Seiichi Izaki

Detection of serine proteinase inhibitors in human cornified cells

Abstract A screening test for serine proteinase inhibitors revealed trypsin and urokinase inhibitors in the extract of human cornified cells. No inhibition for α-chymotrypsin, thrombin or plasmin was detected. Characterization of the inhibitors separated with a Sephacryl S-200 gel column demonstrated that: 1) trypsin inhibitor with a molecular weight of 45,000 was labile to heat, acid and alkali and showed temporary inhibition, and 2) urokinase inhibitor with a molecular weight of 35,000 was found relatively stable and exhibited time dependent inhibition. Both were distinct from a known thiol proteinase inhibitor which showed high stability and immediate inhibition. Regulatory roles of serine proteinase inhibitors are postulated.

Light and Electron Microscopic Immunohistochemistry of Solar Elastosis: A Study with Cutis Rhomboidalis Nuchae

Biopsied skin specimens from 10 males with cutis rhomboidalis nuchae, 50–83 years in age, as well as age‐matched non‐sun‐exposed skin and young normal skin specimens were subjected to a light and electron microscopic immunohistochemical study using anti‐elastin polyclonal antibody and anti‐microfibril HB‐8 monoclonal antibody. Conventional histochemical and electron microscopic techniques were also used.

Purification of epidermal plasminogen activator inhibitor

A plasminogen activator inhibitor was purified from human cornified cell extract by DEAE‐Sepharose, Sephacryl S‐200, and high‐performance liquid chromatographies on hydroxyapatite HPHT and anion‐exchanger Mono Q at pH 7.2 and 8.0. The purified inhibitor showed M r 43000 and pI 5.2. 50% inhibition of fibrinolytic activity (1.5 IU) of urokinase and tissue‐type plasminogen activator was attained by 0.60 ng and 11.0 ng purified inhibitor respectively. Synthetic substrate assay demonstrated slow tight‐binding inhibition to both urokinase and tissue‐type plasminogen activator. The inhibitor did not inactivate plasmin, thrombin, glandular kallikrein or trypsin.

Fibrin and collagen deposition and fibroblasts proliferation in granuloma of murine leprosy. Comparison of two mouse strains with different immune reactions.

Comparative immunofluorescence study with murine lepromas induced in C57BL/6NJcl (immunologically high responder) and CBA/N (low responder) mouse strains revealed that fibrin formation was associated with cellmediated immune resistance against invasive bacilli. Histochemistry on paraffin sections further elucidated fibroblast proliferation and formation of collagen fibers following fibrin deposition only in murine lepromas with positive host reactions.

Elastase activity in granulomatous inflammation in experimental murine leprosy

Proteolytic activity for [3H]elastin, pyro-Glu-Pro-Val-pNA(S-2484), and Suc-(Ala)3-pNA(AAApNA) was demonstrated in the bound fraction extracted with 2 M KSCN + 0.1% Triton X-100 from hypersensitivity-type murine lepromas in C57BL/6N mice, while elastase-inhibitor activity was separately observed in the soluble fraction extracted with a Tris-saline buffer. Sephacryl S-200 gel chromatography showed a peak of elastolytic activity with approximately 20,000 in molecular weight. The following DEAE-Sepharose chromatography demonstrated three fractions of elastolytic activity (E-I, II, III). The inhibitory profile showed that E-I is a thiol proteinase, while E-II and E-III belong to serine proteinase-type elastases. Both E-II and E-III showed different properties with neutrophil elastase or elastase secreted from cultured macrophages, but identical characteristics to membrane bound-type elastase of monocytes. A lower level of elastolytic activity was detected in the bound fraction of nonhypersensitivity-type murine lepromas in CBA/N mice, suggesting a more involvement of membrane bound-type elastase from monocytes/macrophages during the tissue remodelings of hypersensitivity-type granulomas.