ABSTRACT. Type XV and type XVIII collagens are classified as part of multiplexin collagen superfamily and their C-terminal parts, endostatin and restin, respectively, have been shown to be anti-angiogenic in vivo and in vitro. The α1(XV) and α1(XVIII) collagen chains are reported to be localized mainly in the basement membrane zone, but their distributions in blood vessels and nonvascular tissues have yet to be thoroughly clarified. In the present study, we raised monoclonal antibodies against synthetic peptides of human α1(XV) and α1(XVIII) chains and used them for extensive investigation of the distribution of these chains. We came to the conclusion that nonvascular BMs contain mainly one of two types: subepithelial basement membranes that contained type XVIII in general, or skeletal and cardiac muscles that harbored mainly type XV. But basement membranes surrounding smooth muscle cells in vascular tissues contained one or both of them, depending on their locations. Interestingly, continuous capillaries contained both type XV and type XVIII collagens in their basement membranes; however, fenestrated or specialized capillaries such as glomeruli, liver sinusoids, lung alveoli, and splenic sinusoids expressed only type XVIII in their basement membranes, lacking type XV. This observation could imply that different functions of basement membranes in various tissues and organs use different mechanisms for the endogenous control of angiogenesis.Key words: basement membrane/type XV collagen/type XVIII collagen/capillary/smooth muscle cellThe collagen family, which consists of 20 collagen types and 38 collagen α-chains (Myllyharju and Kivirikko, 2001), are known to be major components of connective tissues and/or basement membranes (BMs). They not only serve as scaffolds for tissues and organs but also are involved in various biological events such as development, morphogenesis, inflammation, tissue repair, and filtration, as well as in various pathological processes (Olsen and Ninomiya, 1999).The BM, lying beneath epithelia and around muscle, adipose, and Schwann cells, and made visible by the periodic acid-Schiff reaction under light microscopic observation, is composed mainly of type IV collagen, laminin, nidogen, and heparan sulfate proteoglycan. Multiple components of these materials have been reported to comprise BMs in a tissue-specific fashion. For instance, six α(IV) collagen chains have been identified and at least three molecular forms distribute in various BMs‫ (ޓ‬Hudson et al., 1993;Sado et al., 1998). One form, α3/α4/α5, is specifically present in BMs where it functions as a permeability selective barrier such as in the BMs in glomerulus in kidney and alveolus in lung Saito et al., 2000). Such findings suggest the possibility that the composition of collagen IV molecules in various tissues corresponds with specific biological *To whom correspondence should be addressed: Ichiro Naito, Ph. D., Division of Ultrastructural Biology, Shigei Medical Research Institute, 2117 Yamada, Okayama 701-0202, Japan.Tel: +...

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Prolidase deficiency occurred in a 13-year-old girl. Determinations were made of prolidase and prolinase activities in cultured fibroblasts, and thin layer chromatographic studies of skin prolidase were performed. The patient had chronic, recurrent ulcers on the legs and feet, diffuse telangiectasia, shallow scar-like atrophic lesions on the face and arms, soft and thin abdominal skin, and premature gray hairs. Prolidase in the patient's skin fibroblasts was absent. Greatly reduced prolidase activity was demonstrated in the patient's skin. A review of hitherto reported cases of this disease showed such skin manifestations as (1) skin ulceration or skin fragility with scar formation, (2) purpuric lesions, (3) telangiectasia and/or photosensitivity, and (4) thickening of the skin with lymphedema.

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