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Biomedical subjects

K Sako

Publications and source records attributed to K Sako.

At least 19 recordsLinked to original sources
PubMed1995

[Posttraumatic pseudoaneurysm of the middle meningeal artery: a case report].

An epidural hematoma associated with posttraumatic pseudoaneurysm of the middle meningeal artery is a very rare clinical entity. Only 31 such cases have been reported in the literature. A 54-year-old man was admitted with lethargy and right hemiparesis. A skull X-ray film revealed a linear fracture in the left parietal and temporal bone, extending to the base of the skull. A brain CT scan disclosed an acute epidural hematoma over the left cerebral hemisphere, contusional hematoma in the right frontal lobe and thalamus, and subarachnoid hemorrhage in the left Sylvian fissure. During an emergency craniotomy a large epidural hematoma was evacuated and external decompression was performed. Angiography, which was performed about one month after the head injury, revealed an aneurysm of the middle meningeal artery. The aneurysm was removed to avoid delayed rupture at the time of cranioplasty. Histological diagnosis was pseudoaneurysm. We discussed the pathogenesis of a pseudoaneurysm of the meningeal artery and the necessity to pay attention to the presence of a pseudoaneurysm when an active bleeding point is not observed during surgery of the epidural hematoma.

Aneurysm, False↗
PubMed1995

[Aneurysm surgery using temporary occlusion under SEP monitoring].

Premature rupture of a cerebral aneurysm during operation is a serious hazard. Temporary occlusion of intracranial arteries has emerged as a valuable technical adjunct in the management of intracranial aneurysms. Twenty-five patients (from a group of 43 consecutive aneurysm patients treated during a 13-month period) underwent elective temporary arterial occlusion under somatosensory evoked potential (SEP) monitoring. Median nerve SEPs were used during 19 ICA and MCA aneurysm operations, while posterior tibial SEPs only were used in 7 patients with aneurysm of the ACA. Amplitude of the N20 or P40 was evaluated. A decrease in amplitude more than 50% when compared to baseline value was defined as a significant SEP change. In 11 patients of the 25 cases, SEP changes were observed. Temporary occlusion was applied to the proximal portion of the internal carotid artery 10 times, to the M1 portion of the middle cerebral artery 5 times, to the M1-M2 complex 5 times, to the A1 portion of the anterior cerebral artery 9 times, and to the A2 - A3 once. Of the 26 clipping (25 patients), 12 had SEP alterations, 14 had no SEP changes. Temporary occlusion was released within 3 minutes after disappearance of N20 (or P40) in all the patients with SEP changes except one. Nine of these 11 patients showed complete recovery of SEP and two showed partial recovery. Patients with partial recovery of SEP were associated with postoperative new neurological deficit, which was transient in one of them. There was a correlation between changes in SEP and post operative outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Accumulation of exogenous 45Ca after middle cerebral artery occlusion in rats.

The distribution of exogenous 45Ca in the focal ischemia rat model (middle cerebral artery occlusion) was studied using 45Ca autoradiography. High 45Ca accumulations were observed in the frontal cortex and caudate-putamen corresponding with morphological damage shown by HE staining. Regional 45Ca concentrations were calculated from the optical density on the 45Ca autoradiograms. Rapid uptake of 45Ca in the ischemic brain occurred during the first 5 hours, and continued more slowly between 5 and 24 hours after ischemia. The area of 45Ca accumulation was also expanded between 5 and 24 hours. An area of low 45Ca concentration around the area of high accumulation developed 5 hours after ischemia, which presumably accumulated 45Ca between 5 and 24 hours after ischemia. The lower concentration of 45Ca in the periphery of ischemia may result from: 1) a decrease in the total amount of calcium due to narrowing of extracellular space accompanied by cytotoxic edema, and 2) delayed accumulation of exogenous 45Ca due to reduced clearance of extracellular fluid.

Animals↗
PubMed1992

Effects of intracarotid infusion of neuropeptide Y on cerebral blood flow in rats.

Neuropeptide Y (NPY) was continuously administered to Wistar rats intracarotidly via the external carotid artery and local cerebral blood flow (LCBF) was measured by a quantitative autoradiography using [14C]iodoantipyrine. A remarkable reduction in LCBF was observed in the NPY infused hemisphere. This depression was irregular and was particularly evident in the hippocampus, selective thalamic nuclei and the cerebral cortex.

Animals↗
PubMed1992

Cerebral blood flow and histopathological changes following permanent bilateral carotid artery ligation in Wistar rats.

Cerebral blood flow and histopathological changes after bilateral carotid artery ligation (BCAL) in Wistar rats were studied. Eight of the 38 rats (21%) died within one week. In the 30 survivors, the incidence of histopathological change was 90% in the caudate nucleus, 23% in the cortex, 30% in the hippocampus, and 0% in the other structures. Local cerebral blood flow (LCBF) was measured using the quantitative autoradiographic 14C-iodoantipyrine technique in 24 anatomically discrete regions of the brain. BCAL induced ischemia in the entire forebrain. The percent reduction of LCBF was between 25-94% of the control at 2.5 h after BCAL. LCBF tended to recover 1 week after BCAL except for the regions of neuronal damage. These results suggest that neuronal damage does not correlate with the flow rate. In the present study, selective neuronal damage was also observed in rats with chronic cerebral ischemia.

Animals↗
PubMed1992

Results of surgical resection of pulmonary metastases of squamous cell carcinoma of the head and neck.

In this retrospective review of 58 patients (12 females and 46 males) with pulmonary metastases of squamous cell carcinoma of the head and neck treated between January 1, 1970, and December 31, 1989, we evaluated their clinical courses and analyzed the outcomes of those who underwent pulmonary resection. For the entire group of patients, factors predictive of survival in those patients with a diagnosis of pulmonary metastases included pulmonary resection of metastases (p = 0.0001), locoregional control of the head and neck primary tumor at the time of diagnosis of pulmonary metastases (p = 0.007), TNM stage of the head and neck primary tumor (p = 0.02), a single nodule seen on the chest radiograph (p = 0.02), and disease-free interval (DFI) from the primary tumor of the head and neck of 2 years or more (p = 0.05). Twenty-four of 58 patients underwent thoracotomy for resection of metastases. Four (17%) were found to have a second primary tumor of the lung. Of the 20 remaining patients who underwent explorative surgery for possible pulmonary resection, 18 (90%) underwent complete resection of all malignant disease with an estimated 5-year survival of 29%. In these patients, a DFI of less than 1 year was associated with a 5-year survival rate of 0%, whereas a DFI of 1 to 2 years was associated with a 5-year survival rate of 43% and a DFI of 2 years or longer had a 5-year survival rate of 33%. The number of malignant pulmonary nodules that were resected ranged from one to five and was not significant in predicting survival (p = 0.19). Of eight patients who underwent the resection of more than one malignant pulmonary nodule, 50% survived 2 years, but none survived 5 years. Resection of a solitary pulmonary metastasis from squamous cell carcinoma of the head and neck resulted in long-term survival in selected patients. Important prognostic factors included locoregional control of the head and neck primary tumor, the number of nodules seen on chest radiograph, the TNM stage of the primary tumor, and the DFI from the head and neck primary tumor. The value of resection in patients with more than one malignant pulmonary nodule remains to be defined for this group of patients.

Carcinoma, Squamous Cell↗
PubMed1992

The effects of oxiracetam (CT-848) on local cerebral glucose utilization after focal cerebral ischemia in rats.

The effects of oxiracetam on the reduction of brain metabolism induced by focal cerebral ischemia were investigated by measuring local cerebral glucose utilization (LCGU) in rats 24 hr after left middle cerebral artery occlusion. Focal cerebral ischemia reduced LCGU in the entire ipsilateral cortex, the greatest reduction being in the lateral parts of the frontoparietal cortex. LCGU was slightly reduced in the contralateral cortex; this reduction was considered to be caused by diaschisis. Oxiracetam was administered intraperitoneally for 3 days prior to middle cerebral artery occlusion. In the ipsilateral cortex, LCGU reduction was minimized in the ischemic center areas by oxiracetam at a dose of 400 mg/kg and in more extensive areas, by a dose of 800 mg/kg. Moreover, oxiracetam at a dose of 800 mg/kg enhanced metabolism impaired by diaschisis in the caudal areas of the contralateral cortex. These findings suggest that oxiracetam minimizes the reduction of brain function induced by ischemia and may therefore be useful in the treatment of cerebrovascular disease.

Animals↗
PubMed1992

Lipoma involving the skull. Case report.

The case of an intraosseous lipoma involving the left frontal bone is reported. Lipomas of the bone are rare; only three cases of lipomas involving the skull have previously been reported. The differential diagnosis includes a healing bone infarction or fracture, meningioma, hemangioma, and fibrous dysplasia. Diagnosis prior to surgery is difficult.

Adult↗
PubMed1992

[A ruptured aneurysm at the peripheral collateral circulation of the anterior choroidal artery in a patient with moyamoya disease: a case report].

This 42-year-old man experienced a sudden onset of occipital headache. Neurological examination revealed a moderately disturbed consciousness and a moderate left hemiparesis. CT scan disclosed a hugh hematoma in the right temporo parietal lobe without intraventricular hemorrhage. A cerebral angiography demonstrated typical findings of moyamoya disease and a small saccular aneurysm at the peripheral portion of the right anterior choroidal artery, which was dilated at the collateral circulation to the parietal lobe. The hematoma was removed at once by a craniotomy. He became alert but mild hemiparesis persisted. MRI disclosed a small signal-void lesion lateral to the trigone of the right lateral ventricle. The angiography repeated three weeks after the removal of the hematoma showed the unchanged size of the aneurysm. Direct surgery for the aneurysm was performed via the right parietal transcortical approach. The aneurysm was reached under the guidance of the intraoperative angiography. Trapping of the parent artery and the excision of the aneurysm were performed. On the basis of the presence of an internal elastic lamina at the neck of the aneurysm, the surgical specimen was histologically verified to be a true aneurysm. Since the collateral circulation was well preserved during surgery, no worsening of the neurological manifestation was observed. In view of the unfavorable prognosis for a moyamoya patient with this type of the aneurysm, which often results in a massive ventricular or intracerebral hemorrhage, surgery directed to the aneurysm itself should be considered.

Adult↗
PubMed1992

[A septated syringomyelia with a dramatic clinical course in a young patient with MELAS; a case report].

This is a report of a young girl who showed a recurrence of acute worsening and remission of neurological manifestations, with consistent MRI demonstration of transaxial septated syrinxes in the cervical and the lumbar spinal cord in addition to a tight filum terminale. This 8 year-old girl had developed normally since her birth until August 1989 when she developed a gait disturbance. This worsened acutely on January 1, 1990, with the additional manifestation of a urinary bladder disturbance. General examination failed to show any abnormality or scoliosis. Neurologic examination revealed a monoparesis of the right lower extremity with muscle atrophy and pyramidal tract sign. Fecal constipation and urinary retention were noted. The MRI T1 weighted sagittal image demonstrated an incontinuous low intensity signal in the C1-C7 as well as in the T12-L2 without swelling of the cord. The axial image clearly demonstrated the septations in the syrinx which looked like eye glasses. No definite Gd enhancement was demonstrated. Chiari malformation was not associated, but the tethered cord was well identified. With the administration of steroid, she showed a marked improvement of neurological manifestations. She was able to urinate without difficulty and also walk by herself. For one month thereafter she remained well with minor neurological deficits until she developed a worsening of the gait disturbance with a newly manifested weakness of the left upper extremity. Sensory impairment was also demonstrated below L3. In contrast to the worsening of the clinical symptoms, no definite change in the abnormalities found by MRI was noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis, Lactic↗
PubMed1991

HA1077, a novel calcium antagonistic antivasospasm drug, increases both cerebral blood flow and glucose metabolism in conscious rats.

The effects of a novel calcium antagonistic antivasospasm drug, HA1077, on local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) were studied in 33 anatomically discrete regions of the brain in conscious rats, using the quantitative autoradiographic [14C]iodoantipyrine and [14C]2-deoxyglucose techniques. HA1077 was infused i.v. over a 30-min period (1 or 3 mg/kg). HA1077 significantly increased LCBF in 9 of 33 sites in rats given 1 mg/kg, and in 14 of 33 sites in rats given 3 mg/kg compared to the control group given vehicle. Significant increases in LCGU were also noted in 16 of 33 sites in rats given 3 mg/kg. HA1077 increased both cerebral blood flow and glucose metabolism in conscious rats.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1991

Benign parotid tumors: a 24-year experience.

The medical records of 125 patients benign parotid neoplasms surgically treated over a 24-year period were retrospectively reviewed; 128 tumors were excised. These included 90 pleomorphic adenomas, 33 Warthin's tumors, 3 benign lymphoepitheliomas, and 2 oncocytomas. The surgical procedures consisted of 2 local excisions, 6 enucleations, 88 superficial parotidectomies, 13 subtotal parotidectomies, and 3 radical parotidectomies. The morbidity rate was 49%. There was one total permanent facial nerve paralysis (0.7%), four (3%) partial permanent facial nerve paralysis, five (5%) transient total facial nerve paralysis, and 32 (25%) partial transient facial nerve paralysis. After a median follow-up of 84 months, there was one recurrence (0.7%). A superficial parotidectomy is the minimum procedure that should be performed for the treatment of a benign parotid neoplasm.

Adolescent↗
PubMed1991

Effects of induced hypertension on blood flow and capillary permeability in rats with experimental brain tumors.

To study the possibility of enhancing the delivery of antineoplastic agents to tumor tissue, we conducted an experimental study using induced hypertension with angiotensin II in rats with experimental brain tumors. Drug delivery was evaluated by measuring local cerebral blood flow (LCBF) and regional cerebral capillary permeability with quantitative autoradiography. There was no significant difference of LCBF in the central region of tumor tissue between the control group and the induced hypertension group. LCBF in the peripheral region of tumor tissue in the induced hypertension group was significantly higher than that in the control group. On the other hand, despite induced hypertension, no significant changes in the regional cerebral capillary permeability were observed between the groups. These results indicate that delivery of the lipid-soluble antineoplastic agents, which depend upon cerebral blood flow, can be enhanced by induced hypertension.

Aminoisobutyric Acids↗
PubMed1991

Relationship between 22Na distribution and cerebral blood flow in ischemic gerbil brain.

Sodium transport in the early postischemic period was studied using Mongolian gerbils with right common carotid artery ligation. [22Na]sodium chloride ([22Na]NaCl) was infused immediately after, 10 minutes before, and 4 hours before carotid ligation, and the 22Na distribution was measured in symptomatic animals by autoradiography 1 hour after ischemia. Regional cerebral blood flow was determined by [14C]iodoantipyrine autoradiography. The specific gravity of the brain was measured in symptomatic gerbils 1 and 2 hours after carotid ligation by a gradient column. There was a low uptake of 22Na in the ischemic core and a high uptake in the ischemic periphery when the tracer was given 10 minutes before or immediately after ischemia. In contrast, tracer given 4 hours before ischemia showed an increased radioactivity in both the ischemic core and periphery. It is suggested that increased sodium in the ischemic core is due to a decreased sodium clearance rate and increased sodium in the ischemic periphery is due to some active transport process.

Animals↗
PubMed1991

[Spontaneous disappearance of aneurysm after total removal of accompanying intracranial arteriovenous malformation. Case report].

A 55-year-old male was hospitalized with severe headache. On admission, neurological examination revealed no abnormal findings. Plain computed tomography (CT) showed a slightly high-density area in the medial surface of the right parietal lobe. A marked enhancement in the same region was noted in enhanced CT. Cerebral angiography showed an arteriovenous malformation (AVM) in the medial surface of the right parietal lobe and two aneurysms on the right pericallosal artery which fed the AVM. In addition, a saccular aneurysm was noted at the anterior communicating artery. It was not possible to treat the AVM, two aneurysms nearby the AVM, and the unruptured anterior communicating artery aneurysm simultaneously with a single craniotomy. It was therefore decided to perform surgery for the AVM and two aneurysms nearby the AVM prior to clipping of the anterior communicating artery aneurysm. Total excision of the AVM and two aneurysms nearby the AVM was performed. Cerebral angiography performed 18 days after surgery revealed no AVM and also reduction in size was noted of the anterior communicating artery aneurysm. Three months later, repeated cerebral angiography showed disappearance of the aneurysm. This was further confirmed 15 months after surgery by angiography. From the literature, 117 cases of coexistence of AVM and aneurysms of the brain were collected and classified into three types according to their anatomical and hemodynamic correlation. It is suggested that hemodynamic stress, due to increased blood flow caused by the AVM, played a major role in the development of the aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamics↗
PubMed1990

Uncoupling of local blood flow and metabolism in the hippocampal CA3 in kainic acid-induced limbic seizure status.

Limbic seizure status was induced by microinjection of kainic acid into a unilateral amygdala in rats. Two hours after kainic acid injection, distant neuronal cell damage was produced, especially in the hippocampal CA3 on the kainic acid-injected side. In order to elucidate the mechanism of this neuronal cell damage, local cerebral glucose utilization and local cerebral blood flow were studied by means of an autoradiographic method using [14C]2-deoxyglucose and [14C]iodoantipyrine during kainic acid-induced limbic seizure status. These studies were performed 2 h after kainic acid microinjection into a unilateral amygdala. Both local cerebral glucose utilization and local cerebral blood flow were remarkably increased in the limbic system, ventrobasal complex of the thalamus, septal nucleus, nucleus accumbens, caudate nucleus, substantia nigra and hypothalamus on the kainic acid-injected side. In the hippocampus, local cerebral glucose utilization increased 2.6 times control in CA1 and 4.1 times in CA3, whereas the rates of increase in local cerebral blood flow were similarly low in CA1 and CA3: 1.2 and 1.4 times control, respectively. The results demonstrated that the degree of uncoupling of local cerebral glucose utilization and local cerebral blood flow were higher in CA3 than in CA1, and also suggested that relative hypoxia occurred in CA3 in this high degree of uncoupling, resulting in pyramidal cell damage in CA3 in kainic acid-induced limbic seizure status.

Animals↗
PubMed1990

Measurement of cerebral blood flow, cerebral blood volume, and cerebral capillary permeability in glioma-bearing rats.

Effective chemotherapy and radiation therapy of brain tumors require knowledge of the cerebral circulatory dynamics involved. In this study, regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), and regional cerebral capillary permeability (rCP) were measured in Wistar King Aptekman rats bearing experimental KEG-1 gliomas. These parameters were assessed by autoradiography with 14C-iodoantipyrine, 14C-deoxyglucose-labeled red blood cells, and 14C-aminoisobutyric acid, respectively. rCBF within the tumor was approximately one third that in the contralateral cortex and was consistently higher in the periphery than in the center of the tumor. In the periphery of the tumor, rCBV was approximately twice that in the contralateral cortex, but it was very low in the center of the tumor. Throughout the tumor, rCP was sharply increased relative to that measured in the contralateral cortex, and the increase was especially pronounced in the central portion. Thus, rCBF, rCBV, and rCP each appeared to vary within the tumor, implying that the combined use of lipid- and water-soluble chemotherapeutic agents is reasonable. Measurement of these parameters may also provide indices of radiation sensitivity.

Animals↗