KOSEN 한인과학기술자네트워크

Embolic material (색전물질) 색전술 (embolization) 이란 병변의 혈류 속에 특정 물질을 주입하여 혈류를 차단함으로써 병변을 치료하는 방법으로, 또한 과혈류에 의한 증상의 완화 및 수술시 출혈의 방지 등을 위한 치료 기법입니다. 색전물의 종류에는 입자 색전물, 액체 색전물, 코일형 색전물 등이 있습니다. 입자 색전물의 요구 조건은 생체 적합성(biocompatibility), 균일한 크기 분포, 비이온성 조형제 내에서 균일한 suspension 형성 등입니다. 따라서 균일한 크기의 미세구(microsphere) 형태가 이상적입니다. 대표적인 입자 색전물의 하나는 polyvinyl alcohol (PVA)입니다. 자세한 설명은 Dr. Worthington-Kirsch의 웹사이트를 참조하시기 바랍니다. 생산 업체의 웹사이트도 링크되어 있습니다. http://www.fibroidcorner.com/research/embolicmaterials.ihtml 도움이 되기를 바랍니다. >Embolic material 에 대한 정보를 얻고 싶습니다. > >좀 더 구체적인 범위를 정하고 싶지만 저 역시 아직까진 부족해서... > >Embolic material의 소재라든지.. 현재 개발 생산중인 기업, 대표적인 기술 등에 대한 정보를 알고 싶습니다. > >감사합니다.

>Embolic material 에 대한 정보를 얻고 싶습니다. > >좀 더 구체적인 범위를 정하고 싶지만 저 역시 아직까진 부족해서... > >Embolic material의 소재라든지.. 현재 개발 생산중인 기업, 대표적인 기술 등에 대한 정보를 알고 싶습니다. > >감사합니다. --------------------------------------------------------------------- Please refer to these papers on your request. 1. Non-adhesive cyanoacrylate as an embolic material for endovascular neurosurgery Oowaki, Hisayuki (Kyoto Univ) Matsuda, Shojiro | Sakai, Nobuyuki | Ohta, Takayuki | Iwata, Hiroo | Sadato, Akiyo | Taki, Waro | Hashimoto, Nobuo | Ikada, Yoshito Source: Biomaterials 21 10 2000 Elsevier Science Ltd p 1039-1046 0142-9612 Abstract: 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. In English 30 Refs. Ei tagged | Document availability and cost 2. Development of a digitally-monitored high flow rate system for embolic materials testing used in arteriovenous malformation therapy Zambo, S.J. (Univ of Florida) Gage, K.L. | Rogers, E.S. | Batich, C.D. Source: Transactions of the Annual Meeting of the Society for Biomaterials in conjunction with the International Biomaterials Symposium 1 May 29-Jun 2 1996 1996 Soc for Biomaterials p 590 Abstract: An arteriovenous malformation (AVM) model can successfully carry out liquid embolic materials testing. It consists of a digitally-monitored high flow rate circuit, electronic flow sensors, electronic pressure sensors, a revised Starling resistor, a revised AVM model, and a data acquisition board. The model accurately measures flow in the range of 30 ml/min and measures pressures between 0 mm Hg and 375 mm Hg, which are close to the flow rate and average pressure of the inlet of the most natural AVM. In English 4 Refs. EI96123431417 Ei tagged | Document availability and cost 3. Preparation of poly (D,L) lactide microspheres by emulsion-solvent evaporation, and their clinical applications as a convenient embolic material Grandfils, C. (Univ of Liege) Flandroy, P. | Nihant, N. | Barbette, S. | Jerome, R. | Teyssie, Ph. | Thibaut, A. Source: Journal of Biomedical Materials Research v 26 n 4 Apr 1992 p 467-479 0021-9304 Abstract: The aim of preoperative embolization is to facilitate surgical removal by reducing tumor volume and vascularity, thereby decreasing blood loss during surgery. In a search for a better embolic material, compared to heterogeneous commercial products, we describe here in detail the preparation of poly (D,L) lactide microspheres by an emulsion-solvent evaporation process. The size distribution of the microparticles and their aggregation state - critical parameters in view of such application - have been investigated. Their effectiveness, as an embolic material, has been evaluated by some preliminary experiments undertaken on humans. The results were assessed on clinical and histological grounds. In English 11 Refs EI92050474053 Ei tagged | Document availability and cost 4. Endovascular embolization using hydrogel microspheres Jayakrishnan, A. (Tirunal Inst for Medical Sciences & Technology) Mohanty, M. | Mandalam, R. | Rao, V.R.K. | Gupta, A.K. | Joseph, S. Source: Journal of Materials Science: Materials in Medicine 5 9-10 Sep-Oct 1994 Chapman & Hall Ltd p 723-727 0957-4530 Abstract: Controlled alkaline hydrolysis of crosslinked poly(methyl methacrylate) (PMMA) microspheres produced highly hydrophilic, smooth, compressible, nearly perfect microspheres having a range of water content 40-95%. These particles were found to possess many desirable properties as a material for therapeutic embolization. After successful toxicological and animal evaluation, these particles were used to treat various ailments such as arteriovenous malformations (AVM) of the brain, spinal cord, limbs, face and trunks, preoperative devascularization of tumours and in the management of severe life-threatening haemoptysis and haematemesis in clinical trials involving over 90 patients at this institute. The results of these studies appeared to be very encouraging. The material is found to be an ideal embolic agent in all these clinical situations. In English 23 Refs. EI95012519342 Ei tagged | Document availability and cost 5. MR appearance of endovascular embolic agents in vitro with clinical correlation Spickler, Eric M. (UCLA Sch of Medicine) Dion, Jacques E. | Lufkin, Robert B. | Rachner, Thomas | Vinuela, Fernando | Duckwiler, Gary | Bentson, John R. Source: Computerized Medical Imaging and Graphics v 14 n 6 Nov-Dec 1990 p 415-423 0895-6111 Abstract: A spectrum of embolic agents including PVA, avitene, gelfoam, ethanol, IBCA, silicone microspheres, metal and platinum coils, and balloons containing contrast of HEMA were imaged in vitro at 0,3 Tesla using spin echo, gradient echo, and inversion recovery sequences. Signal intensities associated with these agents and changes created by addition of blood are presented. The in vitro model is also correlated with clinical MR material. Recognition of embolic materials is important to avoid confusion with persistent flow void, hemorrhage, or thrombus. In English 14 Refs EI91010111443 Ei tagged | Document availability and cost 6. Determination of vascular geometry and flow velocity in cerebral arteriovenous malformations (AVMs) using double contrast and high-speed digital subtraction angiography Lieber, B.B. (Toshiba Stroke Research Cent) Wakhloo, A.K. | Divani, A. | Rudin, S. Source: American Society of Mechanical Engineers, Bioengineering Division (Publication) BED v 39 Nov 15-20 1998 1998 Sponsored by: ASME ASME p 53-54 Abstract: Successful therapeutic embolization, i.e., catheter-based occlusion of cerebral arteriovenous malformations (AVMs) using liquid embolic agents requires precise knowledge of highly variant AVM architecture, blood flow velocity, and transit times through the AVM fistulae. In this study we tried to visualize both the AVM vascular substructure and dynamics of discrete microdroplets traveling through the AVM using a single injection composed of both soluble and non-soluble contrast material. The contrast injection is traced with high-speed digital subtraction angiography. This novel technique serves as a valuable diagnostic tool to the interventionist prior to embolization of the AVM. In English EI99014521993 Ei tagged | Document availability and cost 7. Can cerebrovascular microemboli induce cognitive impairment in patients with prosthetic heart valves? Deklunder, G. (CHRU) Prat, A. | Lecroart, J.L. | Roussel, M. | Dauzat, M. Source: European Journal of Ultrasound 7 1 Feb 1998 p 47-51 0929-8266 Abstract: Doppler ultrasonography can be used to detect the presence of emboli (High Intensity Transient Signals, HITS) in the cerebral arterial circulation. Emboli can be produced by different sources and can be of different nature: solid elements as thrombi, platelet aggregates or atheromatous material, or gaseous when they are produced during the decompression phase of diving or during extracorporeal circulation (ECC) procedures. A more recent source of emboli has been found in the mechanical prosthetic heart valves (MHV). The emboli generated by MHV are likely of gaseous nature and are found in the middle cerebral artery blood flow at a variable rate, where they are detected by transcranial Doppler sonography. The mechanism of production of these microbubbles may be related to the rapid leaflet motion especially at closure when very high local pressure gradients appear, which may be able to provoke a release of the dissolved blood gas. Solid element emboli constitute a major cause of cerebrovascular disease and particularly stroke. Conversely, gaseous emboli coming from ECC or MHV are considered as clinically silent. Nevertheless, cognitive alterations have been reported after ECC. As the MHV carriers are chronically submitted to embolic events, it can be assumed that cognitive impairments may occur also in these patients. A preliminary study was designed to assess attention and memory in patients with normally functioning MHV and microemboli, with biological prosthesis and in normal subjects. In the two groups of patients, episodic memory was significantly altered relatively to the control group. In the MHV carriers group, a significant decrease in working memory performance was observed relatively to the two other groups. These results confirm a long term effect of the microembolization occurring during ECC and point out the effect of the chronic exposition to microemboli. In English Ei tagged | Document availability and cost 8. Can cerebrovascular microemboli induce cognitive impairment in patients with prosthetic heart valves? Deklunder, G. (CHRU) Prat, A. | Lecroart, J.L. | Roussel, M. | Dauzat, M. Source: European Journal of Ultrasound 7 1 Feb 1998 p 47-51 0929-8266 Abstract: Doppler ultrasonography can be used to detect the presence of emboli (High Intensity Transient Signals, HITS) in the cerebral arterial circulation. Emboli can be produced by different sources and can be of different nature: solid elements as thrombi, platelet aggregates or atheromatous material, or gaseous when they are produced during the decompression phase of diving or during extracorporeal circulation (ECC) procedures. A more recent source of emboli has been found in the mechanical prosthetic heart valves (MHV). The emboli generated by MHV are likely of gaseous nature and are found in the middle cerebral artery blood flow at a variable rate, where they are detected by transcranial Doppler sonography. The mechanism of production of these microbubbles may be related to the rapid leaflet motion especially at closure when very high local pressure gradients appear, which may be able to provoke a release of the dissolved blood gas. Solid element emboli constitute a major cause of cerebrovascular disease and particularly stroke. Conversely, gaseous emboli coming from ECC or MHV are considered as clinically silent. Nevertheless, cognitive alterations have been reported after ECC. As the MHV carriers are chronically submitted to embolic events, it can be assumed that cognitive impairments may occur also in these patients. A preliminary study was designed to assess attention and memory in patients with normally functioning MHV and microemboli, with biological prosthesis and in normal subjects. In the two groups of patients, episodic memory was significantly altered relatively to the control group. In the MHV carriers group, a significant decrease in working memory performance was observed relatively to the two other groups. These results confirm a long term effect of the microembolization occurring during ECC and point out the effect of the chronic exposition to microemboli. In English Ei tagged | Document availability and cost 9. Dynamic MR imaging of hepatoma treated by transcatheter arterial embolization therapy Yamashita, Y. Yoshimatsu, S. | Sumi, M. | Harada, M. | Takahashi, M. Source: Acta Radiologica v 34 n 3 May 1993 p 303-308 0248-1851 Abstract: The effect of transcatheter arterial chemo-embolization therapy (TACE) for hepatoma was evaluated with dynamic MR imaging with Gd-DTPA in 37 patients (44 tumors). TACE was performed using Lipiodol/cis-platinum and gelatin sponge (or microspheres) as an embolic material. All patients were examined with dynamic CT and MR imaging before and after treatment. On conventional spin echo images, changes of signal intensity after treatment varied regardless of presence of Lipiodol. Dynamic MR imaging revealed changes of tumor vascularity before and after treatment. On histologic correlation, areas of persistent tumor enhancement on dynamic MR imaging corresponded to areas of viable tumor cells while areas of nonenhancement corresponded to areas of necrosis. Dynamic MR imaging was superior in contrast resolution and was not influenced by the presence of Lipiodol compared with dynamic CT, and therefore residual viable tumors were better defined by dynamic MR imaging.13.. EI94081366218 Ei tagged | Document availability and cost 10. Nontoxic embolic liquids for treatment of arteriovenous malformations Kazekawa, Kiyoshi (Fukuoka Tokushukai Medical Cent) Iwata, Hiroo | Shimozuru, Tetsuro | Sampei, Kenji | Sakaki, Nobuyuki | Morikawa, Noriyuki | Matsuda, Shojiro | Ikada, Yoshito Source: Journal of Biomedical Materials Research v 38 n 2 Summer 1997 John Wiley & Sons Inc p 79-86 0021-9304 Abstract: Interventional radiology is becoming one of the standard treatments of arteriovenous malformation (AVM). Cyanoacrylate derivatives and polymer solutions are widely used to occlude the AVM nidus by their injection through a catheter, but they are far from satisfactory embolic liquids. For instance, cyanoacrylate derivatives sometimes glue the catheter to the artery, resulting in serious complications; in addition, the organic solvents used to dissolve polymers cause damage to the surrounding brain tissue of the AVM. Therefore, we attempted to develop embolic liquids by dissolving poly(2-hydroxy-ethyl methacrylate-co-methyl methacrylate) in Iopamiron with an addition of a small amount of ethyl alcohol. This new embolic liquid is not cytotoxic and is easily injected into the AVM through a thin, long catheter to effectively occlude the AVM. In English 14 Refs. EI97063700280

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