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Biomedical subjects

M Komiyama

Publications and source records attributed to M Komiyama.

At least 55 records · Page 3Linked to original sources
PubMed2000

Basal meningoencephalocele, anomaly of optic disc and panhypopituitarism in association with moyamoya disease.

Basal meningoencephalocele is frequently associated with midfacial anomaly, optic disc anomaly, brain anomaly, cerebrospinal fluid rhinorrhea, chiasma syndrome, and endocrinologic disturbance. The combination of basal meningoencephalocele and moyamoya disease is extremely rare. A 29-year-old man had basal meningoencephalocele (transsphenoidal type), anomaly of the optic disc (morning glory syndrome), panhypopituitarism and moyamoya disease. The patient was treated by hormone replacement, but surgical intervention was not required. Basal meningoencephalocele and moyamoya disease are a possible combination of the diseases.

Adult↗
PubMed2000

Fast skeletal muscle isoforms exhibit the highest incorporation level into myofibrils and stress fibers among members of myosin alkali light chain isoform family.

Isoproteins of myosin alkali light chain (LC) were co-expressed in cultured chicken cardiomyocytes and fibroblasts and their incorporation levels into myofibrils and stress fibers were compared among members of the LC isoform family. In order to distinguish each isoform from the other, cDNAs of LC isoforms were tagged with different epitopes. Expressed LCs were detected with antibodies to the tags and their distribution was analyzed by confocal microscopy. In cardiomyocytes, the incorporation level of LC into myofibrils was shown to increase in the order from nonmuscle isoform (LC3nm), to slow skeletal muscle isoform (LC1sa), to slow skeletal/ventricular muscle isoform (LC1sb), and to fast skeletal muscle isoforms (LC1f and LC3f). Thus, the hierarchal order of the LC affinity for the cardiac myosin heavy chain (MHC) is identical to that obtained in the rat (Komiyama et al., 1996. J. Cell Sci., 109: 2089-2099), suggesting that this order may be common for taxonomic animal classes. In fibroblasts, the affinity of LC for the nonmuscle MHC in stress fibers was found to increase in the order from LC3nm, to LC1sb, to LC1sa, and to LC1f and LC3f. This order for the nonmuscle MHC is partly different from that for the cardiac MHC. This indicates that the order of the affinity of LC isoproteins for MHC varies depending on the MHC isoform. Further, for both the cardiac and nonmuscle MHCs, the fast skeletal muscle LCs exhibited the highest affinity. This suggests that the fast skeletal muscle LCs may be evolved isoforms possessing the ability to associate tightly with a variety of MHC isoforms.

Animals↗
PubMed2000

Embolic cerebellar infarction caused by spontaneous dissection of the extracranial vertebral artery--two case reports.

Spontaneous dissection of the extracranial vertebral artery (VA) may cause ischemic stroke in the posterior circulation. A 22-year-old female and a 38-year-old male presented with sudden onset of vertigo and nausea without trauma. Angiography was initially interpreted as normal, but retrospective examination disclosed extracranial VA dissection in the V3 segment in both cases. Arterial dissection resulting in embolic stroke in the territory of the ipsilateral posterior inferior cerebellar artery was highly suspected. Both patients were treated conservatively without sequelae. Careful angiographic interpretation is important for the diagnosis of extracranial VA dissection. Spontaneous extracranial VA dissection should be suspected in young patients presenting with ischemic stroke but without predisposing risk factors or associated trauma.

Adult↗
PubMed2000

Subarachnoid hemorrhage from vertebral artery dissecting aneurysms involving the origin of the posteroinferior cerebellar artery: report of two cases and review of the literature.

OBJECTIVE AND IMPORTANCE: Few reports have been published on ruptured vertebral artery dissecting aneurysms in which the posteroinferior cerebellar artery (PICA) arises from the aneurysm wall, and there is ongoing debate as to the proper management of this type of aneurysm. This article describes two patients. CLINICAL PRESENTATION: Both patients presented with subarachnoid hemorrhage and were admitted to our institution on the day of rupture. Computed tomography revealed that the subarachnoid hemorrhage was located mainly in the posterior fossa. Cerebral angiography demonstrated a vertebral dissecting aneurysm involving the origin of the PICA. In one patient, the PICA was very large. INTERVENTION: One patient was treated by trapping, with the PICA involved in the trapped segment. Postoperatively, the patient experienced transient mild hoarseness and dysphasia but recovered completely. The other patient, whose PICA was very large, was initially treated by endovascular proximal occlusion. This resulted in marked enlargement of the distal part of the aneurysm, indicating a need for surgical treatment. A clip was applied to the origin of the PICA after anastomosis of the occipital artery to the PICA. The patient recovered well and was discharged with no neurological deficits. CONCLUSION: The ideal method of treatment for patients with dissecting aneurysms of the vertebral artery involving the PICA origin is complete isolation of the aneurysm by trapping, with revascularization of the PICA. However, trapping alone is one possible treatment option. If proximal clipping alone is carried out, follow-up angiography is mandatory to observe any changes in the aneurysm.

Adult↗
PubMed2000

[Cervical pyogenic spondylodiscitis: 4 cases report and a review of the literature].

We report 4 cases of cervical spondylodiscitis presenting neurological and/or neuroradiological abnormalities. Such a lesion is rare in the cervical spine of adults, but should be suspected when the patient has radiculopathy and/or myelopathy associated with inflammatory signs. We discussed the clinical characteristics and the procedures of the diagnosis and treatment of cervical spondylodiscitis. Early and definitive diagnosis can be achieved by cervical X-ray, MR imaging and biopsy. It is very important to evaluate the pyogen for the lesion by needle biopsy. When the patient has the compression of the spinal cord and/or nerve roots and the neurological findings of radiculopathy and/or myelopathy, surgical exploration and decompression of the spinal cord and/or nerve roots should be carried out as soon as possible. Anterior debridement and fusion should be performed using the effective antibiotics. We were able to achieve good prognosis by treatment following this procedure of diagnosis in the four cases of cervical spondylodiscitis mentioned.

Adult↗
PubMed2000

[Rerupture mechanism of ruptured intracranial dissecting aneurysm in the vertebral artery following proximal occlusion].

Proximal occlusion is commonly employed to prevent rebleeding of intracranial dissecting aneurysms of the vertebral artery (VA), but rebleeding sometimes occurs. To determine the cause of such rebleeding we reviewed nine cases, including eight reported in the literature and one treated at our hospital. We classified the techniques used to proximally occlude the VA into two types. In Type I, occlusion is performed immediately proximal to the aneurysm so that there are no perforating arteries or the posterior inferior cerebellar artery (PICA) between the clip and the aneurysm. In Type II, occlusion is performed proximal to the PICA so postoperative retrograde flow persists from the contralateral VA through the aneurysm into the ipsilateral PICA. Among the four Type I cases reviewed, it was found that the interval between occlusion and rebleeding was very short: three developed rebleeding within four hours of occlusion, and the fourth showed rebleeding on the fourth day. In the five Type II patients, rebleeding occurred more than four days (mean 15.2 days) after occlusion. It is thought that in Type I occlusion, retrograde flow into the aneurysm immediately after occlusion may raise the intraaneurysmal pressure enough to cause rerupture within just a few hours of occlusion. In Type II occlusion, postoperative retrograde flow through the aneurysm into the ipsilateral PICA exists, so the intraaneurysmal pressure is not likely to rise as rapidly, with the result that rebleeding occurred after more than four days probably due to recurrence of dissection. The short interval between proximal occlusion and rebleeding, especially in Type I cases, suggests that postoperative angiography is only of limited usefulness in evaluating the possibility of rebleeding. The mortality rate reported for cases with reruptured vertebral dissecting aneurysms after proximal occlusion is very high (55.6%). These data indicate that surgical trapping or endovascular intraluminal occlusion, which is difficult to perform in some patients, should be considered the most suitable procedure from the view point of preventing postoperative rebleeding.

Cerebral Hemorrhage↗
PubMed2000

[Dural arteriovenous fistulae in the anterior cranial fossa--report of three cases].

Dural arteriovenous fistulae (DAVF's) in the anterior cranial fossa are uncommon. We encountered three patients with DAVF's in the anterior cranial fossa and reviewed the pertinent literature with regard to the etiology. All patients are middle-aged males. Two of three patients had massive intracranial hemorrhage, subarachnoidal hemorrhage in one and subdural hemorrhage in the other. One patient had a ruptured middle cerebral artery aneurysm and DAVF at the anterior cranial fossa was detected only incidentally. Angiographically, blood supplies were from the bilateral enlarged anterior ethmoidal arteries. These drained into the superior sagittal sinus via dilated frontal cortical veins. In all the patients, coagulation of the fistulous connections was carried out and the postoperative courses were uneventful. Angiographies revealed complete disappearance of the DAVF's. In conclusion, compared to cases of DAVF's in the other locations, DAVF's of the anterior cranial fossa are more likely to be brought on by sudden massive intracranial hemorrhage, and should be treated, even if asymptomatic, at the time of diagnosis. Surgical obliteration of the fistulous connection is sufficient treatment for DAVF in the anterior cranial fossa. Literature review strongly suggests that DAVF's involving the anterior cranial fossa are acquired lesions.

Aged↗
PubMed2000

[The limitations of three-dimensional CT angiography (3D-CTA) in the diagnosis of cerebral aneurysms].

OBJECT: The purpose of this study is to show some limitations of 3D-CTA to diagnose cerebral aneurysms. METHODS: Sixteen saccular aneurysms less than 10 mm in diameter were included. Large and complicated aneurysms were excluded. RESULTS: Although information about perforating arteries from the posterior cerebral artery is very important for surgery of basilar bifurcation aneurysms, 3D-CTA could not delineate the perforating arteries. A small posterior communicating artery (Pcom.A.) was not detected, and it was very difficult to differentiate infundibular dilatation of the Pcom. A. from an aneurysm. A small aneurysm of the distal middle cerebral artery could not be detected. Flow direction can not be determined by 3D-CTA, and nor could the side of the neck of the anterior communicating artery aneurysm be determined. Fenestration of the anterior communicating artery and the origin of the triple anterior cerebral artery were both misdiagnosed as anterior communicating artery aneurysms. CONCLUSION: It is premature to consider 3D-CTA as a replacement for conventional angiography.

Adult↗
PubMed1999

Photoregulation of the Formation and Dissociation of a DNA Duplex by Using the cis-trans Isomerization of Azobenzene.

The duplex-forming activity of an oligonucleotide has been photoregulated by making use of the isomerization of an azobenzene moiety in the side chain. When the azobenzene moiety is isomerized from the trans form to the cis form upon photoirradiation, the melting temperature of the duplex between the oligonucleotide and its complementary counterpart is significantly lowered, and the duplex is largely dissociated into two single-stranded oligonucleotides (shown schematically).

Journal Article↗
PubMed1999

Gamma knife surgery for skull base meningiomas. The effectiveness of low-dose treatment.

BACKGROUND: The surgical removal of skull base meningiomas has a high morbidity rate, even by modern microsurgical standards. We evaluated the results of gamma knife surgery for skull base meningiomas using a relatively low radiation dose for the tumor margins. METHODS: We reviewed 24 cases of skull base meningiomas during a 30-month period. The locations of the tumors were the petroclival region in 11 cases, the cavernous sinus region in 9 cases, and the cerebellopontine angle region in 4 cases. Eight patients (33%) had been operated on previously and fourteen patients (67%) had been treated by neuroimaging. The marginal doses for the tumors were 8 Gy to 15 Gy (median, 10.6 Gy). A large petroclival tumor 58 mm in diameter was treated with a staged treatment protocol with a 6-month interval between treatments. RESULTS: Tumor regression was observed in 46% of the patients imaged during the follow-up period (median, 17.1 months). No patients revealed tumor growth in the follow-up period (100% tumor control rate). Eleven patients (46%) had improved clinically by the time of the follow-up examinations. Preexisting cranial nerve deficit in one patient worsened because of radiation injury. CONCLUSION: Although a longer follow-up period is required, the relatively low minimum tumor radiation dose treatment for skull base meningiomas using a gamma knife seems to be an effective treatment with low morbidity.

Adult↗
PubMed1999

Brachial plexus and supraclavicular nerve injury caused by manual carotid compression for spontaneous carotid-cavernous sinus fistula.

BACKGROUND: Manual carotid compression is an established treatment for a spontaneous carotid-cavernous sinus fistula unless emergency treatment is required for it. CASE REPORT: A 63-year-old woman presented with a spontaneous carotid-cavernous sinus fistula. Manual carotid compression of 5 minutes duration, twice a day, for 10 days resulted in injury to the upper trunk (C 5-6) of the brachial plexus and the supraclavicular nerve (C 3-4), which subsequently resolved within a month after cessation of the procedure. CONCLUSION: It is important to know the possible neurological complications of manual carotid compression.

Arteriovenous Fistula↗
PubMed1999

Thin-filament-binding domains of cardiac and fast skeletal muscle troponin I isoforms as studied by epitope tagging.

We examined the binding domains of cardiac and fast skeletal muscle troponin I (CTnI and FTnI, respectively) to myofibrils (MFs). Deletion mutants containing CTnI amino acid residues 1-79, 43-207 and 80-207 (CTnI-head, CTnI-tail-I and CTnI-tail-2, respectively) and FTnI amino acid residues 1-54 and 55-182 (FTnI-head and FTnI-tail, respectively) were transiently expressed in cardiac and fast skeletal muscle cells. To monitor the intracellular localization of these exogenously introduced truncated TnIs, epitope tagging was used. CTnI-tail-1 was incorporated into cardiac MFs specifically, but CTnI-tail-2 was not assembled onto any MFs examined. This suggests that there is no potent actin filament-binding site in CTnI-tail-2. Since CTnI-tail-1 has an amino acid extension (CTnI residues 43-79) whose sequence is longer than that of CTnI-head-2; it appears that this sequence extension is important in binding to cardiac MFs. FTnI-tail, containing the inhibitory domain of actomyosin ATPase, showed intensive and specific incorporation into fast MFs. FTnI-tail was a homologous fragment of CTnI-tail-2, but the binding patterns of these two domains differed greatly from each other. It is possible that the absence of potent binding affinity of CTnI-tail-2 corresponding to the inhibitory domain of actomyosin ATPase is advantageous for continuous cardiac muscle contraction, since a potent inhibitory activity is a serious obstacle to cardiac muscle contraction. It can be assumed that distinctive binding ability of functional domains of TnI-tails reflect unique adaptations to muscles with different physiological properties.

Amino Acid Sequence↗
PubMed1999

Variations of the extensor indicis muscle and tendon.

Variations of the extensor indicis muscle were examined in 164 hands from 86 Japanese cadavers. Anomalous cases exhibiting supernumerary muscles or tendons were found in 22 hands. These variations were classified into four types: type 1, an additional tendon slip from the extensor indicis tendon; type 2, an extensor indicis radialis or extensor pollicis et indicis accessorius; type 3, an extensor medii proprius with or without extensor medii brevis; and type 4, an extensor indicis radialis and extensor medii proprius. The extensor medii proprius was the most common variation, followed by extensor indicis radialis. There were no clear differences in incidence of variations between men and women or between right and left hands. When variations were bilateral, both sides were identical or similar in type.

Adult↗
PubMed1999

Photo-regulated duplex- and triplex-formation of the modified DNA carrying azobenzene.

The duplex- and triplex- forming activity of oligonucleotide was photo-regulated by using the isomerization of azobenzene in the side chain. When the azobenzene was isomerized from the trans-form to the cis-form by photo-irradiation, the melting temperatures of the duplex and triplex between the oligonucleotide and its complementary counterpart were significantly lowered.

Azo Compounds↗
PubMed1999

Improvement of efficiency of the Ce(IV)-induced DNA scission--relationship between the kinetic parameters (k(cat) and Km) and the DNA structure.

The Michaelis constant (Km) for double-stranded DNA, single-stranded DNA, and dinucleotide hydrolysis by Ce(IV) ion are 4.4, 15, and more than 40 mM, respectively. The order of the k(cat), however, is dinucleotide >> oligonucleotides. Not only the improvement of k(cat) but also that of Km is important for the design of an efficient artificial nuclease.

Base Sequence↗