Effects of various substances on two types of inflammatory reaction in animals

Dissociation between antiinflammatory action of tilorone and its interferon inducing activity

A relation between antiinflammatory action of tilorone and its interferon inducing activity was studied in rats. Tilorone (20-100 mg/kg, p.o.) was dose-dependently effective on both carrageenin oedema and passive Arthus, suggesting that the pharmacological property of the compound is different from nonsteroidal antiinflammatory medicaments which were weak inhibitors of passive Arthus. The antiinflammatory action of tilorone had a time-lag and priming with tilorone 24 hrs prior to inflammatory insult was required to demonstrate maximal efficacy. This time course change was similar to that of serum interferon level. In addition, a high correlation was observed between the antiinflammatory activity and the serum interferon level. However, the antiinflammatory action was scarcely affected even if the serum interferon level was remarkably lowered by treatment of an inhibitor of protein biosynthesis, cycloheximide. These findings suggested that the antiinflammatory action of tilorone could be dissociated from its interferon inducing activity.

Modulation of immune responses in mice by oral administration of niflumic acid

The in vivo effects of non-steroidal anti-inflammatory drugs (NSAIDs) on the host immune system are still poorly understood. However, through inhibition of prostaglandin synthesis, NSAIDs may exhibit immunomodulating properties. The present work was aimed at evaluating the influence of niflumic acid on immune responses when administered orally for 7 consecutive days to 8-week-old inbred mice. Immunological tests were performed 24 h after the arrest of the treatment. At a dosage of 50 mg/kg/day, niflumic acid exerted noticeable immunostimulating effects, as shown by an increase in plaque-forming cell numbers after in vivo immunization with sheep red blood cells, an augmentation of spleen cell proliferation responses to stimulation with T- or B-cell mitogens and of T-cell cytotoxic response to allogenic cells. Phagocytosis-induced chemiluminescence of peritoneal macrophages was also enhanced whereas interleukin-1 production by these cells was depressed, but without concomitant modification in interleukin-2 production by T-cells. Increasing the niflumic acid dosage to 75 mg/kg resulted in the disappearance of the immunostimulatory effects on lymphocytes responses. Macrophage activities were affected similarly in mice receiving 50 mg/kg. These results demonstrate that niflumic acid is able to stimulate in vivo several immunological functions and, consequently, to maintain host immune defenses. Interestingly, it depressed interleukin-1 production, known to play a major role in the inflammatory process.

Anti-inflammatory drugs modulate histamine release from mast cells induced by fibrinogen degradation products

The products resulting from proteolytic degradation of human fibrinogen (FDP) were found to induce the release of histamine from rat peritoneal mast cells. Low molecular weight, dialysable peptides (FDP) showed the highest dose dependent, histamine releasing activity. Histamine release induced by FDP was effectively inhibited by the gold compound auranofin at a concentration of 10(-5)-10(-7) mol/l and also by the non-steroidal anti-inflammatory drugs BW 755c, timegadine, medosan, naproxen, and aspirin at the higher concentration range of 10(-4)-10(-6) mol/l. It is concluded that the release of histamine from mast cells may be modulated to some extent by anti-inflammatory drugs, especially auranofin, BW 755c and timegadine, a functional property which may be beneficial in the management of joint disease.

On two paradoxical side-effects of prednisolone in rats, ribosomal RNA biosyntheses, and a mechanism of action

Liver enlargement and muscle wastage occurred in Wistar rats following the subcutaneous administration of prednisolone. In the liver both the content of RNA and the biosynthesis of ribosomal RNA increased while both the RNA content and ribosomal RNA biosynthesis were reduced in the gastrocnemius muscle. It is suggested that the drug acted in a selective and tissue-specific manner to enhance ribosomal RNA synthesis in the liver and depress such synthesis in the muscle. This view supports the contention that the liver and muscle are independent sites of prednisolone action.

Effect of rat and beta-human interferons on hyperacute experimental allergic encephalomyelitis in rats

Human interferon-beta (human IFN-beta) and rat interferon (rat IFN) were evaluated on experimental allergic encephalomyelitis (EAE) in rats, a delayed cellular reaction resembling human multiple sclerosis (MS). Rat IFN was active by intravenous and intracerebroventricular routes. It decreased the severity of clinical symptoms of paralysis during the 22 days of the assay. Human IFN-beta, on the contrary, had no effect when similarly tested in this rat model. Cyclophosphamide delayed the onset of paralysis, but levamisole enhanced the severity of the EAE.

Auranofin. A preliminary review of its pharmacological properties and therapeutic use in rheumatoid arthritis

Auranofin is the first orally active gold compound for the treatment of rheumatoid arthritis. Like other chrysotherapeutic agents, its exact mechanism of action is unknown, but it probably acts via immunological mechanisms and alteration of lysosomal enzyme activity. Although long term clinical experience with auranofin is limited, its efficacy appears to approach that of sodium aurothiomalate. Further comparative studies with aurothioglucose, hydroxychloroquine and D-penicillamine are required before definitive statements can be made regarding the relative efficacy of auranofin and these agents. While patients have demonstrated clinical remission of rheumatoid arthritis in response to auranofin therapy, radiological studies have been inconclusive regarding its effect on the occurrence or progression of erosive lesions. Auranofin is relatively well tolerated in most patients, but diarrhoea, skin rash, and pruritus are sometimes troublesome, and thrombocytopenia and proteinuria are potentially serious side effects which may occur during therapy. Whereas mucocutaneous side effects are more frequent with injectable gold compounds, gastrointestinal reactions are the most common adverse effect seen with auranofin. The frequency of side effects has been similar with auranofin and sodium aurothiomalate, but they are generally less severe with auranofin. While some of the side effects are controlled by a reduction in dosage, temporary or permanent withdrawal of auranofin may be necessary. Auranofin is clearly a useful addition to the limited list of agents with disease-modifying potential presently available for the treatment of rheumatoid arthritis. It will doubtless generate much interest as its final place in therapy becomes better defined through additional well-designed studies and wider clinical experience.