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T Sakaki

Publications and source records attributed to T Sakaki.

At least 91 records · Page 5Linked to original sources
PubMed1999

Delayed ischemic hyperintensity on T1-weighted MRI in the caudoputamen and cerebral cortex of humans after spectacular shrinking deficit.

BACKGROUND AND PURPOSE: Transient internal carotid artery (ICA)-middle cerebral artery (MCA) occlusion caused by cardiogenic embolus can lead to spectacular shrinking deficit (SSD): sudden hemispheric stroke syndrome followed by rapid improvement. The aim of this study was to investigate sequential neuroradiological changes in the brains of patients after SSD compared with those after brief cardiac arrest and hypoglycemia, which we previously studied with the same methods. METHODS: We serially studied CT scans and MR images obtained at 1.5 T in 4 patients with SSD. All 4 patients suffered from transient neurological deficits due to cardiogenic embolus in ICA-MCA. The symptoms began to disappear from 25 to 50 minutes after onset. RESULTS: Repeated CT scans demonstrated no abnormal findings in the affected cerebral hemisphere in 3 of the 4 patients and a small cortical infarct in the remaining 1. In each patient, repeated MRI between day 7 and month 23 after stroke showed basal ganglionic and cortical lesions. These lesions were hyperintense on T1-weighted and relatively hypointense on T2-weighted imaging. These ischemic lesions of hyperintensity on T1-weighted MRI subsided with time. CONCLUSIONS: Transient ICA-MCA occlusion leading to SSD produces a specific ischemic change with delayed onset in the basal ganglia and cerebral cortex in humans on MRI but not CT scans. We speculate that the lesions represent incomplete ischemic injury, including selective neuronal death, proliferation of glial cells, paramagnetic substance deposition, and/or lipid accumulation. Unlike brief cardiac arrest or hypoglycemia, the localized lesions on MRI of patients after SSD seem to be incomplete and to differ from infarction or hemorrhage.

Aged↗
PubMed1999

Novel brain ischemic change on MRI. Delayed ischemic hyperintensity on T1-weighted images and selective neuronal death in the caudoputamen of rats after brief focal ischemia.

BACKGROUND AND PURPOSE: Specific change of persistent hyperintensity/hypointensity on T1-weighted (T1W) and T2-weighted (T2W) MRI, respectively, has been reported to develop in the human basal ganglia after brief hemispheric ischemia. We investigated whether this ischemic change observed in humans could be reproduced experimentally in rats after brief middle cerebral artery (MCA) occlusion (MCAO), and if so, what the neuroradiological change represented histologically. METHODS: The origin of the right MCA of male Wistar rats (n=25) was occluded for 15 minutes by inserting a silicon-coated nylon thread from the external carotid artery into the internal carotid artery. After 15 minutes' MCAO, coronal MR images (T1W, T2W, and T1W with fat saturation pulse) were obtained once at 3-day reperfusion (n=5) and twice at 3- and 7-day reperfusion (n=20). Brain specimens were examined histologically immediately after the last MRI study in all rats. RESULTS: Neither T1W nor T2W MRI showed marked signal changes 3 days after reperfusion following 15-minute MCAO. However, the ischemic change of hyperintensity and hypointensity on T1W and T2W MRI, respectively, appeared in the striatum following 7-day reperfusion after 15-minute MCAO (n=19/20). Histological examination revealed that the specific lesion in the rat striatum on MRI corresponded to selective neuronal death and proliferation of reactive astrocytes and microglia without infarct, hemorrhage, lipid accumulation, or calcification. CONCLUSIONS: Brief MCAO with reperfusion induces the delayed ischemic changes of hyperintensity and hypointensity on T1W and T2W MRI, respectively, in the rat striatum with high reproducibility. This specific ischemic change on MRI histologically corresponded to selective neuronal death and gliosis with preservation of the macroscopic structure of the brain. A similar MRI pattern reported in patients who have sustained brief ischemia may represent similar histology. We speculate that the ischemic change reflects some biochemical changes affecting the magnetic field as the brain tissue undergoes subtle structural changes.

Animals↗
PubMed1999

No enzyme activity of 25-hydroxyvitamin D3 1alpha-hydroxylase gene product in pseudovitamin D deficiency rickets, including that with mild clinical manifestation.

Pseudovitamin D deficiency rickets (PDDR) is an autosomal recessive disorder caused by defect in the activation of vitamin D. We recently isolated 25-hydroxyvitamin D3 1alpha-hydroxylase gene and identified four homozygous inactivating missense mutations in this gene by analysis of four typical cases of PDDR. This disease shows some phenotypic variation, and it has been suspected that patients with mild phenotypes have mutations that do not totally abolish the enzyme activity. To investigate the molecular defects associated with the phenotypic variation, we analyzed six additional unrelated PDDR patients: one with mild and five with typical clinical manifestation. By sequence analysis, all six patients were proven to have mutations in both alleles. The mutations varied, and we identified four novel missense mutations, a nonsense mutation, and a splicing mutation for the first time. The patient with mild clinical symptoms was compound heterozygous for T321R and a splicing mutation. The splice site mutation caused intron retention. Enzyme activity of the T321R mutant was analyzed by overexpressing the mutant 1alpha-hydroxylase in Escherichia coli cells to detect the subtle residual enzyme activity. No residual enzyme activity was detected in T321R mutant or in the other mutants. These results indicate that all of the patients, including those of mild phenotype, are caused by 1alpha-hydroxylase gene mutations that totally abolish the enzyme activity.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1999

Intrameatal aneurysm successfully treated by meatal loop trapping--case report.

A 77-year-old female presented with a rare intrameatal aneurysm manifesting as sudden onset of headache, hearing loss, tinnitus, and vertigo associated with subarachnoid hemorrhage. Meatal loop trapping was performed. After surgery, the patient's functions recovered almost completely, probably because of the preservation of the 7th and 8th cranial nerves and the presence of effective collaterals in the area supplied by the anterior inferior cerebellar artery.

Aged↗
PubMed1999

Bilateral chronic subdural hematomas resulting in unilateral oculomotor nerve paresis and brain stem symptoms after operation--case report.

An 85-year-old male presented with bilateral chronic subdural hematomas (CSDHs) resulting in unilateral oculomotor nerve paresis and brainstem symptoms immediately after removal of both hematomas in a single operation. Initial computed tomography on admission demonstrated marked thick bilateral hematomas buckling the brain parenchyma with a minimal midline shift. Almost simultaneous removal of the hematomas was performed with the left side was decompressed first with a time difference of at most 2 minutes. However, the patient developed right oculomotor nerve paresis, left hemiparesis, and consciousness disturbance after the operation. The relatively marked increase in pressure on the right side may have caused transient unilateral brain stem compression and herniation of unilateral medial temporal lobe during the short time between the right and left procedures. Another factor was the vulnerability of the oculomotor nerve resulting from posterior replacement of the brain stem and stretching of the oculomotor nerves as seen on sagittal magnetic resonance (MR) images. Axial MR images obtained at the same time demonstrated medial deflection of the distal oculomotor nerve after crossing the posterior cerebral artery, which indicates previous transient compression of the nerve and the brain stem. Gradual and symmetrical decompression without time lag is recommended for the treatment of huge bilateral CSDHs.

Aged↗
PubMed1999

Surgical treatment of internal carotid artery anterior wall aneurysm with extravasation during angiography--case report.

A 54-year-old female presented subarachnoid hemorrhage from an aneurysm arising from the anterior (dorsal) wall of the internal carotid artery (ICA). During four-vessel angiography, an extravasated saccular pooling of contrast medium emerged in the suprasellar area unrelated to any arterial branch. The saccular pooling was visualized in the arterial phase and cleared in the venophase during every contrast medium injection. We suspected that the extravasated pooling was surrounded by hard clot but communicated with the artery. Direct surgery was performed but major premature bleeding occurred during the microsurgical procedure. After temporary clipping, an opening of the anterior (dorsal) wall of the ICA was found without apparent aneurysm wall. The vessel wall was sutured with nylon thread. The total occlusion time of the ICA was about 50 minutes. Follow-up angiography demonstrated good patency of the ICA. About 2 years after the operation, the patient was able to walk with a stick and to communicate freely through speech, although left hemiparesis and left homonymous hemianopsia persisted. The outcome suggests our treatment strategy was not optimal, but suture of the ICA wall is one of the therapeutic choices when premature rupture occurs in the operation.

Aneurysm, Ruptured↗
PubMed1999

Subarachnoid hemorrhage from intracranial dissecting aneurysms of the anterior circulation. Two case reports.

Two rare cases of intracranial dissecting aneurysms of the anterior circulation associated with subarachnoid hemorrhage (SAH) are described. A 56-year-old female presented with a dissecting aneurysm in the proximal segment of the left middle cerebral artery. Proximal occlusion of the affected artery and a superficial temporal artery-middle cerebral artery anastomosis were performed, but the outcome was poor. A 61-year-old male presented with a dissecting aneurysm in the proximal segment of the left anterior cerebral artery. Clipping was enhanced by a piece of fascia lata, allowing patency of the affected artery with a satisfactory outcome. Dissecting aneurysm of the carotid system should be considered in a patient with SAH but no evidence of berry aneurysm.

Anastomosis, Surgical↗
PubMed1999

Intracranial Castleman's disease of solitary form. Case report.

This 62-year-old woman presented with clumsiness in her right hand. Magnetic resonance imaging demonstrated a small lesion mimicking a meningioma, which had arisen from the tentorium and contained notable edema. Full recovery was achieved by total removal of the lesion, which was diagnosed as a lymphoid mass resembling giant lymph node hyperplasia on histological examination. The lack of notable findings on whole-body and laboratory studies was compatible with a rare case of intracranial Castleman's disease of solitary form. The authors document clinical, neuroradiological, and pathological features of this rare disease.

Brain Diseases↗
PubMed1999

Expression of angiogenic growth factors in dural arteriovenous fistula.

OBJECT: Although various mechanisms of the development of dural arteriovenous fistula (AVF) have been described, the exact course of its pathogenesis, including molecular processes mediating its genesis, is still unknown. Recently, the importance of sinus thrombosis and venous hypertension has been reported in experimental and clinical studies. Additionally, a role of angiogenic growth factors in the pathogenesis of vascular malformations of the central nervous system has been reported. In this study, the authors investigated the existence of sinus thrombosis in dural AVF and the expression of angiogenic growth factors (basic fibroblast growth factor [bFGF] and vascular endothelial growth factor [VEGF]) in nine patients with dural AVFs that were surgically resected. METHODS: The authors examined histological features of dural AVFs that involved the transverse/sigmoid sinus in seven patients and the superior sagittal sinus in two. Sinus thrombosis was verified angiographically in seven cases and histologically in all cases. In surgically resected specimens the angiogenic growth factors bFGF and VEGF were examined immunohistochemically in nine patients with dural AVFs, with five dural sinuses from cadavers with unrelated central nervous system diseases serving as a normal control group. The media and perivascular connective tissues of the arteries in the wall of the normal dural sinuses stained faintly for bFGF; on the other hand, the expression of VEGF was not detected. In all patients with dural AVFs, the thick wall of the dural sinus stained strongly for bFGF, mainly in the subendothelial layer and media of the strongly proliferative vessels in the sinus wall, in addition to the perivascular connective tissues. In all nine cases VEGF was expressed in the endothelium of the sinus and perivascular connective tissues. In two cases, VEGF was expressed in many capillaries proliferating in the granulation-like tissues in sinuses that were obliterated by organized thrombi. CONCLUSIONS: It is concluded that the pathogenesis of dural AVF is still unknown, but that angiogenic growth factors, which might be produced by the healing process due to sinus thrombosis, may participate in the genesis of dural AVF. Understanding the mechanism of molecular pathogenesis in the development of dural AVF might aid in the establishment of a new therapeutic strategy for this dynamic vascular disease.

Adult↗
PubMed1999

Genomic alterations in human meningiomas detected by restriction landmark genomic scanning and immunohistochemical studies.

Using restriction landmark genomic scanning (RLGS) methods, 21 samples of human meningioma were analyzed. We found 3 alterations in the genomic DNAs of tumor samples located on chromosomes 5, 14 and 17 which appear to be common to the meningothelial subtype. Two other separate genetic abnormalities located on chromosomes 9-12 and 20 are apparently associated with atypical meningiomas. In addition, the neurofibromatosis type 2 gene is apparently involved in more than half of the tumor samples. There appear to be both common and type-specific genetic mutations associated with the formation and progression of human meningiomas.

Adult↗
PubMed1999

[Effect of deliberate mild hypothermia on the incidence of surgical-wound infection and duration of hospitalization in neurosurgical patients].

We investigated the effect of mild hypothermia on the incidence of surgical-wound infection and duration of hospitalization, retrospectively. We randomly assigned 173 patients undergoing intracranial operation to mild hypothermic group (group H) of 122 patients or normothermic group (group N) of 51 patients. A water blanket and a convective device blanket were used for thermal control in the both groups. The temperature at the tympanic membrane was adjusted to 34.5 degrees C in group H and 36.0 degrees C in group N. Surgical-wound infection was found in 4 of 122 patients (3.3%) of group H but in none of 51 patients (0%) of group N. The duration of hospitalization was 36.0 +/- 25.5 days in group H and 40.2 +/- 36.9 days in group N. There were no statistical differences of the incidence of surgical-wound infection and duration of hospitalization between the two groups. However, the duration to suture removal was significantly longer in group H than in group N (8.3 +/- 1.6 vs 7.8 +/- 0.8 days). Although the effects of deliberate mild hypothermia for neurosurgery on the incidence of surgical-wound infection and duration of hospitalization were little, it may affect the recovery process of such patients.

Adult↗
PubMed1999

Cervical myelopathy due to dynamic compression by the laminectomy membrane: dynamic MR imaging study.

Dynamic magnetic resonance (MR) imaging is useful in assessing delayed neurologic deterioration after multilevel cervical laminectomy. The authors report a case of a 75-year-old woman who deteriorated 24 years after a C4-C7 laminectomy. When the extension MR demonstrated marked spinal cord compression attributable to a laminectomy membrane, the patient had an anterior diskectomy and fusion performed, after which she demonstrated significant neurologic improvement. In this and other cases, the dynamic MR may be a useful tool in discerning the etiology of the delayed neurologic changes occurring in postoperative patients.

Aged↗
PubMed1999

[Serial change of cerebral blood flow after collagenase induced intracerebral hemorrhage in rats].

In case of intracerebral hemorrhage (ICH), many clinical studies have reported that great alterations in regional cerebral blood flow (rCBF) have been observed not only in the acute but also in the chronic stage. However, due to the absence of reproducible animal model, experimental studies have failed to confirm the evidence. We therefore studied the serial change of rCBF and investigated the possibility of secondary brain damage using our collagenase induced ICH model. A total of 60 adult male rats were examined. 2 microliters artificial cerebrospinal fluid, which was adjusted to a pH 7.4 by a buffer, containing 0.25 units of bacterial collagenase was stereotactically injected into the left caudoputamen in 28 rats. 2 microliters artificial cerebrospinal fluid without collagenase was also injected into 28 control rats under sham operation. The remaining 4 rats were studied as a non treatment group. The rCBF of the frontal cortex, parietal cortex, temporal cortex, occipital cortex, caudoputamen, thalamus and the cerebellum was determined bilaterally by [14C]-iodoantipyrine quantitative autoradiography according to Sakurada's method at 2, 4, 12, 24, 48, 168 and 720 hours after the operation. At 4 hours after injection, significant decrease of rCBF was observed in the ipsilateral hemisphere and also in some contralateral regions. In the ipsilateral frontal cortex and caudoputamen, there was significant increase of the rCBF which reached close to the baseline at 24 hours. After that, the rCBF of those regions decreased significantly again and remained at a low value even 1 month after injection. In the other regions of the ipsilateral hemisphere which were located remotedly from the hematoma, the rCBF recovered from 24 to 48 hours after injection. In the contralateral hemisphere, the rCBF also recovered at 24 hours. We suggest that this alteration of the rCBF observed in perihematomatous regions was the result of secondary brain damage caused by the existence of hematoma. On account of this, we conclude that early removal of hematoma is necessary to obtain a better result in cases of ICH.

Animals↗
PubMed1999

[Ventricular fibrillation during mild hypothermic therapy in a patient undergoing neurosurgery].

A 35 year old male for mild hypothermic therapy for neurosurgery, developed ventricular fibrillation. Total resection of cerebral arteriovenous malformation was performed under mild hypothermic therapy, with the target core temperature of 33 degrees C. Intraoperatively cooling rate was low and a reduction of peripheral temperature associated with metabolic acidosis was noted. After the conclusion of the operation and during transferring the patient to an intensive care unit, multiple ventricular premature beats were noted. Thereafter, ventricular tachycardia developed proceeding ventricular fibrillation. We suggest that careful management of thermal and cardiovascular systems is required to prevent adverse events during mild hypothermic therapy.

Adult↗
PubMed1999

[Reverse redistribution of technetium-99m-tetrofosmin after acute coronary revascularization in patients with myocardial infarction].

This study qualified the severity and localization of reverse redistribution of technetium-99 m (Tc)-tetrofosmin rest imaging. Both Tc-tetrofosmin and thallium-201 (Tl) rest imaging with early images and delayed images were obtained in the subacute phase of myocardial infarction in 21 patients with first anterior myocardial infarction and with successful transluminal angioplasty (including stenting). Relative myocardial uptake (%uptake), degree of reverse redistribution (%), and washout rate (%) were evaluated quantitatively in 6 left ventricular segments (inferoseptal, anteroseptal, anterior, anterolateral, lateral, inferolateral and inferior) by circumferential profile analysis. The percentage reverse redistribution in the infarct area was larger in Tc-tetrofosmin imaging than in Tl imaging (p = 0.013). Reverse redistribution was most prominent in the anterior wall (anterior > anteroseptal > inferoseptal, p = 0.020). This suggests that infradiaphragmatic scatter is unlikely as the mechanism of reverse redistribution. The washout rate of Tc-tetrofosmin in the infarct area (reverse redistribution area) was higher than that in the normal area (non-reverse redistribution area), and was also higher than the washout rate of Tl imaging in the infarct area. The %uptake of delayed images in the infarct area was larger in Tc-tetrofosmin than that in Tl imaging, whereas %uptake of early images did not differ. The percentage reverse redistribution did not correlate with the degree of collateral circulation and the residual stenosis. In conclusion, reverse redistribution of Tc-tetrofosmin was more prominent in the infarct area, and this was due to the relatively lower uptake of reverse redistribution of Tc-tetrofosmin than delayed Tl images.

Angioplasty, Balloon, Coronary↗
PubMed1999

[The effect of intraoperative mild hypothermia on the development of perioperative cardiac ischemia].

We evaluated the risk of perioperative cardiac ischemia associated with mild hypothermia as adjunct management for neurosurgical procedures. Forty-seven elective neurosurgical patients were randomly assigned to either hypothermic group (H, n = 24) or normothermic one (N, n = 23). Patients in group H were cooled to and maintained at 34.5 degrees C (tympanic membrane temperature) and rewarmed after main neurosurgical manipulation, while those in group N were kept in normothermic state. Cardiac ischemia was diagnosed with Holter electrocardiogram monitored for 24 hours after admission to the operating room. No differences were observed in demographic data including age, gender, weight, height, rate of having cardiac disease, anesthesia methods, and contents of surgery. Temperature was significantly lower in group H than N both at the lowest point (34.6 +/- 0.5 vs 35.9 +/- 0.6, mean +/- SD) and at the conclusion of anesthesia (35.9 +/- 0.9 vs 36.5 +/- 0.5). Electrocardiographic ST segmental depression was observed in 3 (group H) and 5 cases (group N), and postoperative shivering occurred in 3 (group H) and 2 cases (group N), respectively. Those incidences were not statistically significant (chi-square test, P was set at 0.05). We concluded that intraoperative mild hypothermia might not increase the risk of perioperative cardiac ischemia in patients for neurosurgical procedures.

Adult↗
PubMed1999

Correlation of E-cadherin and alpha-catenin expression with differentiation of oral squamous cell carcinoma.

The precise mechanism of disruption of cell-cell adhesion in oral squamous cell carcinomas has yet to be established. We therefore sought to clearly this mechanism by investigating expression of both E-cadherin (E-CD) and alpha-catenin (alpha-CAT), which is an intracellular CD-binding molecule, in squamous cell carcinomas of the tongue, gingiva and floor of the mouth using immunohistochemical and immunoblotting techniques. We found that reduced expression of both E-CD and alpha-CAT occurred more frequently in moderately- and poorly-differentiated carcinomas than in well-differentiated specimens (p < 0.001), and this reduced expression showed no regional specificity. Relatively frequent loss of alpha-CAT expression in poorly-differentiated carcinomas was detected by both immunohistochemical and immunoblotting analyses. These findings suggest that E-CD and alpha-CAT are both important regulators of intercellular adhesion, and that the reduction of these molecules is also linked to the process of tumor dedifferentiation.

Antibodies, Monoclonal↗