Biomedical subjects

N Saeki

Publications and source records attributed to N Saeki.

At least 19 recordsLinked to original sources

PubMed1999

Delayed postoperative CSF rhinorrhea of intrasellar arachnoid cyst.

CSF rhinorrhea due to a transsphenoidal approach usually follows accidental or intentional arachnoid opening. We report a patient with an intrasellar arachnoid cyst, who developed delayed onset of CSF rhinorrhea. A sixty-two-year-old man presented with bitemporal type visual field defect for the last 3 years. With the diagnosis of arachnoid cyst or Rathke's cleft cyst, based on MRI findings of intra-and supra-sellar cyst with CSF intensity, he successfully underwent transsphenoidal surgery without evidence of intra-operative CSF leakage. He developed CSF rhinorrhea one week later. This needed another operation for sellar floor repair. The pathomechanism of this delayed onset is explained as follows. Incomplete or oneway communication of subarachnoid space to cyst cavity, unrecognized during surgery, might cause delayed onset of CSF rhinorrhea. By using MRI, identification of the residual gland, which was compressed posteriorly, is useful for differentiating an arachnoid cyst from other cystic lesions. In highly suspect cases, even without evidence of intra-operative CSF leakage, peri-operative measures to prevent occurrence of postoperative CSF rhinorrhea are required.

Arachnoid Cysts↗

PubMed1999

Spontaneous disappearance of temporo-frontal arachnoid cyst in a child.

We report a child with a large temporo-frontal arachnoid cyst which resolved spontaneously. There was no history of a head injury. The patient was a boy aged 1.6 years. Though a large head was pointed out (+2SD), no therapeutic intervention was made because the relationship of the head circumference and the cyst was not established. No change in cyst size was visualized on the follow-up CTs at the age of 2.5 years and 6 years. At the age of 7 years, the arachnoid cyst had completely disappeared on CT. In order not to overlook a minute change in cyst size, the volumetry of the cyst and the intracranial cavity was performed, using the Photoshop, Macintosh. Both the cyst volume and the volume ratio of the cyst to the intracranial cavity slightly decreased and then increased. It is speculated that the cyst spontaneously ruptured by factors such as extreme breath holding and crying on the presence of the higher intracystic tension which might become a factor to accelerate spontaneous rupture of the cyst. Since a number of paediatric cases of symptomatic arachnoid cysts in need of surgical intervention has been larger than that of adult cases, we can speculate that a large arachnoid cyst might spontaneously resolve more frequently than we had expected. This case demonstrates that the surgical treatment of asymptomatic arachnoid cyst in the middle cranial fossa is not necessarily indicated in children.

Arachnoid Cysts↗

PubMed1999

Unusual cranial nerve palsy caused by cavernous sinus aneurysms. Clinical and anatomical considerations reviewed.

BACKGROUND: Two cases of intracavernous internal carotid artery aneurysm with unusual clinical findings are reported. The pathomechanism and clinical significance are discussed. CASE DESCRIPTION: The first patient was a 49-year-old woman who presented with 6th nerve palsy and Horner's syndrome caused by a posteriorly located intracavernous aneurysm. The symptoms improved gradually in proportion to the size of the aneurysm. The second patient was a 69-year-old woman with isolated oculomotor superior division palsy caused by an anteriorly located large aneurysm. CONCLUSION: In the first case, a local aneurysmal compression at both the 6th nerve and the sympathetic fibers sent from the plexus on the intracavernous internal carotid artery is the most probable explanation. In the second case, the aneurysm might have selectively compressed the superior division of the oculomotor nerve at the anterior cavernous sinus. Clinical recognition of these syndromes results in a better diagnostic orientation. The authors discuss the pertinent anatomy and pathophysiology of the lesions because these findings are rarely seen clinically or in the literature.

Abducens Nerve↗

PubMed1999

Effect of pituitary microsurgery on acromegaly complicated nephrotic syndrome with focal segmental glomerulosclerosis: report of a rare clinical case.

A case of nephrotic syndrome complicated by acromegaly is presented. The first renal biopsy specimen showed minor glomerular abnormalities with glomerular hypertrophy, corresponding with minimal change nephrotic syndrome. Corticosteroid therapy led to a partial remission, followed by frequent relapses after reduction of the drug. A diagnosis of atypical focal segmental glomerulosclerosis (FSGS) was made based on the second renal biopsy results 6 months after the first. We combined steroid therapy with the administration of an anticoagulant, cytotoxic agents, angiotensin-converting enzyme inhibitor, and low-density lipoprotein adsorption. Except for the angiotensin-converting enzyme inhibitor, these medications were not effective in terms of allowing a reduction in the high dosage of steroid, which in turn threatened progressive osteoporosis and lumbar vertebrae fracture. Administering the steroid at a moderate dosage, treatment was focused on the complicating acromegaly from pituitary microadenoma. Subcutaneous injections of octreotide acetate, a somatostatin analogue, reduced proteinuria and increased urine volume. Subsequent transsphenoidal microsurgery of the adenoma resulted in the normalization of the elevated creatinine clearance and the further reduction in steroid dosage while maintaining a remission state. This is the first reported clinical case with acromegaly followed by FSGS, and it is suggested that hypersecretion of growth hormone participates in the development and progression of glomerular disease.

Acromegaly↗

PubMed1999

Cytosolic Ca2+ movements of endothelial cells exposed to reactive oxygen intermediates: role of hydroxyl radical-mediated redox alteration of cell-membrane Ca2+ channels.

1. The mode of action of reactive oxygen intermediates in cysosolic Ca2+ movements of cultured porcine aortic endothelial cells exposed to xanthine/xanthine oxidase (X/XO) was investigated. 2. Cytosolic Ca2+ movements provoked by X/XO consisted of an initial Ca2+ release from thapsigargin-sensitive intracellular Ca2+ stores and a sustained Ca2+ influx through cell-membrane Ca2+ channels. The Ca2+ movements from both sources were inhibited by catalase, cell-membrane permeable iron chelators (o-phenanthroline and deferoxamine), a *OH scavenger (5,5-dimethyl-1-pyrroline-N-oxide), or an anion channel blocker (disodium 4, 4'-diisothiocyano-2, 2'-stilbenedisulphonic acid), suggesting that *O2- influx through anion channels was responsible for the Ca2+ movements, in which *OH generation catalyzed by intracellular transition metals (i.e., Haber-Weiss cycle) was involved. 3. After an initial Ca2+ elevation provoked by X/XO, cytosolic Ca2+ concentration decreased to a level higher than basal levels. Removal of X/XO slightly enhanced the Ca2+ decrease. Extracellular addition of sulphydryl (SH)-reducing agents, dithiothreitol or glutathione, after the removal of X/XO accelerated the decrement. A Ca2+ channel blocker, Ni2+, abolished the sustained increase in Ca2+, suggesting that Ca2+ influx through cell-membrane Ca2+ channels was extracellularly regulated by the redox state of SH-groups. 4. The X/XO-provoked change in cellular respiration was inhibited by Ni2+ or dithiothreitol as well as inhibitors of Haber-Weiss cycle, suggesting that Ca2+ influx was responsible for *OH-mediated cytotoxicity. We concluded that intracellular *OH generation was involved in the Ca2+ movements in endothelial cells exposed to X/XO. Cytosolic Ca2+ elevation was partly responsible for the oxidants-mediated cytotoxicity.

Animals↗

PubMed1999

Collapsibility of passive pharynx in patients with acromegaly.

Sleep-disordered breathing (SDB), either central or obstructive in nature, is common in patients with acromegaly. However, no study has systematically examined the collapsibility of the pharynx in acromegaly to date. We evaluated intrinsic mechanical properties of passive pharynx in 10 anesthetized and paralyzed patients with active acromegaly before transsphenoidal adenomectomy for their pituitary adenoma. Static pressure-area relationships of the velopharynx and oropharynx were obtained by step changes in airway pressure during endoscopic cross-sectional area measurement of each segment. Moreover, curve fitting analysis by an exponential function estimated the closing pressure (P'close) of each segment. Preoperative nocturnal oximetry identified five acromegalic patients with an oxygen desaturation index (ODI) greater than 10 h-1 and clinical symptoms suggesting presence of SDB. The pharyngeal airway of all five acromegalic patients with SDB was highly collapsible at both velopharynx and oropharynx with positive P'close. Compared with age-, body mass index (BMI)-, and ODI-matched SDB patients without acromegaly, SDB patients with acromegaly had a higher P'close of the oropharynx, indicating that the etiology of SDB in acromegaly appears to differ from that of ordinary sleep apnea. Our results suggest that anatomic abnormality, especially at the base of the tongue, appears to play a significant role in development of SDB in acromegaly.

Acromegaly↗

PubMed1999

MRI detection of suprasellar germinoma causing central diabetes insipidus.

This is a case report of an 18-year-old man with central diabetes incipidus (DI). An MRI done three months after the onset of the DI did not disclose a responsible lesion. Four months later, a second MRI showed the location of the tumor origin at the upper pituitary stalk and median eminence. Eight months later, the tumor occupied the hypothalamic area. The tumor became large and contrast-making enough to be visible on MRI between 3 and 4 months after the onst of DI. Besides the suprasellar tumor, another mass was noted in the pineal region. The growth pattern of the latter mass corresponded well to that of the former. Although the MRI is a sensitive diagnostic tool for the detection of intracranial tumors, no adequate rationale has been given as to how the MRI might be repeated for children and adolescents who have been diagnosed as having the central DI, when their initial MRIs may have been normal. In our patient, the superconductive thin slice MRI revealed the suprasellar germinoma 4 months after the onset. The suprasellar and pineal tumors in this report originated and developed simultaneously. This may indicate a multi-center origin of the tumor. Another possibility is a very early dissemination from the onset of the tumor development.

Adolescent↗

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↗

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

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↗