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Biomedical subjects

W Taki

Publications and source records attributed to W Taki.

At least 109 records · Page 6Linked to original sources
PubMed1989

Cerebral circulation and metabolism in adults' moyamoya disease--PET study.

Regional cerebral blood flow (rCBF), oxygen extraction fraction (rOEF), cerebral metabolic rate for oxygen (rCMRO2) and cerebral blood volume (rCBV) in nine cases of moyamoya disease in adults were studied with positron emission CT (PET) scan, using 15O steady-state methods. Three cases showed ischaemic symptoms and the other six cases showed haemorrhagic symptoms. PET scan was performed during the chronic stage. Control data were obtained from eight normal volunteers. Regional cerebral blood flow and other physiological parameters in cerebral gray matter, white matter and basal ganglia were compared with normal controls. All nine cases of Moyamoya disease showed decreased rCBF, though not significant, in cerebral gray matter, white matter and basal ganglia. Reduction of rCBF was significant in the cerebral cortex of six haemorrhagic cases. This significant decrease was considered to be due to diaschisis and also brain atrophy caused by the cerebral haemorrhage. There was a significant increase in rCBV in white matter of the both ischaemic and haemorrhagic cases. The calculated value of CBF/CBV is considered to be an index of perfusion pressure. This value was significantly decreased in all three regions, though rOEF was not significantly increased in moyamoya disease. Hence the cerebral circulation in adults with moyamoya disease appears to be characterized by a mild decrease in perfusion pressure and prolonged circulated time.

Adult↗
PubMed1989

Regional cerebral blood flow and oxygen metabolism in normal pressure hydrocephalus after subarachnoid hemorrhage.

To clarify the pathophysiology of normal pressure hydrocephalus (NPH) after subarachnoid hemorrhage, the authors measured cerebral blood flow (CBF), cerebral oxygen metabolic rates (CMRO2), the cerebral oxygen extraction fraction (OEF), and cerebral blood volume (CBV) in eight normal volunteers, six SAH patients with NPH, and seven patients without NPH by 15O-labeled gas and positron emission tomography (PET). In the NPH group, PET revealed a decrease in CBF in the lower regions of the cerebral cortex and a diffuse decrease in CMRO2. The decrease in CBF in the lower frontal, temporal, and occipital cortices was significantly greater in the NPH than in the non-NPH group. Reduction of CMRO2 was also more extensive in the NPH group, and both CBF and CMRO2 were more markedly decreased in the lower frontal region. OEF was increased in all areas in both of the patient groups, but the increase was not significant in most areas. CBF, CMRO2 and OEF did not significantly differ between the non-NPH group and the normal volunteers. There was no significant difference in CBV among the three groups. These results indicate that NPH involves impairment of cerebral oxygen metabolism in the lower regions of the cerebral cortex, particularly in the lower frontal region.

Brain↗
PubMed1989

Degradation of neurofilament protein in cerebral ischemia.

Degradation of neurofilament (NF) triplet proteins: NF200 (molecular weight (MW) 200,000), NF150 (MW 150,000), and NF68 (MW 68,000) as well as of other cytoskeletal proteins in the rat brain during ischemia was investigated. Sodium dodecyl sulfate-gel electrophoresis and immunoblot methods with anti-NF200 antibody were used for the study. Selective degradation of NF200 and NF150 was observed during the initial 10 to 15 minutes of ischemia. The degradation was demonstrated both in permanent ischemia caused by decapitation and in transient ischemia induced by four-vessel occlusion followed by reperfusion after 30 minutes of occlusion (modified Pulsinelli method). The degradation suggests that the activation of a protease occurs in the first 15 minutes of cerebral ischemia, which is the earliest irreversible neuronal change ever to be reported.

Animals↗
PubMed1989

[The effect of glycerol on regional cerebral blood flow, blood volume and oxygen metabolism].

Using positron emission tomography with 15O-labelled CO2 O2 and CO gases, the effects of glycerol on regional cerebral blood flow (CBF), blood volume (CBV) and oxygen metabolism (CMRO2) were investigated in 6 patients with meningioma accompanying peritumoral brain edema. The same study was done in 5 normal volunteers. The changes of blood gases, hematocrit and hemoglobin were also examined. After a drip infusion of glycerol, the regional CBF increased not only in the peritumoral cortex and white matter but also in the intact cortex and white matter on the contralateral side. The increase of CBF was extensive and substantially there were no regional differences. In contrast, the changes of CMRO2 were not significant. This was derived from the increase in oxygen extraction fraction throughout extensive areas including the peritumoral area. There were no changes in CBV. Hematocrit and hemoglobin decreased to a small degree. In the normal volunteers, the same findings were noted. Thus, glycerol increases the functional reserve for cerebral oxygen metabolism, not only in the peritumoral regions but also in the intact regions. The effects of glycerol on hemodynamics and metabolism were discussed with reference to some differences from mannitol.

Adult↗
PubMed1988

Cerebral circulation and oxygen metabolism in moyamoya disease of ischemic type in children.

Cerebral rCBF, rOEF, rCMRO2, and rCBV in moyamoya disease were studied by means of positron emmission tomography (PET), using 15O as a tracer. Steady-state methods with C15O2 and 15O2 were used to obtain the functional images of rCBF, rCMRO2, and rOEF. The 15O single-inhalation method was used to obtain the rCBV image. Five children (two boys and three girls) with mean age of 11 years and eight normal volunteers with mean age of 31 years were included in the study. The symptoms of moyamoya disease were due to cerebral ischemia, such as transient ischemic attack (TIA), reversible ischemic neurological deficit (RIND), and minor stroke. The interval between the latest ictus and PET scan ranged from 3 days to 3 years 6 months. Physiological parameters (rCBF, rCMRO2 etc.) in cerebral gray matter, cerebral white matter and basal ganglia were calculated from the single functional images. Any, low density areas appearing in X-ray-CT performed just prior to the PET study were carefully excluded from the analysis. The parameters of moyamoya disease were statistically compared with normal control parameters. Though the value of rCBF was slightly higher in moyamoya disease, this difference was not statistically significant. On the other hand, in moyamoya disease rCBV increased significantly in gray matter, white matter, and basal ganglia. The ratio of CBF to CBV is considered to be the index of perfusion pressure and reciprocal of cerebral mean transit time under the normal autoregulation of CBF. This ratio was calculated and compared with the normal value for each tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Degradation of phospholipid molecular species during experimental cerebral ischemia in rats.

Previous investigators have shown that free fatty acids that accumulate during ischemia are an indicator of evolution in ischemic brain damage. Our study describes the temporal relations between free fatty acid accumulation and degradation of phospholipid molecular species after cerebral ischemia. Using the four-vessel occlusion model of adult Wistar rats, we analyzed quantitatively the cerebral phospholipid molecular species of diacyl phosphatidylcholine and diacyl phosphatidylethanolamine and released free fatty acids during ischemia. Total diacyl phosphatidylcholine molecular species decreased gradually but did not show any significant difference even at 60 minutes. By contrast, total diacyl phosphatidylethanolamine abruptly decreased after 5 minutes and continued to decrease significantly thereafter. Polyunsaturated molecular species showed a higher ratio of degradation than saturated and monounsaturated molecular species of either phosphatidylcholine or phosphatidylethanolamine. Total free fatty acid accumulated according to the time elapsed, and statistical significance was obtained after 10 minutes. Free arachidonic and docosahexaenoic acids were attributed to these significant accumulations at 10, 15, and 30 minutes. At 60 minutes, individual free fatty acids increased nonspecifically. Free fatty acids, which are hydrolyzed from phospholipid classes, are known to be further metabolized to bioactive substances such as prostaglandins and leukotrienes. Rapid degradation of phospholipid molecular species, especially of diacyl polyunsaturated molecular species, could be an important finding to membrane perturbation. Effective prevention of these changes might enhance tolerance to ischemic brain damage.

Animals↗
PubMed1988

[Effects of bifemelane on the free fatty acid levels during ischemia].

Using the four-vessel extracranial one staged occlusion model of adult Wistar rats, we analyzed quantitatively released free fatty acids during ischemia. Also have we analyzed the effect of bifemelane to reduce free fatty acid accumulation after the onset of ischemia. Bifemelane (15 mg/kg, 30 mg/kg) and saline as control were intraperitoneally administered to adult Wistar rat prior to 30 minutes of experimentally induced ischemia. The results obtained were analyzed by one or two way analysis of variance (ANOVA). Physiological variables (systemic arterial pressure, PaO2, PaCO2, pH) did not change significantly in all four experimental groups. Total free fatty acid levels (sum of 5 fatty acid) increased significantly after ischemia (30 minutes). Higher dose (30 mg/kg) of bifemelane administration significantly reduced total free fatty acid accumulation, though lower dose (15 mg/kg) did have no effect. Bifemelane (30 mg/kg) reduced significant accumulation in the amount of saturated and monounsaturated fatty acid (palmitic acid [16:0], stearic acid [18:0] and oleic acid [18:1]). Arachidonic (20:4) and docosahexaenoic (22:6) acid failed to show any effective reduction by bifemelane pre-treatment of lower nor higher dose. Bifemelane is supposed to have many pharmacological effects such as increase in cerebral blood flow, augmentation of glucose uptake, monoamine metabolism, cerebral vasodilatation and platelet antiaggregation. Free fatty acid accumulation is effectively suppressed by the higher dose of bifemelane administration. Although the exact mechanism are not clearly identified by the result obtained in this experiment, selective inhibition of accumulation in saturated and monounsaturated fatty acids by bifemelane pretreatment may be obtained by the improvement of energy metabolism, which may help to reacylation of fatty acid into phospholipid.

Animals↗
PubMed1988

[Cerebral circulation and oxygen metabolism in children's "moyamoya" diseases].

Regional (r) CBF, rOEF, rCMRO2, rCBV in five cases of "moyamoya" disease in children were studied with PET scan, using 15O steady-state methods. All cases showed ischemic symptoms such as TIA, RIND and minor stroke. Intervals from the latest ictus to PET ranged from 3 days to 3 years 6 months. Control data were obtained through PET studies in 8 normal volunteers. Physiological parameters described above, in cerebral gray matter, white matter and basal ganglia were calculated and were carefully compared with normal control. Apparently low density area in X-ray CT were excluded from this analysis. Although rCBF showed a little bit higher value in all gray, white and basal ganglia, it was not statistically significant. rCBV of "moyamoya" disease significantly increased in gray, white and basal ganglia. The calculated value of CBF/CBV is considered to be an index of perfusion pressure and is the reversed value of transit time. This value was significantly decreased in "moyamoya" disease in every three region. Under the normal autoregulation, further decrease of perfusion pressure initiate increase of rOER and also decrease of rCBF. In spite of reduction of CBF/CBV, rOER was not significantly increased in every three region. Hence the cerebral circulation in children's "moyamoya" disease of ischemic type appears to be characterized by the mild decrease of perfusion pressure, dilated resistant vessels and prolonged circulation time.

Adolescent↗
PubMed1987

Nonsuture microvascular anastomosis using an Nd-YAG laser and a water-soluble polyvinyl alcohol splint.

Anastomosis of rat common carotid artery was performed without sutures, using a neodymium (Nd)-YAG laser at 20 W for 100 msec; this power and exposure had been found optimal in preliminary experiments. An intraluminal intervascular splint made of water-soluble polyvinyl alcohol, which dissolved and disappeared within a few minutes after recirculation of blood, was used for precise "intima-to-intima" coaptation. No stay sutures or glue were required during the procedure. There was a 92% patency rate 24 hours after surgery, and the anastomosed vessels were still patent on the 7th and 30th postoperative days. Complications such as aneurysm formation or stenotic change were negligible. The fusion of the muscle layer and collagen fibers of the media in the anastomosis was confirmed histologically. A tensile strength test immediately following operation and 1 week later showed that this anastomosis was significantly better than that achieved with the usual manual suture method. The major advantages of this technique, combined with use of a water-soluble polyvinyl alcohol splint, are rapidity, consistency of results, and firm fusion with no residual foreign body.

Anastomosis, Surgical↗
PubMed1987

[Revascularization for simultaneous carotid and coronary ischemia].

Some of the patients who suffer from cerebral ischemia may at the same time have coronary insufficiency. For such cases, not only extracranial-intracranial (EC-IC) bypass but also cardiac revascularization is considered to be necessary. One-stage surgery of both carotid endarterectomy and coronary artery bypass grafting (CABG) has not infrequently been published. However, the combination of EC-IC bypass and CABG is rarely reported in the literature. The indication of EC-IC bypass and/or CABG for such patients above stated has been searched for. In fact, CABG runs the risk of aggravating cerebral ischemia and/or intracranial hemorrhage by inevitable hypotension, hypothermia and heparinization of a large amount, while EC-IC bypass may safely be carried out so long as cardiac conditions are carefully controlled during the operation. It is consequently presumed that the preliminary EC-IC bypass followed by CABG seems to be the method of choice for simultaneous carotid and coronary ischemia. Two cases underwent the staged revascularization, first for the brain and next for the heart, with a successful result are reported in the present paper.

Aged↗
PubMed1987

[Follow-up results after STA-MCA anastomosis in cases of middle cerebral artery stenosis].

To elucidate hemodynamic changes and prognosis after STA-MCA anastomosis, thirteen cases with middle cerebral artery stenosis were systematically analyzed from the pre- and postoperative findings of cerebral angiography, CT scan and rCBF. They were followed up about 3 years long on the average postoperatively. Postoperative angiography revealed patent bypass in all cases. No remarkable changes at the site of stenosis were observed in the group A (6 in 13 cases), who had angiographically sufficient inherent collateral circulation. By contrast, group B (7 in 13 cases), who had insufficient inherent collateral circulation, showed remarkable progress in the degree of stenosis and significant changes of flow patterns were observed after operation. However, these postoperative changes did not bring any clinical deterioration. During follow-up period (31.2 months on the average) after operation, no cerebrovascular accident were encountered in all cases and clinically improved. In conclusion, the STA-MCA bypass rendered more beneficial effect to the patient with MCA stenosis when compared with natural histories reported in the literature.

Cerebral Angiography↗
PubMed1987

[Sutureless method of micro-vascular anastomosis using low-energy Nd-YAG laser].

Sutureless end-to-end anastomosis of rat common carotid artery was carried out, low energy Nd-YAG laser being used thereby. An intraluminal-intervascular splint, made of water-soluble poval, was used for precise adaptation of the intimas. Neither stay suture nor glue was required. The patency rate of the anastomosed vessels, 24 hours after operation, was as high as 91%. The vessels were confirmed to be likewise patent on the 7th and 30th postoperative day. Complications such as pseudoaneurysm formation or stenotic change, were negligible. The fusion of the anastomosis with Nd-YAG laser was histologically proved to be satisfactory and the result of tensile strength test was excellent. Temperature at the anastomotic site during laser irradiation was measured, optimal energy for anastomosis determined and possible mechanism of vascular fusion by laser beam postulated. The major advantages of the laser technique combined with poval splint, such as rapidity, consistency and no residual foreign body (thread or adhesive), are discussed.

Anastomosis, Surgical↗
PubMed1986

Ruptured cerebral aneurysms in patients with systemic lupus erythematosus.

Two cases of ruptured aneurysms in the cerebral arteries in patients with established systemic lupus erythematosus are presented. A 32-year-old woman with a 3-year history of systemic lupus erythematosus was found to have a ruptured cerebral aneurysm at the top of the basilar artery. Another 38-year-old woman with a 4-year history of lupus erythematosus had a ruptured aneurysm in the anterior communicating artery. Both were treated surgically. Cerebral aneurysms associated with systemic lupus erythematosus are reviewed in the literature and the pathogenesis of these aneurysms is discussed.

Adult↗
PubMed1986

Thalamic tumours invading the brain stem produce crossed cerebellar diaschisis demonstrated by PET.

Two cases of thalamic tumour, spreading through the midbrain into the pons ventrolaterally, showed suppression of cerebellar blood flow on the opposite side to the tumour, and also showed reduction of blood flow in the pons on the side of the tumour in positron emission tomographic studies. The pathophysiological mechanism of crossed cerebellar diaschisis may be due to functional suppression of the pontine nuclei by destruction of descending fibres from the cerebral cortex.

Adult↗
PubMed1986

[One-stage bilateral STA-MCA anastomosis in multiple occlusive cerebrovascular disease].

Out of 12 cases of bilateral stenosis of the internal carotid (IC) system underwent unilateral STA-MCA anastomosis on the symptomatic side, no ischemic signs recurred in 8 cases, while, in the remaining 4, symptoms appeared postoperatively, requiring the anastomosis of the contralateral side. Preoperative findings of CT scan, CAG and r-CBF were reviewed and compared. It has, consequently, become evident that, in the latter 4 cases, angiography showed stenotic lesion of over 50% of the ICA lumen, between the mastoid-mandibular line (MML) and the circle of Willis, on the initially asymptomatic side. Furthermore, in the same 4 cases, multiple thrombotic foci were more liable to be demonstrated on the CT scans and r-CBF was lowered in both hemispheres without significant difference in laterality. In additional 7 cases presenting such characteristics as stated above, one-stage bilateral STA-MCA anastomosis was carried out with a successful result.

Aged↗
PubMed1986

[Follow-up study on the relationship between age at onset of illness and outcome in patients with moyamoya disease].

Follow-up studies over more than one and a half years (average 6.5 years) were performed in 51 patients with "moyamoya disease". Activities of daily living (ADL) was assessed and graded into five levels both at the time of admission into hospital and at the last assessment in the follow-up study, as follows. Grade I: Fully capable of work or study with no or minimal difficulty, II: Capable of limited work or study with difficulty, III: Incapable of work or study but capable of home life alone, IV: Incapable of home life without help, V: Vegetative state or dead. Patients were divided into three groups by the age of clinical onset: younger pediatric, less than 5 years old (21 patients); older pediatric, 5 to 15 years old (14 patients); and adult, 16 years old and over (16 patients). Although analysis of the angiographical and neurological pictures is important, the present paper concerns only the age of clinical onset and whether reconstructive vascular surgery was performed, because of the small number of clinical materials. Seven of 16 adults suffered hemorrhagic attacks and 2 of them died of hemorrhagic insults. In contrast, none of the pediatric cases had hemorrhagic attacks and none died. Both at the time of admission and last assessment, ADL of younger pediatric cases was much lower than that of older ones. These results suggest that clinical course in patients with "moyamoya disease" closely related with the age of the onset of illness, and the border age of onset of illness between patients with good outcome and with poor outcome is around 5 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1985

Histologic study of normal rat brain tissue after neodymium-yttrium aluminum garnet laser irradiation. I. Cerebral hemisphere.

We report a histologic study of normal rat brain tissue after neodymium-yttrium aluminum garnet laser irradiation. Morphological changes occurred at a maximum depth of 5 mm after 60-W, 1-second exposure, at a 2-mm distance between the optical fiber tip and the brain surface. Polymorphonuclear leukocyte infiltration into the irradiated area was observed 48 hours after irradiation. After 72 hours, macrophages and fibroblasts appeared; their number increased thereafter. At 1 month, tissue defects attributable to neodymium-yttrium aluminum garnet laser irradiation were small. Gliotic changes were rarely seen. We conclude that 60-W irradiation is harmful to young rats but not to adult rats.

Animals↗