Biomedical subjects

Susumu Miyamoto

Publications and source records attributed to Susumu Miyamoto.

At least 19 recordsLinked to original sources

PubMed2006

Low-frequency electric cortical stimulation decreases interictal and ictal activity in human epilepsy.

We previously reported that low-frequency electric cortical stimulation (LFECS) directly applied to the epileptic focus by means of subdural electrodes decreased the number of interictal epileptiform discharges in patients with intractable partial epilepsy. In the present study, LFECS was applied to the epileptic foci directly in four patients with medically intractable partial epilepsy through subdural electrodes and evaluated its effect on the number of interictal epileptiform discharges as well as simple partial seizures. We used alternating electric current of 0.3 ms duration presented at 0.9 Hz frequency for 250 s. LFECS did not induce seizures in any of the four patients. In one patient, the number of interictal epileptiform discharge decreased significantly by LFECS, which is in conformity with our previous report. In addition, LFECS applied to the seizure onset zone decreased the frequency of simple partial seizures in one patient. These results suggest that LFECS has an inhibitory effect not only on the interictal but also the ictal activities in patients with intractable partial epilepsy. Further study is required to determine the inhibitory effect of LFECS more in details.

Adolescent↗

PubMed2006

Ipsilateral facial sensory and motor responses to basal fronto-temporal cortical stimulation: evidence suggesting direct activation of cranial nerves.

To clarify the generator mechanism of sensory and motor facial responses ipsilateral to electrical stimulation of the inferior fronto-temporal cortex in epilepsy patients. Out of 30 patients who have been evaluated with chronically implanted subdural electrodes for medically intractable partial seizure or brain tumor involving the basal frontal or temporal cortex, 4 patients (age ranging 24-57 years) showed sensory and motor responses in the ipsilateral face to high frequency electrical cortical stimulation of the inferior fronto-temporal cortex. We investigated motor evoked potentials (MEPs) in the facial muscle by single pulse stimulation in 2 out of 4 patients. Three patients showed both sensory symptoms and muscle contraction in the ipsilateral lower face when the orbitofrontal or basal temporal cortex was stimulated with 50 Hz electric current. One patient had only sensory symptoms in the lower face when ipsilateral basal temporal area was stimulated. MEPs at the left orbicularis oris muscle were constantly elicited with the onset latency of 7 ms throughout the stimulus rate of 2-30 Hz in 1 patient out of 2 patients was tested. In another patient, MEP onset latency was 3.0 ms with 11 Hz stimulation. With electrical stimulation of the basal fronto-temporal cortex, the ipsilateral facial twitch might occur through either the direct activation of the facial nerve by the current spread in the middle cranial fossa or through the mechanism similar to blink reflex.

Adult↗

PubMed2006

Bereitschaftspotentials recorded from the lateral part of the superior frontal gyrus in humans.

To demonstrate the Bereitschaftspotentials (BPs) over the high lateral convexity in the superior frontal gyrus, movement-related cortical potentials with respect to the middle finger extension were recorded in seven patients with refractory epilepsy who underwent subdural implantation of platinum electrode grids and/or strips covering the high lateral frontal convexity. In two out of the seven patients, BPs were recorded from the electrodes placed on the superior frontal gyrus in the vicinity of the border between the medial and lateral frontal lobes, which were distinct from those recorded from the primary sensorimotor cortex. The results suggest the possible contribution of either the lateral dorsal non-primary motor area or the SMA to the generation of the BPs.

Contingent Negative Variation↗

PubMed2006

A step-by-step resection guided by electrocorticography for nonmalignant brain tumors associated with long-term intractable epilepsy.

To delineate a surgical strategy for long-term intractable epilepsy associated with nonmalignant brain tumor, we developed a protocol for 25 patients whereby removal of tumor alone and additional irritative peritumoral tissue between sulci (gyrectomy), as well as further resectioning, was performed based on intraoperative electrocorticogram results. In five patients, no irritative zones were observed that required resectioning following complete removal of tumors. Additional gyrectomy was indicated in 18 patients who demonstrated gliosis or cortical dysplasia in the peritumoral residual irritative zone. Remote irritative zone observed in two patients was correlated with long-term and frequent seizures. During a follow-up period of at least 5 years, seizure outcome was Engel category I in 92%, and all patients have remained tumor-free. Peritumoral gyrectomy as a means of removing likely epileptic tissue following tumor resection appears to be a useful method for treating long-term intractable tumoral epilepsy. Further resectioning of remote tissue should be considered in patients with severely intractable seizures.

Adolescent↗

PubMed2006

Subtemporal hippocampectomy preserving the basal temporal language area for intractable mesial temporal lobe epilepsy: preliminary results.

PURPOSE: Decline in verbal memory as a surgical complication remains an unresolved problem in mesial temporal lobe epilepsy. Some areas in the temporal lobe associated with the language function, often including the basal temporal language area, have been removed or transected by conventional surgical procedures. The authors defined the basal temporal language area and removed only the epileptogenic zone with a subtemporal approach. METHODS: The basal temporal language area was evaluated by using long-term subdural electrodes in five patients with language-dominant-side mesial temporal lobe epilepsy. While preserving this area, the hippocampus and the parahippocampal gyrus were removed by using a combined subtemporal, transventricular, transchoroidal fissure approach. Verbal memory performance was assessed with the Wechsler Memory Scale-Revised (WMS-R) before and after the operation. RESULTS: The basal temporal language area, defined as a part of the inferior temporal gyrus, the fusiform gyrus, and the parahippocampal gyrus, was spared by entering the temporal horn via collateral sulcus. Verbal memory was significantly improved by 3 months and 1 year after the operation. CONCLUSIONS: In language-dominant-side mesial temporal lobe epilepsy, preserving the basal temporal language area would have potential to improve verbal memory outcomes after removal of the epileptogenic zone.

Adult↗

PubMed2006

Acceleration of aneurysm healing by hollow fiber enabling the controlled release of basic fibroblast growth factor.

OBJECTIVE: The objective of this study was to develop an embolization material of hollow fiber combined with gelatin hydrogel for the controlled release of basic fibroblast growth factor (bFGF). We examined feasibility of the material in embolization healing aneurysm by bFGF-induced tissue organization. METHODS: An aneurysm was prepared at the common carotid artery of 60 rabbits by the end-to-side anastomosis of jugular venous pouch. The hollow fibers combined with or without 100 microg free bFGF or gelatin hydrogel incorporating 0, 10, 50, or 100 microg bFGF were applied to the aneurysm. Tissue appearance or histological observation was performed 1, 2, 3, and 6 weeks after application to evaluate the area embolized by fibrous organization in the aneurysm and the neointima formation at the aneurysm orifice. RESULTS: When applied with the hollow fibers combined with gelatin hydrogel containing 100 microg bFGF, the aneurysm was histologically occupied by fibrous tissue newly formed 3 weeks later, whereas neointima was formed at the aneurysm orifice. The histological area occupied by fibrous tissue was significantly larger than that of hollow fibers combined with 100 microg bFGF. No influence of bFGF dose on the aneurysm healing by the fibers combined with hydrogels incorporating bFGF was observed. CONCLUSION: Local, controlled release of bFGF from the hollow fibers combined with gelatin hydrogel incorporating bFGF accelerated the aneurysm healing by tissue organization.

Aneurysm↗

PubMed2006

Outcome of carotid endarterectomy and stent insertion based on grading of carotid endarterectomy risk: a 7-year prospective study.

OBJECT: The authors of this study prospectively compared periprocedural neurological morbidity and the appearance of lesions on diffusion-weighted (DW) magnetic resonance (MR) imaging in patients who had undergone carotid endarterectomy (CEA) or carotid artery stent placement (CASP) with distal balloon protection, based on a CEA risk grading scale. METHODS: Patients undergoing CEA (139 patients) and CASP (92 patients) were classified into Grades I to IV, based on the presence of angiographic (Grade II), medical (Grade III), and neurological (Grade IV) risks. Although not randomized, the CEA and CASP groups were well matched in terms of the graded risk factors except for a greater proportion of neurologically unstable patients in the CEA group (11 compared with 3%, p = 0.037). There were greater proportions of asymptomatic (64 compared with 34%, p = 0.006) and North American Symptomatic Carotid Endarterectomy Trial-ineligible patients (29 compared with 14%, p < 0.0001) in the CASP group. The overall rates of neurological morbidity with ischemic origin and the appearance of lesions on DW MR imaging after CEA were 2.2 and 9.3%, and those after CASP were 7.6 and 35.9% (nondisabling stroke only), respectively. The only disabling stroke was caused by an intracerebral hemorrhage attributable to hyperperfusion in one case (0.7%) of CEA. There were no deaths. There was no significant association between neurological morbidity and the risk grade in patients who had undergone CEA, although the incidence of lesions on DW imaging was significantly greater in the Grade IV risk group compared with that in the other risk groups combined (42.1 compared with 4.2%, p < 0.0001). After CASP, a higher incidence of neurological morbidity and lesions on DW imaging was noted for the Grade II and III risk groups combined as compared with that in the Grade I risk group, regardless of a symptomatic or an asymptomatic presentation (neurological morbidity: 10.5 compared with 3.1%, respectively, p = 0.41; and DW imaging lesions: 47.4 compared with 19.4%, p = 0.01). The incidence of lesions on DW imaging after CEA was significantly lower than that after CASP except for the Grade IV risk groups. CONCLUSIONS: Despite a higher incidence of DW imaging-demonstrated lesions in the Grade IV risk group, there was no significant association between the risk group and neurological morbidity rates after CEA. The presence of vascular and medical risk profiles conferred higher rates of neurological morbidity and an increased incidence of lesions on DW imaging after CASP. Considering that no serious nonneurological complications were noted, CEA and CASP appear to be complementary methods of revascularization for carotid artery stenosis with various risk profiles.

Aged↗

PubMed2006

Absence epilepsy associated with moyamoya disease. Case report.

The authors present the case of a 6-year-old girl with typical absence epilepsy induced by hyperventilation associated with moyamoya disease (MMD). A diffuse 3-Hz spike-and-wave complex induced by hyperventilation was apparent on an electroencephalogram, and her seizures were intractable to medication. Significant ischemia in the bilateral frontal lobes was present. The epilepsy disappeared after superficial temporal artery-middle cerebral artery anastomosis with encephalomyosynangiosis on both sides. In the treatment of children with intractable absence epilepsy, the possibility of underlying MMD and indications that revascularization surgery may be needed should be taken into consideration.

Anticonvulsants↗

PubMed2006

[Therapeutic strategy for isolated dissecting aneurysms of the posterior inferior cerebellar artery: report of three cases and review of literature].

Dissecting aneurysm of the posterior inferior cerebellar artery (PICA) is a relatively rare disease and its treatment has not been well established. The authors analyzed the clinical and anatomical features of 38 reported lesions and three of our cases to clarify the "best therapeutic modality". The average age was 45.0 years old and 27 patients were male. Left-sided predominance (26 cases) was noted. As to the mode of onset, 23 cases were subarachnoid hemorrhage, 16 were ischemia, and 6 were Wallenberg's syndrome. Anatomically, the sites of dissection were located in the proximal segment of PICA in 31 lesions (75.6%). Review of the cases show that 30 (75%) patients underwent surgical therapy, and 7 (17.5%) patients underwent endovascular treatment. Twenty six patients who took surgical therapy and 5 patients who took endovascular treatment had excellent or good outcome. The critical point in therapeutic procedure is the preservation of perforating branches arising from PICA, therefore surgical trapping with the revascularization of PICA (usually extracranial-PICA anastomosis), in which these tiny branches are secured under microscopic manipulation, has the advantage in principle.

Adult↗

PubMed2005

Altered expression balance of matrix metalloproteinases and their inhibitors in human carotid plaque disruption: results of quantitative tissue analysis using real-time RT-PCR method.

BACKGROUND: The balance between degradation and synthesis of extracellular matrix determines its content in atherosclerotic tissue. To examine the role of expression balance of matrix metalloproteinases (MMPs) to their inhibitors, tissue inhibitors of metalloproteinases (TIMPs) and tissue factor pathway inhibitor-2 (TFPI-2) in the development and disruption of atherosclerotic plaque, these gene expressions in human carotid plaque were quantitatively determined by real-time reverse transcription (RT)-polymerase chain reaction (PCR) method. METHODS: Total RNA for cDNA synthesis was extracted from tissues in 24 patients with carotid endarterectomy. The amounts of cDNAs for MMP-1, -2, -3 and -9, TFPI-2 and TIMP-1, -2 and -3 were determined by real-time RT-PCR method, and normalized with glutaraldehyde 3-dehydrogenase. RESULTS: In plaques, the expression MMP-1 (1.53+/-0.25, mean+/-S.E.M.), MMP-3 (1.99+/-0.59) and MMP-9 (2.00+/-0.51) was augmented compared to those in the adjacent control regions (0.60+/-0.16, 0.46+/-0.18 and 0.58+/-0.21, respectively, p<0.05). The expression of TFPI-2 was lower in plaques (0.32+/-0.08) than in controls (0.94+/-0.23, p<0.01). Although the expression of TIMP-1 was higher in plaques (1.28+/-0.23) than in controls (0.81+/-0.10, p<0.05), the indices of MMP-1/TIMP-1, MMP-3/TIMP-3 and MMP-9/TIMP-1 were still significantly higher in plaques. Interestingly, MMP-9 and the resulting MMP-9/TIMP-1 balance in plaques with disruption were significantly higher (3.36+/-1.52 and 1.66+/-0.12, n=11) than those in non-disrupted plaques (1.11+/-0.52 and 0.76+/-0.12, n=13, p<0.05). CONCLUSION: With the decreased expression of TFPI-2, upregulation of MMPs in atherosclerotic plaque was disproportional to that of TIMPs, suggesting that imbalanced degradation and synthesis of extracellular matrix persists in advanced lesions, particularly in plaques with disruption.

Aged↗

PubMed2005

Induced spreading depression activates persistent neurogenesis in the subventricular zone, generating cells with markers for divided and early committed neurons in the caudate putamen and cortex.

BACKGROUND AND PURPOSE: Status epilepticus and cerebral ischemia stimulate persistent neurogenesis in the adult brain, but both conditions cause neuronal damage. We determined whether spreading depression, a common epiphenomenon of these conditions, stimulates persistent neurogenesis. METHODS: We analyzed the effect of KCl-induced spreading depression on persistent neurogenesis and the spatio-temporal distribution of cells exhibiting immunohistochemical markers for divided and early committed neurons (new neurons) in the adult rat brain. RESULTS: After induction of spreading depression for 48 hours, the density of mitotic cells, divided cells, and new neurons in the subventricular zone increased at days 1 to 3, days 3 to 6, and day 6, respectively (P<0.05). The divided cell density in the rostral migratory stream and the stream size increased at day 12 (P<0.001). Vehicle (saline) infusion or induction of spreading depression for 4 hours only did not increase the divided cell density, but the latter increased new neuron density in the subventricular zone (P<0.001). Double-labeled new neuron-like cells also appeared in the caudate putamen or cortex in ectopic fashion at day 3, with dramatic increases at days 6 and 12. Administration of the NMDA receptor antagonist, MK-801, which inhibits the propagation of spreading depression, abolished the increase in new neurons in the subventricular zone and the appearance of ectopic new neuron-like cells after 48-hour KCl infusion. There was no neuronal damage, as evidenced by mature neuron density, neurite density, and apoptotic cell appearance after spreading depression for 48 hours. CONCLUSIONS: Spreading depression has the potential to stimulate persistent neurogenesis or to produce ectopic new neuron-like cells.

Animals↗

PubMed2005

Electric cortical stimulation suppresses epileptic and background activities in neocortical epilepsy and mesial temporal lobe epilepsy.

OBJECTIVE: To evaluate the suppressive effect of electric cortical stimulation upon the seizure onset zone and the non-epileptic cortex covered by subdural electrodes in patients with neocortical epilepsy and mesial temporal lobe epilepsy (MTLE). METHODS: Four patients with medically intractable focal epilepsy had implanted subdural electrodes for preoperative evaluation. Cortical functional mapping was performed by intermittently repeating bursts of electric stimulation, which consisted of 50 Hz alternating square pulse of 0.3 ms duration, 1-15 mA, within 5 s. The effect of this stimulation on the seizure onset zones and on the non-epileptic areas was evaluated by comparing spike frequency and electrocorticogram (ECoG) power spectra before and after stimulation. A similar comparison was performed in stimulation of 0.9 Hz of the seizure onset zones for 15 min. RESULTS: When the seizure onset zone was stimulated with high frequency, spike frequency decreased by 24.7%. Logarithmic ECoG power spectra recorded at stimulated electrode significantly decreased in 10-32 Hz band by high frequency stimulation of the seizure onset zone, and in 14-32 Hz band by high frequency stimulation of the non-epileptic area. Low frequency stimulation of the seizure onset zone produced 18.5% spike reduction and slight power decrease in 12-14 Hz. CONCLUSIONS: Both high and low frequency electric cortical stimulation of the seizure onset zone have a suppressive effect on epileptogenicity. Reduction of ECoG fast activities after electric cortical stimulation suggests the augmentation of inhibitory mechanisms in human cortex.

Adult↗

PubMed2005

Electrocardiographic events and cholesterol reduction with pravastatin in patients with hypercholesterolemia: the Hokuriku Lipid Coronary Heart Disease Study-Pravastatin Atherosclerosis Trial.

BACKGROUND: Cholesterol lowering therapy may offset the development of coronary atherosclerosis, and the resulting reduction in coronary ischemia may be observed in the electrocardiogram (ECG). METHODS: A total of 2039 Japanese adults with hypercholesterolemia were divided into two groups (receiving 10-20 mg pravastatin daily or a normal diet) and were followed up for 5 years. ECG studies were performed at entry and every year during the follow-up period. The occurrence of myocardial infarction and the appearance or worsening of ischemic ST changes were assessed in terms of effects on the ECG. RESULTS: Of the 2039 patients registered, 827 were excluded from the study for various reasons. Consequently, a total of 1212 patients were analyzed. There was a lower degree of worsening in the pravastatin group (n=757) than in the normal diet group (n=455) in the primary prevention cohort [11 (1.8%) vs. 16 (4.3%), respectively, P=0.031]. On the other hand, there was no difference in the frequency of worsening between the two groups in the secondary prevention cohort [7 (4.4%) in the pravastatin group vs. 4 (4.9%) in the diet group, P=0.25]. Event-free survival was better in the pravastatin group than in the normal diet group in the primary prevention cohort (P=0.011), but there was no difference between the two groups in the secondary prevention cohort. CONCLUSIONS: These results suggest that pravastatin may reduce the incidence of coronary heart disease and that this effect may be predominantly observed in patients with early atheromatous lesions.

Aged↗

PubMed2005

Processing of Japanese morphogram and syllabogram in the left basal temporal area: electrical cortical stimulation studies.

Language functions in the left basal temporal area (LBTA) were investigated using electrical cortical stimulation during functional mapping in six Japanese patients with refractory epilepsy. This study provides the first direct evidence that kana (Japanese syllabogram) is processed in the LBTA. Electrical stimulation of some areas within LBTA induced disturbance in overt reading of kana words only in the first trials, with no errors in the subsequent trials. By contrast, stimulation of the same area caused obvious disturbance in kana non-word reading in all trials. Since a kana word carries both meaning and sound while a kana non-word carries only sounds of a letter string, the contrasting results of partial and complete disturbance imply a possibility that there are two distinct pathways for kana reading: one dealing with both phonological and semantic aspects of the words and the other dealing only with phonological aspect. Kanji words (Japanese morphogram) and objects/pictures were found to be processed in an area different from the area for the kana non-word processing. Furthermore, the present study also identified the common area for processing kanji reading and object/picture naming. There were no errors in matching pictures with kanji words, indicating that concepts of pictures and meanings of kanji words were not interfered by the electrical stimulation of that area. The new insight provides a clue for partial description of processing pathways for language-related visual information in LBTA. Three types of information (morphological, phonological, and semantic) are conveyed together at some stages and are separated into different routes at some other stages.

Acoustic Stimulation↗

PubMed2005

An adult case of moyamoya syndrome that developed dural sinus thrombosis associated with protein C deficiency: case report and literature review.

We describe a 54-year-old woman exhibiting MMS who developed delayed dural sinus thrombosis associated with PCD. Angiographic findings of the patient were so unusual that bilateral internal carotid arteries were occluded between their origin and the carotid fork with extensive development of collateral circulation via the external carotid arteries and the posterior cerebral arteries instead of moyamoya vessels at the base of the brain. Seven years after bilateral cerebral revascularization surgery, intracerebral hemorrhage occurred caused by dural sinus thrombosis. In the treatment for the patient with MMS associated with PCD, risk of sinus thrombosis should be taken into account.

Age Factors↗

PubMed2005

Sustained upregulation of inflammatory chemokine and its receptor in aneurysmal and occlusive atherosclerotic disease: results form tissue analysis with cDNA macroarray and real-time reverse transcriptional polymerase chain reaction methods.

BACKGROUND: Although cytokines are known to be pivotal in the development of atherosclerotic diseases, few data exist regarding their expressions in the established stages such as aneurysmal or occlusive lesions. Therefore, in the present study the gene expression levels of cytokine-related substances in abdominal aortic aneurysm (AAA) and carotid artery stenosis (CAS) were determined using cDNA macroarray and real-time reverse transcriptase polymerase chain reaction (RT-PCR) methods. METHODS AND RESULTS: Tissue samples were obtained from 31 patients with AAA and 24 with CAS. The array-specific [33P]-labeled cDNA probe mixture synthesized from 2.5 microg total RNA with gene-specific primers was hybridized with nylon membranes containing 375 cDNA clones. Densitometric analysis confirmed differences in expression (>5-fold) for 97 of the cytokine-related gene products between AAA and adjacent control tissue. Among these, simultaneous upregulation was found in the expression of interleukin (IL)-8 (9-fold) and its receptor, CXCR-2 (11-fold). Thus, the expressions of IL-8 and CXCR-2 were further quantified by real-time RT-PCR. The expression of both the genes was significantly upregulated in both AAA and CAS compared with control regions as followed: IL-8=0.53+/-0.16 vs 0.11+/-0.04 (p<0.01); CXCR-2=2.04+/-0.75 vs 0.29+/-0.10 (p<0.01) in AAA, and IL-8=1.35 +/-0.25 vs 0.60+/-0.16; CXCR-2=2.00 +/-0.51 vs 0.58+/-0.21 (p<0.05) in CAS. Under these conditions, the gene expressions of monocyte chemotactic protein-1 and its receptor, CCR-2, were not significantly different in the control and diseased regions of both AAA and CAS. CONCLUSIONS: Sustained upregulation of IL-8 and CXCR-2 was observed in both AAA and CAS, suggesting the inflammatory process is still active in established dilated and occlusive atherosclerotic diseases. Whether upregulation of this system could be protective or not protective for disease development requires further study.

Aged↗

PubMed2005

Legionella pneumonia associated with adult respiratory distress syndrome caused by Legionella pneumophila serogroup 3.

A 68-year-old man developed pneumonia 2 days after nearly drowning in a bathtub of a hot spring spa. Chest radiography revealed bilateral consolidation shadows associated with adult respiratory distress syndrome. Initial treatment with antibiotics and pulse therapy with methylprednisolone was not effective. The patient died on the 4th hospital day. A urinary antigen test for Legionella was positive. Legionella pneumophila serogroup 3 was recovered from an intratracheal specimen. The same serotype of Legionella was isolated from the hot spring water. Restriction enzyme analysis by pulse-field gel electrophoresis revealed identical restriction fragments. We conclude that the water at the hot spring spa could have been the source of infection.

Aged↗

PubMed2005

Large paraclinoid aneurysm with a calcified neck treated by tailored multimodality procedures.

A 68-year-old woman presented with a large paraclinoid aneurysm with a calcified neck causing visual symptoms. Direct clipping was hazardous because of severe calcification of the neck. Endovascular internal trapping was difficult because of the short distance between the neck and the origin of the posterior communicating artery. Proximal occlusion was likely to be less effective because of large collateral back flow to the aneurysm via the ophthalmic artery (OphA). The aneurysm was successfully treated by a combination of a high-flow bypass, intraoperative coil embolization of the parent artery including the origin of the OphA, and clipping of the internal carotid artery distal to the aneurysm. Paraclinoid aneurysms may be difficult to treat by the simple application of direct clipping, endovascular coiling, or trapping. Multimodality procedures can be tailored to treat such aneurysms.

Aged↗