Background and Purpose-A disordered proliferative process in the vascular wall is thought to underlie the pathogenesis of restenosis after percutaneous transluminal angioplasty and carotid endarterectomy. A growth inhibitory property of overexpressed prostacyclin (PGI 2 ) synthase (PGIS) was recently implicated in the pathological proliferation of vascular smooth muscle cells (VSMC) in vitro. Here, we investigated the effects of increased PGI 2 synthesis on the pathological proliferation of VSMCs. Methods-The cDNA encoding human PGIS was transfected into endothelium-denuded rat carotid arteries after arterial balloon injury with the use of hemagglutinating virus Japan (HVJ). HVJ liposome vector complex without PGIS cDNA was used for vehicle control. The level of 6-keto PGF 1␣ , a stable hydrolyzed metabolite of PGI 2 , the histological distribution of the immunoreactivity for human PGIS and the ratio of neointimal/medial area were analyzed. Results-In the analyses of 6-keto PGF 1␣ , the level in the carotid arteries was significantly elevated 3 days after PGIS expression-vector transfection compared with that in the arteries after vehicle transfection. Seven days after human PGIS expression-vector transfection, the PGIS cDNA-transfected neointimal cells were strongly positive for human PGIS immunoreactivity in 81% sections examined. Fourteen days after the injury, the ratio of neointimal/medial area was 1.2Ϯ0.4 in the PGIS expression-vector transfected group, which was significantly smaller than that of the vehicle control group, 1.7Ϯ0.5; PϽ0.01. Conclusions-It was thus demonstrated that the gene transfer of human PGIS expression-vector into rat carotid arteriesresulted in the increased production of human PGI 2 in the vascular wall, the expression of human PGIS in the developing neointima and significantly inhibited the neointimal formation generated after balloon injury. (Stroke. 1999;30:419-426.)Key Words: carotid arteries Ⅲ genes Ⅲ prostacyclins Ⅲ stenosis Ⅲ rats T he principal contributor to the pathogenesis of cerebral and myocardial infarction is the developing atherosclerosis. The process of atherosclerosis involves a chronic inflammatory response to the injury in the arterial wall, leading to a dysfunction of endothelial cells, the migration and activation of macrophages, and the proliferation of vascular smooth-muscle cells (VSMC). 1 The complex of inflammatory and fibroproliferative processes is manifested as intimal hyperplasia or the formation of fibrous plaques. Similar inflammatory and proliferative processes in the vascular wall are thought to underlie the pathogenesis of restenosis after percutaneous transluminal angioplasty (PTA) and carotid endarterectomy (CE). [2][3][4][5][6] A neointima formation after balloon angioplasty involves a complex interaction between numerous growth-regulatory See Editorial Comment, page 426 molecules that promote the migration and proliferation of VSMC. 2 Possible neointima-generating molecules include thrombin, platelet-derived growth factor (PDGF), basic fibrob...

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A rapid progress made for ultrathin sectioning technique in electron microscopy has contributed much to the analysis of microbial cell structures. Recently, several papers (3,(7)(8)(9)17,18,23) have appeared on the subject of electron microscopic studies of certain dermatophytes, and the structural details of fungal cells have been exposed to some extent through electron microscopy of ultrathin sections. However, the published electron micrographs of the organism, especially those in its early stage, were not of sufficient quality to reveal the detail architectures of the fungus. Moreover, the findings of the cell structures hitherto obtained have not been always agreeable among workers, and many problems of the fine structures of the organism still remained to be studied.Since Watson (1958)(25,26) succeeded in enhancing the contrast and resolution in thin sections of biological materials, using stain technique with heavy metals, several modifications(4,10,16) of his method have been reported, and these electron-opaque stains have been widely applied to tissue sections for electron microscopy. Vitols, North and Linnane (1961)(24) first reported that uranyl nitrate treatment of the whole cells of Saccharomyces cerevisiae after permanganate fixation leads to better preservation of the membrane structures and also to an improvement in general contrast. This paper describes some of the fine structures of Trichophyton mentagrophytes as observed chiefly by staining the thin sections of fungus cells with various heavy metals. MATERIALS AND METHODSOrganism employed: A stock culture of Trichophyton mentagrophytes, strain J-812, maintained on a glucose peptone agar at 27 C, was used. This strain was obtained from Dr. T. Tsuchiya, Professor of Juntendo University School of Medicine.Culture media employed: The medium mostly used was a glucose (1 per cent) peptone (1 per cent) water adjusted to pH 5.6.Electron microscopy of thin sections : Hyphal pellets of the strain grown on the medium for 5 to 7 days at 27 C were harvested by centrifugation and washed with sterile veronal-acetate buffer solution several times. These pellets of about 1 to 2 mm in diameter were fixed in 1 per cent osmium tetroxide solution, or 2 per cent potassium permanganate buffered at pH 6.99 with veronal-acetate buffer, for 24 hr at 4 C.

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