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Biomedical subjects

M Komiyama

Publications and source records attributed to M Komiyama.

At least 37 records · Page 2Linked to original sources
PubMed2001

"Early" apoplexy due to traumatic intracranial aneurysm--case report.

A 76-year-old man presented with a traumatic aneurysm of the left internal carotid artery which caused repeated subarachnoid hemorrhages within 20 hours of a fall from a height. Early computed tomography (CT) detected no brain abnormalities, but repeat CT found subarachnoid hemorrhage. Internal carotid angiography detected a pseudoaneurysm, which was not treated because of his poor clinical condition. He died of multiple organ failure. Early detection of a traumatic intracranial aneurysm is important for the prevention of aneurysmal rupture, or "delayed" apoplexy. Review of 171 cases with traumatic aneurysms from the literature found that false negative angiography occurred only in three cases on post-trauma day 7 and thereafter. Early diagnostic angiography within a week of the initial trauma is indicated if traumatic aneurysm is suspected to detect early signs of irregularity, spasm, and narrowing of the arterial wall. Repeat angiography is indicated if aneurysmal formation is still highly suspected in spite of negative initial angiography.

Acute Disease↗
PubMed2001

Moyamoya disease and coronary artery disease--case report.

A 26-year-old female with idiopathic moyamoya disease developed chest pain with concomitant ST depression on electrocardiography. Coronary angiography detected no stenotic lesions in the epicardial coronary arteries. The clinical diagnosis was vasospastic angina pectoris. She was medicated with calcium antagonists, which reduced the frequency of chest pain episodes. Angina pectoris is a rare occurrence in young patients with moyamoya disease. Coronary artery disease and moyamoya disease may have common etiological factors.

Adult↗
PubMed2001

Primitive trigeminal artery variant aneurysm treated with Guglielmi detachable coils--case report.

A 69-year-old woman had suffered from diplopia on right lateral gaze for the last 4 months due to right abducens nerve paresis. Right carotid angiography showed a cavernous internal carotid artery (ICA) aneurysm of 17 x 16 x 14 mm size and a primitive trigeminal artery (PTA) variant supplying the territory of the posterior inferior cerebellar artery. Intraluminal occlusion of the aneurysm was performed with 15 Guglielmi detachable coils. The flow of the PTA variant and the ICA was preserved. Right abducens nerve paresis improved partially. PTA variant is a primitive artery originating from the cavernous ICA supplying the cerebellum without opacification of the basilar artery. Only four of the 67 cases of PTA variant were associated with an aneurysm of the PTA variant. The possibility of this rare association should be considered when treating cavernous portion aneurysm because of the risk of cerebellar ischemia.

Abducens Nerve Diseases↗
PubMed2001

Evolution of incidentally-discovered fusiform aneurysms of the vertebrobasilar arterial system: neuroimaging features suggesting progressive aneurysm growth.

This study investigated the natural history and biological behavior of incidental fusiform aneurysms in four patients with incidental fusiform aneurysms of the vertebrobasilar arterial system who had been followed up for more than 3 years (mean 3.5 years). Two lesions remained the same size, and two lesions gradually grew. Angiography showed the non-growing fusiform aneurysms as a circumferentially or unilaterally fusiform dilatation of a short segment of the vertebral artery with smooth walls and a steep slope of the dilatation, and the growing fusiform aneurysms as unilaterally fusiform involving a long segment of the vertebral artery or basilar artery with irregular walls and a gentle slope of dilatation. Magnetic resonance (MR) imaging demonstrated the non-growing fusiform aneurysms as a signal-void area, and the growing fusiform aneurysms as high and intermediate signals in addition to the normal flow void. The heterogeneous MR intensities probably correspond to turbulent flow, laminar flow, thrombosis, or intramural hematoma. Differentiation of growing and non-growing fusiform aneurysms is very difficult at the initial diagnosis. However, enlargement of the fusiform aneurysms is consistent with hemorrhage into the aneurysmal wall, which is confirmed by MR imaging. Fusiform aneurysms with the characteristics of the growing aneurysms cannot be overlooked because of the potential to develop into giant fusiform aneurysms which are very difficult to manage therapeutically.

Cerebral Angiography↗
PubMed2001

High incidence of arterial dissection associated with left vertebral artery of aortic origin.

The incidences of arterial dissection of the vertebral artery (VA) of aortic origin and VA of subclavian artery origin were determined. The origins of the left and right VAs were confirmed by angiography in 860 and 717 patients, respectively. Left VA of aortic origin was found in 21 patients (6 females and 15 males) but no right VA of aortic origin was found. Left VA of left subclavian artery origin was found in 837 patients and right VA of right subclavian artery origin in 717 patients. Arterial dissection of the VA occurred in 17 patients (6 females and 11 males), four patients with left VA of aortic origin, seven with left VA of left subclavian artery origin, four with right VA of right subclavian artery origin, and two with bilateral VAs of subclavian artery origin. Left VA of aortic origin (4 of 21 patients) was associated with a significantly higher incidence of VA dissection than left VA of left subclavian artery origin and right VA of right subclavian artery origin (p < 0.001). Left VA of aortic origin is associated with a predilection for VA dissection in comparison to VA of subclavian artery origin.

Aortic Dissection↗
PubMed2001

[Treatment for brain metastasis from lung cancer in the era of radiosurgery].

OBJECTIVE: The treatment for brain metastasis has undergone remarkable changes since the development of radiosurgery. We investigated the results of treatment for brain metastasis from lung cancer since the initiation of gamma knife radiosurgery (GKRS) and we discuss the usefulness of GKRS combined with other treatments in cases with recurrence. METHODS: We treated 142 patients with brain metastasis from lung cancer. Sixteen patients were treated surgically, 11 patients were treated with whole brain radiation therapy (WBRT), and 115 patients were treated with GKRS. Our treatment plan is to use GKRS in cases with less than 5 lesions and lesions less than 3 cm in mean diameter. We use WBRT in cases with 5 or more lesions, and surgery in cases with lesions 3 cm or larger. If new lesions or tumor regrowth appeared after the initial treatment, we retreated them with one of the methods mentioned above. RESULTS: Twice or three-time treatments were performed in 30 patients. Median survival including all cases was 10 months and the number of deaths due to local treatment failure was only 5 (6.5%) out of the total 77 deaths which occurred. CONCLUSION: We were able to carry out less invasive treatment for brain metastasis from lung cancer by utilizing GKRS. Though we have to consider the indications for other treatments, we can say that radiosurgery is usually the treatment of first choice for brain metastasis from lung cancer. When new lesions appear in cases where a particular initial treatment was used, it is possible to maintain or improve the quality of life by retreatment, using a combination of GKRS, surgery or WBRT, to prolong the patient's life.

Adenocarcinoma↗
PubMed2001

A 3.2-French cerebral diagnostic catheter for all ages: technical note.

We report our experience with a 3.2F cerebral diagnostic catheter system. Thirty patients (aged 6 months to 76 years) had undergone cerebral angiography. All targeted brachiocephalic vessels were catheterized except for one artery (98.9% success rate). The image quality obtained with the 3.2F catheter was judged to be comparable with that using the 4F catheter in all cases. This catheter system could be used for cerebral angiography as the standard for patients of all ages.

Adolescent↗
PubMed2000

Catalytic hydrolysis of peptides by cerium(IV).

Oligopeptides are efficiently hydrolyzed by Ce(IV) to the corresponding amino acids under mild conditions. The pseudo first-order rate constants for the hydrolysis of H-Gly-Phe-OH and H-Gly-Gly-OH at pH 7.0 and 50 degrees C are 3.5 x 10(-1) and 2.8 x 10(-1) h(-1), with [Ce(NH4)2(NO3)6]0=10mM (the half-lives are 2.0 and 2.5 h). The catalytic activity of the Ce(IV) is far greater than those of other lanthanide ions and non-lanthanide ions. No oxidative cleavage was observed under the reaction conditions. Catalytic turnover of the Ce(IV) was also evidenced. The hydrolysis is fast especially when the substrates have no metal-coordinating side chains. Tripeptides and tetrapeptides are hydrolyzed at the similar rates as the dipeptides. In the hydrolysis of tripeptides, the amide linkage near the N-terminus is preferentially hydrolyzed. Neither the N-carbobenzyloxy derivative nor the amide of H-Gly-Phe-OH is hydrolyzed to a measurable extent, showing that both the terminal amino group and the carboxylate are coordinated to the Ce(IV) ion. This complexation is further confirmed by 1H NMR spectroscopy. The Ce(IV) ion is therefore one of the most active catalysts for peptide hydrolysis.

Catalysis↗
PubMed2000

Kinetic and theoretical studies on the mechanism of alkaline hydrolysis of DNA.

The reaction mechanism of alkaline hydrolysis of DNA has been investigated by kinetic analysis and density-functional-theory calculation. The rates of hydrolysis of thymidine 3'-monophosphate esters (including thymidylyl(3'-5')thymidine (Tp-OT)) monotonically decrease as the leaving groups get poorer. According to the theoretical calculation in which the solvent effects are incorporated, no intermediate is formed in the course of the reaction. In the alkaline hydrolysis of the activated Tp-OT analogues having good leaving groups, the 3',5'-cyclic monophosphate of thymidine is concurrently formed through the intramolecular attack by the 5'-alkoxide ion. In the hydrolysis of the native dinucleotide, however, this side reaction does not occur, since the transition state leading to the departure of its poor leaving group cannot be formed due to conformational restraint. These arguments are supported by the theoretical analysis on the hydrolysis of both dimethyl phosphate and its O(bridging)-->S substituted analogue.

DNA↗
PubMed2000

Photoregulation of the DNA Polymerase Reaction by Oligonucleotides Bearing an Azobenzene We should like to thank Professor Kazunari Taira for valuable comments. This work was partially supported by the Grant-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture, Japan (Molecular Synchronization for Design of New Materials System). The support of the grant from the "Research for the Future" Program of the Japan Society for the Promotion of Science (JSPS-RFTF97I00301) is also acknowledged.

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Journal Article↗
PubMed2000

Photocontrol of Triple-Helix Formation by Using Azobenzene-Bearing Oligo(thymidine) This work was partially supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture, Japan (Molecular Synchronization for the Design of New Material Systems). The grant from the "Research for the Future" program of the Japanese Society for the Promotion of Science (JSPS-RFTF97I00301) is also acknowledged.

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Journal Article↗
PubMed2000

Chronological changes in nonhaemorrhagic brain infarcts with short T1 in the cerebellum and basal ganglia.

Our purpose was to investigate nonhaemorrhagic infarcts with a short T1 in the cerebellum and basal ganglia. We carried out repeat MRI on 12 patients with infarcts in the cerebellum or basal ganglia with a short T1. Cerebellar cortical lesions showed high signal on T1-weighted spin-echo images beginning at 2 weeks, which became prominent from 3 weeks to 2 months, and persisted for as long as 14 months after the ictus. The basal ganglia lesions demonstrated slightly high signal from a week after the ictus, which became more intense thereafter. Signal intensity began to fade gradually after 2 months. High signal could be seen at the periphery until 5 months, and then disappeared, while low or isointense signal, seen in the central portion from day 20, persisted thereafter.

Adult↗
PubMed2000

Steno-occlusive changes in the external carotid system in moyamoya disease.

To evaluate the steno-occlusive changes in the external carotid system in moyamoya disease, cerebral angiograms of 39 moyamoya patients were retrospectively reviewed. There were 26 females and 13 males, age ranged from 4 to 62 years with a mean of 26 years. Initial symptoms were ischaemia in 27 patients, haemorrhage in 9, and none in 3. Stenosis, occlusion, and dilatation in the external carotid system were analysed angiographically. No stenosis or occlusion of the superficial temporal artery, middle meningeal artery, or occipital artery was observed in either preoperative or postoperative follow-up angiograms in any patients. Steno-occlusive changes do not occur in the external carotid system, but are confined in the internal carotid system in moyamoya disease.

Adolescent↗
PubMed2000

Hydrolysis of DNA by Ce(IV)/EDTA complexes--the mechanism of DNA cleavage and design of artificial restriction enzymes.

Homogeneous Ce(IV) complex of EDTA promptly hydrolyzes oligonucleotides under physiological conditions. Moreover, the activity of Ce(IV)/EDTA for DNA hydrolysis is promoted by the addition of amines. When [Ce(IV)/EDTA] = 5 mumol dm3 and [ethylenediamine] = 100 mmol dm3, the catalytic activity is about 50 times as large as that of Ce(IV)/EDTA. The combination of Ce(IV)/EDTA and amines is eminent tools for the future molecular biology and biotechnology.

Catalysis↗
PubMed2000

Photo-regulation of DNA/RNA duplex formation by azobenzene-tethered DNA towards antisense strategy.

Modified DNA carrying an azobenzene was successfully applied to the photo-regulation of DNA/RNA hybridization. When the azobenzene was isomerized from trans- to cis-form on UV-irradiation, the melting temperature of the duplex was significantly lowered. This process was totally reversible so that the Tm increased by cis-->trans isomerization induced by visible light irradiation.

Azo Compounds↗
PubMed2000

Endovascular treatment of huge cervicofacial hemangioma complicated by Kasabach-Merritt syndrome.

A 2-month-old girl with a huge cervicofacial hemangioma complicated by Kasabach-Merritt syndrome was presented. Two weeks corticosteroid treatment was ineffective, and deterioration of coagulation parameters and compromise of the airway and left vision due to huge hemangioma prompted use of endovascular treatment. Transfemoral arterial embolization using polyvinyl alcohol particles resulted in rapid clinical improvement. Endovascular treatment should be considered as an important therapeutic option for hemangioma complicated by Kasabach-Merritt syndrome.

Anemia, Hemolytic↗