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Biomedical subjects

A Hakuba

Publications and source records attributed to A Hakuba.

At least 37 records · Page 2Linked to original sources
PubMed1998

Occlusion of the sigmoid sinus after surgery via the presigmoidal-transpetrosal approach.

OBJECT: In this paper the authors report on sigmoid sinus occlusion as a surgical complication in seven of 143 operations in which a presigmoidal-transpetrosal approach was used. METHODS: Five patients (Cases 1-5) developed occlusion within 40 days after surgery, and in the remaining two (Cases 6 and 7) occlusion was detected 5.4 and 6.4 years postsurgery by means of cerebral venography, which was performed in 40 of the remaining 138 patients. Of the two patients with occlusion of the hypoplastic transverse sinus, one (Case 1) did not develop symptoms and the other (Case 2) developed brain edema with transient aphasia. Of the three patients suffering from occlusion of the dominant sigmoid sinus, one (Case 3) developed severe intracerebral hemorrhages and had a poor prognosis; one (Case 4) developed profuse supra- and infratentorial brain edema with consciousness disturbance; and the other (Case 5) developed hemorrhagic infarction in the temporal lobe accompanied by aphasia. Two patients whose sinus occlusion was detected later (Cases 6 and 7) did not develop symptoms and displayed well-communicated transverse sinuses. In Case 7, a dural arteriovenous malformation formed at the site of the sinus occlusion. Laceration of the sigmoid sinus was suspected as the cause of occlusion in Cases 2, 3, and 7; compression of the sinus in Cases 5 and 6, sinus laceration and postoperative dehydration in Case 4; and laceration and compression of the sinus in Case 1. CONCLUSIONS: Differences in the clinical course among these patients were attributed to anatomical variations in the venous system. Occlusion of the sigmoid sinus should be weighed as a potential complication when selecting candidates for the presigmoidal-transpetrosal approach.

Adolescent↗
PubMed1998

Identifying mRNAs involved potentially in corticopontine projection by modified differential display.

The basilar pons plays an important role in the establishment of the corticopontine projection by releasing a diffusible molecule which induces and directs collateral branchings along the corticospinal axon shafts. To reveal the molecule which is involved in the developing process of the corticopontine projection, we attempted to modify the mRNA differential display to search for genes expressed differentially in the basilar pons during the formation of the corticopontine projection by introducing the RGD motif (arginine-glycine-asparate) in the primers of the polymerase chain reaction. With our modification, we were able to identify 99 mRNAs expressed in the basilar pons but not in the cerebral cortex where the apparent pontine-derived activity is not observed. Among these 99 gene fragments, 3 novel fragments could be selected as final candidates of the pontine-derived molecule based on their expression patterns. Modified differential display is thus a promising method for identification of these genes.

Animals↗
PubMed1997

A new model of spinal cord edema.

Edema of the spinal cord has not been well understood. Brain edema produced by Marmarou's infusion method is essentially similar to vasogenic edema. This infusion method for producing edema was applied to a cat spinal cord. After laminectomy, a 30-gauge needle was inserted into the intumescentia cervicalis. A total amount of 10 microliters of 2% Evans' blue or autoserum were infused using an infusion pump at a rate of 5 microliters/hr. Macroscopally, Evans' blue was observed in the vicinity of infused site at the same level of the needle insertion and was seen spreading mainly longitudinally in the lateral column for a certain distance. The extracellular space was markedly distended in the in fused white mater and filled with electron-dense materials which were thought to be proteins in the electron microscopic study. The fine structural features were similar to the findings which were seen in Marmarou's infusion type of brain edema. Using this model, it seems to be feasible to produce reproducible spinal cord edema at any location in order to investigate not only the morphological aspect but also physiological aspect of the edema.

Animals↗
PubMed1997

Intramedullary spinal cord tumour associated with neurofibromatosis type 1.

We investigated the characteristic features of intramedullary spinal cord tumour associated with neurofibromatosis type 1 (NF-1). We have experienced 44 cases of pathologically confirmed intramedullary spinal cord tumour. Diagnosis of NF-1 was done according to the criteria set by the National Institute of Health Consensus Development Conference. Within the described population NF-1 was diagnosed in two patients. Both the patients were male and histopathologically the tumours were anaplastic astrocytoma and glioblastoma multiforme respectively. 6 cases of NF-1 associated with intramedullary spinal cord tumour based on the above diagnostic criteria have so far been reported, including our 2 cases. Of these 6 cases, 5 were male and in one sex was not described. The tumour was an astrocytoma in all 6 cases. This finding suggested that intramedullary spinal cord tumour associated with NF-1 tends to occur predominantly in males and that histopathologically the tumour is likely to be an astrocytoma. We conclude that the criteria proposed by the National Institute of Health Consensus Development Conference are contributory in making an accurate pre-operative pathological diagnosis of intramedullary spinal cord tumour associated with NF-1.

Adolescent↗
PubMed1997

Pathogenesis of Chiari malformation: a morphometric study of the posterior cranial fossa.

To investigate overcrowding in the posterior cranial fossa as the pathogenesis of adult-type Chiari malformation, the authors studied the morphology of the brainstem and cerebellum within the posterior cranial fossa (neural structures consisting of the midbrain, pons, cerebellum, and medulla oblongata) as well as the base of the skull while taking into consideration their embryological development. Thirty patients with Chiari malformation and 50 normal control subjects were prospectively studied using neuroimaging. To estimate overcrowding, the authors used a "volume ratio" in which volume of the posterior fossa brain (consisting of the midbrain, pons, cerebellum, and medulla oblongata within the posterior cranial fossa) was placed in a ratio with the volume of the posterior fossa cranium encircled by bony and tentorial structures. Compared to the control group, in the Chiari group there was a significantly larger volume ratio, the two occipital enchondral parts (the exocciput and supraocciput) were significantly smaller, and the tentorium was pronouncedly steeper. There was no significant difference in the posterior fossa brain volume or in the axial lengths of the hindbrain (the brainstem and cerebellum). In six patients with basilar invagination the medulla oblongata was herniated, all three occipital enchondral parts (the basiocciput, exocciput, and supraocciput) were significantly smaller than in the control group, and the volume ratio was significantly larger than that in the Chiari group without basilar invagination. These results suggest that in adult-type Chiari malformation an underdeveloped occipital bone, possibly due to underdevelopment of the occipital somite originating from the paraxial mesoderm, induces overcrowding in the posterior cranial fossa, which contains the normally developed hindbrain. Basilar invagination is associated with a more severe downward herniation of the hindbrain due to the more severely underdeveloped occipital enchondrium, which further exacerbates overcrowding of the posterior cranial fossa.

Adolescent↗
PubMed1997

A biorbitofrontobasal interhemispheric approach for suprasellar lesions.

Suprasellar tumors including pituitary adenomas and craniopharyngiomas, in the case of normofixed or postfixed chiasma and ruptured anterior communicating artery aneurysms in the acute stage, can be approached with minimum brain retraction, increased exposure, and safe manipulation in the shortest possible distance via biorbitofrontobasal interhemispheric approach. Fourteen patients with pituitary adenomas, 3 with craniopharyngiomas, 7 with meningiomas, 2 with mucoceles, 1 with osteoma, and 3 with ruptured anterior communicating aneurysms in the acute stage were operated on, using this approach with excellent results. The operative technique and its results are detailed.

Brain Neoplasms↗
PubMed1997

Direct extracranial-intracranial bypass for children with moyamoya disease.

To improve cerebral hypoperfusion in the ischemic type of Moyamoya disease, we have applied superficial temporal artery-middle cerebral artery (STA-MCA) double anastomoses in combination with encephalo-myo-synangiosis (EMS) for 19 hemispheres of 10 children (age from 5 to 11 years at surgery). Two branches of the STA were anastomosed to the two cortical arteries which were selected in the watershed area of the cerebral hemisphere estimated as a hypoperfusion area on the preoperative angiograms. Before surgery transient ischemic attacks (TIAs) developed from every month to every 6 months in association with hyperventilation or sobbing. No perioperative completed stroke or wound complications was observed, although single TIA developed in four patients within 1 month after surgery. Postoperative angiogram demonstrated that, not only the preoperative watershed area, but also the most of the middle cerebral artery territory was oppacified via the 2 branches of the STA in all 19 hemispheres. In a mean follow-up period of 4 years, no ischemic episode was induced by hyperventilation, and there was no mental or neurological deterioration. STA-MCA double anastomoses, to the cerebral watershed area, in combination with EMS are safe and effective even for younger children with Moyamoya disease.

Anastomosis, Surgical↗
PubMed1996

[A case of middle cerebral artery occlusion caused by dissecting aneurysm].

We reported a case of middle cerebral artery occlusion caused by a dissecting aneurysm that was successfully treated by intra-arterial fibrinolysis. A 38-year-old man suddenly developed left hemiparesis and became confused. He was transferred to our hospital one hour and 27 minutes after the ictus. Right carotid angiogram (CAG) revealed aneurysmal dilatation of the horizontal portion of the middle cerebral artery and occlusion of the anterior trunk. Twelve million IU of tissue plasminogen activator was injected to fibrinolyze the thrombus of the occlusion site through a microcatheter. After this, the patient became alert and hemiparesis disappeared. It took three hours and 30 minutes to gain recanalization after the ictus. Right CAG obtained the next day demonstrated the patency of the anterior trunk and the characteristic finding of the dissecting aneurysm viz "double lumen" as a result of fibrinolysis of the thrombus in the false lumen. Right CAG obtained two weeks later demonstrated "string and pearl sign" instead of the "double lumen" as a result of partial thrombosis in the false lumen. Follow-up CAG obtained nine months after the ictus demonstrated marked reduction of the aneurysmal size as the result of progressing thrombosis of the false lumen. The characteristic angiographic findings of the dissecting aneurysm such as "double lumen" and "string and pearl sign" seemed to be mostly influenced by the status of the thrombus in the false lumen. In case of major cerebral arterial occlusion caused by the embolus or thrombus from the dissecting aneurysm, intra-arterial fibrinolysis seems to be a possible treatment modality, even though it is accompanied by the risk of giving rise to subarachnoid hemorrhage.

Adult↗
PubMed1995

Proliferative potential of meningiomas evaluated by proliferating cell nuclear antigen expression.

Meningiomas are principally benign in nature. Some meningiomas, however, grow fast or recur even after total removal. The biological behavior of meningiomas often can not be predicted from conventional histopathological studies. A monoclonal antibody against proliferating cell nuclear antigen (PCNA) was used to investigate the usefulness of the PCNA index as a parameter to estimate the proliferative activity of meningiomas. Fifty-two meningiomas were examined. The mean PCNA index of recurrent meningiomas (3.37 +/- 0.92%) was significantly higher than that of non-recurrent meningiomas (1.12 +/- 0.51%) (p < 0.005). The PCNA indices of recurrent cases were all higher than 2.0%. A semilog linear regression analysis between tumor doubling time and PCNA index showed a significant correlation (r = 0.90, p < 0.05). An inverse linear correlation between PCNA index and interval to recurrence was observed (r = 0.62, p < 0.05). A good linear correlation was also shown between PCNA index and BUdR labeling index (r = 0.88, p < 0.01). The results of this study suggest that, providing the methods of tissue processing, immunostaining and counting of positive nuclei are unified, the PCNA index is a useful parameter for estimating the biological behavior of meningiomas.

Adult↗
PubMed1995

Variation in equation coefficients in the gravimetric method to determine brain water content.

The gravimetric method to determine the tissue water content is widely used for studying brain edema because the tissue water content can be calculated from only the density of the wet tissue using a gradient column. This method has been used in only a few studies of cerebellar water content. We estimated the water content of the cerebellar cortex by the gravimetric method and compared the results with those measured by the conventional drying-weighing method, and found a significant difference. We therefore propose modified coefficients for the equation for the water content of the cerebellar cortex as follows: % tissue water content = 456.13(1/wet tissue density) - 356.13 This equation and the drying-weighing method were used to investigate normal and edematous cerebellar cortices after compression with an epidural balloon. The modified equation provided results consistent with the drying-weighing method. Differences in the total experimental system including the breed and pre-experimental condition of the cats may be factors in variations in measured values. We recommend that investigators establish equation coefficients valid for individual experimental systems.

Animals↗
PubMed1995

The microsurgical anatomy of the jugular foramen.

The microsurgical anatomy of the jugular foramen was studied in 10 fixed cadavers, each cadaver consisting of the whole head and neck. Five of the cadavers were injected with latex. The jugular foraminal region was exposed using the infratemporal fossa type A approach of Fisch and Pillsbury in five cadavers (10 sides) and the combined cervical dissection-mastoidectomy-suboccipital craniectomy approach in five cadavers (10 sides). The right foramen was larger than the left in seven cases (70%), equal in two cases (20%), and smaller in one case (10%). The dura covering the intracranial portal of the foramen had two perforations, a smaller anteromedial perforation through which passed the ninth cranial nerve (CN IX), and a larger posterolateral perforation, through which passed the 10th and 11th cranial nerves (CNs X and XI) and the distal sigmoid sinus. The perforations were separated by a fibrous septum in 16 specimens (80%). After exiting the posterior fossa, CNs IX, X, and XI all lay anteromedial to the superior jugular bulb (SJB) within the jugular foramen. The inferior petrosal sinus (IPS) entered the foramen between CNs IX and X in most cases; however, in 10% of our cases it entered the foramen between CNs X and XI, and in 10% it entered the foramen caudal to CN XI. The IPS terminated in the SJB in 90% of our cases; in 40%, the IPS termination consisted of multiple channels draining into both the SJB and internal jugular vein. This study shows that the arrangement of the neurovascular structures within the jugular foramen does not conform to the hitherto widely accepted notion of discrete compartmentalization into an anteromedial pars nervosa containing CN IX and the IPS and a posterolateral pars venosa containing the SJB, CNs X and XI, and the posterior meningeal artery.

Accessory Nerve↗
PubMed1995

Central giant cell granuloma of the temporal bone.

We present two cases of central giant cell granuloma in the temporal bone. CT showed an enhancing tumor causing a smoothly margined temporal squamosa and floor of the middle fossa. External carotid angiograms showed tumor stain mainly supplied by the temporal branches of the internal maxillary artery. In one case, MR images showed a hypointense mass on both T1- and T2-weighted images that was thought to reflect the pathologic character of this lesion.

Adult↗
PubMed1995

[A case report of dural sinus thrombosis: direct thrombolytic therapy using endovascular surgery].

Dural sinus thrombosis, a relatively rare disease, is difficult to diagnose because of variable symptomatic manifestations. We successfully treated a case of dural sinus thrombosis by direct thrombolysis using an endovascular technique in combination with postoperative anticoagulant therapy. The patient, a 19-year-old female, developed a headache affecting her whole head on December 13, 1993. She was admitted to our hospital the next day. Neurological examination upon admission revealed no neurological abnormalities, nor was there any abnormality in CT scan, either plain or enhanced, taken on the day of admission. The patient's consciousness deteriorated in the early morning of December 22. MRI and cerebral angiography revealed thrombi from the confluence of the sinuses to the right transverse and sigmoid sinus, with disturbed circulation through deep cerebral veins. Systemic thrombolytics, steroid and mannitol were started, but, on the next day, the third ventricle was compressed by bilateral swelling of the basal ganglia, with hydrocephalus. Since her consciousness deteriorated further despite ventricular drainage and barbiturate therapy, direct thrombolytic therapy was performed on December 25. A catheter was placed in the superior sagittal sinus, and 600,000 units of urokinase was locally injected, followed by postoperative anticoagulant therapy. The patient's condition improved rapidly. On CT scan, the bilateral swelling of the basal ganglia disappeared along with the hydrocephalus. At about 1 month after endovascular surgery, MRI and cerebral angiography revealed recanalization of the deep cerebral veins, straight sinus and confluence of sinuses with improved opacification of the left transverse sinus, although the right transverse sinus was found to be re-occluded.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Intradural chordoma: case report and review of the literature.

Chordomas are rare neoplasms arising from notochordal remnants found predominantly in the clivus and the sacrococcygeal regions. Most clivus chordomas show extradural extension and bone destruction. Such a tumour can rarely be intradural. This report is concerned with the radiological findings in prepontine intradural chordoma.

Brain Neoplasms↗
PubMed1994

Measurements of the skull base for transpetrosal surgery.

To understand the anatomy and the surgical approaches to the petrous, 19 adult human skulls (38 specimens) were studied. The foramen spinosum, groove for greater petrosal nerve, superior and posterior margins of the internal auditory meatus, fissure for the endolymphatic sac, and anterior margin of the groove for sigmoid sinus were the constant, easily identifiable bony landmarks located strategically; they served as guides during the transpetrosal approach. Measurements between various points helped both to understand the local anatomy better and to decide the degree and direction of safe bony removal during transpetrosal surgery.

Adult↗
PubMed1994

Cerebrospinal fluid edema associated with shunt obstruction.

The authors report four hydrocephalic children with cerebrospinal fluid (CSF) edema extending along the ventricular catheter of an obstructed CSF shunt. Three of the patients exhibited massive CSF edema along the ventricular catheter, yet they manifested neither ventricular enlargement nor apparent periventricular CSF edema despite increased intraventricular pressure. These findings suggested ventricular tautness. The remaining patient, who had dilated ventricles with periventricular CSF edema, displayed CSF edema in a limited area along the ventricular catheter. Replacement of the obstructed peritoneal catheter of the shunt resulted in rapid improvement of the edema in all patients. In the three patients with massive CSF edema, however, a small lesion remained in the subcortical white matter along the ventricular catheter as demonstrated by computerized tomography and/or magnetic resonance imaging 3 to 5 years after shunt revision. It is concluded that shunt obstruction may result in massive CSF edema along the ventricular catheter in hydrocephalic children who have ventricular tautness after installation of the shunt causing irreversible although usually asymptomatic damage to the affected area of the brain.

Adult↗