Biomedical subjects

Satoshi Kuroda

Publications and source records attributed to Satoshi Kuroda.

11 recordsLinked to original sources

PubMed2003

Source localization of the re-build up phenomenon in pediatric moyamoya disease-a dipole distribution analysis using MEG and SPECT.

OBJECTS: The "re-build up" phenomenon is a pathognomonic finding induced after hyperventilation in pediatric moyamoya disease, and is closely related to ischemic attacks. However, its precise mechanism remains unknown. METHODS: In this study, MEG, MRI, and SPECT were used to clarify its mechanism in 4 children with moyamoya disease. Cerebral blood flow before and after acetazolamide administration was measured. Spontaneous magnetic brain activity was measured using a whole-head MEG system. The quantified dipole distribution was shown on 3D-MRI. RESULTS AND CONCLUSION: The original current dipoles of the "re-build up" slow waves were predominantly located in the deep cortical sulci in the area with impaired reactivity to acetazolamide. The results suggested that the re-build up waves derive from the deep cortical sulci due to the reduction in the cerebral perfusion reserve.

Adolescent↗

PubMed2003

Calcium-induced mitochondrial swelling and cytochrome c release in the brain: its biochemical characteristics and implication in ischemic neuronal injury.

The objective of the present study was to determine the biochemical characteristics of Ca(2+)-induced mitochondrial swelling (mitochondrial permeability transition; mPT) and cytochrome c release in the brain, and to clarify its role in neuronal injury following transient forebrain ischemia. Mitochondria were isolated from rat brain and liver. Changes in mitochondrial volume were measured via light absorbance at 540 nm. Using Western blot analysis, we examined the in vitro release of mitochondrial cytochrome c under these conditions. Transient forebrain ischemia was induced by 5 min occlusion of the common carotid arteries in the gerbil. Cyclosporin A (CsA), a specific mPT blocker, and/or trifluoperazine, a blocker of phospholipase A(2), were given before and 24 h after ischemia. The number of surviving neurons in the hippocampal CA1 sector was counted 7 days after ischemia. Calcium induced a moderate decrease of light absorbance in brain mitochondria, which was inhibited by CsA. However, calcium induced a much larger decrease of light absorbance in liver mitochondria. Calcium induced a moderate release of cytochrome c from brain mitochondria, which was not inhibited by CsA. However, calcium induced the release of a larger amount of cytochrome c from liver mitochondria. Selective neuronal injury due to transient forebrain ischemia was significantly ameliorated by treatment with high-dose CsA. The biochemical properties of Ca(2+)-induced mitochondrial swelling in the brain are different from those in the liver. Cytochrome c is released from brain mitochondria through an mPT-independent mechanism. CsA potentially ameliorates delayed neuronal injury in the hippocampus due to transient forebrain ischemia.

Animals↗

PubMed2003

Descending aorta to carotid bypass for takayasu arteritis as a redo operation.

In Takayasu arteritis recurrent brain ischemia, due to bypass graft failure, is frequent. Redo bypass grafting from the ascending aorta may be at risk if a failing but patent graft that is critical for brain blood flow is present, because partial clamping the ascending aorta may disturb graft flow if the ascending aorta is short. We report such a patient who successfully underwent redo bypass grafting from the descending aorta. In type I Takayasu arteritis, this operation may be valuable because the descending aorta is usually disease free and brain blood flow is maintained during the operation.

Adult↗

PubMed2003

Role of Chlamydia pneumoniae-infected macrophages in atherosclerosis developments of the carotid artery.

Chlamydia pneumoniae (C. pneumoniae) infection has been recently accepted as an important cause of atherosclerosis. However, the precise mechanisms remain unclear. The present study was aimed to clarify the distribution link among C. pneumoniae, chlamydial HSP 60, and activated macrophages. Atheromatous carotid plaques were obtained from 40 consecutive carotid endarterectomies (CEA). The specimens were prepared for HE and elastica-van Gieson staining. Parallel sections were stained immunocytochemically with monoclonal antibodies for a C. pneumoniae-specific antigen, chlamydial HSP 60, activated macrophages, and smooth muscle cells. Immunoreactivity for the C. pneumoniae-specific antigen was observed within the endothelial cells, activated macrophages, and smooth muscle cells in 36 of 40 specimens (90%). Chlamydial HSP 60 was found in all specimens positive for the C. pneumoniae-specific antigen, and mainly co-localized with the C. pneumoniae-specific antigen within the activated macrophages. The present results suggest that C. pneumoniae is a key microbial organ that causes atheroma developments in the carotid artery. Chlamydia pneumoniae-infected macrophages may come into the arterial intima and mediate inflammatory and autoimmune processes through the production of chlamydial HSP 60, leading to atherosclerosis.

Aged↗

PubMed2003

Migration and differentiation of nuclear fluorescence-labeled bone marrow stromal cells after transplantation into cerebral infarct and spinal cord injury in mice.

There is increasing evidence that bone marrow stromal cells (BMSC) have the potential to migrate into the injured neural tissue and to differentiate into the CNS cells, indicating the possibility of autograft transplantation therapy. The present study was aimed to clarify whether the mouse BMSC can migrate into the lesion and differentiate into the CNS cells when transplanted into the mice subjected to focal cerebral infarct or spinal cord injury. The BMSC were harvested from mice and characterized by flow cytometry. Then, the BMSC were labeled by bis-benzimide, a nuclear fluorescence dye, over 24 h, and were stereotactically transplanted into the brain or spinal cord of the mice. The cultured BMSC expressed low levels of CD45 and high levels of CD90 and Sca-1 on flow cytometry. A large number of grafted cells survived in the normal brain 4 weeks after transplantation, many of which were located close to the transplanted sites. They expressed the neuronal marker including NeuN, MAP2, and doublecortin on fluorescent immunohistochemistry. However, when the BMSC were transplanted into the ipsilateral striatum of the mice subjected to middle cerebral artery occlusion, many of the grafted cells migrated into the corpus callosum and injured cortex, and also expressed the neuronal markers 4 weeks after transplantation. In particular, NeuN was very useful to validate the differentiation of the grafted cells, because the marker was expressed in the nuclei and was overlapped with bis-benzimide. Similar results were obtained in the mice subjected to spinal cord injury. However, many of the transplanted BMSC expressed GFAP, an astrocytic protein, in injured spinal cord. The present results indicate that the mouse BMSC can migrate into the CNS lesion and differentiate into the neurons or astrocytes, and that bis-benzimide is a simple and useful marker to label the donor cells and to evaluate their migration and differentiation in the host neural tissues over a long period.

Animals↗

PubMed2003

Uncleaved legumin in developing maize endosperm: identification, accumulation and putative subcellular localization.

While identifying proteins present in the cytoskeleton and protein body fractions from maize (Zea mays L.) endosperm, a 51 kDa protein was discovered in a fraction containing small (approximately 200 nm in diameter) protein bodies. Based on partial amino acid sequences of V8 protease fragments, degenerate primers were made and fragments of cDNA encoding these partial sequences were cloned. Using 3' and 5' PCR, a full-length cDNA encoding this 51 kDa protein was obtained, which was identified as legumin-1. In other plants, this protein is generally cleaved into 20 and 35 kDa subunits after synthesis. However, SDS-PAGE of both the native and denatured protein indicates that cleavage does not occur in corn endosperm, even though the cleavage site (asparagine) is conserved. The lack of cleavage is presumably because the canonical cleavage sequence downstream from the cleavage site is almost totally absent. levels of transcript and encoded protein were compared in all three varieties and it was shown that both are more abundant in wild-type maize than in opaque-2 or sweet corn. Finally, using TEM, it was shown that the protein apparently occurs in morphologically distinct protein bodies, very similar to the protein bodies in legumes.

Amino Acid Sequence↗

PubMed2003

[Subclavian steal syndrome associated with the right aortic arch in a patient with Peutz-Jeghers syndrome: case report].

We report an adult case who presented vertigo attacks due to subclavian steal syndrome associated with the right aortic arch in a patient with Peutz-Jeghers syndrome. A 29-year-old male diagnosed as having Peutz-Jeghers syndrome developed frequent vertigo attacks and was admitted to our hospital. Blood pressure of the left arm was 20 mmHg lower than that of the right arm. Aortagraphy showed that he had a right aortic arch and isolation of the left subclavian artery. Right vertebral angiography opacified the left vertebral artery and the subclavian artery in retrograde fashion, suggesting subclavian steal phenomenon. Blood flow studies disclosed impaired reactivity to acetazolamide in the bilateral cerebellar hemispheres. We successfully carried out left common carotid artery-transverse cervical artery bypass. Postoperative angiography confirmed the patency of the graft and the disappearance of subclavian steal phenomenon. Vasoreactivity to acetazolamide normalized in the cerebellum. Vertigo attacks were not noted during the one-year follow-up period.

Adult↗

PubMed2003

[Clinical manifestations of infantile moyamoya disease].

PURPOSE: The present study aimed to clarify clinical manifestations of infantile moyamoya disease by comparing them with those of schoolchild moyamoya disease. SUBJECTS AND METHODS: This study included a total of 55 patients who were diagnosed as moyamoya disease on cerebral angiography. Their medical records were precisely evaluated. CT or MRI was performed to examine the location of cerebral infarction in all subjects. Cerebral blood flow was measured in 33 patients before surgery, using the 133-xenon inhalation method and single photon emission computed tomography (SPECT). Postoperative full-scale IQ (FSIQ) was also examined. RESULTS: Of 55 patients, onset age was < 6 yr in 32 (infantile group) and > or = 6 yr in 23 (schoolchild group). Completed stroke was significantly more frequent in the infantile group than in schoolchild group (p = 0.0014). Incidence of cerebral infarct was also higher in the infantile group than in the schoolchild group (p = 0.0023). PCA stenosis/occlusion was observed in 14 of 32 infantile patients, but only in 4 of 23 schoolchild patients (p = 0.0474). Mean cerebral blood flow value was significantly lower than control value in the infantile group, but not in the schoolchild group. The effect of bypass surgery on cerebral ischemic attack was satisfactory in both groups. However, the postoperative FSIQ value was significantly lower in the infantile group than in the schoolchild group (p = 0.0452). CONCLUSIONS: The present study showed that infantile moyamoya disease involves a higher risk for cerebral infarct and completed stroke due to its more advanced stage, and that earlier diagnosis and treatment should be performed to improve the mental prognosis of patients.

Adolescent↗

PubMed2002

Surgical treatment of intracranial dural arteriovenous fistulas.

BACKGROUND: When considering the treatment strategies for dural arteriovenous fistulas (DAVFs), it is important to clarify the exact location of the fistula and venous drainage route from both DAVFs and normal brain tissue. DAVFs with leptomeningeal retrograde venous drainage carry a high risk of neurological deficits and require aggressive treatment. When AVFs involve the dural sinus, transvenous embolization via the transfemoral approach is usually the first choice of treatment. For DAVFs draining directly into the cortical veins without dural sinus involvement, transarterial embolization may be a curative treatment. However, when embolization is technically difficult or results in incomplete occlusion, surgical treatment is required. The purpose of the present study was to review our experience with surgical treatment of DAVFs. METHODS: The present series included 17 patients; 9 had DAVFs involving the dural sinus with leptomeningeal retrograde venous drainage and 8 had DAVFs draining directly into the cortical veins. For DAVFs involving the sinus, embolization of the diseased sinus by direct surgical exposure was performed in 8 patients, and surgical excision in one. For DAVFs draining directly into the cortical veins, interruption of the draining veins close to DAVFs was undertaken in 7 and surgical excision in 1. RESULTS: Complete obliteration of DAVFs was demonstrated in 16 patients. At final follow-up, 15 patients were asymptomatic and the other 2 showed clinical improvement. CONCLUSIONS: For DAVFs involving the dural sinus, direct operative sinus packing is indicated. For DAVFs directly draining into the cortical veins, surgical interruption of the draining veins is indicated.

Adult↗

PubMed2002

[Three cases of successful stenting for radiation-induced carotid arterial stenosis].

We report three cases of radiation-induced carotid arterial stenosis that underwent successful angioplasty with stenting. The patients had received radiation therapy for tongue or laryngeal cancers and developed minor completed strokes 6 to 14 years after irradiation. All patients had multiple and bilateral stenosis, measuring more than 50%, of the carotid arteries. The stenosis was located in the internal, external, and common carotid arteries. We performed percutaneous transluminal angioplasty with stenting. All interventions were successful and carotid stenosis decreased to less than 28%. No permanent complications occurred. During follow-up periods of up to 26 months, all of these cases were free from ischemic symptoms. Neither carotid angiography nor ultrasound sonography showed evidence of restenosis. The present results suggest the usefulness of angioplasty with stenting for radiation-induced carotid arterial stenosis.

Aged↗

PubMed2002

[Clinical significance of posterior cerebral artery stenosis/occlusion in moyamoya disease].

PURPOSE: The present study was aimed at clarifying the clinical significance of posterior cerebral artery (PCA) stenosis/occlusion in pediatric and adult moyamoya disease. SUBJECTS AND METHODS: This study included a total of 132 patients (52 children and 80 adults) who were diagnosed as by cerebral angiography having moyamoya disease. CT or MRI was performed to examine the location of cerebral infarction in all subjects. Cerebral blood flow and vasoreactivity to acetazolamide were measured in 80 patients before surgery, using single photon emission computed tomography (SPECT). Three-dimensional MR angiography (3D-MRA) was repeated in 32 pediatric patients after surgery in order to clarify the natural course of the PCA stenosis/occlusion. RESULTS: Of 264 sides in 132 patients, PCA stenosis/occlusion was observed in 50 sides of 40 patients (30.3%). Its incidence was significantly higher in ischemic-type patients than in hemorrhagic-type and asymptomatic patients, and was higher in patients in the advanced stage of the disease. The hemisphere ipsilateral to PCA stenosis/occlusion had higher incidence of ischemic symptoms, cerebral infarction, and impaired cerebral hemodynamics. TIA (hemianopsia) or cerebral infarction in the occipital lobe was noted in 4 (10%) of 40 patients during follow-up periods after bypass surgery for anterior circulation. Of 32 pediatric patients, none showed progression of PCA stenosis on 3D-MRA during follow-up periods. CONCLUSIONS: The present study showed that the involvement of PCA could increase the risk of TIA and/or cerebral infarction in both anterior and posterior circulation areas, suggesting that the PCA plays an important collateral role in moyamoya disease.

Adult↗