Long-term results of cell-free biodegradable scaffolds for in situ tissue-engineering vasculature: in a canine inferior vena cava model

We have developed a new biodegradable scaffold that does not require any cell seeding to create an in-situ tissue-engineering vasculature (iTEV). Animal experiments were conducted to test its characteristics and long-term efficacy. An 8-mm tubular biodegradable scaffold, consisting of polyglycolide knitted fibers and an L-lactide and ε-caprolactone copolymer sponge with outer glycolide and ε-caprolactone copolymer monofilament reinforcement, was implanted into the inferior vena cava (IVC) of 13 canines. All the animals remained alive without any major complications until euthanasia. The utility of the iTEV was evaluated from 1 to 24 months postoperatively. The elastic modulus of the iTEV determined by an intravascular ultrasound imaging system was about 90% of the native IVC after 1 month. Angiography of the iTEV after 2 years showed a well-formed vasculature without marked stenosis or thrombosis with a mean pressure gradient of 0.51 ± 0.19 mmHg. The length of the iTEV at 2 years had increased by 0.48 ± 0.15 cm compared with the length of the original scaffold (2-3 cm). Histological examinations revealed a well-formed vessel-like vasculature without calcification. Biochemical analyses showed no significant differences in the hydroxyproline, elastin, and calcium contents compared with the native IVC. We concluded that the findings shown above provide direct evidence that the new scaffold can be useful for cell-free tissue-engineering of vasculature. The long-term results revealed that the iTEV was of good quality and had adapted its shape to the needs of the living body. Therefore, this scaffold would be applicable for pediatric cardiovascular surgery involving biocompatible materials.     

The reaction mechanism for the high quantum yield of Cypridina (Vargula) bioluminescence supported by the chemiluminescence of 6-aryl-2-methylimidazo[1,2-a]pyrazin-3(7H)-ones (Cypridina luciferin analogues).

To establish the reaction mechanism of the high-quantum-yield bioluminescence in Cypridina (Vargula), we investigated the chemiluminescence of 6-aryl-2-methylimidazo[1,2-a]pyrazin-3(7H)-ones (1H) as Cypridina luciferin analogues in DMSO-1,1,3,3-tetramethylguanidine and in diglyme-acetate buffer. We found that the chemiluminescence of 1H with an electron-donating aryl group, such as a 4-(dimethylamino)phenyl, 3-indolyl or 3-(1-methyl)indolyl group, gave a high quantum yield (Phi(CL)) in diglyme-acetate buffer. This indicates that the reaction mechanism producing this high Phi(CL) involves the chemiexcitation of a neutral dioxetanone intermediate possessing an electron-donating aryl group to the singlet excited state of neutral acetamidopyrazine (the light emitter). In addition, we investigated the fluorescence of acetamidopyrazines and performed DFT calculations for neutral dioxetanones and the transition states (TS) of the dioxetanone's decomposition. The results made it clear that the electron-donating aryl group gives the TS and the singlet-excited acetamidopyrazine (S(1)) a strong intramolecular charge transfer (ICT) character, and their similar ICT character leads to the ICT TS --> S(1) route in the charge transfer-induced luminescence (CTIL) mechanism for efficient chemiexcitation. The reaction mechanism of the chemiluminescence of 1H can explain the highly efficient chemiexcitation of Cypridina bioluminescence.     

Remarkably enhanced inhibitory effects of hybrid liposomes on the growth of specific tumor cells.

The highly specific inhibitory effects of the hybrid liposomes composed of 90 mol% L-alpha-dimyristoylphosphatidylglycerol and 10 mol% polyoxyethylene (10) dodecyl ether on the growth of lung adenocarcinoma and stomach tumor cells in vitro were obtained for the first time.     

Enzymatic synthesis of novel oligosaccharides by use of transglycosylation activity of endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae.

The transglycosylation activity of endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae was used for the enzymatic synthesis of novel oligosaccharides. When (Man)6(GlcNAc)2Asn was used as a substrate for the transglycosylation, (Man)6GlcNAc-Glc, (Man)6GlcNAc-Man, (Man)6GlcNAc-chitobiose, and (Man)6GlcNAc-gentiobiose were synthesized. Their structures were identified by HPLC, ion spray mass spectrometry, and digestion with glycosidases. Endo-beta-N-acetylglucosaminidases hydrolyzed the pyridylamino derivatives of these oligosaccharides.     

Rapid and efficient production of L-lactate from xylose using electrodialysis culture-associated product separation

L-Lactate was produced from xylose using electrodialysis culture (ED-C)-associated product separation. In a medium containing 50g xylose/l, the ED-C was completed in only 32h (i.e. less than half the time taken by the control culture, without electrodialysis). At 80g xylose/l, the control culture was unable to consume more than 50g xylose/l, whereas the ED-C showed increased xylose consumption and was completed by 45h. The maximum rate of lactate production in the ED-C was higher than that in the control culture. ED-C was also carried out (at 80g initial xylose/l) with a supply of fresh xylose-free medium. This ED-C was completed within 30h, which represents a reduction in fermentation time of 15h when compared to ED-C without addition of xylose-free medium. Thus, rapid production of L-lactate was achieved by using ED-C which supplied fresh xylose-free medium.     

Degradation of d,l-syringaresinol,a β-β′ linked lignin model compound,by Fusarium solani M-13-1

A - linked lignin model compound, d,l-syringaresinol monobenzyl ether (Ib) was incubated with Fusarium solani M-13-1 in a shaking culture. From the culture filtrates, three compounds II, IIIb and IV were isolated and identified. Substrate Ib was oxidized at the -position of the side chain to give a hemiketal, an -hydroxylated compound IIA, which was then transformed to the ketoalcohol, 3-hydroxymethyl-2-(4-benzyloxy-3,5-dimethoxyphenyl)-4-(4-hydroxy-3,5-dimethoxybenzoyl)-tetrahydrofuran (IIB). These products were converted to a -lactone derivative, 6-oxo-2-(4-benzyloxy-3,5-dimethoxyphenyl)-3,7-dioxabicyclo-[3,3,0]-octane (IIIb), via alkyl-aryl cleavage. The syringyl moiety released from II by the cleavage reaction was identified as 2,6-dimethoxy-p-benzoquinone (IV). Incubation of 2,6-dimethoxyphenol (V) in fungal culures did not give the p-quinone IV. d,l-Syringaresinol dimethyl ether was not degraded and the etherated moiety of Ib was not attacked by the fungus, indicating that the degradation of d,l-syringaresinol was catalyzed by phenol oxidizing enzymes. The oxidation products of Ib with peroxidase/H₂O₂ was investigated and discussed in relation to the degradation products of the fungus.Abbreviation TLC thin layer chromatography     

Studies on the uronic acid-containing glycoproteins of Fusarium sp. M7-1: III. The primary structures of the acidic polysaccharides of the glycoproteins.

Two O-glycosidically linked acidic polysaccharides, AP I and AP II, were released, respectively, from glycoproteins GP I and GP II of Fusarium sp. M7-1 by alkaline borohydride treatment and purified by gel filtration chromatography. They were found to be apparently homogeneous on gel filtration chromatography and analytical ultracentrifugation. Their molecular weights were estimated to be 8.2 x 10(4) and 3.1 x 10(4), respectively. The various oligosaccharide fragments obtained from AP I and AP II by acetolysis and partial acid hydrolysis were purified by gel filtration chromatography and HPLC. Their primary structures were resolved mainly by NMR spectrometry in combination with methylation mass spectrometry. Analyses of the acetolysis and partial acid hydrolysis products and the 1H-NMR spectrum of AP I and AP II showed that they are analogues. Thus, we propose that the main parts of the acidic polysaccharides have the following structures. [formula: see text] *X, unidentified oligosaccharide chains. The numbers on the left and the numbers in parentheses outside the brackets indicate the approximate number of side chains of AP I and AP II, respectively, the saccharide sequences of which are not specified.     

Studies on the uronic acid-containing glycoproteins of Fusarium sp. M7-1: IV. Isolation and identification of four novel oligosaccharide units derived from the acidic polysaccharide chain.

Four novel oligosaccharide units were isolated from the acetolysis products of the acidic polysaccharide chain derived from the glycoproteins of Fusarium sp. M7-1. Their chemical structures were resolved mainly by 1H-NMR spectrometry in combination with methylation analysis and mass spectrometry. The results indicate that these oligosaccharide units originated from the side chains, GlcNAc alpha 1-->4GlcA alpha 1-->2(GlcNac alpha 1-->4)GlcA alpha 1-->2Gal, GlcNAc alpha 1-->4GlcA alpha 1-->2(GlcNAc alpha 1-->4)GlcA alpha 1-->2(GlcNac alpha 1-->4)GlcA alpha 1-->2Gal, ChN<--P--> 6Man beta 1-->4GlcA alpha 1-->2Gal, and Man beta 1-->2(ChN<--P-->6)Man beta 1-->4GlcA alpha 1-->2Gal linked together with the other units reported previously [Jikibara et al. (1992) J. Biochem. 111, 236-243] through beta 1-->6galactofuranoside linkages in the acidic polysaccharide chain.