady state hyperpolarization of ASM cells and decreased the sensitization-induced development of the isometric force. Furthermore, pretreatment with either steroid significantly attenuated electrical and contractile responses to a specific antigen challenge. Inhibition of the events observed during sensitization occurred at steroid concentrations as low as 10(-8) M. We have also found that the duration of exposure of ASM cells to either of the tested steroids is critical in determining the magnitude of this inhibitory effect and seems to be more important than concentration of tested steroids.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of dexamethasone in vivo on blood and peritoneal neutrophils (PMN) in rabbits with peritonitis

Neutrophils play an essential role in the host's defense against infection. Our previous studies have shown that blood and peritoneal neutrophils (PMN) have different basal activities and responses to infection. We also demonstrated that peritonitis produces divergent changes in the cellular function of PMN both in the blood and in the peritoneal fluid. Steroids are well documented to cause immunosuppression both clinically and, more variably, at the cellular level. Understanding the mechanism of steroid-induced immunosuppression in surgical infection may impart insight on the management of this condition. Using a model of surgical peritonitis, we studied the effects of immunosuppression on rabbit blood and peritoneal PMN. Blood and peritoneal PMNs were harvested after the development of fibrinopurulent peritonitis. Rabbits were divided into two groups: immunosuppressed and control. Immunosuppression was accomplished by intramuscular injection of dexamethasone (2 mg/kg) for 10 days preoperatively and 10 days postoperatively. Purified PMNs were studied for phagocytosis, adhesiveness, superoxide anion production and chemotaxis from both groups. Survival was computed from the number of days the rabbit survived after the operation up to a total of 10 at which time they were sacrificed. Immunosuppression with dexamethasone resulted in inhibition of peritoneal phagocytosis and peritoneal adhesiveness; there were no changes in blood adhesiveness nor blood phagocytosis. Also, there was no significant change in superoxide anion production nor in chemotaxis. Survival of the rabbits was significantly reduced when treated with dexamethasone.(ABSTRACT TRUNCATED AT 250 WORDS)

Improvement in efficacy of corticosteroid therapy in an animal model of proliferative vitreoretinopathy by pretreatment

Intraocular injection of the corticosteroid triamcinolone acetonide reduces the incidence of retinal detachment in rabbit eyes injected with tissue-cultured fibroblasts. When the steroid was injected simultaneously with the cells, a reduction of retinal detachment from 93% (control) to 75% (treated) was achieved on day 28. When the steroid was injected 24 h preceding cell injection, the reduction of retinal detachment was from 85% (control) to 43% (treated). The development of retinal detachment is caused by proliferation of injected fibroblasts. Reduction of this proliferation is probably achieved partially through direct inhibition of mitosis, but more important may be the reduction of the reactive inflammatory process.

Modification of the murine immune system by glucocorticosteroids: alterations of the tissue localization properties of circulating lymphocytes

Glucocorticosteroids have proven capable of suppressing both developing and ongoing immune responses via mechanisms that are not fully understood. Most investigations into the mechanisms of glucocorticosteroid-mediated immunosuppression have examined the direct effects of these agents on the lymphocyte itself. In this paper, we have analyzed the effects of glucocorticosteroids on the lymphocyte receptive capacity of lymph nodes and bone marrow in mice. These effects appear to be mediated via reversible changes in the capacity of steroid-treated vascular endothelial cells to interact with normal lymphocytes, and are both dose and time dependent. The most striking effects on lymphocyte localization were observed in mice given microgram quantities of glucocorticosteroids over a 6-day period via a continual release pellet. The direct exposure of lymphocytes to these drugs in vitro was shown to have no effect on their subsequent localization potential in vivo. Further studies revealed that the ability of antigen-sensitized effector lymphocytes to localize into sites of antigen deposition was also markedly depressed in mice pretreated with glucocorticosteroids. Therefore, steroids also appear to have effects on tissue associated endothelial cells which prevent the localization of sensitized effector lymphocytes into sites of active inflammation. Our observations have potential clinical implications, both in understanding the anti-inflammatory effects of glucocorticosteroids more fully, as well as suggesting that low-dose continual-release steroid administration may result in enhanced immunosuppression.

Corticosteroids for rheumatic disease. 1. Physiology, pharmacology, and therapeutic strategies

Of the corticosteroid preparations available, the intermediate-acting agents are the preparations most commonly used in the rheumatic diseases. Careful tailoring of dosage is important to avoid adrenal atrophy and signs of adrenocortical hypofunction. The best regimen in a given patient depends on the amount of antiinflammatory and immunosuppressive activity required. The therapeutic strategies in use include pulse therapy, daily high-dose therapy, daily low-dose therapy, and alternate-day dosing. The latter two methods are preferable because of the decreased likelihood of adverse reactions, yet are not sufficient in cases of fulminant systemic inflammatory processes.

Dose related effects of dexamethasone treatment on the ultrastructure of articular cartilage in rats

Corticosteroid administration is known to cause degenerative changes in articular cartilage interfering with the cell metabolism of chondrocytes. The present study analyzes the ultrastructural changes in chondrocytes after systemic dexamethasone acetate treatment in relation to dosage, using a standardized morphometrical method. Five male Wistar rats of 300 g body weight in each experimental group were subjected to 3, 4 and 5 mg dexamethasone acetate by intramuscular injections of 1 mg per week. 1000 electron micrographs of single chondrocytes in the middle zone of hyaline cartilage from the knee joints were evaluated with standardized morphometry and nonparametric statistics. With increasing dexamethasone dosage the amount of rough endoplasmic reticulum and Golgi apparatus decreased. Considerably increased glycogen granula and clusters indicated a severe change in glycolytic pathways. Lysosomes duplicated in number. Degenerative changes were also manifested in lipid droplets and myeloid bodies, which, like the amount of microfilaments, exhibited a clear dosage-dependent increase under dexamethasone treatment. The ratio of dead versus living chondrocytes increased in relation to dosage up to 25% cell mortality.

Relation of early mononuclear and polymorphonuclear cell infiltration to late scar thickness after experimentally induced myocardial infarction in the rat

This report describes the relationship between the intensity of early inflammation after acute myocardial infarction and the later thickness of the left ventricular (LV) scar. Histologic sections of hearts from methylprednisolone-treated (MP), cobra venom factor-treated (CVF), and untreated control rats that had been subjected to either 2 or 21 days of coronary artery occlusion were studied. In the rats examined at 2 days (n = 20 for MP, n = 16 for CVF, and n = 20 for controls), a semiquantitative inflammation score (1-4) was attributed to each infarct. Mononuclear (MN) cells were counted in 4 oil-immersion fields per section and polymorphonuclear (PMN) cells in 9 oil-immersion fields per section. In the rats examined at 21 days (n = 22 for MP, n = 22 for CVF, and n = 26 for controls), the thickness of the LV scar was measured every 1.6 mm along its circumference. Inflammation scores at 2 days were 3.5 +/- .6 for controls, 1.5 +/- .5 for MP, and 2.9 +/- .8 for CVF (p less than .05 among groups). The MN cells counted were 73 +/- 7 for controls, 47 +/- 5 for MP, and 61 +/- 9 for CVF (p less than .05 among groups). There was no difference in PMN infiltrate among groups. Scar thickness at 21 days were .9 +/- .1 mm for controls, .7 +/- .1 mm for MP, and .9 +/- .1 mm for CVF (MP compared to CVF and controls, p less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Prednisolone decreases exercise-induced acid hydrolase response in mouse skeletal muscle

Male NMRI-mice were subjected to exhaustive treadmill exercise. 3 and 6 days after the exertion, quadriceps femoris muscles were examined histologically and analyzed for acid hydrolases in order to follow the degree and progress of injuries. Prednisolone (PRED), an anti-inflammatory corticosteroid, was given to some of the animals in order to modify the exercise response. The PRED administration began 14 h before exercise and continued until the end of the experiment (6 days). The doses were 25 and 50 mg . kg-1 i.p. twice a day. The activities of both arylsulphatase and beta-glucuronidase increased significantly in the exercise control group after 3 and 6 days. The increase in activity correlated with fibre necrosis and an abundant infiltration of inflammatory cells, and was greatest after 3 days. After 6 days the inflammatory response decreased and regenerating muscle fibres were seen. PRED decreased the exercise-induced acid hydrolase response. The decrease was most prominent after 3 days with PRED 50 mg . kg-1 . day-1. PRED also diminished degeneration and inflammation. The results suggest that the decrease in acid hydrolase activities was due to a lesser infiltration of inflammatory cells to the injured area.

The effects of dexamethasone on palate mesenchymal cell phospholipase activity

Corticosteroids will induce cleft palate in mice. One suggested mechanism for this effect is through inhibition of phospholipase activity. This hypothesis was tested by measuring the effects of dexamethasone, a synthetic corticosteroid, on phospholipase activity in cultures of palate mesenchymal cells. Palate mesenchymal cells were prelabeled with [3H]arachidonic acid. The cells were subsequently treated with various concentrations of dexamethasone. Concurrently, cultures of M-MSV-transformed 3T3 cells were prepared identically. After treatment, phospholipase activity was stimulated by the addition of serum or epidermal growth factor (EGF), and radioactivity released into the medium was taken as a measure of phospholipase activity. Dexamethasone (1 X 10(-5) or 1 X 10(-4) M) could inhibit serum-stimulated phospholipase activity in transformed 3T3 cells after 1 to 24 hr of treatment. However, no inhibition of activity was measured in palate mesenchymal cells following this period of treatment. Not until 120 hr of treatment with dexamethasone (1 X 10(-4) M) was any significant inhibition of serum-stimulated phospholipase activity observed in palate mesenchymal cells. When EGF was used to stimulate phospholipase activity, dexamethasone (1 X 10(-5) M) caused an increase in phospholipase activity in palate mesenchymal cells. These observations suggested that phospholipase in transformed 3T3 cells was sensitive to inhibition by dexamethasone. However, palate mesenchymal cell phospholipase is only minimally sensitive to dexamethasone, and in certain instances can be enhanced. These results cannot support the hypothesis that corticosteroids mediate their teratogenic effect via inhibition of phospholipase activity.

The influence on the dermal cellular infiltrate of topical steroid applications and vehicles in guinea pig skin: normal skin, allergic and toxic reactions

The mechanisms of the anti-inflammatory effects of corticosteroids are uncertain but could be explained by an influence on infiltrating leukocytes. Our method for the qualitative and quantitative investigation of the dermal cellular infiltrate makes it possible to study the effects of topically applied corticosteroid preparations and vehicles on the infiltrating leukocytes of normal skin, allergic and toxic reactions in guinea pig skin. Ointment and cream vehicles as well as corticosteroid cream and ointment preparations often caused erythema and increased mononuclear infiltrate after only short periods of application (24-72 h). The strongest steroid ointment gave the most marked macroscopic response and propylene glycol preparations the most marked cellular response. In both toxic and allergic reactions, application of steroid preparations after the provocation gave no beneficial result either macroscopically or microscopically. Macroscopic scores were worsened by cream and ointment preparations. Although steroid solutions had no beneficial effect, they caused no detrimental effect. The guinea pig seems to be extremely sensitive to irritants and has not proved to be a suitable model for this approach to the study of the efficacy of topically applied steroids.

Effect of hydrocortisone on immune system of the lizard, Chalcides ocellatus. II. Differential action on T and B lymphocytes

Lymphocytes of thymus, spleen, peripheral blood (PB) and bone marrow (BM) collected from adult lizards, Chalcides ocellatus were cultured for 24 hr in the presence of 10(-3)M hydrocortisone acetate (HC) in order to assess the effect of in vitro HC on lizard T and B cell viability. The results indicated that HC induced stepwise, time-dependent mortality of the majority of thymocytes carrying T cell specific antigen(s) (TSA), 30-50% of T cells of spleen, PB and BM, and of a proportion of splenic B lymphocytes. Administration of 1 mg/g body weight HC to adult Ch. ocellatus lead to depletion of all TSA+ thymocytes. In contrast, T lymphocytes in the peripheral lymphoid compartments revealed both sensitivity and resistance to HC; similarly, B lymphocytes constituted susceptible and resistant subpopulations.

Cell lines (VMDk) derived from a spontaneous murine astrocytoma. Morphological and immunocytochemical characterization

Three cell lines (VMDk) derived from a spontaneous, murine astrocytoma, which produce tumours when injected either subcutaneously or intracranially into syngeneic mice, have been examined in vitro. Ultrastructurally, the cells show astrocytic features but each line differs in its degree of differentiation. Treatment with both dexamethasone and dibutyryl adenosine 3',5'-cyclic monophosphate (dbcAMP) increases intracytoplasmic differentiation and causes surface structural changes. The addition of dbcAMP also induces a statistically significant increase in the length and number of cell processes. All three cell lines express the astrocyte-specific markers, glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS), by indirect immunofluorescence, with two lines showing an increased propensity to stain for GFAP following dbcAMP treatment. The cell surface antigen fibronectin is also detected in all lines. Thus these VMDK cell lines exhibit both the morphological and antigenic characteristics of astrocytes and respond to dexamethasone and dbcAMP and may be used to provide a suitable in vivo-in vitro model system for the study of astrocytoma.

Modulation of disseminated intravascular coagulation (DIC) by steroidal and non-steroidal anti-inflammatory drugs

Activation of the coagulation systems by endotoxin and release of vasoactive agents are both essential for the production of microthrombosis. Glucocorticoids prevent activation of factor XII by endotoxin in vivo and decrease production of tissue factor by macrophages. NSAID do not interfere with factor XII activation and increase the severity and risks of microthrombosis by inhibiting synthesis and release of protective prostaglandins. On the other hand, prolonged administration of glucocorticoids results in the reduction of the immune defence and fibrinolysis, increases the alpha-adrenergic response to endotoxin and sensitizes to endotoxin-induced intravascular coagulation like NSAID.

Comparison of the effect of nonsteroidal and steroidal antiinflammatory agents on prostaglandin production during ovulation in the rabbit

The nonsteroidal antiinflammatory agents diclofenac, fenoprofen and aspirin were tested to determine how well they inhibit the preovulatory elevation in prostaglandin (PG) production in rabbit follicles in comparison to indomethacin. In addition, the steroidal antiinflammatory agent dexamethasone and the antipyretic agent acetaminophen were tested. The agents were administered 8 h after the ovulatory process was stimulated by hCG (50 I.U./kg). At 10 h after hCG (i.e., at the expected time of ovulation) control follicles had PGF and PGE levels of 370.0 and 582.6 pg/mg of follicle, respectively. Diclofenac inhibited PG production the most--reducing PGF and PGE to 22.8 and 53.6 pg/mg, respectively. Indomethacin reduced the PGF and PGE levels to 27.4 and 76.6 pg/mg, respectively. Fenoprofen was less effective, reducing the PGF and PGE to 77.8 and 222.4 pg/mg, respectively. Aspirin reduced the PGF and PGE to 123.4 and 174.6 pg/mg, respectively. Dexamethasone and acetaminophen did not inhibit PG production. Ovulation was completely inhibited by diclofenac and indomethacin, partially inhibited by fenoprofen, and unaffected by aspirin, acetaminophen, or dexamethasone. The results suggest that any potent nonsteroidal antiinflammatory agent can inhibit ovulation provided it adequately reduces PG production; whereas steroidal antiinflammatory agents are ineffective. The antiinflammatory agent must completely abolish the preovulatory elevation in PGs in mature follicles in order to totally inhibit ovulation.

Vacuoles in macrophages and reticular cells of regional lymph nodes of the rat after injection of large doses of steroids

The ultrastructure of macrophages and reticular cells of regional lymph nodes of the rat after administration of large doses of cortisone acetate, estrone, progesterone, and cholesterol in aqueous suspensions was investigated. A large number of vacuoles, most of which were surrounded by unit membrane, and lipid droplets not surrounded by unit membrane were observed in the cytoplasm of both macrophages and reticular cells. They were not seen in these cells of control animals and in experimental animals that had received smaller doses of these steroid hormones. After cholesterol injection, many lipid droplets were observed in the cytoplasm of macrophages. These observations suggest that steroids injected in suspension accumulate in macrophages and reticular cells of the regional lymph nodes. Electron-dense material was often present in vacuoles of macrophages but not in those of reticular cells.

Comparison of the effects of glucocorticoid and indomethacin treatment on the acute inflammatory reaction in rabbits

We have recently shown that indomethacin and ASA diminish the elevated blood flow, protein exudation, and leukocyte infiltration during acute inflammation induced by killed Escherichia coli, the reversed Arthus reaction, or zymosan-activated plasma (ZAP; C5ades-arg) in rabbit skin. All of these effects were likely due to the inhibition by these drugs of prostaglandin (PG) synthesis in the lesions. Because glucocorticoids are also reported to inhibit PG production and, in large doses, to suppress inflammation accompanying various clinical conditions, we investigated the effects of hydrocortisone (HC), and methylprednisolone (MP), administered in large doses (100 mg/m2/d of MP or 2.5 g/m2/d of HC) on the above three forms of acute inflammation in rabbits. The effect of indomethacin treatment was studied in parallel for comparison. Blood flow, protein exudation, and leukocyte infiltration were quantitated simultaneously with 86Rb Cl, 125I-labelled rabbit albumin and 51Cr labelled blood leukocytes. Systemic indomethacin therapy decreased the blood flow and permeability, while local indomethacin (2.5 micrograms) significantly inhibited leukocyte infiltration into the lesions. In contrast, HC and MP caused only a mild decrease in blood flow, without altering protein exudation or leukocyte influx. However, HC and MP did inhibit protein exudation induced by bradykinin or histamine injection. These results indicate that, at least in rabbits, HC and MP, in contrast to indomethacin, have very weak anti-inflammatory actions on three complement- and neutrophil-mediated inflammatory responses, i.e., E. coli, ZAP (C5ades-arg) and reversed Arthus reactions.

Enhanced breakdown of bovine articular cartilage proteoglycans by conditioned synovial medium in vitro. The effect of glucocorticoids and protein synthesis inhibitors

Addition of conditioned synovial medium (SM) from cultured calf knee-joint synovium to cultures of articular cartilage from the same animal resulted in a significant increase in breakdown of cartilage proteoglycans. Culturing the synovium in the presence of glucocorticoids (hydrocortisone, dexamethasone, prednisolone) or protein synthesis inhibitors (cycloheximide or actinomycin D) reduced the breakdown effect. In contrast, enhancement of proteoglycan breakdown was observed when the cartilage was exposed to glucocorticoids in the presence of SM from synovium cultured without these drugs (control SM). The stimulatory effect on cartilage breakdown of control SM or control SM + glucocorticoids was markedly reduced in the presence of actinomycin D or cycloheximide. The authors conclude that glucocorticoids under certain conditions enhance cartilage degradation and therefore, although they exert the temporary anti-inflammatory effects, treatment of joint diseases with glucocorticoids may not be beneficial in the long-term.

Glucocorticoid receptors in human polymorphonuclear and mononuclear leucocytes. Concentrations and binding characteristics

Both polymorphonuclear (PMN) and mononuclear (MN) leucocytes constitute targets for glucocorticoid hormones. In order to comparatively characterize the earliest steps of steroid action in these cell populations, we investigated the concentrations and specificities of glucocorticoid receptors in purified human PMNs and MNs by a whole-cell binding assay using (3H)dexamethasone as the ligand. PMNs and MNs were found to contain the same amounts of glucocorticoid receptors (4720 and 4900 receptor sites/cell, respectively). The equilibrium dissociation constant (KD) of the interaction between the cellular receptor and (3H)dexamethasone was about the same (1 x 10(-8)M) in both cell populations. No significant difference in the specificities of the steroid binding sites in PMNs and MNs were found; competition studies revealed the following order of relative binding affinities for a number of compounds: betamethasone greater than dexamethasone greater than prednisolone greater than cortisol greater than deoxycorticosterone = progesterone greater than aldosterone greater than testosterone greater than estradiol-17 beta. We conclude that known differences in the sensitivities of PMNs and MNs to glucocorticoids are apparently not caused by differences in the concentrations or characteristics of their glucocorticoid receptors.

The development of an acth-induced renal glomerular lesion in Mus musculus. An ultrastructural study

Male house mice (Mus musculus) were injected with 4 international units of ACTH daily for 1, 2, 3 and 4 weeks and with four units daily for four weeks followed by 8 units for 8 days. Light microscopy of kidneys showed a glomerular lesion characterised by the expansion of the mesangium, deposition of PAS positive material in the glomerular mesangium and extraglomerular mesangium hypertrophy of juxtaglomerular cells and a successive increase in oil red-O staining material in the glomerulus. Electron microscopy revealed the progressive accumulation in the mesangial matrix of three morphologically distinct forms of deposits: amorphous, globular and particulate. The accumulation of amorphous deposit apparently is partially responsible for the increased PAS positive staining of the mesangium. Globular (and possibly particulate) deposit probably corresponds to the oil red-O positive material. The evidence suggests that the deposits are extraglomerular in origin, but their chemical nature is unknown.

Some effects of products from necrotic regions of tumours on the in vitro migration of cancer and peritoneal exudate cells

The invasion of normal tissues by cancer cells and the infiltration of tumours by macrophages to some degree involves active translatory movements by these cells. As necrosis is a common occurrence in solid tumours, we have studied the interactions of saline extracts from the necrotic regions of rat Walker-256 tumours and mouse Gardner lymphosarcomas on the transmembrane, in vitro migration of Walker and Gardner cancer cells, and rat and mouse peritoneal macrophages. Necrotic extracts enhanced cell migration independently of chemotactic activity, an effect which was partially reduced by Trasylol, an inhibitor of neutral proteases. Rat liver lysosomal preparations which contain lower levels of neutral proteases than necrotic extract, inhibited or had no effects on cell migration, and the lysosomal stabilizer hydrocortisone did not inhibit the action of necrotic extracts. The results indicate that necrosis may enhance the migration of cancer cells out of tumours and the migration of macrophages into them. The extracts act partially through their neutral protease content. In contrast to the enhancement of cell detachment by necrotic extracts, which previous work has shown to be partially mediated by their indirect effect in causing lysosomal labilization and which is partially inhibited by hydrocortisone, this indirect mechanism is not demonstrable in the enhancement of cell migration. The results indicate that the consequences of necrosis are worthy of consideration in attempts at understanding the biology of solid tumours.