Suguru Suzuki

A new dermatan polysulfate, chondroitin sulfate H, from hagfish notochord

Abstract A novel oversulfated mucopolysaccharide was isolated from the notochord of hagfish, which belongs to the more primitive branch of cyclostomes. It is concluded that the mucopolysaccharide is a new type of dermatan polysulfate consisting mainly of (1 → 4)-α-L-idopyranuronosyl-(1 → 3)-2-acetamido-2-deoxy-β-D-galactopyranosyl 4,6-disulfate unit. The name of chondroitin sulfate H is proposed for this dermatan polysulfate.

The heterogeneity of dermatan sulfate and heparan sulfate in rat liver and a shift in the glycosaminoglycan contents in carbon tetrachloride-damaged liver

The glycosaminoglycan of rat liver can be separated into five distinct fractions; a hyaluronic acid fraction, a heparan sulfate fraction with a molar ratio of sulfate to hexosamine (S/HexN) around 0.7, a heparan sulfate fraction with a S/HexN ratio around 1.4, a dermatan sulfate fraction with a S/HexN ratio near unity, and a dermatan sulfate fraction with a S/HexN ratio around 1.3. Enzymatic analysis of the two dermatan sulfate fractions indicates that they differ significantly in that the high sulfated fraction contains relatively more N-acetylgalactosamine 4,6-bissulfate units (about 26% of the total hexosamine). In experimental injury produced by carbon tetrachloride, the low sulfated fraction increases as much as 9-fold on a dry weight basis, bearing no linear relationship to the amount of the high sulfated fraction which increases only 2-fold. A significant shift is also observed in the levels of the two heparan sulfate fractions. In this case, however, the high sulfated fraction shows a much more pronounced increase than does the low sulfated fraction. On the basis of these observations, it is suggested that for each of the dermatan sulfate and heparan sulfate classes there are at least two pools, distinguished by sulfation degree and perhaps by turnover rate and physiological function.

Synthesis of a fluorogenic mucopolysaccharide by chondrocytes in cell culture with 4-methylumbelliferyl β-d-xyloside

Culture of chondrocytes in the presence of 4-methylumbelliferyl beta-D-xyloside resulted in a synthesis of protein-free, fluorogenic chondroitin sulfate which was heterogeneous on DEAE-cellulose chromatography. Degradation of the major chromatographic fraction with chondroitinase-ABC yielded, in addition to a large quantity of delta4-glucuronic acid-containing disaccharides, two fluorogenic oligosaccharides of different size. Quantitative analysis showed that delta4-glucuronic acid, galactose, xylose, and 4-methylumbelliferone were present in the small oligosaccharide fragment in a molar ratio of 1:2:1:1. Since these analytical data are analogous to those reported for glycopeptides derivedfrom proteochondroitin sulfates, it may be suggested that 4-methyl-umbelliferyl beta-D-xyloside replaces the need for xylosyl protein core in the normal synthesis of proteochondroitin sulfate with a resultant production of the unusual polysaccharide bearing the added xyloside at the reducing end.

Thrombolytic Properties of a Novel Modified Human Tissue-type Plasminogen Activator (e6010): A Bolus Injection of E6010 Has Equivalent Potency of Lysing Young and Aged Canine Coronary Thrombi

Summary: The thrombolytic properties of a novel modified human tissue plasminogen activator (E6010), in which cysteine 84 in the epidermal growth factor domain is replaced by serine and that has a prolonged biological half-life, were examined. The thrombolytic efficacies of E6010 and recombinant human tissue plasminogen activator (rt-PA) on the duration of coronary artery thrombus were evaluated in a canine model (123 anesthetized dogs) with copper coil–induced left anterior descending coronary artery thrombus. Thrombi established for periods of 1, 3, or 6 h, as documented by coronary arteriography, were employed. A single bolus i.v. injection of E6010 or rt-PA and an i.v. infusion of rt-PA over 60 min were compared (n = 6). Thrombolytic efficacy was evaluated by three criteria: time to reperfusion (TR), reperfusion rate at 60 min (RR), and reocclusion rate at 60 min after reperfusion (OR). With a bolus i.v. injection of E6010 at a dose of 0.2 mg/kg or an i.v. infusion of rt-PA at a dose of 0.6 mg/kg/h, these parameters were as follows: TR, 30.0 × 15.3 and 27.5 × 4.8 min; RR, 100 and 100%; OR, 17 and 33% for 1-h aged thrombi; TR, 30.0 × 9.5 and 35.0 × 8.2 min; RR, 83 and 50%; OR, 20 and 67% for 6-h aged thrombi. These data indicate that a bolus injection of E6010 is almost equally efficacious in lysing thrombi aged both 1 and 6 h. On the other hand, in the case of rt-PA, the thrombi aged 6 h were lysed significantly less than the thrombi aged 1 h. Plasma half-lives of E6010 were t1/2α, 4.8 × 0.95 (estimated by antigen level) and 3.0 × 0.78 min (estimated by activity), and t1/2β, 51 × 5.4 (antigen level) and 22 × 7.0 min (activity). The half-lives of rt-PA were t1/2α, 3.6 × 0.23 (antigen level) and 2.1 × 0.61 min (activity), and t1/2β, 36 × 2.3 (antigen level) and 7.0 × 3.5 min (activity). We conclude that a bolus injection of E6010 may have a more potent and longer-lasting effect than i.v.-infused rt-PA in clot lysis therapy.

Intracoronary infusion of E6010 has more potent thrombolytic activity than tissue plasminogen activator (t-PA) in dogs : a higher plasma level of E6010 than t-PA causes potent thrombolytic activity

Summary: We examined the thrombolytic properties of a novel modified human tissue plasminogen activator (PA) (E6010), in which cysteine 84 is replaced by serine, and which has a prolonged biologic half-life (t½). We compared the thrombolytic efficacy of continuous intracoronary (i.e.) infusion of E6010 with that of recombinant human tissue PA (rt-PA) in a canine model with copper coil-induced 1-h-old coronary artery thrombi and also compared the relation between thrombolytic efficacy and plasma clearance represented by pharmacokinetic parameters of i.e.-infused E6010 and rt-PA. Sixty-minute E6010 and rt-PA i.e. infusions were compared. The thrombolytic effects of i.e.-infused E6010 and rt-PA, represented by time to reperfusion (TR), reperfusion rate at 60 min (RR), and reocclusion rates at 60 min after reperfusion (OR) were as follows. E6010: Dose 0.06, 0.15, 0.3 (mg/kg/h); TR 25 ± 10, 15 ± 10, 13 ± 5 (min); RR 100, 100, 100 (%); and OR 0, 0, 17 (%), respectively. Recombinant t-PA: Dose 0.06, 0.15, 0.3 (mg/kg/h); TR 47 ± 12, 18 ± 17, 14 ± 4 (min); RR 50, 75, 100 (%); and OR 100, 33, 33 (%), respectively. These findings indicate that E6010 has more potent thrombolytic activity than rt-PA. After the i.e. infusion of E6010 and rt-PA at doses of 0.3 mg/ kg/h, the i.e. and peripheral venous (intravenous, i.v.) plasma clearances, represented by the area under the plasma concentration-time curve (AUC), were assessed by antigen and by activity: E6010 assessed by antigen, i.e. 200.1 ± 88.6, i.v. 70.0 ± 39.9 (µg · min/ml); assessed by activity, i.e. 142.5 ± 93.3, i.v. 23.5 ± 15.3 (µg · min/ ml); and rt-PA assessed by antigen, i.e. 81.4 ± 47.4, i.v. 14.1 ± 7.1 (µg · min/ml); and assessed by activity, i.e. 55.1 ± 23.0, i.v. 9.4 ± 5.0 (µg · min/ml). We conclude that the higher plasma level of the active form of E6010, especially its i.e. level, was responsible for its enhanced thrombolytic effect

Development of Pressure Sensitive Molecular Film as a Measurement Technique for Micro‐Flows

The pressure‐sensitive paint (PSP) has potential as a diagnostic tool for pressure measurement in the high Knudsen number regime because it works as a so‐called “molecular sensor.” However, there are few reports concerning application of the PSP to micro devices, because the conventional PSP is too thick owing to the use of polymer binder. In our previous work, we have adopted Langmuir‐Blodgett (LB) technique to fabricate pressure sensitive molecular films (PSMFs) using Pd(II) Mesoporphyrin IX (PdMP). The PSMF based on PdMP has pressure sensitivity only at low pressure range (below 3 kPa). In this study, we have constructed PSMF composed of Pt(II) Mesoporphyrin IX (PtMP) to be applied to pressure measurement near atmospheric pressure. The pressure sensitivity of PSMF based on PtMP has been tested, and it is clarified that the PSMF of PtMP has equivalent pressure sensitivity of polymer PSP. Moreover, we have applied PSMF to measurement of pressure distribution of micro‐channel gas flow, showing its usefulness.