The aorta-gonad-mesonephros (AGM) region is involved in the generation and maintenance of the first definitive hematopoietic stem cells (HSCs). A mouse AGM-derived cell line, AGM-S3, was shown to support the development of HSCs. To elucidate the molecular mechanisms regulating early hematopoiesis, we obtained subclones from AGM-S3, one of which was hematopoiesis supportive (S3-A9) and the other one of which was non-supportive (S3-A7), and we analyzed their gene expression profiles by gene chip analysis. In the present study, we found that Glypican-1 (GPC1) was highly expressed in the supportive subclone AGM-S3-A9. Over-expression of GPC1 in non-supportive cells led to the proliferation of progenitor cells in human cord blood when cocultured with the transfected-stromal cells. Thus, GPC1 may have an important role in the establishment of a microenvironment that supports early events in hematopoiesis.

When the conidia of Blumeria graminis f. sp. hordei (Bgh) are inoculated on barley coleoptile cells they produce short germ tubes called primary germ tubes (PGTs) about 2h after inoculation. We evaluated the positive role of a PGT in inducing accessibility of the host cell under the germ tube. When an appressorium (APP) penetrated the same cell on which a PGT was present, the ratio of haustorium formation (penetration efficiency) was significantly higher than when an APP penetrated the cell adjacent to the one on which a PGT was present. When an APP penetrated the cell laterally adjacent to the one on which a PGT was present we killed the cell under the PGT by puncturing it with a microneedle and then investigated the penetration efficiency of the cell adjacent to the dead cell. As a control we killed the cell longitudinally adjacent to the one on which a PGT was present and investigated the penetration efficiency of the laterally adjacent cell. The results showed that the penetration efficiency of the former was significantly lower than that of the latter. This suggests that some accessibility factor might transfer from a cell on which a PGT is present to a laterally adjacent cell. The existence of a conidium body but not a PGT was not effective for induced accessibility of the host cell. Moreover, when a Bgh germling was removed 6h after inoculation and another germling was transferred to the same cell, the penetration efficiency was significantly higher than that of control. As a control, a Bgh germling was transferred to a cell on which no germling was present. These results suggest that the existence of PGT is effective for induced accessibility of a host cell when penetrated by Bgh. However, it is unclear whether or not a PGT secretes some substance(s) which suppresses the resistance induction of a host cell.

The interaction between stem cells and their supportive microenvironment is critical for their maintenance, function, and survival. Whereas hematopoietic stem cells (HSCs) are among the best characterized of tissue stem cells, their precise site of residence (referred to as the niche) in the adult bone marrow has not been precisely defined. In this study, we found that a Gata2 promoter directs activity in all HSCs. We show that HSCs can be isolated efficiently from bone marrow cells by following Gata2-directed GFP fluorescence, and that they can also be monitored in vivo. Each individual GFP-positive cell lay in a G0/G1 cell cycle state, in intimate contact with osteoblasts beside the endosteum, at the edge of the bone marrow. We conclude that the HSC niche is composed of solitary cells and that adult bone marrow HSC are not clustered.

Lithium ion conducting gel polymer electrolytes composed of insoluble lithium tetrakis(pentafluorobenzenethiolato) borate (LiTPSB), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and ethylene carbonate–propylene carbonate mixed solvent (EC–PC) were prepared and their ionic conductivities and electrochemical stabilities were investigated. Ionic conductivity was largely dependent on the contents of EC–PC and LiTPSB. Gel polymer electrolyte containing optimized content of 50 (LiTPSB)–50 (PVDF-HFP/EC–PC (13:87wt.%)) exhibited ionic conductivity of 4×10−4Scm−1 at 30°C, lithium ion transference number of 0.33 and anodic oxidation potential of 4.2V.

Block copolymers consisting of poly(L-lactide) (PLLA) and poly(oxyethylene-co-oxypropylene), with various compositions, were synthesized and characterized in vitro and in vivo for their application as postoperative adhesion prevention membranes. It was found that the flexibility and degradability of the cast films of the block copolymers grew with increasing Pluronic F68 [PN; poly(oxyethylene-co-oxypropylene] composition. The receding contact angle of the copolymer films against water became lower than that of the PLLA film, because the surface was predominantly covered with more hydrophilic PN segments in a wet state. This surface property significantly affects the cell attachment property of the copolymer films, and the fibroblasts cultured on the films exhibit a spheroid-like morphology. The copolymer films subcutaneously implanted in the back of rats induced milder tissue responses compared with PLLA homopolymers, because of the increased surface hydrophilicity in the former. In vivo evaluation using a uterus horn model in rats revealed that the performance of these copolymer films as an adhesion-prevention membrane is comparable to that of a conventionally utilized membrane of oxidized regenerated cellulose. These results indicate that the copolymer films are biocompatible materials with controllable mechanical properties and biodegradability as adhesion-prevention membranes.

Endovascular neurosurgery is now becoming available as one of strategies for the treatment of cerebro-spinal arterio-venous malformations and aneurysms. For this treatment, a microcatheter is advanced into or close to a lesion and then an embolic material is administered through it to obliterate the lesion. N-butyl-2-cyanoacrylate (NBCA) has preferentially been used as an embolic material in Europe and America. However, its exceptionally strong adhesive force sometimes causes adhesion between the tip of the microcatheter and the artery. In this study, a new non-adhesive cyanoacrylate, isostearyl-2-cyanoacrylate (ISCA), was developed. It carries a long hydrophobic side isostearyl group with lower reactivity and adhesion than other cyanoacrylates. Its polymerization rate is, however, too low to obliterate a vascular lesion with a rapid blood flow. To increase the polymerization rate, ISCA was mixed with NBCA. As a result, the adhesive force of the mixture became extremely low, compared with that of NBCA. The viscosity of the mixture was low enough to allow its’ use as an embolic material. Tissue reactions against the mixture was milder than those against NBCA. Radio-angiography became possible by mixing further with Lipiodol. The evaluation of this new embolic material with a rabbit renal artery showed that the obliteration effect of the mixture of ISCA and NBCA was excellent to use as an embolic material for clinical applications.

A multiblock copoly(ester-ether) consisting of poly(L-lactic acid) (PLLA) and poly(oxypropylene-co-oxyethylene) (PN) was prepared and characterized. Preparation was done via the solution polycondensation of a thermal oligocondensate of L-lactic acid, a commercially available telechelic polyether (PN: Pluronic-F68), and dodecanedioic acid as a carboxyl/hydroxyl adjusting agent. When stannous oxide was used as the catalyst, the molecular weight of the resultant PLLA/PN block copolymers became very high (even with a high PN content) under optimized reaction conditions. The refluxing of diphenyl ether (solvent) at reduced pressure allowed the efficient removal of the condensed water from the reaction system and the feed-back of the intermediately formed L-lactide at the same time in order to successfully bring about a high degree of condensation. The copolymer films obtained by solution casting became more flexible with the increasing PN content as soft segments. (C) 1999 John Wiley & Sons, Inc.

An amphiphilic graft-copolymer consisting of ionic segments (quatemary ammonium groups) and aliphatic polyester segments which are compatible with various polymers was synthesized by radical copolymerization of a (methacryloxyethyl)trimethylammonium chloride and a poly(beta-methyl-delta-valerolactone) macromer. Polymer blends containing this graft-copolymer showed both low surface resistance and low volume resistivity, due to the network formation of the graft-copolymer in the polymer matrix. Scanning electron microscopy revealed that the graft copolymer forms interconnected granular aggregates, which function as ion-conducting channels.

Human ribosomal RNA genes (rDNA) are arranged as tandem repeat clusters on the short arms of five pairs of acrocentric chromosomes. We have demonstrated that a majority of the rDNA clusters are detected as 3-Mb DNA fragments when released from human genomic DNA by EcoRV digestion. This indicated the absence of the EcoRV restriction site within the rDNA clusters. We then screened for rDNA-positive cosmid clones using a chromosome 22-specific cosmid library that was constructed from MboI partial digests of the flow-sorted chromosomes. Three hundred twenty rDNA-positive clones negative for the previously reported distal flanking sequence (pACR1) were chosen and subjected to EcoRV digestion. Seven clones susceptible to EcoRV were further characterized as candidate clones that might have been derived from the junctions of the 3-Mb rDNA cluster. We identified one clone containing part of the rDNA unit sequence and a novel flanking sequence. Detailed analysis of this unique clone revealed that the coding region of the last rRNA gene located at the proximal end of the cluster is interrupted with a novel sequence of ∼ 147 bp that is tandemly repeated and is connected with an intervening 68-bp unique sequence. This junction sequence was readily amplified from chromosomes 21 and 15 as well as 22 using the polymerase chain reaction. Fluorescence in situ hybridization further indicated that the ∼147-bp sequence repeat is commonly distributed among all the acrocentric short arms.

A novel monoclonal antibody against human osteocalcin, recently established in our laboratory, was shown by immunoblotting and immunohistochemistry to react specifically with human osteoblasts. In the present study, the antibody was applied to the immunohistochemical diagnosis of human bone tumours, especially osteoblastic tumours. The antibody reacted with all 27 osteosarcomas. No positive reaction was found either in chondrosarcoma, giant cell tumours of bone, soft tissue tumours or epithelial tumours. A positive reaction was found preferentially in the cytoplasm of most of the osteosarcoma cells, but not in the extracellular matrix. Since the antibody reacted with formalin-fixed and paraffin-embedded tissues, it will be a useful tool for routine immunohistochemical diagnosis of osteoblastic lesions.

Murine monoclonal antibodies specific for human bone gamma-carboxyglutamic acid containing protein (BGP) were produced against BGP purified from young adult human long bones. The amino acid composition of purified protein corresponds with that of human BGP, and Western blot analysis revealed that the antibodies reacted most intensely with the cytoplasm of osteoblasts and less intensely with the cytoplasm of osteocytes, but did not react with any other cells, such as chondrocytes, or osteoclasts. Because of their ability to react with routinely processed tissue sections and their marked reactivity with human osteoblastic cells, the antibodies are expected to be a useful tool for studying the process of ossification in human bones and for the immunohistochemical diagnosis of human osteogenic tumours.

Boneγ-carboxyglutamic acid containing protein (BGP) was isolated from human bone and anti-BGP antibody was produced in rabbits. Localization of BGP was investigated immunocytochemically by light and electron microscopy in human bones in various developmental stages and pathological conditions. In the bones of a 12 week fetus, osteoblasts stained strongly in areas of bone formation. However in bones of late fetal stages and in newborns and adults, BGP was localized predominantly in the osteoid and bone matrix in the ossifying front. Osteoblasts and osteocytes also stained positive, but less dominantly than in the early fetus. Electron microscopy showed that BGP was localized in the ER and Golgi cisternae of osteoblasts and osteocytes, and the collagen fibers of the osteoid and bone matrix. The intensity and distribution of staining were not significantly different in osteoporosis and osteoarthritis. These observations indicate that BGP is synthesized by osteoblasts most actively in early fetal life and is then deposited on collagen fibers of the osteoid and bone matrix.

Butadiene was found to oligomerize readily with bis(π-cycloocta-1,5-diene)nickel in alcohols, yielding linear conjugated and unconjugated dimers, trimers, and tetramers. The oligomers and their yields were affected by the solvents used. When primary alcohols, such as methyl, ethyl, and n-butyl, were used as the solvent, only small amounts of hydrooligomers were formed. On the other hand, in tert-butyl and isopropyl alcohols n-octa-1,6- and -2,6-diene and n-octa-1,3,6-triene were catalytically obtained, accompanied by small quantities of cyclododeca-1,5,9-triene, n-dodeca-1,6,10-triene, and n-hexadeca-2,6,10,14-tetraene. Addition of amines had little effect, except that diethylamine deactivated the catalysts. From the results of spectrometric analyses and pyrolysis of the nickel complex formed in the reaction of bis(π-cycloocta-1,5-diene)-nickel with butadiene in isopropyl alcohol, it has been deduced that the linear butadiene oligomers are formed through a complex composed of monomeric butadiene, butadiene oligomer, isopropoxy group, and nickel atom.

Chemischer Informationsdienst. Organische ChemieVolume 2, Issue 35 Heterocyclic Compounds ChemInform Abstract: OLIGOMERISATION VON BUTADIEN IN GEGENWART DER DURCH ELEKTROLYSE VON NICKEL(II)-CHLORID GEBILDETEN NICKELKOMPLEXE TAKAYUKI OHTA, TAKAYUKI OHTASearch for more papers by this authorKEISUKE EBINA, KEISUKE EBINASearch for more papers by this authorNOBORU YAMAZAKI, NOBORU YAMAZAKISearch for more papers by this author TAKAYUKI OHTA, TAKAYUKI OHTASearch for more papers by this authorKEISUKE EBINA, KEISUKE EBINASearch for more papers by this authorNOBORU YAMAZAKI, NOBORU YAMAZAKISearch for more papers by this author First published: August 31, 1971 https://doi.org/10.1002/chin.197135211Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume2, Issue35August 31, 1971 RelatedInformation

Abstract The oligomerization of butadiene has been found during the electrolysis of solutions containing nickel(II) chloride and electron donors. The oligomerization was affected by the nature of the electron donors used. When the ethanolic solutions of tetrakis(pyridine)nickel(II) chloride or nickel(II) chloride and pyridine with tetra-n-butyl ammonium perchlorate or methanolic solutions without the perchlorate were electrolyzed in the presence of butadiene, a number of linear and dihydrogenated oligomers, with small amounts of branched oligomers, were obtained. The main oligomers were identified as n-octadiene, n-dodecatriene, and n-hexadecatetraene. By adding triphenylphosphine to the reaction system in place of pyridine, n-octatriene and alkoxyoctadiene were catalytically produced instead of hydrooligomers, accompanied by tetrakis(triphenylphosphine)nickel(0). A mechanism involving π-allyl intermediates was proposed for the oligomerization.

Oligomerization of butadiene with the catalyst system of nickel(II)chloride, electron donor, and lithium aluminum hydride or sodium borohydride has been studied. Most oligomers obtained with this catalyst were linear, and dihydrogenated dimers, trimers, and tetramers. They were n-octa-1,6-diene, n-octa-1,7-diene, n-dodeca-1,6,10-triene, and n-hexadeca-1,6,10,14-tetraene, which were identified by means of infrared, nuclear magnetic resonance, and mass spectrometry. Yields of each oligomer were strongly affected by the nature of the electron donors used. The hydrogen required for the formation of the hydrooligomers was assumed to originate from the lithium aluminum hydride or sodium borohydride used as a reducing agent. A proposed mechanism for the hydrooligomerization is that butadiene is oligomerized on the nickel atom, and the produced oligoolefins, bonded to the nickel by two terminal π-allylic bonds, are dihydrogenated to linear hydrooligomers.