Purpose: Tissue inhibitors of metalloproteinases (TIMPs) are crucial for the maintenance of retinal extracellular matrix such as interphotoreceptor matrix and internal limiting membrane. This study is to examine whether retinal cells respond to mechanical stretching and produce TIMPs. Methods: Chick retinal adherent cells in near confluency were exposed to mechanical stretching of the bottom of a 6-cm Petri dish at the maximum magnitude of 4,500 microstrain and at a cycle of 30 s for 72 h. TIMP-1 and TIMP-2 levels in the medium at 24, 48 and 72 h after the beginning of stretching were measured by enzyme immunoassay, and their expression was examined by immunohistochemistry. Results: The number of retinal cells during the 72-hour period of stretching did not change significantly both in the stretched group and in the nonstretched control group. Retinal cells in the stretched group produced significantly larger amounts of TIMP-1 and TIMP-2 at 48 h after stretching, compared with nonstretched controls (p = 0.0163 and p = 0.047, respectively, Mann-Whitney U test). Immunohistochemically, a large part of retinal cells in nonstretched Petri dishes was positive for glial fibrillary acidic protein, indicative of glial cells, while some small foci of cells were positive for neuron-specific enolase, indicative of neurons. Fluorescent double labeling demonstrated that both glial cells and neurons were positive for TIMP-1 and TIMP-2. Conclusion: Chick retinal cells, most of which were glial cells mixed with a small number of neurons, produced TIMP-1 and TIMP-2. Their production was enhanced by cyclic mechanical stretching.

In vivo deposits of fibrin, fibrinogen, plasminogen, complements and immunoglobulins were observed using immunofluorescent (IF) staining of psoriatic lesions. Deposits of fibrin were seen in either the horny layer or the dermal papillae. A linear cytoplasmic appearance of fluorescence in the psoriatic scales was a common pattern of the staining. "IFstaining of the psoriatic horny/layer for fibrinogen and plasminogen' yielded essentially the same pattern as those of fibrin and IgG.These findings suggest that some fibrinolytic processes may be associated with an immune reaction in psoriatic skin, although they be secondary phenomena.The autoimmune hypothesis concerning the etiopathology of psoriasis is largely based on the demonstration of serum autoantibody to stratum corneum and complement-mediated immune complexes in the superficial layers of the psoriatic epidermis. It has been shown by Krogh (1), Beutner et al. (2) and Jablonska et al. (3) that in psoriasis, as well as in healthy controls, circulating antibodies are present and reactive with the membrane of the horny layer cells. These antibodies are of complement binding type. The in vivo binding of either immunoglobulin or complement with horny layer cells has also been demonstrated in psoriatic lesions (2-5). Cormane et al. (6) have observed in addition the presence of various immunoglobulins in the nuclei of the parakeratotic cells. The deposits of various immunoglobulins and complements In psoriatic skin are also associated with the appearance of fibrin and fibrinogen (7-10).The objectives of the studies presented in this report were to demonstrate the association of a fibrinolytic process with the immune reaction in psoriatic skin. MATERIALS AND METHODS Case studiedEighteen cases, II males and 7 females, of common psoriasis with characteristic lesions and histologic changes were studied. The age of the patients ranged from 22 to 83 years, and the duration of the disease was from I to 14 years. Immunofluorescent (IF) methodsThe biopsied skin specimens were quick-frozen, cut on a cryostat, air-dried without fixation and incubated with either antisera or FITC-labeled conjugates for 30 minutes at room temperature. Antisera and FITC-labeled conjugates were absorbed twice with mouse liver acetone powders and diluted to suitable concentrations before incubation. The direct IF method was utilized for the detection of IgG, IgM, PIc, c, activator (CsA), Clq and fibrin, while the indirect method was used to detect plasminogen, fibrinogen and fibrin degradation product (FDP) in the skin using FITClabeled antirabbit y-globulin antibody. The FITClabeled conjugates were purchased from Medical and Biological laboratories LTC and antiplasminogen, fibrinogen and FDP sera from Dakopatts and Behringwerke AG. The F -P molar ratio of the conjugates ranged from 1.0 to I. 78 and antibody concentrations were between 30 and 50,ulml. Blocking tests were performed on the serial sections using unlabeled antisera and antigens.

A case of Schonlein-Henoch-purpura is presented. The immunofluorescent study of skin lesions of the patient showed granular deposits of IgA and C3 in the blood vessel walls perivascular deposits of plasminogen and diffuse localization of fibrin and fibrinogen in the upper dermis. Complement activation via the alternative pathway through IgA, C3 and plasminogen deposits was suggested.

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