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Biomedical subjects

K Moritake

Publications and source records attributed to K Moritake.

At least 91 records · Page 5Linked to original sources
PubMed1988

[Experimental hemodynamic study on carotid ligation combined with EC-IC bypass for giant aneurysm].

Although carotid ligation or balloon occlusion has been an accepted method for the inaccessible ICA aneurysm, there have been several reports of growth or rupture of the aneurysm, and cerebral embolism originating from the site of arterial occlusion or from the aneurysm. The hemodynamic changes after operation are suspected to play some role in these events. It is, therefore, very important to predict what will happen after operation in individual patients. However, it is usually difficult because multiple factors are related in a complex fashion in a living body. One of the effective means is to simulate these hemodynamic conditions by a hydraulic vascular model. We have already reported the hemodynamic changes resulting from EC-IC bypass for MCA stenosis. In this research, a glass-model aneurysm of 2.5 cm in diameter is placed at the ICA bifurcation of the model to evaluate hemodynamics after therapeutic carotid occlusion with or without EC-IC bypass. Dye was injected into the aneurysm and intensity change of the light transmitted there was measured by a photocell. Half-life of the dye was calculated from thus obtained clearance curve and was regarded as an index of intraaneurysmal stagnation, while embolus formation in an aneurysm is considered to be due to the stagnation there. The results obtained are: 1. Half-life of the dye increases significantly after carotid ligation even if collateral flow through the anterior communicating artery (A-com) or EC-IC bypass equals the ICA flow before ligation. 2. The higher collateral flow through A-com results in the more normograde flow in M1 portion, which shortens the half-life.(ABSTRACT TRUNCATED AT 250 WORDS)

Carotid Arteries↗
PubMed1988

[Experimental simulation study on EC-IC bypass--Part 1: Optimum conditions for bypass on the basis of hydraulic and theoretical models with autoregulation mechanism].

There have been several reports about unexpected occlusive change of stenotic lesion in the internal carotid artery (ICA) or middle cerebral artery (MCA) following bypass surgery, rupture or formation of an aneurysm after carotid ligation and ICA EC-IC bypass for the treatment of inaccessible ICA aneurysm. These suggest that operation for one vessel causes hemodynamic changes in others, not only near the operation site but in remote sites. Although complete hemodynamic analysis in the brain and quantitative speculation of the possible effect of a cerebrovascular operation are essential to prevent these complications, these measures are usually very difficult to carry out because multiple factors are related mutually in complex fashion in a living body. One effective means to simulate these changes would be the use of a vascular model. A hydraulic model of unilateral ICA stenosis (resistance of stenosis: R) with EC-IC bypass (resistance of bypass: Rby) has been manufactured with silicone and glass tubes. Peripheral vascular resistance (Rp) is adjusted to obtain an arterial flow of 180 ml/min at poststenotic pressures of 60, 70, 80, 90, and 100 mmHg. To simulate the autoregulation mechanism, appropriate Rp is selected for each combination of R and Rby so as to make, as far as possible, a hemispheric flow (sum of stenosis flow and bypass flow) of 180 ml/min. The Rp with the lowest value (60/180 mmHg/ml/min) is to be chosen in flow conditions of lower than 180 ml/min, where autoregulation is no longer functioning. Twelve kinds of stenosis segments with an inner diameter from 0.37 to 2.59 mm are prepared and used in the models.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Revascularization↗
PubMed1988

[Experimental simulation study on hemodynamics in multiple cerebral arterial stenoses and EC-IC bypass].

In recent years, unilateral or bilateral multiple stenoses in the internal carotid artery have been increasing in number. Full understanding and complete analysis of these hemodynamics are, however, sometimes difficult because multiple factors such as number, size and location of the stenotic lesions, and capacity of collateral circulation differ with individual cases and are related mutually in complex fashions. One of the effective means to solve these problems is to study the hemodynamics and to simulate their changes after an expected operative procedure by the use of a hydraulic vascular model, where any factor can be managed independently. A vascular model of the internal carotid artery (ICA) has been manufactured with silicone and glass tubes in similar dimensions to averaged adults. Peripheral vascular resistance (Rp) is so adjusted as to obtain an arterial flow of 180 ml/min at an intraluminal pressure of 60 mmHg. Four kinds of stenosis segments, Ra (2.59 mm in diameter), Rb (1.94 mm), Rc (1.12 mm) and Rd (0.84 mm) are prepared and used in various models simulating unilateral multiple stenoses, unilateral solitary long stenosis and bilateral multiple stenosis. The results obtained are; 1. In case of two stenoses of different degree arranged in series, advanced one was found to have a dominant effect on flow reduction. This implies that only its removal can results in good augmentation of flow in unilateral multiple stenoses of the ICA. 2. In case of more than three stenoses of the some degree arranged in series, increase in flow can not be obtained until the last one is cleared.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Ischemia↗
PubMed1988

[Experimental simulation study on cerebral hemodynamics--Part 2: Bilateral severe internal carotid arterial stenosis and theoretical study].

Although cerebrovascular surgery, typically bypass procedure for example, is considered to change hemodynamics not only near the region but in remote sites, their quantitative speculation and evaluation are usually difficult because of mutually related multiple factors in a living body. One of the effective means is to stimulate expected operative procedures and resulting changes by use of a hydraulic vascular model. We have already reported the hemodynamics in bilateral moderate ICA stenosis and their changes after EC-IC bypass. In this research, vascular model of bilateral severe ICA stenosis has been manufactured with silicon and glass tubes. Peripheral vascular resistance (Rp) is so adjusted as to obtain an arterial flow of 180 ml/min at an intraluminal pressure of 60 mmHg. Four kinds of stenosis segments, Ra (2.59 mm in diameter), Rb (1.94 mm), Rc (1.12 mm) and Rd (0.84 mm) are prepared and used in the models. In addition, theoretical study was performed in an unilateral ICA stenosis to evaluate quantitatively and extensively the effects of stenosis and cut bypass flow on the ICA flow and bypass flow. The results obtained are as follows: 1. Under marked low flow conditions from 55% to 30% of normal value simulated in this study, collateral flow from the opposite ICA has reached the maximum and therefore its increase is no more expected against the advance of the stenosis. 2. Both increase of the hemispheric flow and decrease of the carotid flow were still observed after EC-IC bypass procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Carotid Artery Diseases↗
PubMed1987

Malignant melanoma metastatic to sphenoid bone with an unknown primary origin: report of a case with an immunohistochemical analysis of the infiltrating lymphocytes.

A rare case of hemorrhagic malignant melanoma from an unknown primary origin to the right sphenoid bone in a 37-year-old woman is presented. The tumor occupied an extensive intracranial extradural space with a mild orbital infiltration, but little involvement of the leptomeninges and parenchymal tissues. Immunohistochemical analysis of the tumor-infiltrating lymphocytes showed that the majority expressed pan-T or Leu-1 surface antigens and that the lymphocytes bearing the Leu-3 antigen, or helper phenotype, were predominant compared to the Leu-2 population representing both suppressor and cytotoxic T cells. Furthermore, most of the T lymphocytes stained with HLA-DR antigens. Because few B cells were seen, this observation indicates the presence of T cells in an activated state. The literature pertinent to associated organ involvement of metastatic melanomas and the correlations between the tumor and immunological cellular responses are discussed.

Adult↗
PubMed1987

[The potential usefulness of transcranial Doppler sonography in cerebrovascular surgery].

In 30 patients undergoing neurosurgical intervention, the authors evaluated the hemodynamics in the circle of Willis by transcranial Doppler sonography. By avoiding confusion with collateral effects, the transcranial Doppler sonography yielded direct and more significant information concerning the intracranial hemodynamics than extracranial Doppler sonography. Therefore, it made possible to detect intracranial occlusive lesions with less false findings. It gave us more accurate information on the effectiveness of reconstructive vascular surgery. In two of five consecutive patients with a proven aneurysmal subarachnoid hemorrhage, sound-spectrogram specific to stenosis was detected from the basal cerebral arteries which accompanied increase of the time-mean velocity of the upper spectrum and decrease of S/D ratio. Transcranial Doppler sonography was considered to contribute to the establishment of a protocol for early diagnosis and treatment of vasospasm. Transcranial Doppler sonography was also utilized as a useful tool for classification of arteriovenous malformation from the viewpoint of hemodynamics, namely high-flow or low-flow and with or without steal phenomenon. Transcranial Doppler sonography appears sufficiently promising to justify further development and utilization in cerebrovascular surgery.

Carotid Artery Diseases↗
PubMed1987

[Experimental study of evoked potentials in predicting the reversibility of brain function following tentorial herniation].

Brainstem auditory evoked potentials (BAEP), somatosensory evoked potentials (SEP) and EEG were recorded sequentially in cat with mass-induced intracranial hypertension in correlation with mass volume, intracranial pressure (ICP), systemic blood pressure (BP) and size of the pupils. 1) As the intracranial pressure was raised by expansion of a supratentorial epidural balloon, suppression of cortical SEP (CSEP) and pupillary abnormality appeared first, EEG, waves IV and III of BAEP and wave III of short latency SEP (SSEP) were suppressed in this order. 2) As far as wave IV of BAEP remained and decompression was started within 30 minutes after peaks of CSEP completely suppressed, changes in P1 and N1 of CSEP were reversible. 3) Further raising of ICP was followed by loss of waves IV and III of BAEP and wave III of SSEP in this order. Simultaneously with loss of wave III in SSEP, systemic blood pressure dropped rapidly. By immediate balloon deflation after disappearance of wave III of SSEP, animals recovered from hypotension, but hardly from suppression in EEG, CSEP and BAEP. 4) Preservation of wave IV of BAEP indicated good improvement of pupillary abnormality even after removal of compression. These results suggest that for the patient with disturbed consciousness caused by supratentorial mass lesion, decompressive procedure should be started before wave V of BAEP and brainstem components of SEP disappear. EP monitor seems to be useful clinical method for preventing irreversible change of the brain in patients with coma caused by supratentorial mass lesions.

Animals↗
PubMed1986

[Technical problems in intraoperative monitoring of sensory evoked potentials].

Recent advances in both the equipment and the recording technique of sensory evoked potentials (EP) have brought high levels of versatility and reliability of objective measurement to the assessment of nervous system function. They have also allowed the use of intraoperative evoked potentials. The operating room, however, is usually considered a hostile environment, where various kinds of artifacts from surgical manipulation and generated by electrical armamentaria disturb electrophysiological recordings. Although several authors have reported on intraoperative EP monitoring, they have described few of the practical details of recording techniques. Having developed an intraoperative recording technique for evoked potentials over the past 3 years, we present the technical measures taken to overcome interference and obtain sufficiently stable and reliable EP recordings for intraoperative monitoring. All electrical equipment used in the operating rooms must, of course, be grounded securely. Even after grounding in the usual manner, however, artifacts appeared intermittently. The source was found to be a Mayfield-Kees three-pin head rest and a self-retaining retractor, both of which seemed to pick up electromagnetic radiation originating from electrocauteries and others. These artifacts could be minimized by grounding the head pins all each point of insertion into the patient's head and by use of a silicon-coated spatula rather than a metal one. In addition automatic artifact rejection by voltage overload sensing seems to be indispensable to eliminate the effect of extraneous mechanical and electrical interference which occur inevitably in surgical procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Stem↗
PubMed1986

[One-stage bilateral STA-MCA anastomosis in multiple occlusive cerebrovascular disease].

Out of 12 cases of bilateral stenosis of the internal carotid (IC) system underwent unilateral STA-MCA anastomosis on the symptomatic side, no ischemic signs recurred in 8 cases, while, in the remaining 4, symptoms appeared postoperatively, requiring the anastomosis of the contralateral side. Preoperative findings of CT scan, CAG and r-CBF were reviewed and compared. It has, consequently, become evident that, in the latter 4 cases, angiography showed stenotic lesion of over 50% of the ICA lumen, between the mastoid-mandibular line (MML) and the circle of Willis, on the initially asymptomatic side. Furthermore, in the same 4 cases, multiple thrombotic foci were more liable to be demonstrated on the CT scans and r-CBF was lowered in both hemispheres without significant difference in laterality. In additional 7 cases presenting such characteristics as stated above, one-stage bilateral STA-MCA anastomosis was carried out with a successful result.

Aged↗
PubMed1986

[Technical details for recording trigeminal evoked potentials in the cat].

Experiments were undertaken to establish technical standards for recording of trigeminal evoked potentials (TEP) as a tool for assessment of the effectiveness of various therapeutic procedures for trigeminal neuralgia. Serial changes in the action potentials of the maxillary nerve and TEP were studied when parameters of electrical stimulation, namely, intensity and frequency, and position of electrodes were altered. The effects of use of muscle relaxants and change of body temperature of animals on TEP were also studied. On the basis of these experimental results, the technical details most suitable for TEP recording in cat were explored. The most distinct TEP was recorded under the following animal conditions and parameters: keeping rectal temperature between 37.5 degrees C and 38.5 degrees C, slackening with muscle relaxants, stimulating the infraorbital nerve with 10 volts of square-pulse electricity 5 times per second in short latency TEP and 2 times per second in long latency TEP, placing the active electrode on the vertex for short latency TEP and on the primary sensory area for long latency TEP. Eight positive peaks and three negative peaks were recorded under these conditions. The average and standard deviations of peak latency of potential from 10 cats were as follows: P 1, 0.67 +/- 0.04 msec; N 1, 0.89 +/- 0.07 msec; P 2, 1.35 +/- 0.10 msec; P 3, 1.89 +/- 0.08 msec; P 4, 2.43 +/- 0.26 msec; P 5, 3.17 +/- 0.15 msec; P 6, 3.36 +/- 0.21 msec; P 7, 5.02 +/- 0.39 msec; P 8, 6.07 +/- 0.35 msec; N 2, 10.4 +/- 1.15 msec; N 3, 18.5 +/- 1.74 msec.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[Effects of thiopental on sensory evoked potentials in the cat].

Noninvasive electrophysiological evaluation with sensory evoked potentials would be of clear diagnostic and prognostic value in evaluating comatose patients with stroke or severe head injury. In order to protect the brain from such kinds of insults, barbiturate coma therapy has been employed and its effectiveness has been already established. However, in the barbiturate coma therapy, it is occasionally difficult to distinguish the pharmacological effect of barbiturate from the preexisting brain dysfunction caused by the underlying process of the disease. In adult cats, authors studied changes of sensory evoked potentials following cumulative intravenous administration of thiopental which is used clinically for barbiturate coma therapy. P1 and N1 of cortical SEP showed tendency of gradual decrease in amplitude. However, no significant changes occurred in latency by stepwise increment of thiopental dose. Changes in amplitude of P1 and N1 of cortical SEP preceded to the flattening on electroencephalogram. Around at the level of the concentration where EEG changes began, I-II interpeak latency of BAEP and latency of wave I of short latency SEP started to increase. BAEP and early components of SEP (I.II.III.IV) persisted even in by far the higher level of serum concentration of thiopental than that of clinical use. Furthermore, most of these parameters showed no statistically significant change neither in amplitude nor in latency. These experimental results suggest that sensory evoked potentials will provide us with useful information in the assessment of the brainstem function in patients under thiopental induced deep coma.

Animals↗
PubMed1986

[Implantable continuous epidural morphine infusion system for relief of chronic cancer pain].

Chronic cancer pain remains intractable by standard treatment in many patients and interferes with their mobility and independence. Epidural morphine infusion therapy is adopted for providing adequate analgesia in patients who are generally morphine independent and have intractable pain. A totally implantable pump system, Infusaid, has allowed continuous epidural morphine infusion without wound care or frequent percutaneous injections and with a potentially lowered risk of adverse reactions including respiratory suppression. Since December 1984, the authors have used this totally implantable drug delivery system for continuous epidural morphine infusion in two patients who had been suffering from chronic pain caused by pelvic cancer associated with metastatic and/or invasive lesions: Case 1: a 61-year-old man with rectum cancer; and Case 2: a 44-year-old man with colon cancer. Before system implantation, a therapeutic response to epidural morphine was confirmed by a one-shot test injection. Pain relief was evaluated by use of Visual Pain Analogue Scale Scores (VPASS). In spite of the presence of an artificial anus on the left abdomen in both patients and of pus discharge from a sacral infectious fistula on admission in Case 2, no infectious complication occurred in either case. Urinary retention developed after the implantation in Case 2, but this improved following the reduction of morphine concentration. No other adverse reaction was observed. In Case 1, the system was effective for 6 months until his death from advancing malignancy, and the patient was able to return to work three months after discharge.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Follow-up study on the relationship between age at onset of illness and outcome in patients with moyamoya disease].

Follow-up studies over more than one and a half years (average 6.5 years) were performed in 51 patients with "moyamoya disease". Activities of daily living (ADL) was assessed and graded into five levels both at the time of admission into hospital and at the last assessment in the follow-up study, as follows. Grade I: Fully capable of work or study with no or minimal difficulty, II: Capable of limited work or study with difficulty, III: Incapable of work or study but capable of home life alone, IV: Incapable of home life without help, V: Vegetative state or dead. Patients were divided into three groups by the age of clinical onset: younger pediatric, less than 5 years old (21 patients); older pediatric, 5 to 15 years old (14 patients); and adult, 16 years old and over (16 patients). Although analysis of the angiographical and neurological pictures is important, the present paper concerns only the age of clinical onset and whether reconstructive vascular surgery was performed, because of the small number of clinical materials. Seven of 16 adults suffered hemorrhagic attacks and 2 of them died of hemorrhagic insults. In contrast, none of the pediatric cases had hemorrhagic attacks and none died. Both at the time of admission and last assessment, ADL of younger pediatric cases was much lower than that of older ones. These results suggest that clinical course in patients with "moyamoya disease" closely related with the age of the onset of illness, and the border age of onset of illness between patients with good outcome and with poor outcome is around 5 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1986

[Experimental study on the origins of far-field SEP to median nerve stimulation in the cat].

Results of various experimental and clinical studies on the origins of somatosensory evoked potentials (SEP) suggested that the far-field and early near-field potentials are generated primarily from sources within the dorsal column-medial lemniscal system. However, there are a few studies where direct depth recordings of SEP were performed and they were compared with surface-recorded SEP components. The purpose of this investigation is to determine the origins of somatosensory far-field and early near-field evoked potentials in cat by the analysis of distribution mode of surface-recorded SEPs, the comparison of depth recorded with surface-recorded SEPs and by the study of SEP changes caused by serial destruction of the structures relating to sensory pathway. A complex patterns of evoked potentials were recorded from cerebral epidural surface in cat by forelimb median nerve stimulation. The largest positive to negative slope was recorded from the epidural electrode on the sensory cortex contralateral to the stimulation. Five small positive potentials could be identified on the positive slope. We labeled these potentials as I, II, IIIA, IIIB, IV according to the report by Iragui-Madoz. The largest positive potential recorded from the VPL was coincident with the surface-recorded IIIB in latency at different interstimulus intervals. After transection of the midbrain-pons junction, IIIA remained unchanged, and the following waves disappeared. However, IIIA decreased in latency and markedly decreased in amplitude after transection of the pons at its rostral level. IIIA seems to be generated from the medial lemniscus at the level of osseous cerebellar tentorium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[Effects of pentobarbital anesthetic induction on sensory evoked potentials in the cat].

During the last decade, noninvasive electrophysiological tests with sensory evoked potentials have rapidly blossomed into useful clinical tools. They have been studied in large groups of normal subjects and in patients with a wide variety of neurologic diseases. Almost all experimental animal studies on sensory evoked potential, however, have not been undertaken under sufficient consideration on the effects of drugs used for induction into anesthesia on evoked potentials. In order to use evoked potentials as a tool for assessing neurological function in animals, it is necessary to known the effect of anesthetic agents on evoked potentials. Pentobarbital, Somnopentyl, is one of the drugs most commonly used for induction into anesthesia is animal experiments. Authors have attempted to study the long term effects of pentobarbital on evoked potentials. Intramuscular administration of anesthetic dose of pentobarbital was followed by prolongation of 11 and III waves of SEP and I-II interpeak latency of BAEP. Latency of N1 of SEP was also prolonged. On electroencephalogram, amplitude have increased and frequency have got slower after pentobarbital administration. These electrophysiological changes persisted over 5 hours after pentobarbital administration. These results suggest that in some studies on animals the residual effect of agents used for induction into anesthesia must be taken account for analysis of data obtained.

Anesthesia↗
PubMed1985

Cavernous angioma in the fourth ventricle.

A cavernous angioma in the fourth ventricle of a 47-year-old man is reported. Because of a progressive clinical course and a ring-like enhancement on computed tomography, a brain tumor, rather than a vascular disease, was suspected. The lesion was removed totally and verified histologically as a cavernous angioma.

Brain Neoplasms↗