Biomedical subjects

Koichi Iwasaki

Publications and source records attributed to Koichi Iwasaki.

5 recordsLinked to original sources

PubMed2006

[A case of bow hunter's stroke treated with endovascular surgery].

Bow hunter's stroke results from vertebrobasilar insufficiency due to a mechanical occlusion or stenosis of the vertebral artery caused by head rotation. We report here a case of bow hunter's stroke that was successfully treated with endovascular surgery. A 69-year-old male complained of intractable vertigo when he rotated his head to the right side. Neuroradiological studies proved that the symptom was attributed to the mechanical severe stenosis of the left vertebral artery at the C1-C2 level on head rotation, in addition to the atherosclerotic stenosis at the origin of the right vertebral artery. Two different treatments were considered, including direct surgeries to prevent the mechanical stenosis of the left vertebral artery, and an endovascular dilatation of the atherosclerotic stenosis of the right vertebral artery. Endovascular surgery with a stenting technique, which was thought to be less invasive, was undertaken and resulted in a complete relief of the patient's symptom. To our knowledge, this is the first report to have shown the efficacy of endovascular surgery on this uncommon disease.

Dilatation↗

PubMed2006

[Treatment of a ruptured giant internal carotid artery pseudoaneurysm following transsphenoidal surgery: case report and literature review].

We report here a case of giant internal carotid artery (ICA) pseudoaneurysm as a complication of transsphenoidal surgery. This 50-year-old acromegalic male presented to our clinic with a status of hypovolemic shock due to serious epistaxis. Neuroradiological examinations at his admission revealed a giant aneurysm in the right cavernous portion projecting into the sphenoid sinus. Eight years before this presentation, he had undergone a transsphenoidal surgery for growth hormone producing pituitary tumor at the other clinic. Then intraoperative arterial bleeding was reported, probably as a result of carotid injury. His medical history and radiological findings suggested that his epistaxis resulted from a rupture of the iatrogenic pseudoaneurysm which had gradually grown after the ICA injury at the previous surgery over 8 years. Emergent coil embolization using Guglielmi detachable coils (GDCs) resulted in a successful homeostasis. Major part of the aneurysm dome was obliterated via the intervention, however small part of the aneurysm neck was unable to be obliterated due to a technical difficulty. His postoperative course was favorable, but he suffered from a recurrence of serious epitaxis 4 weeks after the embolization. Emergent angiography suggested a rupture of the un-obliterated aneurysm neck remnant. Thus, trapping of the aneurysm combined with high flow bypass was necessitated. Relevant literatures are reviewed, and possible therapeutic strategies for this rare lesion are discussed.

Aneurysm, False↗

PubMed2004

Relationship between liver injury and transglutaminase activities in guinea pigs and rats.

We investigated the effect of transglutaminase (TGase) on in guinea pigs and rats. Serum alanine aminotransferase (ALT) level increased 1 d after CCl(4) treatment of both in guinea pigs and rats since TGaese activity was greatly higher in guinea pigs than rats. However, serum ALT level in guinea pigs was very much lower than that in rats. Liver TGase activities decreased after CCl(4) treatment in both guinea pigs and rats. However, TGase activities in the liver from guinea pigs were higher than that from rats. Decreased TGase activities by CCl(4) in the liver from guinea pigs and rats were significantly recovered by retinoic acid treatment that was reported to increase TGase. Degree of recovery of serum ALT level by retinoic acid in rats was larger than in guinea pigs. These results suggested that the distinction of the effect of retinoic acid on serum ALT level in CCl(4)-treated animals was due to the different TGase activity that increased membrane stability.

Alanine Transaminase↗

PubMed2004

Stent-supported coil embolization for carotid artery pseudoaneurysm as a complication of endovascular surgery--case report.

A 57-year-old male presented with right amaurosis fugax and left transient ischemic attack caused by stenosis of the intracranial segment of the right internal carotid artery (ICA). Percutaneous transluminal angioplasty with stenting was successfully performed to dilate the stenosis. However, serial angiography revealed the development of a large pseudoaneurysm in the cervical ICA, probably as a result of carotid wall injury caused by the guiding catheter during the procedures. The patient underwent a second endovascular angioplasty. A Palmaz stent was placed across the aneurysm neck to stabilize the carotid wall. Guglielmi detachable coils were then inserted into the aneurysm cavity through the stent struts to successfully obliterate the aneurysm. Both the angiographical results and the patient's outcome were favorable. Stent-supported coil embolization is an effective and safe technique for medically refractory pseudoaneurysms, and may be a useful alternative to direct surgery.

Angioplasty, Balloon↗

PubMed2002

Cerebellopontine angle epidermoids presenting with cranial nerve hyperactive dysfunction: pathogenesis and long-term surgical results in 30 patients.

OBJECTIVE: To provide the characteristics and long-term surgical results of patients who present with cerebellopontine angle epidermoids and trigeminal neuralgia (TN) or hemifacial spasm. METHODS: A total of 30 patients (23 women, 7 men) who presented with cerebellopontine angle epidermoids and TN (28 patients) or hemifacial spasm (2 patients) between 1982 and 1995 were reviewed, with emphasis being placed on the clinical manifestations, the mechanisms of symptom development, the long-term follow-up results, and the anatomic relationship between the tumor and the surrounding neurovascular structures. RESULTS: The average age of the patients was 37.8 years at symptom onset and 49.3 years at the time of the operation. The tumor-nerve relationships were classified into four types: complete encasement of the nerve by the tumor, compression and distortion of the nerve by the tumor, compression of the nerve by an artery located on the opposite side of the unilateral tumor, and compression of the nerve by an artery on the same side of the tumor. Total resection was achieved in 17 patients (56.7%). Microvascular decompression of the respective cranial nerve was achieved in nine cases of direct arterial compression in addition to tumor removal. The symptom was relieved completely in all cases. In an average follow-up period of 11.5 years, three patients developed recurrent symptoms: two experienced tumor regrowth, and one had arachnoid adhesion. CONCLUSION: Hyperactive dysfunction of the cranial nerves, especially TN, may be the initial and only symptom that patients with cerebellopontine angle epidermoids experience. The occurrence of TN at a younger age was characteristic of TN patients with epidermoids, in contrast to patients with TN due to a vascular cause. The symptom is elicited by compression of the nerve by the tumor per se, by an artery that is displaced to the nerve, or by both. Careful resection of the tumor, whose capsule occasionally is strongly adherent to the neurovascular structures, is necessary, and microvascular decompression to straighten the neuraxis should be performed in some cases to achieve a complete, permanent cure of symptoms with a low rate of recurrence.

Adult↗