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Biomedical subjects

W Taki

Publications and source records attributed to W Taki.

144 records · Page 8Linked to original sources
PubMed1980

Radiopaque solidifying liquids for releasable balloon technique: a technical note.

Recently we have reported a catheter having a balloon which can be released simply by twisting the catheter. In the technique, 2-hydroxyethylmethacrylate (HEMA) has been used as a solidifying liquid to prevent the released balloon from deflating. Since HEMA is not radiopaque, the place and the size of the balloon cannot be visualized under an X-ray image intensifier. The present investigation involves the preparation of a radiopaque, solidifying liquid, by mixing HEMA with a suitable contrast medium such as metrizamide, sodium iothalamate or meglumine sodium iodamide. The use of HEMA-contrast medium mixtures made injection of the solidifying liquids much more controllable.

Acrylic Resins↗
PubMed1980

The releasable balloon technique with activated high frequency electrical current.

A new releasable balloon catheter was developed which has a soluble joint connecting the balloon and the catheter. The joint is made from a polyvinyl alcohol tube and has two electrodes. When a high frequency electrical current is activated, the resulting heat causes the joint to disappear within one second. The type of generator used in the experiment was an Aesculap GK-34. This catheter was used for embolization of carotid-jugular fistulas in dogs.

Animals↗
PubMed1979

Embolization and superselective angiography by means of balloon catheters.

Three types of thin flexible balloon catheters were made. One of them is a releasable balloon catheter, which is prepared for embolization of intracranial aneurysms, arteriovenous malformations and fistulas. The other two are nonreleasable balloon catheters that are utilized for temporary occlusion, catheterization, and superselective angiography of the intracranial arteries. These catheters are useful experimentally for the above mentioned purposes. Our clinical experiences with catheterization and superselective angiography with our balloon catheter are reported.

Animals↗
PubMed1979

Balloon embolization of a giant aneurysm using a newly developed catheter.

A new catheter with a releasable balloon has been developed for the controllable embolization of intracranial vascular lesions located beyond many arterial curves such as the carotid siphon. Embolization is accomplished by introduction of the balloon to the lesion, followed by inflating the balloon with a polymerizable liquid. After this liquid sets to a gel, the catheter is twisted off to detach the balloon at a specially designed joint. This balloon catheter has been used clinically to embolize an aneurysm of the middle cerebral artery.

Aged↗
PubMed1979

[Nonsuture microvascular anastomosis--experimental arterial end-to-end anastomosis using plastic adhesive and a soluble PVA tube (author's transl)].

Microvascular anastomosis is now widely applied and many improved methods of the nonsuture anastomosis have been developed instead of the suture anastomosis for the purpose of saving time and making the reconstruction easier. We introduced a new nonsuture method of microvascular anastomosis using plastic adhesive and a soluble tube made of polyvinylalcohol (PVA). PVA, which had been utilized as a plasma expander, is a water-soluble polymer and its solubility is changeable depending on the degree of polimerization and percent saponification. We have made two kinds of soluble PVA tubes, the one has monolayer wall and the other double layered wall. The inner wall of the latter is more soluble than the outer wall. As plastic adhesives, we employed ethyl 2--cyanoacrylate, isopropyl 2--cyanoacrylate, and isobutyl 2--cyanoacrylate which were much superior to methyl 2--cyanoacrylate. Common carotid arteries of rats of 1.0 to 1.3 mm external diameter range were reconstructed and re-exploration was carried out at intervals of more than 7 days after operation. The anastomotic technique was very easy and it took about five minutes to reconstruct. In our last series, approximately 98 percent patency rate was achieved. The advantage of our method is that the blood stream is regained in the small soluble at the anastomotic site immediately after the release of hemostatic clamps.

Animals↗
PubMedDate not supplied

Experimental nonsuture microvascular anastomosis using a soluble PVA tube and plastic adhesive.

This article describes a new nonsuture method for microvascular anastomoses that uses plastic adhesives and soluble tube stents made of polyvinyl alcohol (PVA). Three soluble tubes were studied: one tube with a monolayered wall and two bilayered tubes of different thicknesses. The layers of the bilayered tubes consisted of PVA of different degrees of solubility. As plastic adhesives, ethyl 2-cyanoacrylate, isopropyl 2-cyanoacrylate, isobutyl 2-cyanoacrylate, and methyl 2-cyanoacrylate were employed; methyl 2-cyanoacrylate was by far the least effective. Anastomoses were performed on the common carotid artery of rats, and macroscopic, angiographic, and histologic investigations were carried out at intervals ranging from seven days to six months. The patency rates were 81% for the monolayered tube, and 92% and 98% for the bilayered tubes. The principal advantage of this method is that blood flow can be reestablished through the anastomosed site immediately after release of the hemostatic clamps.

Adhesives↗
PubMedDate not supplied

Distribution of the blood flow supplied by the vertebral artery in humans as assessed by emission CT.

Though unilateral blood distribution of the vertebral artery has not been studied in humans, it is significant when considering the ischemic events especially embolic occlusion in vertebrobasilar system. To clarify the blood distribution, Krypton-81m was continuously infused into the vertebral arteries of 10 patients. Radioactivity was recorded by a rotating gamma camera. The perfusion images, reconstructed by computer in the transaxial plane, were classified according to whether the distribution was equal, or predominantly unilateral. Overlapping of blood supply from each vertebral artery was studied. In addition, the perfusion from one of the vertebral arteries revealed four distribution patterns with respect to laterality. A) ipsilateral; B) contralateral; C) bilateral; D) mosaic. Images obtained following perfusion of the vertebral artery show less uniformity compared to that of the internal carotid artery, suggesting a complicated vascular supply of the vertebral basilar territory. This complex distribution can be classified by the use of continuous infusion of Krypton-81m.

Adult↗
PubMedDate not supplied

Scalp vein detected using internal carotid angiography that did not result in venous sinus compromise.

We present an unusual case of a scalp vein detected by using angiography of the internal carotid artery. The vein arose from the superior sagittal sinus and drained into the deep posterior cervical vein via the parietal emissary vein. This scalp vein may be a collateral pathway for venous sinuses; however, the patient had no evidence of venous sinus occlusive disease or intracranial hypertension.

Aged↗
PubMedDate not supplied

A new liquid material for embolization of arteriovenous malformations.

We have developed a liquid material for embolization of arteriovenous malformations that is a mixture of ethylene vinyl alcohol copolymer and metrizamide dissolved in dimethyl sulfoxide. Upon contact with blood, dimethyl sulfoxide rapidly diffuses into the blood and forms an ethylene vinyl alcohol copolymer elastic soft sponge that obstructs both the feeder and the nidus. The material, which is not adhesive, was used for embolization of three left cerebral arteriovenous malformations with satisfactory results.

Adolescent↗
PubMedDate not supplied

A study of regional cerebral blood flow and hemodynamics in cerebrovascular diseases by selective continuous infusion of Kr-81m.

A tomographic study of regional cerebral blood flow and hemodynamics was performed on 25 patients with cerebrovascular diseases by selective continuous infusion of krypton-81m (Kr-81m). Kr-81m single photon emission computed tomograms were superimposed on X-ray computed tomograms to assess topographically the perfusion of the entire brain. Study of cerebrovascular diseases using this method showed: (1) regional cerebral blood flow change; (2) perfusion distribution change; (3) the route by which blood reached the brain or the obstructed artery proximal to the circle of Willis; (4) development of a collateral system and its actual function; and (5) efficacy of surgical bypass after extracranial-intracranial anastomosis. This method is especially useful in hemodynamic assessment in patients with ischemic cerebrovascular disease.

Adult↗
PubMedDate not supplied

Treatment of a spontaneous carotid cavernous fistula using an electrodetachable microcoil.

The authors detail their use of a modified version of an electrolysis coil currently manufactured in the United States. They connect a platinum wire to a stainless steel wire via a copper segment, and apply low voltage current to induce thrombosis while electrolysis of the copper effects separation of the platinum coil. Their technique shows potential for treatment of complicated carotid cavernous fistulas.

Arteriovenous Fistula↗