Research Projects
a. Scanning electron microscopy of microvascular corrosion casts
(ref. 6, 9)
Three dimensional architecture of microvascular system has been investigated using scanning electron microscopy of corrosion casts which was developed by Murakami (1971). This method has beem applied to all organs and tissues and revealed three dimensional architecture of the microvascular architecture. Using this technique, rat biliary tree including bile canaliculi was analized. In addition, blood microvascular organization of the suncus tonsil was investigated.
b. Histochemical analysis of glycoconjugates in tissues
(ref. 1, 2, 4, 5, 7, 8, 10)
Certain neurons in the mature brain have well-developed perineuronal nets around the nerve cell bodies. Histochemical analysis using lectin staining and colloidal iron staining combined with specific enzyme digestion has been performed. Our results showed that the perineuronal nets consists of proteoglycan containing hyaluronic acid, chondroitin sulfate and some other glycoseaminoglycans.
Basement membrane beneath the high endothelial cells in the lymphoid tissues has rich negatively charged sites. Using cationic colloidal iron staining, cytochemical analysis was performed to show that it contain chondroitin sulfate rich proteoglycan.
Perisynaptic barrier of proteoglycans
Glycocalyx on the small intestinal microvilli
c. Functions of collagen type IV in blood vessel basement membranes
Collagen type IV is a major constituent of the basement membranes, and consists of six distinct (IV) chains [#1, #2]. Three different assembly forms are found. Subendothelial basement membrane contains the 1/ 1/ 2 assembly form, while that surrounding the smooth muscle cell has the 5/ 5/ 6 form in addition [#3]. How do they work in blood vessels? The knockout mouse of col4a6, a gene encoding 6(IV) chain, loses the 5/ 5/ 6 assembly form. Recently, we have found the lower blood pressure in the knockout mice comparing with that in the wild type. Now, the analysis of the mechanism is in progress under collaboration with Deparment of Molecular Biology and Biochemistry.
α chains of type IV collagen in renal glomerulus immunofluorescence microscopy
Refferences
#1: Ninomiya Y, Kagawa M, Naito I, et al.: J Cell Biol. 1995 Sep;130(5):1219-29.
#2: Saito K, Naito I, Seki T, et al.: J Biochem (Tokyo). 2000 Sep;128(3):427-34.
#3: Seki T, Naito I, Oohashi T, et al.: Histochem Cell Biol. 1998 Oct;110(4):359-66
d. Specific blood cell removal in endotoxemia treatment
Lipopolysccharide (LPS) is one of the major causes of septic shock. The polymyxin B-immobilized filter column (PMX) was developed for the adsorptio0n of endotoxin by direct hemoperfusion and has been used for the treatment of LPS-induced septic shock. In this study, we demonstrated that PMX also specifically bound monocytes from the peripheral blood leukocytes of septic patients by the analysis of bound cells using immunocytochemical and electron microscopic techniques. The specific removal of monocytes from septic patients may produce beneficial effects by reducing the interaction between activated monocytes and functionally associated cells including vascular endothelial cells.
This projected is in progress under collaboration with Department of Pharmacology.