In acute inflammatory responses, a series of adhesive interactions occurs consecutively between circulating leukocytes and vascular endothelial cells of inflamed tissues. Recent studies have demonstrated that this leukocyte-endothelial adhesion cascade is mediated by a number of adhesion molecules and that the controlled inhibition of the adhesion cascade results in significant suppression of inflammatory and/or immune responses. Here we summarize our own attempts in such antiadhesion therapy in various experimental animal models and discuss its potential, limitation and future perspective.

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Rat peritoneal mast cells purified on a Percoll gradient were challenged with different concentrations of substance P (SP), and the effect of 8-methoxypsoralen (8-MOP) plus long-wave ultraviolet light (UVA) irradiation (PUVA) on SP-induced histamine release from the cells was investigated. SP at a concentration of 10^-5 mol/l caused a significant histamine release with a significant increase in intracellular calcium concentrations ( [Ca²⁺] _i) . 8-MOP or UVA irradiation alone at doses used in the present study induced no histamine release from the cells, and showed no significant effects on the SP-induced histamine release from the cells. On the other hand, PUVA inhibited the SP-induced histamine release in a dose-dependent manner of UVA at doses from 0.5 to 3.0 J/cm² in parallel with the reduction of [Ca²⁺] _i. These data suggest that PUVA inhibits histamine release from SP-activated rat peritoneal mast cells through the suppression of [Ca²⁺] _i.

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Platelet-derived adherence-inhibiting factor (AIF) has been known to regulate the neutrophil binding to type IV collagen through the competitive inhibition of the binding. However, it has been not clear whether AIF affects the neutrophil adherence to endothelial cells. In this study, we have examined the effect of AIF on neutrophil adherence to confluently-cultured human umbilical vein endothelial cell monolayers (HUVEC) . AIF inhibited neutrophil adherence to resting, TNF-α- or thrombinstimulated HUVEC by about 54%, 44%, 75%, respectively. When the AIF-binding sites of HUVEC were estimated using ¹²⁵I-AIF, resting endothelial cells have about 2500 sites/cell, and the binding sites were increased up to about 9300 or 3400 sites/cell, respectively, after stimulation with TNF-α or thrombin. To analyze the AIF-binding proteins, resting, TNF-α or thrombin-stimulated HUVEC were surface-labeled with ¹²⁵I, and the extracts were chromatographed on AIF-affinity columns. Western blot analysis of the radio-active fractions from the columns revealed that E-selectin and P-selectin molecules were upregulated in stimulated HUVEC. These above observations suggest the possibility that AIF binds to E-and P-selectins of endothelial cells, and regulates neutrophil adherence to endothelial cells.

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Objective : In order to investigate the dynamics of PTHrP in the patients with rheumatoid arthritis (RA), we measured the PTHrP levels in serum, synovial fluid, and immunohistochemically examined the expression of this peptide in joint tissues including synovial and bony tissues in destructed regions.
Method : Serum, synovial fluid and joint tissues were taken at operation of total knee replacement from the patients who met the criteria of RA proposed by ACR in 1987. Total number of RA patients was 12. As controls, we used 3 cases of osteoarthritic (OA) patients. PTHrP levels in serum and joint fluid were measured by radioimmunoassay. Immunohistochemical study was performed using anti-PTHrP antibody which was made by immunization of synthetic peptide of PTHrP.
Result : PTHrP levels in RA was 54.2±33.4 (pMO1/1), while 50.5±15.2 in OA cases. PTHrP levels in synovial fluid was 183.2±77.8, while 86.4±35.3 in OA cases. There were no positive or negative correlations between PTHrP in serum and synovial fluid and major laboratory data such as blood sedimentation ratio (BSR), c-reactive protein (CRP) in serum.
Many kinds of cells such as osteoclast and osteoblast neighboring to deteriorating bony tissues, synovial cells in superficial layer, macrophage in deeper layer, and endothelial cell in blood vessels, demonstrated PTHrP. In comparing the inflammatory grade of synovial tissues with PTHrP level in the synovial fluid, the severer the inflammatory grade, the higher the level of PTHrP.
Conclusion : PTHrP was expressed in RA patients, probably suggesting some relation with inflammation including bony destruction or regeneration.

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Stimulation of rat peritoneal macrophages by the endomembrane Ca²⁺-ATPase inhibitor thapsigargin, or by the protein kinase C activator 12-O-tetradecanoylphorbol 13-acetate (TPA), enhanced the production of cell-associated plateletactivating factor (PAF) and extracellular prostaglandin E₂ (PGE₂) . Both the thapsigargin-and the TPA-induced PAF production were further enhanced dose-dependently by the cyclooxygenase inhibitor indomethacin in accordance with the decrease of PGE₂ production. The addition of exogenous PGE₂ counteracted the enhancing effect on PAF production by the cyclooxygenase inhibitors indomethacin, naproxen, and ibuprofen. In addition, dibutylyl cAMP also lowered the indomethacin-induced increase of PAF production. On the other hand, PAF acetylhydrolase activity in the cells was not inhibited by indomethacin treatment. These findings suggest that the stimulation of PAF production by the cyclooxygenase inhibitor is due to the inhibition of PGE₂ production, but not due to the inhibition of the degradation of PAF by PAF acetylhydrolase.

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To clarify the mechanism of action of 5- [4- (2-carboxyethylcarbamoyl) -phenylazo] -salicylic acid disodium salt dehydrate (BX661A) as a therapeutic drug for ulcerative colitis, we investigated the effects on carrageenin edema, adjuvant arthritis, polymorphonuclear leukocyte (PMN) chemotaxis and degranulation of mesenteric mast cell, and following results were obtained.
1. Although BX661A, salazosulfapyridine (SASP), 4-aminobenzoyl-β-alanine (4-ABA) and sulfapyridine (SP) did not inhibit the carrageenin edema at pretreatment for 30 min, BX661A and SASP showed the inhibitory effect on carrageenin edema at pretreatment for 8 hrs.
2. SASP showed the slight therapeutic effect on adjuvant arthritis, but BX661A and 5-aminosalicylic acid (5-ASA) had no effect.
3. BX661A, SASP and SP dose-dependently inhibited the PMN chemotaxis induced by zymosan-treated serum, N-formyl-methionyl-leucyl-phenylalanine (FMLP) and leukotriene B₄ (LTB₄) . 4-ABA only inhibited the FMLP-induced chemotaxis. On the other hand, 5-ASA at concentration up to 10 mM exhibited almost no effects on all PMN chemotaxis.
4. BX661A, SASP and SP dose-dependently inhibited the mast cell degranulation induced by compound 48/80, substance P and IgE. 5-ASA showed the inhibitory effects on compound 48/80 and IgE-induced mast cell degranulation, but 4-ABA only inhibited the IgE-induced degranulation.
From these results, it was suggested that inhibitory effect of BX661A on carrageenin-induced edema may be due to 5-ASA, further that inhibitory effects on PMN chemotaxis activity and degranulation of mesenteric mast cell partially may be concerned in therapeutic effects of BX661A on ulcerative colitis.

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Blood, liver cytosol and nuclear levels of a synthetic glucocorticoid, betamethasone were measured by the specific radioimmunoassay after administration to rats. Betamethasone receptor in liver cytosol was also measured by the ³H-betamethasone binding assay.
Betamethasone levels in blood and liver cytosol reached peak levels 1 hour after oral administration and then decreased gradually. Nuclear betamethasone reached peak levels slightly later, compared to blood and cytosol betamethasone peaks. Betamethasone receptor in liver cytosol decreased in reversed relation to the increase in the nuclear betamethasone level.
Glucocorticoid receptor mRNA levels, in cultured HeLa cells were only marginally suppressed by cortiso1 10^-5M, while prednisolone and dexamethasone suppressed glucocorticoid receptor mRNA levels to 67% and 57% of the initial levels, respectively.
Dynamic changes in tissue levels of the orally administred glucocorticoids as well as the changes in glucocorticoid receptor and its mRNA expression may give insight into the understanding of the molecular mechanism of antiinflammatory glucocorticoid actions.

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