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Biomedical subjects

K Moritake

Publications and source records attributed to K Moritake.

At least 73 records · Page 4Linked to original sources
PubMed1991

Foster Kennedy syndrome and optociliary shunt vessels in a patient with an olfactory groove meningioma.

A 48-year-old woman complained of acute loss of vision in her right eye. Ophthalmoscopically, the right optic disk appeared pale, and abnormally dilated vessels were noted on the disk. The left optic disk was reddish and swollen. Fluorescein angiography revealed abnormal vessels on the right optic disk that might be venous. The patient had right-sided anosmia. Computed tomography and magnetic resonance imaging showed a lesion in the frontal lobe that was deviated to the right and attached to the olfactory groove. A histopathologic study of the excised specimen disclosed a meningioma. We believe that this patient with olfactory groove meningioma represents a rare case of Foster Kennedy syndrome and optociliary shunt vessels.

Ciliary Body↗
PubMed1991

Hemodynamic study of posterior circulation using hydraulic vascular model--critical stenosis of the vertebrobasilar artery and tolerance to occlusion therapy.

A hydraulic vascular model with glass and silicone tubes of the intracranial portion of the vertebro-basilar artery was used to determine the critical stenosis causing vertebrobasilar insufficiency, and the minimum diameter of the posterior communicating arteries (PComAs) necessary to tolerate therapeutic vertebrobasilar occlusion for unclippable aneurysms. The critical stenosis of one vertebral artery (VA) or basilar artery (BA) differed greatly depending upon the anatomical variations of the PComA and the posterior cerebral artery (PCA): 1.14 mm diameter when the artery supplies 80 ml/min to the cerebellum and brainstem only, 1.33 mm when 140 ml/min to these structures and one PCA, and 1.56 mm when 200 ml/min to these structures and both PCAs. The minimum PComA diameter to tolerate therapeutic occlusion depended largely upon the occlusion site: one PComA with 1.54 mm diameter for bilateral VA occlusion and 1.25 mm for BA occlusion distal to the branching of the superior cerebellar arteries. The total volume of collateral flow through both PComAs can be estimated by summing the squares of the diameters. These values cannot be applied rigidly to clinical cases, but are useful standards to evaluate the stenotic lesion or tolerance to occlusion.

Blood Flow Velocity↗
PubMed1991

Effects of long-term cerebral ischemia caused by bilateral carotid artery ligation on the acceleration or the development of hypertension in spontaneously hypertensive rats (SHR) or Wistar-Kyoto rats (WKY).

Bilateral carotid artery ligation (BCL) was performed with one week interval between the each operation in male spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) aged 4 months. BP rose immediately after unilateral carotid artery ligation (UCL) and BCL in both WKY and SHR due to carotid sinus reflex. Once returning to preoperative levels after both UCL and BCL, BP of SHR and WKY increased again gradually one and 4 months after BCL and thereafter, respectively. BP was significantly higher than that in the controls of each strain, and the BP increment was significantly greater in SHR than in WKY. A significant regional cerebral blood flow (rCBF) increase on the contralateral side of carotid ligation was observed in SHR in contrast to a little change in that of WKY and a reduction of rCBF after BCL was significantly greater in SHR than in WKY. Behavioral activities in SHR were also reduced after BCL. Cerebral edema with nerve cells damage was recognized in SHR. In contrast, little change was found in WKY. On the other hand, upper cervical sympathectomy attenuated convulsive seizures after BCL more markedly in SHR, which survived longer than non-denervated SHR. These results suggest that chronic mild cerebral ischemia caused by BCL with one week interval accelerates the development of severe hypertension in SHR and developed mild hypertension in WKY. Sympathetic innervation might play much more important role in collateral circulation through the vertebrobasilar system in SHR.

Animals↗
PubMed1991

[Pathophysiological study of corona radiata infarcts by clinically available diagnostic methods].

The authors evaluated 18 patients who presented with corona radiata infarction, one of the 'water-shed infarctions', on CT and/or MRI to determine its etiology and pathophysiology using cerebral angiography, single-photon emission computed tomography (SPECT), and tests of hemostatic function including hematocrit, platelet aggregation and adhesiveness. On angiography, 8 of these 18 patients had ulcerative lesions in the common carotid artery bifurcation with or without minimal stenosis and exhibited no or a minimal area of hypoperfusion localized to the corona radiata on SPECT. In these, microembolism from the lesions at the common carotid bifurcation seemed play an important role in the genesis of corona radiata infarction. In 7 of the remaining 10 patients, cerebral angiography showed occlusive lesions of the internal carotid artery around its origin in 3, more than 90% stenosis of the internal carotid artery in 1, severe stenosis of the M1 segment of the middle cerebral artery in 2, and M1 occlusion in 1. In 5 of these 7, SPECT demonstrated a larger area of hypoperfusion than the corona radiata in the involved hemisphere. In the remaining 2, SPECT demonstrated a hypoperfusion area localized to the corona radiata. In all 7, the hematocrit was elevated. A collateral blood supply was visualized in 5 of 7 on cerebral angiography. In these 7 patients, hemodynamic disturbance was considered to contribute to the pathogenesis of infarction in the corona radiata. In the final three patients, cerebral angiography showed significant occlusive lesions in the main trunk of the cerebral arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Clinical evaluation of a newly developed enteric nutrient given to the neurosurgical patients with disturbances of consciousness.

An enteric nutrient 'SAN-ET-A', rich in protein and electrolytes, was given to 8 patients with disturbances of consciousness. Although the adminstered dosage had a calorie content so low that basal metabolism was barely maintained, the level of serous proteins increased following administration. Electrolyte imbalance was not found, and the patients did not suffer from severe renal or liver dysfunctions. No notable gastrointestinal troubles occurred except in one case. It is concluded that a low dosage of SAN-ET-A was sufficient to maintain the patients in good nutritional condition. Furthermore, it is suggested that this nutrient can be safely given for a long period.

Aged↗
PubMed1990

Intracellular pH regulation of normal rat brain: 31P-MRS study.

Intracellular pH changes in rat brain tissue were investigated during low or high extracellular pH induced by acetazolamide or sodium bicarbonate, respectively. Intracellular pH was measured by 31P-MRS in the brain of spontaneously breathing rats under intraperitoneal sodium pentobarbital anaesthesia. Extracellular pH was calculated from the results of blood gas analysis. After intravenous injection of sodium bicarbonate (280 mg/kg), the extracellular pH rose significantly (p less than 0.05) from 7.47 +/- 0.06 to 7.82 +/- 0.15 (mean +/- SE). After administration of acetazolamide (50 mg/kg), the extracellular pH dropped significantly (p less than 0.05) from 7.45 +/- 0.02 to 7.34 +/- 0.03. Despite the changes in extracellular pH, the intracellular pH of rat brain did not change significantly under either condition. The following four factors are thought to contribute to the maintenance of intracellular pH in the normal brain: 1) production and consumption of H+ by brain metabolism, 2) physicochemical buffering, 3) transmembrane transport of H+ and its equivalent, 4) compensatory adaptation of circulatory factors. These mechanisms are not disturbed in the brain of rats that are breathing spontaneously, because the cerebral circulation and energy metabolism are preserved in the normal range.

Acetazolamide↗
PubMed1990

Intracerebral malignant lymphoma with fluctuating regression and spatial evolution.

Seven patients with histologically proven primary intracerebral malignant lymphoma, characterized by a fluctuating nature with both transient regression and spatial evolution of the tumors without contiguity to the initial lesion, are presented. Although the overall outcome was unfavorable, two cases had a long-term survival of 3 years or more and one of them showed a good quality of life. Correlation among characteristic clinical presentations, computed tomography scans, and prognostic factors after management with surgery, radiation, and chemotherapy, including steroids, is discussed.

Aged↗
PubMed1990

Two surgically cured cases of subependymoma with emphasis on magnetic resonance imaging.

The authors describe two surgically cured cases of symptomatic subependymomas located in the lateral ventricle and septum pellucidum with emphasis on magnetic resonance imaging study. Both computed tomography and MRI revealed a calcified mass with repeated intratumoral hemorrhages. Cerebral angiograms disclosed rather hypovascular lesions. The histologic diagnosis was proven to be of subependymoma. The pertinent literature of surgically treated subependymomas is reviewed, and the characteristic biologic features are also discussed.

Adult↗
PubMed1990

[Experimental study on the difference of ischemic threshold between cerebral cortex and thalamus with middle latency auditory evoked potentials].

Middle latency auditory evoked potentials (ML-AEPs) have not yet been established as a device of assessing neurological events because their origins have not been definitely identified. In this study, we assessed the neurological usefulness of MLA-EPs through experimental approach using canine models of acute ischemia localized within the cerebral cortex or thalamus. Two types of localized cerebral ischemia were produced in mongrel dogs by clipping of major cerebral arteries and inducing of hypotension; they were, unilateral cortical ischemia involving the right primary auditory area (group A) and unilateral thalamic ischemia involving the right medial geniculate body (group B). Using these two ischemia models, auditory evoked potentials (AEPs) were intracranially and extracranially recorded in addition to the measurement of local cerebral blood flow (1-CBF). Prior to the induction of ischemia, it was confirmed that positive waves with a latency of 20 ms (P20) were evoked in the bilateral primary auditory areas by sound stimulation (90 dB 5 Hz click) given to the ear contralateral to the planned ischemic side in both groups. The right P20 disappeared when the 1-CBF in the right primary auditory area decreased below the ischemic flow threshold of synaptic transmission failure, approximately 18 ml/100 g/min, in group A, and when the 1-CBF in the right medial geniculate body decreased below the threshold, 10 ml/100 g/min, in group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Experimental analysis of anti-tumor cytotoxic mechanism for hybrid resistance to mouse neuroblastoma].

A spontaneous neuroblastoma (NB-85, H-2a/a) was tested for hybrid resistance (HyR) after subcutaneous (s.c.) inoculation into syngeneic and semisyngeneic mice. The hybrids (F1) (H-2a/b) between A/Sn and Leaden mice and the F1 between A/Sn X C57BL/6 mice were more resistant to the s.c. inocula of 10(6) to 5 X 10(5) cells than syngeneic recipients. Thymectomy, followed by irradiation and fetal liver reconstitution, abrogated the HyR against NB-85, whereas intravenous (i.v.) administration of anti-asialo-GM1 antibodies had no influence on the resistance. Surface phenotypic analysis revealed that NB-85 expressed H-2 Kk (-), Dd (+) and beta 2-microglobulin (-), showing a dissociation of the cell surface. Anti-H-2a-specific cytotoxic T lymphocytes exhibited a significant lytic activity against NB-85, while NB-85 was highly refractory to natural killer cell (NK)-mediated lysis. In vivo NK-mediated rejection assays showed that 125I-iododeoxyuridine (IUdR) labeled NB-85 cells were not eliminated more efficiently from the highly resistant F1 hybrids than from the parental strain. Furthermore, genotypic study with segregating (A/Sn X Leaden) F1 X A/Sn backcross mice showed that the HyR was attributable primarily to heterozygosity within the H-2 complex. Taken together, it was suggested that the HyR to an NK-resistant mouse NB-85 neuroblastoma might involve a T cell-dependent immunosurveillance with H-2 genetic control.

Animals↗
PubMed1990

[Hypertensive recurrent intracerebral hemorrhage accompanied with orthostatic hypotension and labile hypertension].

Authors reported a case of recurrent intracerebral hemorrhage accompanied by severe orthostatic hypotension. A 51-year-old women had recurrent intracerebral hemorrhage 3 times during a period of 2 years. The first and third hemorrhages were located in the right putaminal region, and the second hemorrhage in the left thalamic region. Cerebral angiography revealed neither evidence of vascular malformation nor that of tumor vessels. At the third admission, she became unconscious for three hours after admission, and emergent fronto-temporal craniotomy was performed. Light microscopic histological investigation with congo-red stain demonstrated the absence of cerebral amyloid angiopathy. Laboratory examination revealed no hemorrhagic diathesis. During hospitalization, She complained of dizziness in the standing position. When systolic blood pressure fell from 140 mmHg in the supine position to less than 80 mmHg in the standing position, she became unconscious. Her blood pressure was very labile with orthostatic changes and her systolic blood pressure was also very labile without orthostatic changes, changing from 108 mmHg to 218 mmHg. Severe orthostatic hypotension and labile hypertension made the medical control of hypertension difficult. In conclusion, both severe orthostatic hypotension and labile hypertension were risk factors of recurrence of intracerebral hemorrhage.

Cerebral Angiography↗
PubMed1990

[A comparison of the functional vulnerability of the cerebral cortex and thalamus to acute ischemia].

Using cerebral cortical and thalamic ischemia models produced in mongrel dogs, the reversibility of short-latency somatosensory-evoked potentials (SSEPs) and the effects of ischemic brain edema on reversibility were compared. The mean systemic blood pressure (MSBP) of animals was reduced by exsanguination until cortical SSEPs disappeared, and was held constant at that level. The MSBP was recovered by autogenous blood transfusion at 30 minutes (subgroup A), 60 minutes (subgroup B) and 90 minutes (subgroup C) after SSEP disappearance in the cortical ischemia group; and at 15 minutes (subgroup D) and 30 minutes (subgroup E) after SSEP disappearance in the thalamic ischemia group. Local cerebral blood flows (lCBF) were measured and SSEPs were monitored serially up to 2 hours after blood transfusion. At the end of measurement, the leakage of Evans blue was evaluated and brain tissue water content was measured. Cortical SSEPs disappeared when lCBF in the right cerebral cortex, measured by hydrogen clearance method decreased to 18.4 +/- 5.4 ml/100 g/min (mean +/- SD) and neuronal transmission failure in thalamus occurred when thalamic blood flow decreased to 10.0 +/- 3.3 ml/100 g/min. After blood transfusion. SSEP reappeared in all 12 animals in subgroup A, but did not appear in 2 of 9 animals in subgroup B and in all of 7 animals in subgroup C.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Communicating hydrocephalus occurring in the postoperative course of glioblastoma multiforme.

We experienced a case of glioblastoma multiforme which exhibited dementia, gait disturbance, headache, and urinary incontinence six months after subtotal removal of the tumor. These symptoms were not due to tumor recurrence, but to communicating hydrocephalus. Communicating hydrocephalus in cases of malignant brain tumors has not often been reported. We discuss the development of this abnormality.

Brain Neoplasms↗
PubMed1989

[Experimental simulation study on EC-IC bypass: Part 2, Hemodynamics of superficial temporal artery and clinical application of the stenosis model].

In the preceding paper, Part 1, hemodynamics of the internal carotid artery stenosis and their changes after EC-IC bypass have been simulated and discussed in hydraulic and theoretical vascular models. In this study, theoretical model simulation has been advanced and applied to evaluate possible hemodynamic changes due to systemic blood pressure drop and to discuss the difference in efficacy between bypass and pressure elevation for its treatment. Dimensions of the STA have been referred to sometimes in relation to the technical problems for anastomosis but rarely for its cut bypass flow values. A hydraulic model of the STA has been manufactured with silicone and glass tubes to determine the relations between dimensions and cut bypass flow of STA. This was done because cut bypass flow is one of the important factors to be considered when speculating bypass capacity. STA main trunk is assumed to be 50 mm in length and 2 mm in inner diameter, and its branches reaching anastomosis sites about 40 mm in length. Effects of such factors as number of branches (single or double anastomosis), inner diameter and length are measured in this model to determine their effects on STA cut flow. In addition to these two problems, cortical arterial pressure and STA bypass flow are measured and compared to each other to determine in what hemodynamic conditions EC-IC bypass should be performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1988

[Experimental study of the usefulness of evoked potentials in predicting the reversibility of the brainstem function following infratentorial epidural balloon compression].

With few warnings signs, posterior fossa mass lesions can affect life-supporting brainstem systems directly and cause a precipitous failure of vital functions. Consequently, a technique, by which brainstem dysfunction could be detected at its reversible stage, would have clinical value. Recently manly reports have suggested that the evoked potentials might be advantageous in assessing a developing brainstem dysfunction and might be a more sensitive or reliable detector of deteriorating neurological function than the physical or neurological signs. To explore this possibility, we recorded somatosensory evoked potentials (SEP) and brainstem auditory evoked potentials (BAEP) serially during inflation and deflation of balloons placed in the suboccipital epidural space of cats, as a model of an acutely expanding posterior fossa lesion. The results were correlated simultaneously recorded cardiovascular and pupillary function and with supratentorial and infratentorial epidural pressure. In this study, N1 of cortical SEP (CSEP), wave IV of BAEP, and wave III of short latency SEP (SSEP) were found to be useful parameters in predicting the electrophysiological reversibility. Experimental results were as follows: 1) As the infratentorial epidural balloon was expanded, CSEP, wave IV of BAEP and wave III of SSEP showed remarkable changes both in latency and in amplitude. Decrease in blood pressure and pulse rate preceded or developed at the same time as the apparent change in CSEP. Futher expansion of the balloon resulted in Cushing phenomenon and lability of blood pressure.2) As long as wave IV of BAEP remained, and decompression was started within 15 minutes after N1 of CSEP were completely suppressed, changes in SEP. BAEP and cardiovascular function were all reversible.2+ decompression. (ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗