Biomedical subjects

S Sakaki

Publications and source records attributed to S Sakaki.

At least 55 records · Page 3Linked to original sources

PubMed1998

Usefulness of heavily T2-weighted magnetic resonance imaging in patients with cerebellopontine angle tumors.

OBJECTIVE: Heavily T2-weighted magnetic resonance imaging (MRI) has been reported to be useful for the diagnosis of lesions of the inner ear or its central connections. We evaluated the usefulness of heavily T2-weighted MRI in 18 patients with cerebellopontine angle tumors. METHODS: The lesions were acoustic neuromas in 14 patients and meningiomas in 4 patients. The findings of heavily T2-weighted MRI were compared with those of three-dimensional T1-weighted gradient field echo MRI. RESULTS: An accurate description of the situation of the tumor in the internal auditory canal (IAC) was possible, because the inner ear was clearly shown on the heavily T2-weighted magnetic resonance images. We could therefore detect the acoustic neuromas located at the fundus of the IAC and the meningiomas growing into the IAC. The residual tumor in the IAC can be shown postoperatively. It was difficult to demonstrate these findings using three-dimensional T1-weighted gradient field echo MRI because of the poor presentation of the petrous bone structures. The lower cranial nerves and the VIIth and VIIIth cranial nerves were more clearly demonstrated by heavily T2-weighted MRI than by three-dimensional T1-weighted gradient field echo MRI. Using heavily T2-weighted MRI, the VIIth and VIIIth cranial nerves of the lesion side were demonstrated in half of the patients with acoustic neuromas smaller than 2.5 cm. CONCLUSION: We conclude that heavily T2-weighted MRI is useful to detect the relationship among the tumor, the IAC, the inner ear, and the surrounding cranial nerves.

Adult↗

PubMed1998

Angioplasty after intra-arterial thrombolysis for acute occlusion of intracranial arteries.

BACKGROUND AND PURPOSE: The purpose of this study was to report our experience with percutaneous transluminal angioplasty (PTA) of intracranial arteries in acute stroke patients who were resistant to intra-arterial thrombolysis alone. METHODS: PTA was performed within 6 hours from symptom onset in 13 acute stroke patients in whom no hypodensity areas were observed on initial CT. PTA was classified into 3 categories: immediate (3 patients), delayed (3 patients), and rescue (7 patients) angioplasty. Treatment results in the PTA group for 9 cases of middle cerebral artery (MCA) occlusion were compared with those in the thrombolysis alone group for 12 cases of thrombotic MCA occlusion. RESULTS: Technical success rates for immediate, delayed, and rescue angioplasty were 100%, 100%, and 71%, respectively, and that of angioplasty for the MCA was 100%. Ten patients (77%) showed improvement in the National Institutes of Health (NIH) stroke score after treatment. Improvement in NIH stroke scores in the PTA group for MCA occlusion was greater than that in the thrombolysis alone group (P<0.01). Nine patients (69%) had an excellent, good, or fair outcome 3 months after treatment. In 9 patients who had follow-up angiography 1 month after treatment, no restenosis or reocclusion was demonstrated. There were no symptomatic complications during or after treatment. CONCLUSIONS: This limited study demonstrates the technical feasibility of angioplasty for intracranial arteries in acute ischemic stroke and suggests that angioplasty may be an effective option for improving the success rate of recanalization and preventing reocclusion of the MCA. The present results encourage us to perform further clinical trials in a larger number of patients to assess the efficacy of this procedure.

Aged↗

PubMed1998

Efficacy of coronary artery bypass grafting in patients with a dilated left ventricle due to myocardial infarction.

This study was designed to clarify the efficacy of coronary artery bypass grafting (CABG) on left ventricular (LV) function in 16 patients with a dilated LV due to myocardial infarction (LV end-systolic volume index: LVESVI >60 ml/m2). All had attained complete revascularization. To estimate the LV wall motion quantitatively using echocardiography, a wall motion score (WMS) was used (LV was divided into 17 segments with a four-point scale: akinesis=3, severe hypokinesis=2, hypokinesis=1, normal=0 and then summed). Exercise stress tests were performed after surgery, revealing that anginal symptoms had vanished in all the patients. In 5 patients with a preoperative end-systolic volume index (ESVI) >100 ml/m2, the ejection fraction (EF) did not change, and both were under 30% (before to after: 26+/-4 to 26+/-4%). Neither the ESVI (148+/-50 to 133+/-39 ml/m2) nor the end-diastolic volume index (end-diastolic volume index (EDVI): 198+/-62 to 180+/-37 ml/m2) changed; the WMS did not change (33+/-2 to 33+/-3). During exercise, in spite of the increase in heart rate (HR) (at rest, 81+/-20; HR during exercise, 111+/-21 beats/min, p<0.005) and LV end-diastolic pressure (EDP) (22+/-9; 35+/-13 mmHg, p<0.02), both cardiac index (CI) (2.4+/-0.3; 2.6+/-0.4 L/min x m2) and minute work (MW: 4.0+/-1.1; 4.1+/-0.4 kg x M/min) did not increase. In 11 patients with a preoperative ESVI <100 ml/m2, EF was extremely increased in 5 patients (more than 10%, 35+/-4 to 60+/-6%, p<0.005=improved subgroup) in whom the EDVI (130+/-16 to 120+/-13 ml/m2) did not change whereas the ESVI (82+/-14 to 48+/-7 ml/m2) was reduced. However, in the 6 remaining patients (ie nonimproved subgroup), neither ESVI (78+/-8 to 74+/-12 ml/m2), EDVI (115+/-10 to 115+/-20 ml/m2) nor EF (31+/-7 to 35+/-3%) changed. During exercise, HR (at rest, 88+/-13; during exercise, 108+/-11 beats/min, p<0.005), LVEDP (20+/-6; 29+/-7 mmHg, p<0.01), CI (2.5+/-0.6; 3.3+/-0.5 L/min x m2, p<0.05), MW (4.6+/-1.0; 6.5+/-1.5 kg x M/min, p<0.05) increased. The WMS in the nonimproved subgroup did not change (29+/-6 to 27+/-2), but in the improved subgroup it reduced after surgery (27+/-3 to 19+/-4, p<0.01). These data suggested that CABG in patients with a dilated LV was effective against anginal symptoms, but was restricted to left ventricular function. It may be possible to estimate postoperative LV function, including exercise tolerance, from the preoperative LVESVI.

Aged↗

PubMed1998

[A case of bow hunter's stroke caused by bilateral vertebral artery occlusive change on head rotation to the right].

We report a case of bow hunter's stroke caused by simultaneous bilateral vertebral artery occlusive changes at the right C3-4 and the left C1-2 level on head rotation to the right side. The pathogenesis and surgical treatment for this particular case are discussed. A 61-year-old male with cervical spondylosis repeatedly experienced vertebrobasilar insufficiency when he rotated his head over 60 degree from the mid-position to the right side. Bilateral vertebral angiography demonstrated severe compression of the right vertebral artery by a lateral osteophyte and instability at the C3-4 level accompanied with the mechanical stenosis of the left vertebral artery at the C1-2 level only at the time of turning his head to the right. As the surgical treatment we performed osteophytectomy of the right uncovertebral joint at the C3-4 level in addition to anterior decompression with fusion using hydroxyapatite spacer and titanium plate at that level. Postoperatively, the patient had no ischemic episodes and there was angiographical resolution of the rotational stenosis at the C3-4 level. For the clinical manifestation of bow hunter's stroke on head rotation, it is indispensable that simultaneous severe occlusive changes present on bilateral vertebral arteries. In case of a vertebral occlusive change caused by lateral osteophyte at the unstable vertebral joint, anterior decompression and fusion with osteophytectomy may be a wiser approach than arterial decompression or posterior fusion at the C1-2 level to another vertebral artery occlusive lesion.

Cerebrovascular Disorders↗

PubMed1998

[Surgical management for preserving motor function in patients with gliomas near the primary motor cortex: usefulness of preoperative identification of motor cortex and intraoperative monitoring of motor evoked potentials].

Preoperative identification of precentral gyrus and intraoperative monitoring of motor evoked potentials (MEPs) were performed to preserve postoperative motor function in seven patients with gliomas near the primary motor cortex. Tumors were astrocytomas in 3 patients, glioblastomas in 2 patients, anaplastic astrocytoma and mixed glioma in one patient each. Preoperative identification of the primary motor cortex was performed by three-dimensional (3D) display of magnetic resonance (MR) images and by functional images using MR imaging and single-photon emission tomography. The primary motor cortex identified by 3D display of MR images coincided well with that identified by functional images. 3D display of MR images was also useful for detecting the relationship between the tumor and the primary motor cortex. Intraoperatively, the central sulcus was confirmed by the finding of phase reversal of cortical somatosensory evoked potential, and this corresponded with the preoperative identifications by 3D display and by functional mapping. The primary motor cortex was stimulated electrically, and MEP (corticospinal evoked potential) was continuously monitored during surgery using electrodes inserted in the cervical epidural space. The amplitude of direct waves of MEPs during surgery was maintained above half of that recorded at the beginning of tumor removal, and all patients showed preservation of preoperative motor function. These results suggest that preoperative identification of precentral gyrus and intraoperative MEP monitoring provide useful information for preserving motor function in patients with gliomas near the primary motor cortex.

Adult↗

PubMed1998

Evaluation of cerebral perfusion from bypass arteries using selective intraarterial microsphere tracer after vascular reconstructive surgery.

BACKGROUND AND PURPOSE: To detect areas of cerebral perfusion from bypass arteries after vascular reconstruction, we administered selective intraarterial microsphere tracer into the external carotid arteries and determined (via single-photon emission computed tomography [IA-SPECT]) whether the distribution of radiotracer matched the arteriographic distribution of contrast material as shown on external carotid angiograms. METHODS: We compared the extent of regional distribution of tracer after external carotid artery injection of 20 to 40 MBq of 99mTc-HMPAO or 99mTc-ECD with that of contrast medium on the external carotid angiograms in 582 cortical regions in 12 patients with atherosclerotic occlusive disease and in 18 patients with moyamoya disease. RESULTS: Marked accumulation of tracer was found only in the expected, specific, newly developed areas of cerebral perfusion from bypass arteries. The regional distribution of tracer corresponded to that of contrast medium in 523 regions (90%) and did not correspond in 59 regions (10%). Significant overestimation of the distribution of contrast material relative to that of tracer was observed in the patients with moyamoya disease. CONCLUSION: SPECT showed slightly different distribution of tracer from that predicted by conventional angiography. IA-SPECT should enhance the analysis of newly developed areas of cerebral perfusion from the bypass arteries.

Adult↗

PubMed1997

Protein synthesis inhibitor transiently reduces neuronal death in the thalamus of spontaneously hypertensive rats following cortical infarction.

Using stroke-prone spontaneously hypertensive rats with permanent occlusion of the middle cerebral artery (MCA), we investigated whether the secondary thalamic degeneration following cortical infarction is related to apoptosis, and whether the protein synthesis inhibitor cycloheximide (CHX) ameliorates this degenerative process. TdT-mediated dUTP-biotin nick end labeling (TUNEL staining) revealed a distinct pattern of nuclear staining in many ventroposterior (VP) thalamic nucleus neurons on the lesioned side at 1 week after MCA occlusion. In rats with a single or continuous intraventricular infusion of CHX, starting just after brain ischemia, in the VP thalamic neurons were significantly more numerous than those in the thalamic nucleus of rats with vehicle infusion at 1 week after MCA occlusion. However, at 2 weeks after MCA occlusion, the numbers of VP thalamic neurons were similar in the CHX- and vehicle-treated groups. These findings suggest that the secondary thalamic degeneration following cortical infarction is an event reminiscent of apoptosis and that CHX prevents the secondary thalamic neuronal death transiently.

Animals↗

PubMed1997

Neuroprotective nitric oxide synthase inhibitor reduces intracellular calcium accumulation following transient global ischemia in the gerbil.

By observing the ultrastructural intracellular Ca2+ distribution with Ca(2+)-oxalate-pyroantimonate method, we examined whether the protective mechanism of the nitric oxide (NO) synthase inhibitor, N omega-nitro-L-arginine (LNNA), involves change of the intracellular Ca2+ movement in delayed neuronal death (DND) in gerbil hippocampal CA1 neurons following 5-min forebrain ischemia. In the group intraventricularly administered 5.0 mg/ml LNNA, 15 min after reperfusion the intracellular Ca2+ deposits and the mitochondrial Ca2+ uptake index increased to levels similar to those in the control group administered only artificial cerebro-spinal fluid, but by 180 min after reperfusion they had returned to the preischemic level. By 15 min after reperfusion Ca2+ deposits in the endoplasmic reticulum (ER) had almost disappeared in both groups, but at 180 min of reperfusion, the ER in only the LNNA group showed Ca2+ deposits. It is suggested that the neuronal toxicity of NO involves the dysfunction of the intracellular Ca2+ transport system including the mitochondria and ER.

Animals↗

PubMed1997

Endovascular treatment for acute thrombotic occlusion of the middle cerebral artery: local intra-arterial thrombolysis combined with percutaneous transluminal angioplasty.

We report our experience in treating 15 patients with acute thrombotic occlusion of the M1 or M2 segment of the middle cerebral artery who underwent intra-arterial thrombolytic therapy alone or in combination with percutaneous transluminal angioplasty (PTA). The results were compared with those of 30 patients with acute embolic occlusion of the same artery. Intra-arterial thrombolysis was performed in 10 patients and thrombolysis combined with PTA in 5 in whom symptoms reappeared due to restenosis or reocclusion, or in whom recanalisation was not successfully accomplished by thrombolysis alone. In the patients with embolism recanalisation was observed in 28 (93 %) and there was no patient with reocclusion. In the patients with thrombosis recanalisation immediately after thrombolysis alone was observed in 9 of 15 (60%). Restenosis, with reappearance of symptoms, occurred in 2 of these (22 %). In the patients who also underwent PTA, angiography after 1 month did not demonstrate any restenosis or reocclusion. Thrombolysis combined with PTA for acute thrombotic stroke may provide an effective procedure for restoring patency and preventing reocclusion of the occluded artery.

Aged↗

PubMed1997

Three-dimensional imaging for presentation of the causative vessels in patients with hemifacial spasm and trigeminal neuralgia.

BACKGROUND: In patients with hemifacial spasm and trigeminal neuralgia, preoperative detection of the relationship between the blood vessels and the cranial nerves involved is essential. METHODS: We studied the causative vessels in 20 patients with hemifacial spasm and six patients with trigeminal neuralgia by means of magnetic resonance (MR) imaging with spoiled gradient recalled acquisition in the steady state (SPGR), MR angiography, and three-dimensional (3-D) imaging reconstructed from the data of SPGR MR imaging by the surface rendering method at a workstation. RESULTS: In all patients, the preoperative SPGR MR images demonstrated that the causative vessels compressed or were in contact with the root exit or root entry zone (REZ) of the facial or trigeminal nerve. These causative vessels were identified by inspection of the MR angiographic and 3-D images. The 3-D images provided clear information as to the anatomic relationship between the causative vessels and the REZ of these nerves. These findings were corroborated by the intraoperative findings. The symptoms were completely relieved after surgery in 18 of the patients with hemifacial spasm and in all six patients with trigeminal neuralgia. In all patients, sufficient decompression was depicted on the postoperative SPGR MR images at the causative vessels and the REZ of the nerve. CONCLUSION: SPGR MR images, MR angiography, and 3-D images are useful for the identification of the causative vessels in patients with hemifacial spasm or trigeminal neuralgia. The 3-D images are particularly useful for the simulation planning of the operative procedure.

Adult↗

PubMed1997

Evaluation of prognostic factors following expansive laminoplasty for cervical spinal stenotic myelopathy.

BACKGROUND: Expansive laminoplasty of several types has been proposed for patients with cervical multisegmental stenotic myelopathy to reduce postlaminectomy complications. Its effectiveness has not been fully explored by evaluating long-term results and magnetic resonance imaging (MRI) findings before and after surgery. METHODS: We conducted a 5-year follow-up study of 22 patients with cervical spondylotic myelopathy and/or ossification of the posterior longitudinal ligament surgically treated with expansive laminoplasty. The operative results were examined using the Japanese Orthopedic Association (JOA) disability scale, with reference to the findings of MRI, computed tomography, and radiography. RESULTS: Postoperative improvement was observed in 18 (81.8%) of the 22 patients. In 11 patients the percentage recovery of the JOA score was higher than 50% (average: 83.1%), while in the remaining 11 patients it was lower than 50% (average: 20.1%). Factors contributing to incomplete recovery appear to be related mainly to cord degeneration with atrophy (depicted as a T2-high intensity area) and to specific factors such as long symptom duration, age higher than 70 years, deterioration due to trauma, severe cord compression, radiculopathy, and kyphotic cervical curvature. CONCLUSIONS: In cervical myelopathy, patients with multisegmental stenosis, expansive laminoplasty can be expected to provide a favorable outcome by providing sufficient cord decompression and stabilization of the cervical spine, when the stenotic cervical canal is enlarged to the normal range (over 12 mm residual anteroposterior diameter and 200 mm2 residual canal area). The efficacy can be restricted by various factors, especially irreparable cord degeneration.

Aged↗

PubMed1997

Asymptomatic, unruptured carotid-ophthalmic artery aneurysms: angiographical differentiation of each type, operative results, and indications.

BACKGROUND: Some types of carotid-ophthalmic artery aneurysms are still difficult to clip successfully because their exposure requires opening the cavernous sinus and/or retracting the optic nerve. It is useful to know the complications and to determine the type of aneurysm preoperatively for the management of carotid-ophthalmic artery aneurysms. METHODS: The operative results in 15 patients with asymptomatic unruptured carotid-ophthalmic artery aneurysms were surveyed. The aneurysms were small in all the patients, and they underwent direct operation. Four patients presented with other ruptured aneurysms, four with other diseases (infarction, trauma, or pituitary adenoma), and seven were evaluated with magnetic resonance angiography for symptoms such as vertigo or headache. Among them, five had carotid cave aneurysms and one had paraclinoid aneurysm. RESULTS: Neck clipping was performed in 13 patients. Postoperatively, ipsilateral visual loss was encountered in one patient, and ipsilateral visual field defect was encountered in three patients. The visual field defect was lower nasal quadrant hemianopsia in two patients and lower hemianopsia in one patient. The cause of this complication was suspected to be retraction and/or the heat of the drill near the optic nerve. It seemed to be possible to distinguish the carotid cave or the paraclinoid aneurysm from the other carotid-ophthalmic aneurysms using carotid angiography preoperatively. CONCLUSION: When direct operation is performed for a carotid-ophthalmic artery aneurysm, care must be taken to avoid optic nerve injury caused by the retraction and/or the heat of the drill.

Adult↗

PubMed1997

Assessment of myocardial distribution of retrograde and antegrade cardioplegic solution in the same patients.

OBJECTIVE: In order to clarify intramyocardial delivery and distribution of retrograde cardioplegic solution in humans, we induced both ante- and retrograde methods in the same patients to compare their respective delivery and distribution using myocardial contrast echocardiography during surgery. METHODS: 15 patients consisting of nine patients with valvular heart diseases and six patients with coronary artery diseases (including two patients with myocardial infarcted areas and two patients with areas supplied by coronary collateral situation associated with totally occluded coronary arteries without myocardial infarction). Induction of cardioplegia was initially accomplished antegradely and thereafter retrogradely. RESULTS: In valvular heart disease, retrograde cardioplegic solution was distributed less homogeneously, and was not delivered to the midportion of the interventricular septum in two-thirds of the patients (6/9). The transmural myocardial distribution in the anterior, lateral, and posterior walls in the left ventricle were similar for both ante- and retrograde cardioplegic solution, while delivery to the endocardial halves was better than to the epicardial halves (endo-/epicardial intensity ration in antegrade versus retrograde: 1.31 +/- 0.24 versus 1.29 +/- 0.26; 1.19 +/- 0.05 versus 1.36 +/- 0.23; 1.33 +/- 0.28 versus 1.44 +/- 0.35, respectively (all NS)). For delivery to the right ventricle, the existence of small cardiac vein was important. In patients with small cardiac vein (34% in our study), the delivery to the right ventricular dorsal walls was shown. In coronary heart disease, retrograde cardioplegic solution was well delivered to the areas by coronary collateral situation associated with totally occluded coronary arteries, but antegrade solution was not. Neither ante- nor retro grade solution was delivered to myocardial infarcted areas. CONCLUSIONS: These results have important implications for planning strategies for myocardial protection. We think that it is necessary to fully grasp the coronary arterial and venous anatomy of individual patients and to know how to use either ante- or retrograde cardioplegia properly.

Aged↗

PubMed1997

Protective effects of hydroxybenzoic acids and their esters on cell damage induced by hydroxyl radicals and hydrogen peroxides.

The purpose of this study was to evaluate the hydroxyl radical scavenging activities of hydroxybenzoic acids and their esters from both chemical and biological aspects. These activities of hydroxybenzoic acids and their related compounds were estimated by ESR-spin trapping method, in which 3,4,5-trihydroxybenzoic acid and its ethyl and propyl esters showed the highest activities as estimated by IC50 value (50% inhibition concentration of hydroxyl radicals generated in the system): 78.04 +/- 11.23, 95.95 +/- 2.64, and 86.46 +/- 2.31 microM, respectively. In addition, 3,4,5-trihydroxybenzoic acid (gallic acid) at a concentration of 25 microM, protected against dermal fibroblast cell damage induced by H2O2, and enhanced the survival to 83.8 +/- 3.1%, in which the survival of control was 44.2 +/- 1.0%. Based on these results, the pretreatment effects of 3,4,5-trihydroxybenzoic acid n-alkyl esters on cell damage induced by H2O2 were examined. The survival of fibroblasts pretreated with the esters increased depending on the alkyl chain-length. Both C12 and C16 alkyl esters gave almost complete cell survival of 89.5 +/- 2.0% and 91.3 +/- 1.0%, respectively. The order of the protective effects of the compounds was in good agreement with that of their partition coefficients, suggesting that 3,4,5-trihydroxybenzoic acid alkyl esters are incorporated into fibroblasts, and thus prevent the cells from the toxicity caused by H2O2. In addition, an increase of intracellular peroxide formation in fibroblasts induced by UVA-irradiation, was suppressed to 2.27 +/- 0.41 nmol/10(4) cells by pretreatment with C16 alkyl ester at a concentration of 25 microM. Since 3,4,5-trihydroxybenzoic group has been demonstrated to possess a potent scavenging activity of hydroxyl radicals, this moiety was indicated to be important in preventing cell damage induced by UVA or H2O2: in turn, these produce hydroxyl radicals in the presence of trace metal ions such as iron and copper in cells.

Cell Survival↗

PubMed1997

[A case of cranial osteomyelitis after head injury with exaggeration and remission for thirty years].

We report a case of cranial osteomyelitis after head injury with exaggeration and remission for 30 years. A 41-year-old man was referred to our hospital with redness, swelling and pain in the left frontal region. He had noted a hard mass in the same region after an injury at the age of 12 years, and local heat and redness again in the same region which had disappeared without definite treatment at the age of 20 years. Presently, skull roentogenogram showed an erosive lesion in the left frontal bone. Plain CT revealed bone defect, epidural mass lesion, calcification of the dura mater and thickness of the extracranial soft tissue in the left frontal region. T1-weighted MR images showed an isointense lesion and T2-weighted MR images showed a high intensity lesion in the inner table and a diploic layer in the left frontal bone. 99thTc MDP bone scinntigram showed abnormal uptake in the same region. Operation performed through a left frontotemporal craniotomy revealed a degeneration of temporal muscle and frontal bone, and granulation tissue and pus in the subcutaneous and epidural spaces. These were removed together with the calcified dura mater. The subdural space was intact. Dural plasty was performed using fascia lata, but the craniotomied bone was replaced. Histological examination revealed typical findings of osteomyelitis. Postoperative course was uneventful, and he was discharged without neurological deficit. Cranioplasty was performed 8 months after the first surgery. The mechanism by which osteomyelitis continued over a long course of time was suspected to be the formation of a focus of recurrent inflammation due to the head injury 30 years earlier.

Adult↗

PubMed1996

Nitric oxide synthase inhibitor reduces delayed neuronal death in gerbil hippocampal CA1 neurons after transient global ischemia without reduction of brain temperature or extracellular glutamate concentration.

We planned a study to determine whether or not the mechanism of nitric oxide (NO) neurotoxicity involves the elevation of extracellular glutamate or changes of brain temperature in the pathogenesis of delayed neuronal death of gerbil hippocampal CA1 neurons following 5-min transient forebrain ischemia. Intraventricular injection of 5 microliters of 5.0 mg/ml N omega-nitro-L-arginine (LNNA) significantly preserved neuronal density in the central part of the CA1 region examined 7 days after 5-min ischemia [188.5 +/- 8.5/mm: 90.0% of the 209.5 +/- 11.1/mm density in the sham-operated controls vs. 16.7 +/- 6.4/mm in those injected with artificial cerebrospinal fluid (CSF) only]. There was no difference between these two groups in hippocampal temperature before, during or after 5-min ischemia. The glutamate concentration ([Glu]) during 5-min ischemia measured by a microdialysis technique was similar in the two groups (peak [Glu.] = 2.76 +/- 0.62 pmol/microliters dialysate in the artificial CSF group and = 2.93 +/- 0.64 pmol/microliters dialysate in the LNNA group). It was found that the neuronal toxicity of NO does not involve hyperthermia or the increase of extracellular glutamate concentration in the hippocampal CA1 region during 5-min ischemia.

Analysis of Variance↗

PubMed1996

Ciliary neurotrophic factor attenuates spatial cognition impairment, cortical infarction and thalamic degeneration in spontaneously hypertensive rats with focal cerebral ischemia.

Ciliary neurotrophic factor (CNTF) has been shown to exhibit potent neurotrophic activity on peripheral and central neurons in vitro and in vivo. However, it remains to be determined whether or not CNTF rescues neuronal loss due to focal cerebral ischemia and prevents ischemia-induced disability of space navigation in rats. In the present in vivo study, we infused CNTF continuously for 4 weeks into the lateral ventricle, starting just after permanent occlusion of the left middle cerebral artery (MCA) of stroke-prone spontaneous hypertensive rats. CNTF infusion prevented the occurrence of ischemia-induced learning disability in a dose-dependent manner in rats subjected to the Morris water maze task. Subsequent histological examinations showed that cortical infarction and retrograde degeneration of the ipsilateral thalamic neurons in ischemic rats infused with CNTF were significantly less severe than those in ischemic rats infused with vehicle alone. These findings suggest that postischemic CNTF treatment prevents the occurrence of spatial learning disability in rats with permanent MCA occlusion, possibly by reducing neuronal damage within the cerebral cortex and secondary retrograde degeneration of the thalamus.

Analysis of Variance↗

PubMed1996

Origins of nitric oxide synthase-containing nerve fibers in the rat basilar artery with reference to the fine structure of the nerve fibers.

The origins of nitric oxide synthase (NOS)-containing nerve fibers in the rat basilar artery were studied by a combination of Fluoro-Gold retrograde tracing and immunohistochemistry. After application of Fluoro-Gold onto the middle part of the basilar artery, the dye accumulated in the sphenopalatine, otic, trigeminal, superior cervical, nodose ganglia and in the spinal ganglia at level C2 and C3. Nerve cells with NOS-like immunoreactivity were detected in the above ganglia, except for the superior cervical ganglion. Neurons that showed both NOS-like immunoreactivity and Fluoro-Gold fluorescence were numerous in the sphenopalatine and otic ganglia, and less numerous in the trigeminal, nodose and spinal ganglia. Under electron microscopy, a number of unmyelinated nerve terminals with neuronal NOS-like immunoreactivity was seen in proximity to smooth muscle cells in the tunica media of the basilar artery. These findings provide morphological evidence that NOS-containing nerve fibers in the rat basilar artery have multiple origins, and suggest that the control of posterior cerebral circulation by the parasympathetic and sensory ganglia are more complex than previously considered.

Animals↗