Anti-inflammatory planar chiral [2.2]paracyclophaneacetic acid enantiomers.

OBJECTIVE AND DESIGN: To elucidate if the planar chiral paracyclophane moiety conveys pharmacological activity to arylacetic acid analogs in two animal models. MATERIAL OR SUBJECTS: Female NMRI mice (6 mice/group); female Wistar rats (8 rats/group); thrombocytes from human blood. TREATMENT: The enantiomers of [2.2]paracyclophaneacetic acid were applied locally (10(-7) and 10(-6) mol/ear) and orally (10-100 mg/kg). METHODS: (a) Phorbol myristyl acetate model of acute inflammation of the inner auricle. (b) Oxazolone model of allergic contact dermatitis. (c) Carrageenan model of acute inflammation. (d) Inhibition of cyclooxygenase-1 and 12-lipoxygenase (in vitro). RESULTS: (a) PMA model: pR-(-)-[2.2]paracyclophaneacetic acid (10(-6) mmol/ear): 58% inhibition after 24 h (p < 0.05). (b) Oxazolone model: pR-(-)-[2.2]paracyclophaneacetic acid (10(-6) mmol/ear): 42% inhibition after 24 h (p < 0.05). (c) Carrageenan model: pR-(-)-[2.2]paracyclophaneacetic acid (10 mg/kg): 31.4% inhibition (paw volume 0.48 +/- 0.13 ml). (d) Cyclooxygenase-1 and 12-lipoxygenase: no inhibition at concentrations up to 10 microM. CONCLUSIONS: The easily accessible [2.2]paracyclophane moiety should find its use in medicinal chemistry as it is a pharmacophoric substituent with the interesting feature of planar chirality.

[Hypothenar hammer syndrome: causes, sequelae and diagnostic aspects]. / Das Hypothenar-Hammer-Syndrom--Ursachen, Folgen und diagnostische Aspekte.

PURPOSE: To investigate the reasons and disease course of Hypothenar Hammer Syndrome. INTRODUCTION: Occlusion of the ulnar artery at the level of the hamate bone due to repetitive trauma to the hypothenar eminence is implicated as the cause of the rarely diagnosed hypothenar hammer syndrome (HHS). The thrombotic occlusion and the formation of an aneurysm of the ulnar artery and the superficial palmar arch with possible peripheral embolism of the digital arteries are a direct cause of the chronic damage to the vessel wall. Generally, HHS is diagnosed too late for recanalization to be a viable therapeutic option. METHODS: From 1996 to 1998 the diagnosis of an HHS was made in 8 patients at our hospital. Etiology, clinical settings and disease course were assessed. RESULTS: Our analysis suggests that HHS may be caused by a single severe trauma in addition to repetitive injuries. The pathogenesis of the syndrome is dependent on the vascular anatomy of the individual hand. Interindividual variations in the arterial supply of the affected hand influences the clinical symptomatology with possible masking of arterial occlusions. CONCLUSION: An exact investigation concerning the pathogenesis of HHS is a precondition for treating the disease and may help to establish HHS as an occupational disease. MR-angiography may be a new approach for assessing HHS.

Rapid non-genomic feedback effects of glucocorticoids on CRF-induced ACTH secretion in rats.

PURPOSE: The present study investigates fast negative feedback actions of corticosterone (corticosteroid type I/type II receptor agonist) and RU 28362 (corticosteroid type II receptor agonist) on corticotropin-releasing factor (CRF)-induced adrenocorticotropic hormone (ACTH) secretion in rats. METHODS: To induce fast feedback, glucocorticoids were administered intravenously immediately before injection of the hypophyseotropic stimulus CRF. Plasma ACTH levels, being determined 5 to 30 min thereafter, were used as markers of fast feedback. RESULTS: Fast inhibitory effects on CRF-induced ACTH secretion became evident within 15 min (corticosterone) and 5 min (RU 28362) after steroid administration. Rapid feedback inhibition was also observed in the presence of other corticosteroids (cortisol, dexamethasone, aldosterone), whereas structurally-unrelated steroids (beta-estradiol, progesterone, potassium canrenoate, alphaxalone) were inactive in this respect. Pretreatment of rats with the corticosteroid type II receptor antagonist RU 486 or the transcription inhibitor actinomycin D left fast feedback effects unaltered. CONCLUSIONS: Our results demonstrate that glucocorticoids exert fast negative feedback at the pituitary level via a mechanism that is independent of corticosteroid type II receptor occupation and de novo synthesis of mRNA. In conclusion, corticosteroid-specific nongenomic effects may underly rapid glucocorticoid responses on CRF-induced ACTH secretion.

Dexamethasone megadoses stabilize rat liver lysosomal membranes by non-genomic and genomic effects.

PURPOSE: Membrane-stabilizing effects may be part of glucocorticoid action during high-dose glucocorticoid therapy. The present study investigates the mode of action of dexamethasone megadoses on rat liver lysosomal membranes. METHODS: Following intravenous administration of dexamethasone in rats, the release of beta-glucuronidase from liver lysosomes was assessed ex vivo as a marker for lysosomal membrane integrity. RESULTS: Dexamethasone megadoses significantly inhibited beta-glucuronidase release 10 min post-administration by 38% (3 mg/kg dexamethasone) and 33% (10 mg/kg dexamethasone) at corresponding dexamethasone liver concentrations of 3.9 x 10(-5) mol/kg and 15.1 x 10(-5) mol/kg, respectively. Comparable inhibition of beta-glucuronidase release (34% for 3 mg/kg and 38% for 10 mg/kg) was observed 24 h after administration of dexamethasone, although dexamethasone liver concentrations had already declined to 0.09 x 10(-5) mol/kg and 0.19 x 10(-5) mol/kg, respectively. A 2-h oral pretreatment of rats with the glucocorticoid receptor antagonist RU 486 (10 mg/kg) did not alter immediate (10 min) stabilization by dexamethasone (3 mg/kg). but almost completely prevented lysosomal membrane protection 24 h after dexamethasone injection. CONCLUSIONS: Dexamethasone megadoses may preserve lysosomal membrane integrity by a dual action involving both rapid nongenomic effects occurring instantaneously after administration and long-term receptor-dependent genomic events.

Biological effects of the dihydroorotate dehydrogenase inhibitor polyporic acid, a toxic constituent of the mushroom Hapalopilus rutilans, in rats and humans.

Inhibitors of dihydroorotate dehydrogenase (DHO-DH), such as brequinar or leflunomide, have been intensively tested for their antitumour and immunomodulating effects. Polyporic acid (PA) from the mushroom Hapalopilus rutilans (H. r.) also is a DHO-DH inhibitor (50% inhibitory concn., IC50, 10(-4)-10(-3) M). As three people had been poisoned following ingestion of H. r. we wanted to investigate the effects of PA in rats and in cell cultures. Rats given PA via probang (100-800 mg/ kg) within 24 h developed strongly reduced locomotor activity, depressed visual placing response and impaired wire manoeuvre. Laboratory investigation of blood revealed hepatorenal failure, metabolic acidosis as well as hypokalaemia and hypocalcaemia. All symptoms closely paralleled the effects seen in the poisoned people. Proliferation of cultured cells (including rat brain neurons and glia, fibroblasts, tumour cells) was depressed at 10(-4)-10(-3) M PA. We conclude that the intoxication of people poisoned with H. r. is due to the high content of the DHO-DH inhibitor PA.

Effects of leflunomide on the course of listeriosis in mice. Short communication.

The intensity of an infection with Listeria monocytogenes depends on the immunological stab1p4f the body. Impairment of the specific or unspecific defence can lead to severe and partly fatal complications such as meningitis or septicaemia. In a normal defence situation affected individuals are often not diagnosed because the infection appears as an unspecific indisposition. The new immunomodulator leflunomide (n-(4-trifluoro-methyl-phenyl)-5-methyl-isoxazol-4-carboxamide, CAS 75706-12-6, HWA 486) acts mainly as immunosuppressive. Therefore, the influence of leflunomide was investigated on the number of spleen bacteria in the first phase and on the lethality in both phases of mouse listeriosis. The infected mice were either in a normal defence state or in an immunocompromised situation, which was produced by injection of cyclophosphamide or by dextran sulfate. A treatment with leflunomide, 20 mg/kg i.p., twice daily over a period of 3 days, caused no change of the lethality compared with control mice. Likewise, combined administration of leflunomide and ampicillin produced no alteration of the lethal outcomes in comparison with the ampicillin medication alone, the latter being highly effective in any case. However, the number of spleen bacteria was significantly higher in the group with combined treatment than in the ampicillin group. In summary, the treatment with leflunomide most likely will cause no additional risk regarding an infection such as listeriosis, although in the case of an infection an increased care should be given to diagnostic and therapy.

Effects of (D-Ala2)methionine enkephalinamide in PMA-induced mouse ear edema.

The synthetic opioid peptide (D-Ala2) methionine enkephalinamide (DAMEA) was reported to be an extremely potent inhibitor of the "respiratory burst" of polymorphonuclear neutrophils (PMNs). In the present paper the activity of DAMEA was investigated in the PMA-induced mouse ear edema since there is strong evidence that reactive oxygen species (ROS) are involved in the pathogenesis of this inflammatory reaction. DAMEA inhibited PMA-induced mouse ear edema in a dose-dependent manner between 10(-6) and 10(-9) mol/ear. The well-known anti-inflammatory activity of narcotic analgesics could be explained partly by an inhibition of ROS production.

Alteration of structural order of human erythrocyte ghost membrane by glucocorticoids and the influence of the glucocorticoid receptor antagonist RU 486.

High-dose pulse glucocorticoid therapy has been used successfully in the clinic in severe pathological conditions for about 20 years. The mode of glucocorticoid action after administration of such megadoses is inexplicable up to now. It is supposed that some effects may be due to membrane alterations. In the present in-vitro experiments the effect of dexamethasone, of further glucocorticoids, and of the glucocorticoid receptor antagonist RU 486, on structural order of human erythrocyte ghost membranes was investigated by determining the steady-state fluorescence anisotropy of diphenylhexatriene (DPH). Dexamethasone was found to induce a significant decrease in membrane structural order at concentrations of about 10(-6) M in a concentration-dependent manner. We found a correlation between the uptake of dexamethasone by the ghost membranes and the decrease in the structural order. The other glucocorticoids tested, methylprednisolone and corticosterone, were also effective at concentrations of 10(-5) M or greater. We observed no change in membrane structural order with RU 486 up to a concentration of 10(-4) M. However, simultaneous incubation of RU 486 with dexamethasone caused a distinct interference of RU 486 with dexamethasone. Thus, the glucocorticoid-induced membrane perturbation, the possibility to inhibit it by RU 486, and the inactivity of the structurally related progesterone, refer to relatively specific binding sites for the glucocorticoids in the membrane of erythrocyte ghosts.

Megadose glucocorticoid therapy: investigations in rat anaphylactic shock and experimental allergic encephalomyelitis.

Glucocorticoids are the most potent antiinflammatory drugs. Large doses of dexamethasone and other glucocorticoids are widely used in the clinic but the mechanism of the beneficial effects of megadoses still remains to be explained. We tested the effects of a dexamethasone (DEX) megadose therapy in a rat model of anaphylactic shock. By combining DEX with the potent glucocorticoid receptor antagonist RU 486 we looked for evidence of a non-specific action of the glucocorticoid at high doses. A dose of 10 mg/kg DEX given 2 h before challenge protected the heart against the symptoms of cardiac anaphylaxis: heart rate was improved by 22%, ventricular contractility by 13% and coronary flow by 5%. Administration of 20 mg/kg RU 486, 30 min before dexamethasone, reduced the beneficial effect of DEX by about 30%, although this failed to reach statistical significance. We found no dose-response relationship for the high dexamethasone doses of 0.5-10 mg/kg. In experimental allergic encephalomyelitis (EAE) there was a surprising toxic action of DEX after daily doses of 0.25 mg/kg for 5 days, and also following single administration of 2.5 or 10 mg/kg. A single dose of 1.25 mg/kg, given on the day of immunization alone or with additional doses at weekly intervals for 3 weeks, caused a strong inhibition of the EAE. In summary we conclude that the present data of cardiac anaphylaxis hardly point to extra glucocorticoid megadose effects. The present dexamethasone effects in cardiac anaphylaxis and in EAE have to be cleared up by further experiments.

The plasma corticosterone level in rat 6-sulfanilamidoindazole arthritis and influence of RU 486.

The inflammatory reaction of the hindpaws inducible in rats by systemic administration of the sulfonamide 6-sulfanilamidoindazole (6-SAI) is characterized by a special tolerance reaction, i.e. the paw inflammation decreases despite a continued medication of 6-SAI. We found no change of the plasma corticosterone level in 6-SAI-dosed animals, neither at the beginning of 6-SAI administration nor when the inflammation reached maximal values nor during the remission of paw swelling. Thus, a presumed regulatory increase of the endogenous glucocorticoid concentration cannot be the reason for the spontaneous remission of this special inflammatory process. Administration of the receptor antagonist RU 486 caused an increased corticosterone plasma level by about 40% but had no significant influence on paw swelling.

A comparison of serotonin (5-HT) blood levels and activity of 5-HT2 antagonists in adjuvant arthritic Lewis and Wistar rats.

The total plasma 5-HT levels of adjuvant arthritic rats were increased in animals of both strains in comparison to healthy controls. The exception was day 1, when the 5-HT plasma level in arthritic Lewis rats was decreased by 77%, but only by 17% in Wistar rats. Treatment with the 5-HT2 receptor antagonist ritanserin caused a significant inhibition of macroscopic arthritis at day 14 in Lewis but not in Wistar rats. The total plasma 5-HT level was significantly decreased by the 5-HT2 antagonists in both strains at various times. 5-HT as an autacoid with effects on the T-lymphocytes and on delayed hypersensitivity reactions might be responsible, at least in part, for strain differences regarding the incidence of secondary lesions in rat adjuvant arthritis.

Phospholipase A2 inhibition by alkylbenzoylacrylic acids.

3-(4-Alkylbenzoyl)acrylic acids (ABAAs) were synthesized by acylation of alkylbenzenes with maleic anhydride and then screened in vitro for inhibition of phospholipase A2 (PLA2) from snake venom and from porcine pancreas. The inhibitory potency of ABAAs increased with the length of the alkyl residues resulting in IC50 values of between 10(-7) and 10(-4) mol/L. The most potent inhibitors of the snake venom PLA2 were the 4-(n)-hexadecyl and octadecyl (OBAA) derivatives. Kinetic experiments referred to a time-dependent inhibitory reaction. Irreversibility was examined by dilution and dialysis. A molar ratio of inactivation of OBAA of nearly 20 was estimated. Double reciprocal replots of the apparent inactivation constants to the concentration of OBAA gave a (pseudo) first order rate constant of inactivation of 2.3 min-1. For the dissociation constant of the enzyme-inhibitor intermediate, a value of 6 x 10(-6) mol/L was obtained. On the other hand, the PLA2 from porcine pancreas seemed hardly to be inhibited by ABAAs. The present data are discussed in relation to the proposed model for PLA2 inactivation by manoalide. In human PMNs leukotriene B4 and 5-HETE production was essentially reduced. In human platelets the thrombin-induced TxA2 production was reduced. Since these effects disappeared after addition of arachidonic acid, these findings refer to a PLA2 inhibition. The immunologically induced bronchospasm in guinea pigs was significantly and dose-dependently inhibited by OBAA. This indicates that ABAAs might be useful in treating allergic diseases, such as asthma, eczema, allergic shock and others.