Abstract. We classify, up to orbit equivalence, all cohomogeneity one actions on the hyperbolic planes over the complex, quaternionic and Cayley numbers, and on the complex hyperbolic spaces CH n , n ≥ 3. For the quaternionic hyperbolic spaces HH n , n ≥ 3, we reduce the classification problem to a problem in quaternionic linear algebra and obtain partial results. For real hyperbolic spaces, this classification problem was essentially solved byÉlie Cartan.

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We classify all totally geodesic submanifolds of connected irreducible Riemannian symmetric spaces of noncompact type which arise as a singular orbit of a cohomogeneity one action on the symmetric space.

The reduction of copper oxide thin films by a hydrogen plasma generated by an atmospheric-pressure glow (APG) discharge was investigated. The copper oxide films were prepared by heating the sputtered copper films to C in the air (heat-formed copper oxide) or by sputtering (sputtered copper oxide). Both films were composed of . The reduction occurs first on the surface, then the interface gradually shifts from the surface into the inner region and finally the whole layer is reduced to metallic copper. This process is approximately explained by assuming that the diffusion of the atomic hydrogen in the reduced layer is the rate-deyermining step. By transmission electron microscopic (TEM) observation, a layer of 3 - 5 nm thickness composed of many microcrystals was observed along the surface of the heat-formed copper oxide. After the APG hydrogen plasma treatment, the crystal layer disappeared and the crystalline lattice was re-arranged to form large crystal Cu grains.

Protein C inhibitor (PCI), a member of the serine protease inhibitor family, is produced in various human tissues, including the liver, kidney and testis. In addition to inhibiting the anticoagulant protein C pathway, PCI also inhibits urinary plasminogen activator (uPA), which is a well-known mediator of tumor cell invasion. In the present study, to clarify the biologic significance of PCI in the kidney, we compared the expression of PCI between human renal cell carcinoma (RCC) tissue and nontumor kidney tissue. The PCI antigen level in RCC tissue was found to be significantly lower than in nontumor kidney tissue, and expression of PCI mRNA was detected in normal renal proximal tubular epithelial cells (RPTEC), but not in RCC or in an RCC cell line (Caki-1 cells). Key words: protein C inhibitor; urinary plasminogen activator; renal cell carcinoma; tumor invasionProtein C inhibitor (PCI) was originally identified as an inhibitor of the anticoagulant protease, activated protein C, 1 and was subsequently found to inhibit other proteases involved in blood coagulation and fibrinolysis, such as thrombin, 2 thrombin-thrombomodulin complex, 3 factor Xa, 2 factor XIa, 4 plasma kallikrein 4 and urinary plasminogen activator (uPA). 5 Human plasma PCI is believed to be produced mainly by the liver, 6 but is also synthesized in the kidneys and the reproductive organs, including the testis, seminal vesicles and ovary. 7,8 Thus, besides its function in the regulation of blood coagulation, PCI may also play a role in the regulation of reproduction. Recently, Uhrin et al. 9 reported that PCI knockout male mice are apparently healthy but infertile, and that this infertility is caused by abnormal spermatogenesis induced by destruction of the Sertoli cell barrier. In the kidneys, PCI is mainly synthesized by proximal tubular epithelial cells, 10 and most urinary PCI is present in complex with uPA, 11 which it inhibits; hence, PCI is also referred to as plasminogen activator inhibitor-3 (PAI-3). However, the physiologic role of uPA inhibition by PCI in the urinary tract is unknown.It is known that metastasis and invasion of various tumor cells are mediated by uPA and its receptor. 12 uPA is inhibited by PAI-1 and PAI-2, 13 the former of which has been reported to be essential for regulation of tumor cell invasion and metastasis by promoting angiogenesis. 14,15 Previously, it was shown that the expression of uPA is lower, that the expression of uPA receptor is moderately higher and that the expression of PAI-1 is significantly higher in human renal cell carcinoma (RCC) than in nontumor kidney tissue. 16,17 Furthermore, Swiercz et al. 18 suggested that the expression of uPA, its receptor and PAI-1 correlate with the aggressive phenotype of RCC. These studies suggest the importance of the plasminogen activator system, including uPA, its receptor and PAI-1, in the process of RCC tumor cell invasion; however, there is no direct evidence yet that uPA regulates the invasiveness of RCC cells. It is also known that uPA and/or plasmin may ...