Biomedical subjects

T Yoshimoto

Publications and source records attributed to T Yoshimoto.

At least 217 records · Page 12Linked to original sources

PubMed1999

Clinical course, surgical management, and long-term outcome of moyamoya patients with rebleeding after an episode of intracerebral hemorrhage: An extensive follow-Up study.

BACKGROUND AND PURPOSE: Revascularization surgery for moyamoya patients is believed to prevent cerebral ischemic attacks by improving cerebral blood flow. However, measures preventing the occurrence of hemorrhagic moyamoya in patients have not yet been established in the literature due to the low rate of hemorrhage onset as well as the originally limited numbers of patients with moyamoya disease, poor understanding of the clinical course of rebleeding, correct surgical management, and long-term outcome. We present here the results of an overall survey of patients with hemorrhagic moyamoya disease in a district of Miyagi Prefecture in Japan and examine their clinical course, efficacy of revascularization surgery, and long-term outcome. METHODS: This study included 28 moyamoya patients with episodes of intracranial hemorrhage between 1976 and 1988. The mean follow-up period was 14.2 years. There were 4 males and 24 females, aged 7 to 69 years (mean 39.2 years). Cerebral angiography and CT scans were performed for all patients. Surgical treatment was performed in 19 patients (67. 9%), and 10 patients (35.7%) underwent revascularization surgery. We observed the clinical course of all 28 patients. We also studied the relationship between the efficacy of surgical treatment and long-term outcome. RESULTS: Five of the 28 patients (17.9%) died of the initial intracranial hemorrhage, and 2 patients died of other causes. Rebleeding occurred in 6 of the remaining 21 patients (28. 6%). The interval to rebleeding ranged from 2 to 20 years (mean 7.3 years). Of these 6 patients, 4 died of rebleeding. Rebleeding was observed in 1 of 8 patients who underwent bypass surgery and in 5 of 13 patients who did not, which suggested that rebleeding was less likely to occur in patients who had undergone bypass surgery. However, there was no significant difference in rebleeding ratio or mortality between patients with and those without revascularization surgery (P>0.05). CONCLUSIONS: In this study, we compiled the results of meticulous follow-up conducted over the past 10 years for patients with hemorrhagic moyamoya disease. Because hemorrhagic moyamoya disease is known for its high rate of mortality at the time of rebleeding and often causes rebleeding long after the initial episode (as much as 20 years later), implementation of long-term preventive measures for rebleeding is necessary. This suggests that a long-term prospective study of a large number of patients with hemorrhagic moyamoya disease is required to determine whether bypass surgery prevents rebleeding of hemorrhagic moyamoya disease.

Adolescent↗

PubMed1999

Amelioration of vasospasm after subarachnoid hemorrhage in transgenic mice overexpressing CuZn-superoxide dismutase.

BACKGROUND AND PURPOSE: To clarify the effect of superoxide dismutase (SOD) on vasospasm after subarachnoid hemorrhage (SAH), we investigated sequential changes in arterial diameter after SAH in transgenic mice overexpressing CuZn-SOD (SOD-1). METHODS: SOD-transgenic mice and nontransgenic littermates (35 to 40 g) were subjected to SAH produced by endovascular perforation of left anterior cerebral artery. At 4 hours and 1, 3, 7, and 14 days after SAH, the mice were perfused with 10% formalin and consequently with a mixture of carbon black and 10% gelatin to cast all vessels. Vasospasm was evaluated by measuring the diameter of the left middle cerebral artery (MCA) with a microscope. RESULTS: In nontransgenic mice, the diameter of the MCA on day 3 after SAH (110.5+/-20.5 microm [mean+/-SD]; n=16) was significantly reduced compared with that without SAH (138.5+/-14.5 microm; n=12) (P<0.01). Moreover, on day 3 after SAH, the diameter of the MCA in SOD-transgenic mice (127. 9+/-20.2 microm; n=20) was significantly larger than that in nontransgenic mice (110.5+/-20.5 microm; n=16) (P<0.05). CONCLUSIONS: These results suggest that SOD is effective on the amelioration of vasospasm after SAH and that oxygen free radicals, particularly superoxide, play an important role in the pathogenesis of vasospasm after SAH.

Animals↗

PubMed1999

Cloning of L-amino acid deaminase gene from Proteus vulgaris.

The L-amino acid degrading enzyme gene from Proteus vulgaris was cloned and the nucleotide sequence of the enzyme gene was clarified. An open reading frame of 1,413 bp starting at an ATG methionine codon was found, which encodes a protein of 471 amino acid residues, the calculated molecular weight of which is 51,518. The amino acid sequence of P. vulgaris was 58.6% identical with the L-amino acid deaminase of P. mirabilis. A significantly conserved sequence was found around the FAD-binding sequence of flavo-proteins. The partially purified wild and recombinant enzymes had the same substrate specificity for L-amino acids to form the respective keto-acids, however not for D-amino acids.

Amino Acid Oxidoreductases↗

PubMed1999

Dose-related effects of single focal irradiation in the medial temporal lobe structures in rats--magnetic resonance imaging and histological study.

The dose-related effects of single focal irradiation on the medial temporal lobe in rats were investigated by sequential magnetic resonance imaging and histological examination. Irradiation of 200 Gy as a maximum dose using 4 mm collimators with a gamma unit created an area of necrosis consistently at the target site within 2 weeks after irradiation. Irradiation of 100 Gy caused necrosis within 10 weeks, and 75 Gy caused necrosis within one year. Irradiation of less than 50 Gy did not induce necrosis consistently, although a restricted area of necrosis was created in the medial temporal structures including the intraparenchymal portion of the optic tract. 75 Gy may be the optimum dose for creating necrosis consistently in the medial temporal lobe structures. However, careful dose planning considering both dose-time and dose-volume relationships in necrosis development is necessary to avoid injury to vulnerable neural structures such as the optic tract when applying radiosurgical techniques to treat functional brain disorders in medial temporal lobe structures such as temporal lobe epilepsy.

Amygdala↗

PubMed1999

Surgical treatment of intractable epilepsy originating from the primary sensory area of the hand--case report.

A 14-year-old right-handed girl presented with intractable epilepsy originating from the primary sensory area of the hand, manifesting as sensory partial seizures in the left hand with secondary generalization. Neurological examination showed no abnormal findings. Magnetic resonance imaging, magnetoencephalography, and cortical stimulation using chronic subdural electrodes demonstrated a lesion located in the primary sensory cortex of the hand, in which the ictal onset zone was identified by 24-hour intracranial electroencephalographic recording. Surgical resection of the lesion and multiple subpial transections of the adjacent cortices were performed. The histological diagnosis was dysembryoplastic neuroepithelial tumor (DNT). She was completely free of seizures without permanent sensory deficits postoperatively. DNT located in the primary sensory hand area may be resectable without causing postoperative sensory deficits, if accurate functional mapping and surgical resection are performed.

Adolescent↗

PubMed1999

Anterior approach for dumbbell type cervical neurinoma.

A one-stage anterior approach was performed in four patients for total removal of dumbbell type neurinoma at the cervical level. In each case, the neurinoma compressed the spinal cord in the cervical canal, developed anteriorly through the intervertebral foramen, and compressed the vertebral artery. A conventional cervical anterior approach at the tumor site was performed, followed by confirmation of the tumor located outside the spinal canal. After identification of the vertebral artery, corpectomy was carried out and the extradural component of the tumor was resected. In cases with a portion of the tumor located also within the dura mater, the dura mater was opened for removal of the intradural tumor. We found the anterior approach to be effective for the total removal of some kinds of cervical dumbbell type neurinomas.

Adult↗

PubMed1999

Clinical, pathological and mineralogical features in two autopsy cases of workers exposed to agalmatolite dust.

An agalmatolite miner and processor showed large shadows at the bilateral hila accompanied by surrounding emphysematous changes and irregular shadows on chest X-ray films. Chest CT scans were characterized by a mixture of tiny irregular structures and small round opacities. Histopathological examination revealed massive fibrosis, which corresponded to large shadows, but only a small number of typical silicotic nodules, indicating mixed dust pneumoconiosis. Mineralogical examination of the autopsy lungs showed quartz, pyrophyllite, mica, and kaolinite. Quartz accounted for 70% of the amount of all mineral dust in both patients, but pyrophyllite accounted for 10.8% and 14.4%. The pulmonary mineral dust composition in the two patients was well consistent with the mineral composition of the raw clays in the agalmatolite mine. In the two patients, chest X-ray findings and histopathological findings of the lungs also suggested agalmatolite pneumoconiosis, which was confirmed by mineral analysis of the lungs.

Aged↗

PubMed1999

[Relationships among health-promoting activities, going out and perceived transportation problems of elderly people living in a small town far from the nearest train station].

To estimate the change in health-promoting activities among elderly people affected by community organizing environments, we examined the relationships among health-promoting activity, going out and perceived transportation problems. A questionnaire was sent to 567 men and women aged 60 years old and over living in a small town in Kanagawa prefecture between July 27 and August 12 in 1995. The questionnaire consisted of 42 items concerning health, social ability of daily living (including the desire to participate in social activities), attitude toward health-promoting activities, and perceived transportation problems. A total of 397 people responded and the answers from 368 people were analyzed after excluding responses from those unable to go out by themselves and those who seldom went out. Single regression analysis and multiregression analysis were used with the sum of responses for each question representing factors related to health-promoting behavior. A probability level of 5 percent was considered significant. The reliability of the data was examined with Cronbach's coefficient alpha. Coefficients of determination for health promoting behavior were 42% in men and 48% in women. In both men and women, age, social ability of daily living and attitudes toward health-promoting behavior were related to health-promoting activity. In women, more actively going out was related to more active health-promoting activity. Higher perception of transportation problems had a negative effect on going out. In men, neither of these factors had any relationship with health-promoting activity. In men, poorer health conditions were related to more active health-promoting activity, but in women, there was no relationship between those factors. These results show that there are gender differences in the relationships among the factors related to health-promoting activities in elderly people. In women, a higher perception of transportation problems restrained actively going out and health-promoting activity.

Aged↗

PubMed1999

Induction of cyclooxygenase-2 messenger RNA after transient and permanent middle cerebral artery occlusion in rats: comparison with c-fos messenger RNA by using in situ hybridization.

OBJECT: Recently, two different cyclooxygenase (COX) genes, COX-1 and -2, were identified. In this study, topographic and chronological profiles of COX-2 messenger (m)RNA and c-fos mRNA expression were investigated using in situ hybridization after focal cerebral ischemia. METHODS: Rats undergoing permanent ischemia were decapitated at 30 and 90 minutes and at 2, 4, 8, and 24 hours after middle cerebral artery (MCA) occlusion, and rats undergoing transient ischemia were decapitated at 4, 8, and 24 hours after MCA occlusion that lasted for either 30 or 90 minutes. After brief transient MCA occlusion, c-fos mRNA was induced in the whole MCA territory, adjacent cortex (cingulate cortex), and distant brain regions such as the hippocampus and substantia nigra. In contrast, COX-2 mRNA was not induced in the ischemic core (lateral striatum) but only in the penumbral area (MCA cortex). Long transient and permanent MCA occlusion did not induce c-fos and COX-2 mRNAs in the ischemic core but strongly induced both mRNAs in the penumbral area (medial striatum and periphery of MCA cortex) and adjacent cortex (cingulate cortex). In brain regions distant from the ischemic territory, although c-fos mRNA was induced in the thalamus, substantia nigra, and hippocampus after extended transient and permanent occlusion, COX-2 mRNA was only induced in the bilateral hippocampi. The induction of COX-2 mRNA persisted in all locations even at 24 hours after MCA occlusion. CONCLUSIONS: The distribution of COX-2 mRNA induction was apparently different from that of c-fos mRNA after MCA occlusion. These results pertaining to COX-2 mRNA agree well with the previous observations of changes in prostaglandin metabolism induced by focal cerebral ischemia. However, whether this induction of the COX-2 gene contributes to the histopathological outcome of cerebral ischemia remains to be elucidated.

Animals↗

PubMed1999

Ruptured cerebral pseudoaneurysm caused by the removal of a ventricular catheter. Case report.

A rare case of cerebral pseudoaneurysm located at the internal carotid artery (ICA) was caused by the removal of a ventricular catheter in an infant. This 4-month-old girl underwent ventriculoperitoneal shunt revision, during which the old ventricular catheter was removed from the posterior horn of the left lateral ventricle, but the choroid plexus was pulled out by the tip of the catheter. Intraventricular hemorrhage (IVH) and subarachnoid hemorrhage were observed postoperatively. Magnetic resonance (MR) angiography performed on the 12th postoperative day revealed ICA stenosis and aneurysm formation at the C1 portion of the left ICA. Contrast-enhanced computerized tomography (CT) scans obtained on the 21st postoperative day revealed recurrent IVH and enlargement of the lesion. The patient underwent surgery for treatment of the aneurysm. Operative findings revealed a pseudoaneurysm arising from the left ICA at the proximal end of the anterior choroidal artery (AChA). The aneurysm was removed and the wall of the ICA was reconstructed. Postoperative three-dimensional CT scanning and MR angiography demonstrated disappearance of the aneurysm and preservation of the ICA. The patient was discharged without additional neurological deficits. Many complications, including IVH, are associated with removal of a ventricular catheter. This case shows that pseudoaneurysm formation can occur in a remote region due to avulsion of the AChA from the ICA. In most circumstances a ventricular catheter can be removed without difficulty. However, precision and caution should be exercised when removing a ventricular catheter.

Aneurysm, False↗

PubMed1999

Use of porous hydroxyapatite graft containing recombinant human bone morphogenetic protein-2 for cervical fusion in a caprine model.

OBJECT: The efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2) for enhancing anterior cervical spine interbody fusion when added to a porous hydroxyapatite (HA) graft was investigated. METHODS: Fourteen mature goats underwent three-level anterior discectomies after induction of endotracheal anesthesia. Porous HA grafts that contained 0, 5, and 50 microg of rhBMP-2 were placed concurrently with anterior cervical spine plates to achieve interbody fusion. The fusion rate, radiological findings, biomechanical stiffness, and histological appearance were evaluated in 42 spinal units immediately and again at 4 and 12 weeks after graft and plate placement. At 12 weeks postsurgery, manual testing showed a 100% fusion rate in the spines with HA grafts containing high-dose rhBMP-2; however, only a 50% fusion rate was shown in spines with grafts that contained no or low-dose rhBMP-2. On radiographic and histological studies the process of solid fusion was seen to be more advanced in relation to the use of larger amounts of rhBMP-2. Biomechanical testing demonstrated significantly higher stiffness values for grafts that contained high-dose rhBMP-2 than those without rhBMP-2 in flexion at 4 weeks, as well as in flexion, extension, and lateral bending tests at 12 weeks. Histological analysis demonstrated that rhBMP-2 increased the amount of bone apposition on the surface of the implants and promoted bone formation in the porous structure without increasing the penetration distance. CONCLUSIONS: Through osteogenesis at the fusion site, the addition of rhBMP-2 to a porous HA ceramic graft enhances the rate of anterior cervical fusion.

Animals↗

PubMed1999

[A case of unruptured cerebral aneurysm treated by intra-aneurysmal embolization during outpatient hemodialysis for chronic renal failure].

A 70-year-old woman, who had been receiving hemodialysis in a local hospital every other day for 2 years, complained of occasional headaches. Magnetic resonance imaging showed a large middle cerebral artery (MCA) aneurysm. Angiography in the midterm day of hemodialysis demonstrated a large aneurysm on the right MCA bifurcation. Her chronic renal failure made us hesitate to perform craniotomy. Intra-aneurysmal Guglielmi detachable coil (GDC) embolization was performed also in the midterm day of hemodialysis. She was admitted to our hospital after hemodialysis on the day before the embolization. The embolization was carried out under local anesthesia and systemic heparinization. The aneurysm was almost completely embolized with five GDCs. She was transferred to the local hospital to receive the next hemodialysis on the day after the embolization. Patients with chronic renal failure are not suitable for neurosurgical therapy because mortality of patients undergoing dialysis is 45-80%, which is mainly due to disequilibrium syndrome and a hemorrhagic tendency. We propose that some cases like this case should be treated with an intra-vascular neurosurgical technique. In conclusion, this report demonstrates that intra-aneurysmal embolization is less invasive and is a more suitable treatment for patients who are considered to be at high risk for surgery and general anesthesia.

Aged↗

PubMed1999

99mTc-bicisate and 99mTc-HMPAO SPECT imaging in early spontaneous reperfusion of cerebral embolism.

Two patients with a cerebral embolism were evaluated by using both 99mTc-ethyl cysteinate dimer (ECD, or Bicisate) and 99mTc-hexamethylpropyleneamine oxime (HMPAO) single-photon emission computed tomography (SPECT). In one patient, 99mTc-ECD SPECT images revealed hypoactivity in a reflow hyperemic area where an infarct was seen later on CT scans. In another patient, a reperfused area showed hyperactivity on 99mTc-ECD SPECT without any abnormality on follow-up CT. 99mTc-ECD represents a potential agent with which to evaluate cerebral tissue viability in early reperfusion after ischemia.

Aged↗

PubMed1999

[Angiotensin II receptor subtype in human adrenal glands].

Although adrenal gland is one of the major target organs of angiotensin II (Ang II), the pathophysiological significance of the its receptor subtype has not been elucidated. We demonstrated by reverse transcription-polymerase chain reaction with Southern blot analysis mRNA expression of both AT1 and AT2 in human adrenal tissues of normal adrenocortical tissues, aldosterone-producing adenoma, Cushing's syndrome, and pheochromocytoma. Ang II-induced aldosterone secretion in vitro was suppressed only by 50% in the presence of selective AT1 antagonist CV-11974, while AT2 agonist CGP-42112 increased aldosterone secretion by 55% over the control. Ang II or CGP-42112 did not affect cortisol secretion. In addition, Ang II could stimulate aldosterone secretion in AT1a knockout mice both in the presence and absence of CV-11974. These results suggest that non-AT1 receptor subtype(s) including AT2, as well as AT1, is involved in the stimulation of aldosterone secretion from human adrenals.

Adrenal Gland Neoplasms↗

PubMed1999

Developmental changes of cerebral blood flow and oxygen metabolism in children.

BACKGROUND AND PURPOSE: Normal values for cerebral blood flow (CBF) and metabolism in adults are well established, but not for children. Our goal, therefore, was to clarify functional developmental changes of the brain in children in relation to CBF and oxygen metabolism. METHODS: We measured regional CBF (rCBF), regional cerebral metabolic rate for oxygen (rCMRO2), and regional oxygen extraction fraction (rOEF), using positron emission tomography (PET). We performed 30 PET studies in 24 children ages 10 days to 16 years (nine boys, 15 girls), using a steady inhalation method with C(15)O2, (15)O2, and 15CO in order to measure rCBF, rCMRO2, and rOEF, respectively. Regions of interest were set in the primary cerebral areas (sensorimotor, visual, temporal, and parietal cortex), cerebral association areas (frontal and visual association), basal ganglia (lenticular and thalamus), and posterior fossa (brain stem and cerebellar cortex). Subjects were grouped by age (< 1, 1 to < 3, 3 to < 8, and > or = 8 years), and the absolute values of the parameters were compared with those obtained from 10 healthy adults. RESULTS: rCBF and rCMRO2 were lower in the neonatal period than in older children and adults, and increased significantly during early childhood. rCBF was higher as compared with adults, peaking around age 7, whereas rCMRO2 was relatively high, with the last area to increase being the frontal association cortex. Both rCBF and rCMRO2 reached adult values during adolescence. No difference in rCBF was observed between the basal ganglia and the primary cerebral cortex; however, it was prominent in the occipital lobe in every age bracket. No significant changes in rOEF were found during childhood. CONCLUSION: The dynamic changes of rCBF and rCMRO2 observed in children probably reflect the physiologic developmental state within anatomic areas of the brain.

Adolescent↗

PubMed1999

[Pathological features of dysembryoplastic neuroepithelial tumor (DNT): study of five surgical cases with intractable epilepsies].

The dysembryoplastic neuroepithelial tumor (DNT), characterized by its favorable prognosis, must be precisely differentiated from other gliomas to prevent overtreatment by radio/chemotherapy. We studied, here, pathological features of five surgical cases of DNT with intractable epilepsies. There were two males and three females with a median age of 20.4 years (range 12-41). We evaluated lesional topography, gross appearances and microscopic findings including immunohistochemical data. One tumor was located in the temporal lobe, another two in the parietal lobe, another in the occipital lobe, and the other one in the occipito-parietal junction. The lesions were predominantly intracortical in all cases. Macroscopically, two tumors were grayish-soft, another two were yellowish-elastic, and the other one was resected as soft-mucinous fragments. Microscopically, the main glial components were oligodendrocyte-like cells (OLCs) in all cases, except for one case in which atypical glial cells were also prominent. Histopathological characteristics of the DNTs included the specific glioneuronal elements (the mixture of OLCs and neurons) in four cases, alveolar pattern (all cases), microcystic degeneration (all cases), multinodular architecture (four cases), and adjacent cortical dysplasia (all cases). Immunohistochemically, Ki-67 labelling indices ranged from 0 to 0.8%. OLCs were positive for glial fibrillary acidic protein in two cases, for S-100 protein in all cases, for synaptophysin in two cases, and for class III beta tubulin in all cases. Pathological features of our cases were characterized by its heterogeneous histological appearances and divergent cellular differentiation.

Adolescent↗

PubMed1999

[Ruptured middle cerebral artery aneurysm successfully treated by intra-aneurysmal GDC embolization in a patient with idiopathic thrombocytopenic purpura: a case report].

We report a case of a ruptured middle cerebral artery (MCA) aneurysm treated by an intra-aneurysmal Guglielmi detachable coil (GDC) embolization in a patient with idiopathic thrombocytopenic purpura (ITP). A 57-year-old female, who had been suffering from ITP for 4 years, experienced sudden severe headache. She was diagnosed as having subarachnoid hemorrhage due to a ruptured MCA aneurysm and the hematological examination showed moderate thrombocytopenia. Considering the risk of open surgery, we treated the aneurysm by intra-aneurysmal GDC embolization in the acute stage and platelet transfusion was carried out after the therapy. She had a good clinical course and recovered without any complications or neurological symptoms. The follow-up cerebral angiogram at 1 week and 2 years after the treatment showed complete obliteration of the aneurysm. Recently, endovascular treatment tends to be applied to surgically high-risk patients. A GDC embolization for a patient with thrombocytopenia has rarely been reported and the risk and efficacy is unknown. So, we conclude that for a patient with thrombocytopenia, intra-aneurysmal GDC embolization could be adopted as one of the less invasive treatment for ruptured aneurysm.

Aneurysm, Ruptured↗

PubMed1999

[A case of TSH-secreting pituitary adenoma associated with an unruptured aneurysm: successful treatment by two-stage operation and gamma-knife].

We report a successfully treated case of invasive TSH-secreting pituitary adenoma associated with an unruptured internal carotid artery aneurysm by two-stage operation and gamma-knife radiosurgery. A 64-year-old woman was admitted to our department with a 3-year history of general fatigue and 1-year history of anxiety, palpitation and hyperhydrosis. Endocrinological examination revealed hyperthyroidism with elevated TSH, GH and somatomedin C. Magnetic resonance images demonstrated a tumor in the sella turcica which extended into the left cavernous sinus, furthermore, indicated aneurysm-like flow void at the ventral part of the left internal carotid artery. The aneurysm was confirmed by conventional angiography. Neck clipping of the aneurysm was performed through pterional approach as the first operation. One month later, at the second operation, the pituitary adenoma except for cavernous sinus portion was resected via the transsphenoidal approach. Immunohistological examination revealed positive for TSH and GH. Gamma-knife radiosurgery with a central dose of 33.3 Gy and peripheral dose of 17 Gy was carried out for residual tumor at the cavernous sinus under both MRI and CT guidance. Posttreatment course was uneventful with normalization of thyroid function at 16 months after gamma-knife. Two-stage operation and gamma-knife radiosurgery is effective for TSH-secreting adenoma extending into the cavernous sinus associated with an unruptured aneurysm.

Adenoma↗