Polymorphonuclear leukocytes (PMNs) adherent to fibrinogen exhibit a delay in onset of respiratory burst reaction and a biphasic formation of diradylglycerol (DRG) in response to formyl-Met-Leu-Phe. The H₂O₂ release coincides with the second phase of DRG formation by activation of phospholipase D (PLD) . Propranolol and ethanol abolish both H₂O₂ release and the second wave of DRG formation. PLD-mediated generation of [³H] -phosphatidylethanol from [³H] -phosphatidylcholine (PC) corresponds to the second phase of DRG formation. Intracellular calcium chelation blocks the H₂O₂ release as well as the second DRG formation. Addition of ionomycin and synthetic DRG to the calcium dampening PMNs stimulated them to release H₂O₂, showing the importance of DRG derived from calcium-dependent PLD activation.
Accumulation of ceramide is observed in adherent PMNs when H₂O₂ release is terminated. The H₂O₂ release is suppressed by addition of exogenous free sphingoid amines and short chain ceramides. The inhibitory effects of N-acetyl-conjugated sphingols (C₂ ceramides) on PC-specific PLD and phosphatidate phosphohydrolase are markedly different from those of related sphingoid bases. C₂ ceramides demonstrate to inhibit oxidant release in stimulated PMNs. The effect of ceramide in respiratory burst is structurally specific, because either a 4, 5-trans double bond or 4-hydroxy group is required for the inhibition.
The oxidant release in adherent human PMNs is stimulated or inhibited through PLD pathway, suggesting the regulatory role of PLD in the respiratory burst reaction.

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Interference with either keratinocyte-keratinocyte adhesion or epidermal basement membrane zone develops skin lesions in autoimmune bullous skin diseases by autoimmune mechanisms. The most important machinery for the cell-cell adhesion and dermo-epidermal adhesion is the desmosome and hemidesmosome, respectively.
Recent studies using cDNAs for the constituent proteins of the desmosome and hemidesmosome have revealed that these proteins are actually the autoantigens in various autoimmune skin diseases. In addition, several new disease entities with distinct clinical and immunological features have recently been proposed. Characterization of the autoantigens is also important for the diagnosis of these diseases. Further studies using the biochemical and molecular biological techniques should provide us with more information about the pathogesis and develop various novel methods in both diagnostic and therapeutic standpoints in this group of disease.

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We found that hyposmotic conditions rapidly induce human neutrophil apoptosis. In an attempt to define the molecular events involved in neutrophil apoptosis, we investigated the effect of protein kinase inhibitors and a protein synthesis inhibitor. Neutrophils undergoing apoptosis induced under different conditions (i.e, aging, hyposmotic conditions, and TNFα) exhibited various responses to these inhibitors suggesting that a variety of distinct molecular events occur in neutrophil apoptosis induced by different stimuli.
On the other hand, we also found that activated neutrophils with phorbol 12-myristate 13-acetate (PMA) showed morphological changes quite different from those of typical apoptosis or necrosis due to oxygen radicals (especially hydroxyl radical) produced by neutrophil itself through PKC activation. A certain population of neutrophils phagocytosing opsonized zymosan also showed changes similar to those observed in PMA treated cells. Although the precise biological implication of the hyperactivation induced cell suicide is unclear, a variety of distinct molecular events characteristic of human neutrophil apoptosis may contribute to prevent prolongation of inflammation by eliminating unwanted cells.

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Gene mutations of Cu/Zn superoxide dismutase (SOD) have been discovered in familial amyotrophic lateral sclerosis (ALS) . Oxidative stress also plays a role in the pathogenesis of sporadic ALS. Whether antioxidant therapy is beneficial in this fatal disease is now crucial. We have shown that phosphatidyl choline-bound Cu/Zn SOD (PC-SOD) treatment improves neuromuscular dysfunction and morphological changes in wobbler mouse motor neuron disease. Progressive spinal motor neuronopathy and axonopathy, predominantly in the cervical cord, occur at postnatal age 3-4 weeks, leading to muscle weakness and contracture of the forelimbs in this animal. These motor deficits rapidly increase by postnatal age 6-8 weeks, and then slowly progress.
Wobbler mice were given two doses daily of PC-SOD, unmodified SOD (10⁴, 10⁵ U/kg, respectively) or a vehicle solution by intraperitoneal injection from postnatal 3-4 to postnatal 7-8 weeks of age. PC-SOD, but not unmodified SOD treatment attenuated progression of motor dysfunction, prevented denervation muscle atrophy, and delayed degeneration of spinal motor neurons in wobbler mice. Intraperitoneally administered PC-SOD was significantly transferred into the spinal cord, as compared with unmodified SOD.
This raises the possibility that PC-SOD may have therapeutic potential in human motor neuron disease or ALS.

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We measured levels of 11-dehydro-thromboxane B₂ (11DT) and 2, 3-dinor-6-ketoprostaglandin F_1α (23D6) in samples of urine collected at rest early in the morning from 72 normal children (36 boys and 36 girls), ranging in age from 1 to 18 years. Prostaglandins (PGs) were extracted from acidified sample by octadecylsilyl silica (Fuji Gel, Tokyo) suspension. After deproteinization and defattation were performed, PGs were eluted by ethylacetate. Then the dried residue containing PGs were fractionated by silica minicolumn BOND ELUT Si (Varian, Harbor City, Calif.) . We assayed PGs using RIA method.
No significant sex-related differences were observed in urinary 11DT or 23D6 levels. Urinary levels of 11DT and 23D6 were significantly high during the latter half of infancy (between 1 and 3 years after birth), and they tended to decrease gradually with age thereafter, without showing any further particularly marked change until puberty.
11DT and 23D6 are major metabolites of thromboxane A₂ (TXA₂) and prostaglandin I₂ (PGI₂) eliminated by way of urine, respectively. Their levels in urine are promising as indicators of systemic TXA₂ and PGI₂ production and replace the place of plasma prostanoid levels, a less reliable indicator conventionally used.

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The antinephritic effect of Butein on original-type anti-GBM nephritis in rats was investigated. Butein was given to original-type anti-GBM nephritic rats for 15 days from the day of anti-GBM serum injection.
Butein prevented urinary protein excretion on 1, 11 and 15 days. Histopathological observations of the glomeruli indicated that although the number of nuclei and adhesion of capillary walls to Bowman's capsule in nephritic control rats were significantly increased, butein reduced the degree of histopathological changes such as hypercellularity and adhesion as compared to the control rats. Although the expression of intercellular adhesion molecule-1 (ICAM-1) in the nephritic glomeruli was significantly greater than that in normal rats on 5 days, the increase of ICAM-1 expression was suppressed by butein.
In vitro studies, butein inhibited the up-regulation of ICAM-1 on the surface of cultured endothelial cells in response to tumor necrosis factor-α or phorbol 12-myristate 13-acetate (PMA) .
These results suggest that antinephritic action of butein is due to the suppression of the intraglomerular infiltration of leukocytes through the inhibition of the up-regulation of ICAM-1 expression in nephritic glomeruli.

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We have previously reported that blockers of acylation of lyso-PAF, such as triacsin C or merthiolate, enhanced PAF production in the stimulated rat neutrophils. The present study demonstrated that pretreatment with triacsin C or merthiolate enhanced the arachidonic acid release by 2 to 3-fold in rat neutrophils when stimulated with opsonized zymosan, Ca-ionophore A23187 or phorbol myristate acetate.
From these results we conclude that the release of arachidonic acid from rat neutrophils may also be controlled by acylation pathway in addition to the activation of phospholipase A₂.

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