Structural analysis of the sugar chains of human urinary thrombomodulin

The sugar chains of human urinary thrombomodulin were studied. N- and O-linked sugar chains were simultaneously liberated by hydrazinolysis followed by N-acetylation and were tagged with 2-aminopyridine. Then the structures of the N- and O-linked pyridylamino (PA-) sugar chains were analyzed by two-dimensional sugar mapping combined with exoglycosidase digestion. The major N-linked sugar chains of human urinary thrombomodulin were found to be monosialo- and disialofucosylbiantennary chains, while the major O-linked sugar chain was +/-Siaalpha2-3Galbeta1-3(+/-Siaalpha2-6)GalNAc. Thrombomodulin also contained the reported structure SO4-3GlcAbeta1-3Galbeta1-3(+/-Siaalpha2-6)Galbeta1-4Xyl [H. Wakabayashi, S. Natsuka, T. Mega, N. Otsuki, M. Isaji, M. Naotsuka, S. Koyama, T. Kanamori, K. Sakai, and S. Hase (1999) J. Biol. Chem. 274, 5436-5442]. In addition to these sugar chains, a single Glc was linked to Ser 287.

Novel proteoglycan linkage tetrasaccharides of human urinary soluble thrombomodulin, SO4-3GlcAbeta1-3Galbeta1-3(+/-Siaalpha2-6)Galbeta1-4Xyl

O-linked sugar chains with xylose as a reducing end linked to human urinary soluble thrombomodulin were studied. Sugar chains were liberated by hydrazinolysis followed by N-acetylation and tagged with 2-aminopyridine. Two fractions containing pyridylaminated Xyl as a reducing end were collected. Their structures were determined by partial acid hydrolysis, two-dimensional sugar mapping combined with exoglycosidase digestions, methylation analysis, mass spectrometry, and NMR as SO4-3GlcAbeta1-3Galbeta1-3(+/-Siaalpha2-6)Galbeta1+ ++-4Xyl. These sugar chains could bind to an HNK-1 monoclonal antibody. This is believed to be the first example of a proteoglycan linkage tetrasaccharide with glucuronic acid 3-sulfate and sialic acid.

Soluble thrombomodulin purified from human urine exhibits a potent anticoagulant effect in vitro and in vivo

We examined the anticoagulant activity of two major molecules of soluble thrombomodulin purified from human urine. The apparent molecular weights of these urinary thrombomodulins (UTMs) were 72,000 and 79,000, respectively. Both UTMs showed more potent cofactor activity for protein C activation [specific activity > 5,000 thrombomodulin units (TMU)/mg] than human placental thrombomodulin (2,180 TMU/mg) and rabbit lung thrombomodulin (1,980 TMU/mg). The UTMs prolonged thrombin-induced fibrinogen clotting time (> 1 TMU /ml), APTT (> 5 TMU/ml), TT (> 5 TMU/ml) and PT (> 40 TMU/ ml) in a dose-dependent fashion. These effects appeared in the concentration range of soluble thrombomodulins present in human plasma and urine. In the rat DIC model induced by thromboplastin, administration of UTMs by infusion (300-3,000 TMU/kg) restored the hematological abnormalities derived from DIC in a dose-dependent fashion. These results demonstrate that UTMs exhibit potent anticoagulant and antithrombotic activities, and could play a physiologically important role in microcirculation.

Plasma exchange for treatment of intractable psoriasis

Hemofiltration and plasma exchange, using a plasma separator with membranes, were used in 14 psoriatic patients. The efficacies of the treatments were compared. Among the patients, 13 were treated with hemofiltration and/or direct hemoperfusion, 5 experienced complete remission, 5 improved, and 3 remained unaffected. In these 3 cases, plasma exchange was performed. The first patient, who suffered from psoriasis pustulosa with arthropathica, achieved complete remission with only two treatment of 2-L plasma exchange. Joint pain was also eliminated. Both skin lesions and joint pain were markedly improved in the second patient, who suffered from psoriasis vulgaris with arthropathica. The third patient showed marked improvement with only two plasma exchanges, and is under continuing observation.

Problems with activated charcoal and alumina as sorbents for medical use

Although activated charcoal and alumina have been used extensively as sorbents in uremic patients, the following problems remain to be solved: 1) elution of SO4--from activated charcoal which does not adsorb it; 2) production of methylguanidine from creatinine on the surface of activated charcoal; 3) production of lipoperoxide from fatty acids by chemical reaction of activated charcoal; 4) adsorption of Ca++ and Mg++ when alumina adsorbs inorganic phosphate. These problems are studied in vitro and clinically.