Immunohistochemical changes of perilesional GABA neurons in alumina cream-induced focal motor epilepsy.
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Aluminum Oxide↗
Biomedical subjects
T Sakaki
Publications and source records attributed to T Sakaki.
Use of local cerebral blood flow monitoring to predict brain damage after disturbance to the venous circulation: cortical vein occlusion model by photochemical dye.
A rat model of cortical vein occlusion by the photochemical thrombotic technique was used to evaluate whether monitoring the change in the local cerebral blood flow (LCBF) could predict brain damage after cortical vein occlusion. The cortical vein occlusion was attained by using the photochemical thrombotic technique, and the sequential LCBF was measured by using a laser Doppler flowmeter positioned over the middle frontal cortex between two adjacent dorsal veins for 120 minutes after the start of the irradiation to the cortical vein. Rats were assigned to one of three experimental groups. In Group A (n = 10), one dorsal cerebral vein was occluded; in Group B (n = 10), two adjacent dorsal cerebral veins were occluded; and in a sham-operated group (n = 5), the rats also underwent craniotomy and light exposure but received injections of saline rather than the rose bengal dye. After 24 hours, the rats were submitted to perfusion fixation and were examined histopathologically. After irradiation-induced cortical vein occlusion, a gradual and significant decrease of the LCBF was observed in both Group A (significantly different from the LCBF of the sham-operated group after 90 min, P < 0.05, and 120 min, P < 0.01) and Group B (significantly different from the LCBF of the sham-operated group at 30 min, P < 0.05, and at 60, 90, and 120 min, P < 0.01). Significant differences (P < 0.01) in the LCBF were also seen between the two experimental groups at 90 and 120 minutes after the start of the irradiation and the subsequent brain damage.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Immunohistochemical study of glutathione S-transferase-pi in meningiomas.
Immunostaining for glutathione S-transferase-pi was investigated in various subtypes of meningioma for the purpose of biological characterization. Specimens included five normal meninges and 25 meningiomas (10 meningothelial type, 6 fibrous type, 5 transitional type, 3 microcystic type, and 1 secretory type). In the meningothelial type, most cells showed strongly positive staining. In the fibrous type, all cells were negative. In the transitional type, only the meningothelial components were positive. In the microcystic type, meningothelial cell clusters and arachnoid trabecular cells were positive. In the secretory type, the meningothelial components and the pseudopsammoma-body-producing cells were positive. These results suggest that the meningothelial type and the fibrous type have a different basis of development and biological features. The results also suggest that arachnoid trabecular cells and meningothelial cells share the same origin, and that the arachnoid trabecular cells serve as supportive cells and as cells which detoxify harmful substances in the subarachnoid space. The pseudopsammoma-body-producing cells in the secretory type represent the outcome of epithelial differentiation of meningothelial cells with their biological character being preserved.
Culture Techniques↗
Eighth cranial nerve lipoma manifesting as intractable vertigo--Case report.
A 49-year-old female presented with an extremely rare lipoma of the cerebellopontine angle (CPA) manifesting as intractable vertigo and tinnitus. Subtotal removal of the lipoma was performed to debulk the tumor and decompress the cranial nerve VIII. Her complaints were resolved without new neurological deficit. We recommended surgery in patients with symptomatic CPA lipomas for diagnosis, debulking, and decompression of cranial nerves to relieve the symptoms.
Cerebellopontine Angle↗
Middle cranial fossa arachnoid cyst developing in infancy. Case report.
The pathophysiology of primary arachnoid cysts of the middle cranial fossa is still unclear, and no widely accepted therapeutic criteria for this condition have been established. The authors present the case of a 7-year-old boy with this cyst accompanied by temporal lobe hypoplasia. On the basis of computerized tomography taken on the 2nd day after birth and magnetic resonance imaging upon admission, the arachnoid cyst in this case was attributed to brain hypoplasia secondary to abnormal arachnoid development and was confirmed to have developed primarily during infancy. Experience with this case yielded new findings useful in clarifying the pathophysiology of this condition and establishing therapeutic criteria for such a case.
Arachnoid Cysts↗
[A case of basilar artery occlusion caused by vertebrobasilar artery dissection presenting with mild clinical symptoms].
We reported a first case of basilar artery occlusion caused by vertebrobasilar artery dissection presenting with mild clinical symptoms. A 45-year-old female was admitted to our department due to the abrupt onset of pain in her posterior neck and occipital head, and numbness in the right upper and lower extremities. She had no other neurological complaints. Computerized tomography and magnetic resonance imaging (MRI) disclosed no abnormalities in parenchyma, but MRI revealed a linear high intensity structure in front of the medulla oblongata on T1 and T2 weighted images. Cerebral angiogram showed the pearl and string sign from the left vertebral artery to the proximal basilar artery, and showed the basilar artery occlusion, but the basilar artery distal to the occlusion site was perfused sufficiently by the carotid via posterior communicating arteries. We diagnosed it as basilar artery occlusion caused by vertebrobasilar artery dissection, which was confirmed during the operation to prevent a hemorrhage from the aneurysmal dilatation. In this case, collateral good circulation was thought to have contributed to her good clinical course.
Aortic Dissection↗
Clinicopathological study on pineocytoma.
Six cases of pineocytoma, which had developed in the parenchyma of the adult pineal body, were examined immunohistochemically and under an electron microscope, after the malignancy of each case had been determined using our classification. One case was rated as grade 1 showing a lobular structure and resembling the normal pineal body. Two cases were rated as grade 2 without a lobular structure but with pineocytomatous rosettes (P-rosettes). Two cases were rated as grade 3 without P-rosettes but with few mitotic figures. One case was rated as grade 4 with marked cellular pleomorphism, numerous mitotic figures and necrotic foci. When examined immunohistochemically, neuron-specific enolase was positive but glial fibrillary acidic protein was negative in all cases. Under an electron microscope, all cases showed abortive synapses, and clear or dense core vesicles. These findings allow us to make two conclusions. First, pineocytoma is always a tumor of neuronal lineage, regardless of their grade of malignancy. Second, the grade 4 pineocytoma should be distinguished from the type of tumor classically called "pineoblastoma." That is, the former seems to be a biologically dedifferentiated tumor, while the latter seems to be biologically undifferentiated tumor.
Adult↗
[Experimental study on hypertensive crises in epileptic seizures--changes in pial artery diameter, intracranial pressure and regional cerebral blood flow].
It is well known that severe hypertension occurs during epileptic seizures, but little information is available concerning these hypertensive crises. We therefore investigated them by monitoring regional cerebral blood flow (rCBF), intracranial pressure (ICP) and pial artery diameter (PAD) in paralyzed mechanically-ventilated cats with penicillin-induced seizures. The animals were assigned to two groups. In one (Group H), they were maintained in an untreated state. In the other (Group C), spinal cord injury was performed in advance to prevent the rise in arterial blood pressure during the seizures. In both groups, the values of the various parameters increased during seizure activity, but the increases in group H, were greater than in group C. In both groups, PAD, rCBF and ICP increased immediately at the onset of the seizures with no hypertension. In group H, further increases in PAD, rCBF, and ICP were found concurrent with the elevation of arterial blood pressure in the latter half of the seizure, while in group C, rCBF decreased concurrent with the increase in ICP in the latter half of the seizure, although PAD was found to be maximal. These findings suggest that hypertensive crises during epileptic seizures represent a protective mechanism to maintain perfusion pressure.
Animals↗
Further oxidation of hydroxycalcidiol by calcidiol 24-hydroxylase. A study with the mature enzyme expressed in Escherichia coli.
The coding region of the cDNA for rat kidney calcidiol 24-hydroxylase (P450cc24), which is involved in calcium homeostasis in animals, was inserted into an expression vector pKK223-3. The recombinant plasmid was formed in a specific manner without deletion or substitution of any parts of the coding region of the cDNA. When the resulting plasmid was introduced into Escherichia coli JM109, the recombinant cells produced a protein which was immunoreactive to an antibody against P450cc24. When the cell-free extract of the transformed cells was incubated with calcidiol together with bovine adrenodoxin and NADPH-adrenodoxin reductase, not only hydroxycalcidiol but also other metabolites such as oxocalcidiol and oxohydroxycalcidiol were produced. Similarly, calcitriol was converted not only to calcitetrol but also to oxocalcitriol and oxohydroxycalcitriol. These results indicate that a single enzyme expressed in the bacteria is responsible for all these successive reactions.
Animals↗
Rotation and membrane topology of genetically expressed methylcholanthrene-inducible cytochrome P-450IA1 lacking the N-terminal hydrophobic segment in yeast microsomes.
A modified rat liver cytochrome P-450IA1, lacking amino acids 2-30, a proposed membrane anchor for cytochrome P-450, was expressed genetically in yeast microsomal membranes. This truncated cytochrome is practically active in the deethylation of 7-ethoxycoumarin. A full-length cytochrome P-450IA1 was also expressed in yeast microsomes. Rotational diffusion of P-450IA1 was examined by observing the flash-induced absorption anisotropy r(t) of the P-450.CO complex. The anisotropy decayed to a time-independent value within a 2-ms time range. Since the decay curve has the characteristics of a slow rotation of membrane-embedded cytochrome, the theoretical analysis of r(t) was performed based on a "rotation-about-membrane normal" model. 41% of the shortened P-450IA1 was rotating with the rotational relaxation time phi of 1020 microseconds, whereas 27% of the full-length P-450IA1 was mobile with phi = 1101 microseconds. The high salt treatment did not remove the shortened cytochrome from the membrane and also did not drastically weaken the interactions of the cytochrome with the membrane, as judged from the slow rotation characteristics (phi = 830 microseconds). These results demonstrate that the N-terminal shortened P-450IA1 is incorporated properly into the yeast microsomal membrane and that the N-terminal hydrophobic segment is not solely responsible for attachment to the membrane, providing evidence that additional segments of P-450IA1 are involved in the membrane binding.
Animals↗
Kinetic studies on a genetically engineered fused enzyme between rat cytochrome P4501A1 and yeast NADPH-P450 reductase.
Three expression plasmids, pAMC1 for rat P4501A1, pAMR2 for P4501A1 and yeast NADPH-P450 reductase, and pAFCR1 for a fused enzyme between P4501A1 and the reductase, were constructed, and each was introduced into Saccharomyces cerevisiae AH22 cells. The microsomal fraction prepared from the recombinant yeast cells was subjected to kinetic studies of zoxazolamine 6-hydroxylation at 10 degrees C. The apparent Km and Vmax values for hydroxylation by the fused enzyme in AH22/pAFCR1 microsomes were 0.38 mM and 0.42 s-1, respectively. The rate constant for reduction of the fused enzyme with NADPH in the presence of 1 mM zoxazolamine was larger than 50 s-1 using a dual-wavelength stopped-flow spectrometer, indicating that electrons are rapidly transferred from NADPH through FAD and FMN to the heme iron of the fused enzyme. The rate constant kon for substrate binding to the fused enzyme was 25 mM-1.s-1, which is not much different from that of nonfused P4501A1. These results together with spectral data measured during the hydroxylation reaction in the steady state suggest that the rate-limiting step of the reaction by the fused enzyme might be the release of product. On the other hand, the apparent Km and Vmax values for the hydroxylation of P4501A1 in AH22/pAMC1 and AH22/pAMR2 microsomes were 0.32 and 0.33 mM, and 0.015 and 0.29 s-1, respectively. The rate constants for the reduction of P4501A1 were 0.025 and 0.40 s-1, respectively, for AH22/pAMC1 and AH22/pAMR2 microsomes.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Electron microscopic evidence of a viral nature for osteoclast inclusions in Paget's disease of bone.
Circumstantial evidence from electron microscopic and immunological studies support the view that Paget's disease of bone represents a slow virus infection. However, there is only limited information available regarding its electron microscopic, enzyme and immunocytochemical characteristics. Two cases were studied using electron microscopy with particular emphasis on the inclusions in osteoclasts. Detailed ultrastructural and cytochemical studies including immuno-electron microscopy were performed. Some osteoclasts demonstrated specific virus-like structures composed of aggregations of microtubules in the nucleus and cytoplasm. The structures were easily digested by trypsin or protease, and were sensitive to RNase, which provided substantial evidence of a proteinaceous nature and inclusion of ribonucleic acid. Immunocytochemical examination identified binding of anti-respiratory syncytial virus and anti-measles virus antibodies in the tissue obtained from one of the two cases examined. The presence of viral antigens in structures in the cytoplasm of Pagetic osteoclasts supports the theory of paramyxovirus involvement in this disease.
Antigens, Viral↗
Changes in the basal ganglia and thalamus following reperfusion after complete cerebral ischaemia.
We report specific changes bilaterally in the basal ganglia and thalamus following reperfusion after complete cerebral ischaemia. A 69-year-old man, resuscitated after cardiac arrest, showed symmetrical low-density lesions in the head of the caudate nucleus and lentiform nucleus on CT. MRI revealed methaemoglobin derived from minor haemorrhage in the basal ganglia and thalamus, not evident on CT. We suggest that this haemorrhage results from diapedesis of red blood cells through the damaged capillary endothelium following reperfusion.
Aged↗
Management of dissecting aneurysms of the posterior circulation.
We analysed the clinical presentation, treatment and outcome of our own 36 cases of posterior circulation dissecting aneurysms (DA) and discussed the surgical indications and procedures regarding posterior fossa DA. Twenty one cases were male, 15 cases were female. Their mean age was 54 +/- 14 years. Clinical manifestations were subarachnoid haemorrhage (SAH) in 14 cases (39%) and ischaemic attacks in 22 cases (61%). Three of 14 SAH cases had rebleeding in the acute stage. Angiographic findings were aneurysmal dilatation in 16 cases, retention of contrast medium in 12 cases, string sign in 9 cases, double lumen in 4 cases, pearl and string sign in 3 cases, and occlusion of parent artery in 2 cases. Surgical treatment was performed on nineteen cases (53%). The operation was carried out in the acute stage on the SAH group; in the subacute or chronic stage on the ischaemic group. The surgical procedure was the proximal ligation, trapping and removal of DA with or without revascularization of the parent artery. 84% of the surgically managed patients and 71% of the nonsurgical cases had a favourable outcome (good recovery or moderate disability). Poor prognosis was revealed from the rebleeding and primary neurological stage. We recommend surgical treatment in the acute stage on the SAH group. On the ischaemic group surgical treatment in the subacute or chronic stage is recommended, if the DA has the risk of rupture or progression of the dissection.
Adolescent↗
Effects of superficial temporal to middle cerebral artery bypass for ischaemic retinopathy due to internal carotid artery occlusion/stenosis.
The effects of superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis for retinopathy is discussed and analysed in 19 cases of occlusive internal carotid artery disease (4 with stenosis and 15 with occlusion) according to Doppler sonography (DS) of the retinal artery, optic fundi and visual impairment symptoms. Preoperatively, all cases showed abnormal DS findings (stenosis patterns in 2 cases and the reversed flow patterns in 17 cases). All cases showed ischaemic changes of the optic fundi. Visual symptoms were amaurosis fugax in 2 cases, decline of visual acuity in 13 cases and both in 4 cases. At one month after the bypass, two stenosis pattern cases showed almost normal DS findings. In the 17 reversed flow pattern cases, 13 cases had a marked improvement of the reversed flow. The ischaemic changes of the optic fundi were ameliorated in 12 cases. In the follow-up stage, greater improvement in the DS findings and the optic fundi could be seen in all cases. In all cases worsening of the visual acuity was prevented, and in some cases the decreased visual acuity improved. The above improvements correlated well with the improvement of DS findings. It is believed that this procedure should be performed to prevent and improve ischaemic retinopathy caused by ischaemic ICA lesion.
Aged↗
Bilateral organized chronic subdural haematomas: high field magnetic resonance images and histological considerations.
The authors describe a 66-year-old man with progressive gait disturbance caused by bilateral organized chronic subdural haematomas. The characteristics of these lesions on magnetic resonance (MR) images have not yet been clarified. The organized haematoma in our patient exhibited slight hypo-intensity on T 1-weighted MR images and marked hypo-intensity on T 2-weighted MR images obtained at 1.5T. Preoperative MR imaging may give us useful information about surgical strategy in the case of chronic subdural haematoma with an unusual appearance on computed tomographic (CT) scans.
Aged↗
Effect of physical properties of direct bonding adhesives on bonding to etched enamel.
Five types of light-cured direct bonding adhesives with different volumes of microfiller were prepared for study of the relationships between bond strength to enamel, resinous tag length, and flexural strength, and between viscosity and resinous tag length. The resinous tag length was measured with the combination of 2,4,6-trichlorophenoxy methacrylate as a tracer and electron-probe microanalyzer. Correlating resinous tag length versus viscosity or bond strength after 1-day immersion, and flexural strength with bond strength after 1-day and 30-day immersion resulted in high correlation coefficients. However, the bond strength after thermocycling did not correlate with resinous tag length or flexural strength.
Acid Etching, Dental↗
Herbicide-resistant tobacco plants expressing the fused enzyme between rat cytochrome P4501A1 (CYP1A1) and yeast NADPH-cytochrome P450 oxidoreductase.
Transgenic tobacco (Nicotiana tabacum cv Xanthi) plants expressing a genetically engineered fused enzyme between rat cytochrome P4501A1 (CYP1A1) and yeast NADPH-cytochrome P450 oxidoreductase were produced. The expression plasmid pGFC2 for the fused enzyme was constructed by insertion of the corresponding cDNA into the expression vector pNG01 under the control of the cauliflower mosaic virus 35S promoter and nopaline synthase gene terminator. The fused enzyme cDNA was integrated into tobacco genomes by Agrobacterium infection techniques. In transgenic tobacco plants, the fused enzyme protein was localized primarily in the microsomal fraction. The microsomal monooxygenase activities were approximately 10 times higher toward both 7-ethoxycoumarin and benzo[a]pyrene than in the control plant. The transgenic plants also showed resistance to the herbicide chlortoluron.
Animals↗