Spin trapping is powerful technique to detect oxygen radicals (O₂^-/^⋅O₂H and ^⋅OH) since these radicals have very short life. The free radical reacts with a spin trap to produce a more stable radical adduct, which can be measured by electron spin resonance (ESR) spectroscopy. Nitrones, such as DMPO (5.5'-dimethyl-1-pyrroline N-oxide), PBN (α-phenyl N-tert-butylnitrone) and POBN (α-pyridyl-l-oxide N-tert-butylnitrone), are used as spin traps because of relatively high solubility in water and stability of the radical adducts, though they are not necessarily ideal reagents. Oxygen radical adducts of nitrones have finite life time, especially their ^⋅O₂H adducts decay within several minutes in water, while the carbon centered radical adducts are sufficiently stable. Practical suggestions on the advantage and disadvantage of these spin traps are presented. Recent applications of this technique on the action mechanism of antitumor agents and the initiator of lipid peroxidation are also reviewed. It is clearly revealed that quinoid antitumor mediated ^⋅OH causes significantly DNA degradation and metal ion plays important role in the ^⋅OH generation (Fenton's reaction) . On the other hand, ^⋅OH, which is produced during the enzymatic reduction of a mixture of Fe³⁺-ADP-phosphate complex and adriamycin or of Fe³⁺-ADP-EDTA complex, induces no lipid peroxidation.

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The lymphocytes in the synovial tissues of patients with rheumatoid arthritis (RA) showed a cytotoxic activity against synovial cultured cells taken from patients with RA, in a similar extent to that of normal peripheral lymphocytes. However, the activity was weaker than that of polymorphonuclear leukocytes in synovial fluids of RA patients. In addition, the synovial lymphocytes of RA patients showed the natural killer activity against K 562 cells which were higher than that of normal peripheral lymphocytes and also ADCC activity which was similar to that of normal peripheral lymphocytes.

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Buffalo (BUF) rats of an adjuvant-arthritis low responder strain (a 39% incidence) responded to subcutaneously and intravenously injected dextran to a more intensive degree, as compared to F 344 rats which were highly susceptible to adjuvant arthritis (a 100% incidence) . Six days after subcutaneous implantation of coverslips, the newly formed granulation tissue was found in F 344 rats, but scarcely in BUF rats. Multinucleated giant cells, together with lymphocytes and mononuclear cells, appeared frequently on the surface of the implanted coverslips in BUF rats, while clusters of polymorphs as well as other blood and tissue cells were predominant in F 344 rats. Levamisole, cyclophosphamide and D-penicillamine enhanced significantly the incidence and severity of adjuvant disease in BUF rats only when administered daily for 3 days starting from one day before adjuvant injection or daily for 5 days from the day of injection. Administration of carbon particles, alginate and other substances failed to produce any significant enhancement of the disease onset in the adjuvant-injected animals of this strain. However, swelling in the adjuvantinjected hind foot continued to increase for a long time, and responded rapidly to administered anti-inflammatory drugs. The present communication discusses a possible important role of macrophages in the inflammatory lesions induced in BUF rats.

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Granules were isolated from sonicated rat mast cells on a Percoll gradient and incubated with [γ ³²P] ATP in the presence of Mg²⁺. After stopping the reaction, lipid extraction of the intact membrane granules was performed with acidic medium and phospholipids were separated by thin layer chromatography on 1% (w/v) oxalic acid and potassium oxalate impregnated silica gel plates. Considerable amounts of radioactivity were found to be incorporated into DPI. The radioactivity in DPI was associated with the granule themselves and not detected in the granule supernates. Extensive washing of the granules did not significantly affect DPI formation and areas of the Percoll gradient containing cytosol fraction had no demonstrable DPI forming activity and did not increase the response when added back to the granules. When suspensions of intact and broken membrane granules which contained approximately equivalent amounts of granule membrane proteins were compared with respect to DPI formation, broken membrane granule preparations were found not to exceed in DPI production than intact membrane granules, suggesting that DPI formation is occuring on the cytoplasmic side of granule membranes.

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Lobenzarit disodium (CCA) showing an electron donating and an anti-oxidative activity was synthesized from the aspect of quantum chemistry using simple LCAO MO method of π electrons in our research laboratories. CCA showed a quenching action against active oxygen-induced weak chemiluminescence. CCA and also levamisole scavenged hydroxyl radicals in the Udenfriend system. From the above-mentioned results, CCA was examined in the model of acute fatty liver of ethanol-treated rats in comparison with DPPD, a famous anti-oxidant. They inhibited the onset of this disease. It would be worthwhile to investigate if CCA affects immune responses or not, because of a reason that immunopotentiators and -modulators such as vitamin A, vitamin E or levamisole also have anti-oxidative and/or radical scavenging actions.

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Non-steroidal antiinflammatory drugs (NOSAID) produce the gastric mucosal lesions by inhibiting prostaglandin (PG) synthesis in the gastric mucosa. We tested the ulcerogenicity and the potential of PG inhibition with tiaprofen and indomethacin in a same antiinflammatory dose (ED₅₀ on the carrageenin-induced foot edema) in rats. The animals were intragastrically given tiaprofen three times before sacrifice in a dose of 6 mg/kg or indomethacin in a dose of 4 mg/kg. Endogenous PGE₂ and prostacyclin in fundic and antral mucosa were determined by radioimmunoassay. Tiaprofen (3 times of 6 mg/kg, i.g.) is less potent than indomethacin (3 times of 4 mg/kg, i.g.) to produce the gastric mucosal lesions (ulcer index, 6.6±1.0 vs. 20.6±2.9, significantly different at P<0.005) . Gastric mucosal PGE₂ is completely decreased in a same degree by either tiaprofen or indomethacin. However, the decrease of mucosal prostacyclin is significantly (fundus; P<0.025, antrum; P<0.005) less in tiaprofen-treated rats than in indomethacin treated one. These results suggest that the ulcerogenicity of tiaprofen is less potent than indomethacin, and this difference may cause from the mucosal prostacyclin levels.

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Effects of methyl-B₁₂ on the inflammation induced by CdCl₂ in the testis of rats, in which a remarkable increase of oxidative reaction was observed, were investigated. The results are summarized as follows: 1) Serum enzyme activities, i.e., Al-p, LDH, GOT, GPT, did not show any change by the premedication of methyl-B₁₂. 2) Hemorrhage, the damage of blood vessel epithelia and the migration of wondering cells in the testis were reduced markedly by the premedication of methyl-B₁₂. 3) The increase of Ca contents in the rat testis induced by CdCl₂ was also supressed significantly by the premedication of methyl-B₁₂. These suggest that methyl-B₁₂ has anti-inflammatory effect against the hemorrhagic inflammation in the testis of rat administered CdCl₂.

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In a dermatological experiment, the plasma and tissue levels of zinc in rats undergoing healing of artificially created wounds was investigated. In groups of animals not pretreated with zinc, tissue and plasma zinc concentrations showed no appreciable changes during the initial stage of inflammation, then increased at the climax of local inflammatory reaction, with noticeable elevation in the injured skin as well, but returned to initial levels as epidermal regeneration took place with increased collagen synthesis. In rats pretreated with zinc, local inflammatory reactions were less intense, together with a hastening of the healing process to cutaneous regeneration. These animals demonstrated low tissue and plasma zinc levels during inflammation despite pretreatment with zinc, and there was a gradual accumulation of zinc in their organs as epidermal regeneration progressed. The results indicate the necessity for zinc in the healing process of wounds, and points out the decreased duration of the healing process when zinc is utilized.

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