Biomedical subjects

N Saeki

Publications and source records attributed to N Saeki.

At least 91 records · Page 5Linked to original sources

PubMed1999

Sleep-disordered breathing in acromegalics--relation of hormonal levels and quantitative sleep study by means of bedside oximeter.

Sleep-disordered breathing (SDB) is common in patients with growth hormone (GH) secreting pituitary adenomas. Since long-term untreated SDB aggravates systemic conditions (hypertension and arrhythmia etc.), the therapeutic outcome of SDB is important in reducing morbidity and mortality rates. But the results of a quantitative analysis of the lowered GH and IGF-1 levels in SDB in a relatively large number of patients are not detailed. Ten consecutive acromegalic patients were studied with a bedside oximeter. Preoperatively they were divided into two groups based on the presence (SDB group = 6 patients) or absence (non-SDB group = 4 patients) of clinical symptoms of SDB such as habitual snoring, excessive daytime somnolence and nocturnal apneic episodes. The serum IGF-1 averaged 931.7 ng/ml in SDB group and 898.3 ng/ml in non-SDB group. The oxygen desaturation index (ODI) (the number of oxygen desaturations exceeding 4% from the base line) was 29.1+/-15.4 in the SDB group and 2.5+/-1.8 in the non-SDB group (P=0.01). Other oximeter parameters such as the percent of the time spent at O2 saturation < 90% and the mean and the lowest O2 saturations closely correlated with the degree of the clinical symptoms. A postoperative sleep study was conducted in 5 patients in the preoperative SDB group, 4 months or more after the surgery. The serum GH and IGF-1 levels normalized in 3 patients but remained slightly high in 2. ODI became 9.1+/-5.6, which was significantly lower than the preoperative value (P=0.026). One patient had a complete clinical resolution. The other 4 obtained slight to moderate improvement clinically and oximetrically despite normalized or decreased hormonal levels. This study clarified that the response of SDB to lowering of the GH level varies from one patient to another and persisting SDB despite the normalization of the hormonal levels suggests the involvement of other factors in the production of SDB.

Acromegaly↗

PubMed1999

Paraganglioma in the frontal skull base--case report.

A 56-year-old female presented with a paraganglioma in the left anterior cranial fossa who manifesting as persistent headache. Computed tomography and magnetic resonance imaging showed a solid, enhanced tumor with a cystic component located medially. The tumor was attached to the left frontal base and the sphenoid ridge. Angiography demonstrated a hypervascular tumor fed mainly by the left middle meningeal artery at the left sphenoid ridge. The preoperative diagnosis was meningioma of the left frontal base. The tumor was totally resected via a left frontotemporal craniotomy. Histological examination revealed the characteristic cellular arrangement of paraganglioma generally designated as the "Zellbaren pattern" on light microscopy. Only 10 patients with supratentorial paraganglioma have been reported, seven located in the parasellar area. The origin of the present tumor may have been the paraganglionic cells which strayed along the middle meningeal artery at differentiation.

Cerebral Angiography↗

PubMed1999

Long-term magnetic resonance imaging follow-up of asymptomatic sellar tumors. -- their natural history and surgical indications.

Serial magnetic resonance (MR) images and clinical symptoms were analyzed in 23 patients with sellar lesions, who were followed up without initial therapy for mass reduction to evaluate their natural history and surgical indication for these lesions. The patients were aged 17 to 78 years (mean 47.3 years) and the follow-up period was 1.5 to 11.6 years (mean 5.1 years). Lesions were divided into two types based on the MR imaging findings, regardless of their histological types. Type C was cystic with or without enhancement of the smooth and thin wall. Type S had enhanced solid components. Ten patients had Type C tumors. Three patients presented with sudden onset of headache. The tumor size spontaneously decreased with intensity change, indicating pituitary apoplexy as the trigger of the onset and intensity change. Four patients presented with the visual disturbance which improved with the reduction of tumor size, but three patients deteriorated and required surgery. The operation revealed Rathke's cleft cyst. The remaining three patients were found incidentally and have been asymptomatic without MR imaging changes. Thirteen patients had Type S tumors. Six patients of nine with 14 mm or larger tumors developed symptomatic tumor enlargement over the follow-up period of 1.2 to 8.6 years (mean 4.9 years) and required treatment. The remainder showed no change. Type C tumors frequently shrink or even disappear spontaneously. We can justify conservative follow-up of Type C tumors in patients with no or only transient symptoms. Type S tumors, larger than 14 mm in size, need closer observation or treatment because they often enlarge and become symptomatic.

Adenoma↗

PubMed1998

MRI prediction of fibrous pituitary adenomas.

The transsphenoidal approach is a less invasive and safer procedure for removing pituitary adenomas. However, this procedure becomes extremely difficult when the tumour consistency is fibrous as encountered in about 10% of pituitary adenomas. In this study, we investigated predicting factors of tumour consistency in magnetic resonance images (MRIs). MRIs of two groups, twenty-one soft and five firm (fibrous) adenomas, were retrospectively evaluated and compared in respect of tumour consistency. To compare the two groups objectively, tumour densities on MRI films and percentage of collagen content on operative specimens were expressed as numerical data using NIH-image. The relationships between collagen content and T1-weighted images, T2-weighted images, grade of enhancement effect, and heterogeneity of enhancement were investigated. Signal intensities on T1-weighted images were not correlated with tumour consistency, whereas those on T2-weighted images were significantly correlated with the percentage of collagen content. Adenomas, showing lower signal intensities on T2-weighted images, contained more collagen. On enhanced images, homogeneously enhanced adenomas tended to include more collagen, even though the grade of enhancement effect showed only weak correlation with the tumour hardness. MRIs give us useful information on tumour consistency. Adenomas may be firm and fibrous if they show low signal intensities on T2-weighted images and homogeneous enhancement. To remove such tumours, a long sized and small-calibred ultrasonic aspirators applicable to transsphenoidal approach must be prepared and multistaged operations may be more than likely needed.

Adenoma↗

PubMed1998

Brain stem contusion due to tentorial coup injury: case report and pathomechanical analysis from normal cadavers.

This report is in two parts. First, a case report on a 20-year-old man with a localized brain stem contusion. Second, in order to elucidate the mechanism of this injury, an anatomical study was performed. Ten cadaver heads were analysed to reveal the variations of spatial anatomy around the tentorial incisura. The lateral tentorial incisura (lateral to brain stem) was situated at the level of pontomesencephalic junction and nearest to the brain stem along its course. The shortest distance between them averaged 1.0 mm (0-4 mm). Based on these findings, primary brain stem injury caused by tentorial incisura occurs at its lateral portion due to the shortest distance to the brain stem and near the level of pontomesencephalic junction. In patients with a tentorial incisura closely related to or touching the brain stem, tentorial coup injury to the brain stem may occur even with a relatively minor injury. In our case, repeated CT and MRI proved that the location of contusion was at the pontomesencephalic junction, coinciding with the level of the tentorial edge. The injury started at the surface of brain stem. The tentorial edge was close to brain stem in this case. These radiological findings support the hypothesis that the brain stem contusion was caused by a tentorial coup injury.

Adult↗

PubMed1998

Surgical indication after bromocriptine therapy on giant prolactinomas: effects and limitations of the medical treatment.

Bromocriptine (BC) is now an accepted primary therapeutic agent for patients with microadenoma. But, for patients with large or giant prolactinomas, the treatment choice is controversial. This report focuses on long-term results of the BC effect on 10 giant prolactinomas (maximum diameter more than 40 mm and the serum PRL level more than 1000 ng/ml) with particular emphasis on cases that needed surgical intervention due to unsatisfactory results from BC therapy alone. BC was effective in 6 cases (60%). They had the serum PRL level normalized in less than one year, with BC maintenance doses between 5-15 mg/day. MRI revealed complete or nearly total disappearance of the tumor. Discontinuation of the medicine was achieved in one patient. In the remaining 4 cases, surgery was needed for various reasons: 1) BC resistant prolactinomas in 2 cases, 2) large hematomas in one of the previous cases, 3) regrowth of tumor size, despite the nearly normalized PRL level due to bulk increase in non-secretory adenomatous portion in 1 case, and 4) intolerable side effect in 1 case. BC is effective even for giant prolactinomas in 60% of cases. But, this therapy needs surgical intervention more often than microadenomas. Surgical indications and timing should be decided on based on closer follow-up of neuroimaging and visual evaluation as well as the serum PRL level.

Adult↗

PubMed1997

Hemorrhagic type moyamoya disease.

The clinical picture of hemorrhagic type Moyamoya disease was analyzed in 20 cases. Hematoma at the basal ganglia was noted in 40% of cases, intraventricular hemorrhage (IVH) in 30%, thalamic hemorrhage with ventricular rupture in 15% and subcortical hemorrhage in 5%. The location was undetermined in two cases (10%) due to bleeding in the pre-computed tomography (CT) era. The frequencies shown above were correlated well to previous reports. In magnetic resonance imaging (MRI) performed 1 year or more after IVH, the primary bleeding site was demonstrated at the lateral wall of lateral ventricle, in portion density weighted and T2 weighted images. MRI can detect the site of old bleeding points and its chronological change if the study is repeated. In a follow-up period of 6.2 years, 35% of the cases had rebleeding once or twice. The second bleeding occurred seven times and the third twice. IVH occurred five times and the most common, basal ganglia hematoma three times while thalamic hemorrhage once. As a result, the rate of good outcome was 60% after the first bleeding and 40% after rebleeding. The mortality rate was 5% after the first 25% after rebleedings. Factors related to rebleedings and their poorer outcome are sex (with women being more susceptible), massive ICH and early recurrence. Rebleeding worsened the outcome. Therefore, prevention of rebleeding is important. From a therapeutic viewpoint, although a close relation between rebleeding and untreated hypertension could not be established, blood pressure control is critical at the both acute and chronic stages. Bypass surgery for bleeding type of Moyamoya disease seems to be less promising than ischemic type, even though a definite answer may not be obtained from our small number of cases.

Adolescent↗

PubMed1997

Microsurgical anatomy and clinical significance of the anterior communicating artery and its perforating branches.

OBJECTIVE: Precise identification of the anomalous anterior communicating artery (ACoA) or the perforating branches of the ACoA is usually difficult on preoperative angiograms because of the vascular complexity around the ACoA and its small-caliber branches. The purpose of this study was to review the microsurgical anatomy of the ACoA and its branches to show their importance for the interhemispheric trans-lamina terminalis approach and ACoA aneurysmal surgery. METHODS: In 30 cadaver brains, the ACoA and its branches were examined under magnification using a surgical microscope. RESULTS: The ACoA was evident in all specimens and had variations consisting of plexiform (33%), dimple (33%), fenestration (21%), duplication (18%), string (18%), fusion (12%), median artery of the corpus callosum (6%), and azygous anterior cerebral artery (3%). The perforating branches were also observed in all cadaver brains. They were classified into subcallosal, hypothalamic, and chiasmatic branches according to their vascular territories. The subcallosal branch, usually single and the largest, supplied the bilateral subcallosal areas, branching off to the hypothalamic area. The hypothalamic branches, multiple and of small caliber, terminated in the hypothalamic area. CONCLUSION: The incidence of anomalous ACoA was higher than has been previously reported, and any segment of the anomalous ACoA may have perforating branches regardless of diameter. Among the three branches, the subcallosal branch is the most important because it feeds bilateral subcallosal areas branching to the hypothalamic area.

Aged↗

PubMed1996

Midbrain tegmental lesions affecting or sparing the pupillary fibres.

Two patients with oculomotor palsy caused by midbrain infarction are reported. In the first, pupillary reaction was affected and in the second this reaction was spared. Because the lesions in the anterior part of the tegmentum were in the upper midbrain in the first patient and in the lower midbrain in the second, it is suggested that the pupillary components of the oculomotor nerve are located in the upper midbrain.

Aged↗

PubMed1994

Three-dimensional audiogram.

We used a three-dimensional audiogram which displays duration of the disease on the X-axis, frequency on the Y-axis, and hearing level on the Z-axis, to aid observation of hearing changes during the course of various otologic diseases. An overall, quantitative view of the changes in a patient's hearing level with time was easily obtainable with this technique, as the temporal element is shown on the X-axis. The basal view position of the three-dimensional audiogram displays most of the information necessary to form a diagnosis, determine treatment, and evaluate is efficacy in various otologic diseases. The three-dimensional audiogram was found to be most useful in observing changes in hearing level in sudden deafness, with its often rapid recovery period, and Meniere's disease, with its long-term fluctuating hearing loss. In some patients, a better understanding of the hearing changes could be obtained from a view angle other than the basal view position.

Adult↗

PubMed1994

Assessment of prognosis in sudden deafness.

We investigated the usefulness of three-dimensional audiograms in assessing prognosis during the early phase in 116 patients with sudden deafness. The initiation time of improvement in middle-frequency hearing at 15 dB or more was valuable in assessing prognosis in patients with deafness and scale-out types of hearing loss. Improvement within 13 days in patients with the deafness type, and within 17 days in those with the scale-out type, was correlated with a high incidence of marked improvement or complete recovery. Patients with an initial mean hearing level below 80 dB, or in whom the glycerol test and electrocochleography results suggested the presence of endolymphatic hydrops, had a good hearing outcome. Patients without tinnitus showed an unfavorable hearing outcome.

Adult↗

PubMed1994

[Microsurgical anatomy of the anterior communicating artery and its perforating arteries important for interhemispheric trans-lamina terminalis approach: analysis based on cadaver brains].

Microsurgical anatomy of anterior communicating artery (ACoA) and its perforating arteries important for interhemispheric trans-lamina terminalis approach is examined in 25 cadaver brains under magnification using a surgical microscope. ACoA were found in all cases but 60% of those cases had variations such as plexiform ACoA, dimple ACoA, fenestrated ACoA, triple A2 and azygous ACA. In cases with variations such as plexiform ACoA, triple A2 and azygous ACA, it seems difficult to section and divide the ACoA to obtain a better operative field. Perforating arteries of ACoA were noted in all cases. They were classified into the subcallosal artery, hypothalamic artery and chiasmatic artery according to caliber, origin, course and termination. Among these three arteries, subcallosal artery is thought to be an offending artery in memory impairment, character change and psychological abnormalities, because it terminates at the bilateral subcallosal areas. We stress in this paper that the subcallosal artery is the most important perforating artery of ACoA and the incidence of variations of ACoA is higher than previously reported.

Aged↗

PubMed1992

[Oculomotor nerve palsy due to small midbrain infarct--functional topography based on MRI findings].

This is a report of 3 cases presented with oculomotor nerve palsy caused by small midbrain infarct. The aim of this report is to clarify the functional topography of intranuclear and intrafascicular portion of the oculomotor nerve with MRI. Three cases are 2 males and 1 female, ranging 51 to 68 years in age. Except for the long tract signs at the acute stage, cardinal sings were all eye-related, incomplete in 1 case and pupil sparing-type in 2 cases. In MRI, the size of the lesion extended 5 to 12 mm. In the incomplete palsy case, the infarction extended from the level immediately below the 3rd ventricle into the whole length of midbrain, whereas in the pupil-sparing types, more limited lesion excluding the upper part of the midbrain was noted. Anatomically the longitudinal size of the nucleus is 10mm and nerves functionally related to pupil reaction, eye motion and eyelid elevation are arranged in rosrocaudal order. Therefore, it is speculated that in midbrain, intrafascicular location of nerve fibers associated with pupil reaction is rostral and oculomotor nerve palsy of pupil sparing type is caused by the lesion excluding the rostral midbrain. MRI findings of the present 3 cases are compatible with this speculation. The lowest border of red nucleus is at the level of superior colliculus, whereas oculomotor nucleus has its lowest margin at the inferior colliculus. Therefore, red nucleus becomes an informative landmark to visualized the level of oculomotor nerve injury, since the red nucleus is clearly demonstrated in high intensity in T2 weighted image.

Aged↗

PubMed1991

[Simple allergen skin test device Multi skit (tentative name)].

We have developed a device tentatively named Multi Skit (Mu), a simple allergen test device, in order to conduct the skin test safely, accurately and conveniently. The utility of this device was evaluated by determining how the results obtained by the intradermal test (In) and Mu were correlated with those obtained by IgE RAST (RA) in 65 AD patients. RA values concerning nine antigens were compared to results obtained by the In and Mu in terms of the positive and negative response coincidence rates, overall coincidence rates, and false-positive and false-negative response rates. The correlation between RA data obtained from the literature and the results of the scratch test (Sc) was also evaluated. The results of In and RAST values showed no correlation regardless of the food antigen used. Mu and RAST values showed correlation with respect to all 4 food antigens except soy-bean, resulting in overall coincidence rates of 66.2 to 87.7%, which were higher than those concerning the Sc. With respect to false-positive responses to environmental antigens, the rate obtained by Mu was higher than that by the Sc, but it was lower than that by the In. However, Mu was the most excellent test with respect to the other indices, i.e., positive and negative response coincidence rates, overall coincidence rates (73.9-89.2%) and false-negative responses. The mechanism of Mu makers it possible to minimize variations from one investigator to another, and the major drawback of all other skin tests. Mu is a safe and convenient screening skin test device which provides accurate and specific test results.

Adolescent↗

PubMed1991

[Hemorrhagic type of moyamoya disease].

Clinical picture of Moya Moya Disease was analyzed in 18 cases. In 16 cases whose CT scan were available at the time of the first bleeding, hematoma at the basal ganglia was noted in 43.8%, primary ventricular hemorrhage in 37.5%, thalamic hemorrhage with ventricular rupture in 12.5% and subcortical hemorrhage in 6.3%. The frequencies shown above were well correlated to previous reports. In MRI performed 1 year or more after primary ventricular hemorrhage, the primary bleeding site was demonstrated at the lateral wall of the lateral ventricle, in proton weighted and T2 weighted images. MRI can detect the site of old bleeding points and its chronological change if the study is repeated. In a follow-up period of 5.4 years, 27.8% of the cases had rebleeding one or more times. As a result, good outcome was noted in 72.2% after the 1st bleeding, and in 55.6% after re-bleedings. Death occurred in 5.6% of patients after the 1st bleeding and in 22.2% after further rebleeding. Rebleeding worsened the outcome. Therefore, prevention of rebleeding is important. From a therapeutic viewpoint, although a direct relation between rebleeding and untreated hypertension could not be established, blood pressure control is critical at both the acute and the chronic stages. Reconstructive vascular surgery is a recommendable method for properly selected patients.

Adult↗

PubMed1990

Movement of vesicles in cytoplasmic streaming in plasmodium.

The moving velocities of vesicles in the cytoplasmic streaming of a slime mold were measured, in which all of the vesicles passing through a designated window were counted. Vesicles in the streaming are distributed in their moving velocities and the distribution itself varies with time. The mean velocity of vesicles and its standard deviation were found to exhibit a linear relationship, suggesting a possibility that vesicles in the cytoplasm would also be involved in force generation.

Cytoplasmic Streaming↗

PubMed1990

Dissecting aneurysms of the intracranial vertebral artery.

Among 86 patients with aneurysms arising from the vertebral artery or its branches, 24 had dissecting aneurysms. The patients with dissecting aneurysms were characteristically relatively young males. Twenty-one patients presented with subarachnoid hemorrhage (SAH) and three with ischemia. Severe headache or neck pain occurred in all three patients with ischemia. Five of the 21 patients with SAH and all three patients with ischemia experienced recurrent episodes. Angiography typically showed fusiform dilatation and proximal and/or distal narrowing of the affected artery. The difficulty of diagnosing this disorder is pointed out. Surgery was performed in 19 patients, the most common technique being clip-occlusion of the proximal vertebral artery. There were no postoperative deaths or rebleeding; a lateral medullary syndrome developed in three patients. The observation at surgery of intramural clot with characteristic discoloration was limited to the cases operated on within 36 days after the ictus. After this period, the aneurysm was whitish gray in color and had become firm. Of 36 other cases of vertebral dissecting aneurysm reported in the literature, 20 were operated on. The indications for surgery are discussed.

Adult↗

PubMed1990

[One and a half syndrome and MRI--a case report and functional neuroanatomy of the syndrome].

This is a case report of 63 year old men who presented one and a half syndrome with ipsilateral peripheral type facial palsy due to lacunar infarct. MRI taken one week after the onset (TR 2000, TE 38) demonstrated small high intensity lesion, 4 mm in diameter, located at the dorsal portion of pontine tegmentum, contacting with the floor of 4th ventricle. This MRI coincides with the lesion limited to the abducens nucleus and genu of facial nerve. Traditionally, projections from the PPRF to the ipsilateral abducens nucleus and opposite MLF was postulated. Recently, however, experiment on monkey and autopsy cases showed projection from abducens nucleus, instead of PPRF, to the opposite MLF has been proposed. MRI findings in this case support the latter hypothesis. It is expected that, with the advent of MRI, more meticulous functional neuroanatomy will be developed.

Dementia, Multi-Infarct↗