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Biomedical subjects

R Shirane

Publications and source records attributed to R Shirane.

At least 37 records · Page 2Linked to original sources
PubMed2001

Surgical treatment of posterior fossa tumors via the occipital transtentorial approach: evaluation of operative safety and results in 14 patients with anterosuperior cerebellar tumors.

OBJECT: To determine the safety and usefulness of performing surgery via the occipital transtentorial approach to treat anterosuperior cerebellar tumors, evaluation of 14 patients was performed over a 5-year period. METHODS: The study was performed in 14 patients, aged 6 months to 71 years, who harbored anterosuperior cerebellar tumors of the posterior fossa including four hemangioblastomas, three cerebellar astrocytomas, three medulloblastomas, two metastatic tumors, one recurrent astrocytoma, and one rhabdoid cell tumor. All patients underwent surgical treatment by the same surgical team and via the same surgical approach. Endoscopy combined with neuronavigation was used for large, deep-seated tumors extending to the fourth ventricle. Of the 14 patients, total or gross-total removal was achieved in 12 patients and subtotal removal in two patients. There was no incidence of mortality or morbidity in the 14 patients, and all functional outcomes were good to excellent postoperatively. Postoperative magnetic resonance imaging revealed that none of the patients had suffered brain damage or infarction around the cerebellum, brainstem, or occipital lobe. CONCLUSIONS: Although this study was the first in which a specific examination of the efficacy of the occipital transtentorial approach in patients with anterosuperior cerebellar tumors was undertaken, our findings suggest that this surgical approach is very useful, safe, and accurate for removing the primary tumor and evaluating the surrounding anatomy, as well as for determining operative strategy.

Adolescent↗
PubMed2001

[Primary aldosteronism presented with intracranial hemorrhage].

Although primary aldosteronism (PA) has been reported as a relatively benign form of hypertension and is associated with low incidence of vascular complications, recent reports indicate that PA complicated by cerebral vascular accidents is not rare. The authors reported here that a 57-year-old man was diagnosed as a case of PA 4 years after initial treatment of intracerebral hemorrhage (ICH) and hypertension. The patient was transferred to our department for further management of his left hemiplegia and hypertension after surgical treatment for a putaminal ICH at the age of 53. During the first 2 years of follow-up, he did well except for an episode of transient motor weakness. Diastolic hypertension was moderately good, controlled by calcium antagonists and ACE inhibitors. Laboratory data was normal, and the serum potassium levels were in the lower limits of normal. In the last 2 years, episodes of motor weakness have increased. He was admitted to our hospital, under the suspicion of recurrent Todd's paralysis. The serum potassium level ranged from 1.9 to 2.1 despite administration of potassium agents. Abdominal CT scans and 131 I-scintigraphy disclosed a left adrenal tumor. Elevation of plasma aldosterone and suppression of plasma renin were observed. The diagnosis of PA due to hypersecretion of aldosterone from an adrenal tumor was thus confirmed. We performed a total left adrenectomy 4 weeks after his admission. Histological examination showed a clear-cell type of benign adrenal adenoma. After the operation, laboratory data were normal and ACE inhibitors were able to normalize his diastolic hypertension. According to the literature, PA complicated by ICH is associated with a high rate of recurrence of cerebral vascular accidents if treatment of PA is not performed. Although diagnosis of PA in the early stage is difficult, as it was in our presented case, high suspicion of PA is essential for patients with diastolic hypertension and persistent hypopotassiumemia, particularly in young adults and middle-aged patients.

Adenoma↗
PubMed2000

Endovascular treatment of aneurysms associated with cerebral arteriovenous malformations: experiences after the introduction of Guglielmi detachable coils.

The authors have treated 172 patients with arteriovenous malformation (AVM) since 1993. Among them, 25 patients had aneurysms with a total number of 43. The aneurysms were divided into four groups; proper feeder aneurysm (4), flow-related distal aneurysm (beyond the circle of Willis or M1, 7), flow-related proximal aneurysm (26) and remote aneurysm (6). Guglielmi detachable coil (GDC) embolisation was performed in 12 patients with 15 aneurysms. Gamma knife radiosurgery for AVM was performed in 10 of those 12 patients. Two of the proper feeder aneurysms were embolised with liquid material, together with the corresponding part of the AVM. The other aneurysms were treated surgically (14) or observed (12). There was no bleeding from aneurysms after treatment. In conclusion, GDC embolisation is a useful treatment for aneurysms associated with AVM, especially if the AVM is treated by radiosurgery. Liquid embolisation of a proper feeder aneurysm is one of the treatment options. Ltd.

Adult↗
PubMed2000

Effects of an agent inducing dominant lethals on rat sperm--examination with ethyl methanesulfonate.

Ethyl methanesulfonate (EMS), an alkylating agent which induces dominant lethals, was administered in oral doses of 100 mg/kg to Crj:CD(SD)IGS male rats for 5 consecutive days. At the termination of treatment and after a 28-day withdrawal, mating with untreated females and sperm analysis (motion, number, and morphology) were performed. The copulated females were sacrificed at 20 days of gestation. At the termination of treatment, no clinical signs related to EMS were observed except for a decrease in body weight. Gross pathology and sperm analysis revealed no abnormalities in treated males. However, females mated at the termination of treatment had a clearly higher fetal mortality. Females mated after the 28-day withdrawal exhibited lower fetal mortality than females mated at the termination of treatment. On the other hand, females mated after the 28-day withdrawal exhibited a lower implantation rate that was not observed in females mated at the termination of treatment. For males after a 28-day withdrawal, sperm analysis revealed both a decrease in sperm motion and number and an increase in morphological change. These findings indicate that two types of male reproductive toxicity induced by EMS can be distinguished. One induces a low implantation rate that can be detected by sperm analysis, while the other induces fetal lethals that could not be detected by sperm analysis in this study.

Animals↗
PubMed2000

Congenital primary cerebral angiosarcoma. Case report.

Reports of angiosarcoma arising in the central nervous system are rare. The authors present the case of a 30-day-old infant with clinical manifestations of projectile vomiting and tense anterior fontanelle resulting from a left frontotemporal tumor. Total excision of this highly vascular, well-circumscribed tumor was performed without incident, and histopathological examination revealed a malignant angiosarcoma. Immunohistochemical reaction of the neoplastic cells was diffusely positive for endothelium-specific antigens including factor VIII-related antigen, CD31, and CD34. The final diagnosis of congenital primary cerebral angiosarcoma was thus confirmed. The patient's postoperative course was uneventful, and he was discharged 2 weeks after the operation. He was in good condition with no sign of recurrence after 11 months; follow-up computerized tomography, magnetic resonance (MR) imaging, and abdominal ultrasonography studies demonstrated no tumor regrowth. The characteristic findings for this tumor on MR imaging, the immunohistochemical findings, and surgical outcome are discussed.

Biomarkers, Tumor↗
PubMed2000

Cerebral circulation and metabolism in the acute stage of subarachnoid hemorrhage.

OBJECT: The mechanism of reduction of cerebral circulation and metabolism in patients in the acute stage of aneurysmal subarachnoid hemorrhage (SAH) has not yet been fully clarified. The goal of this study was to elucidate this mechanism further. METHODS: The authors estimated cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), O2 extraction fraction (OEF), and cerebral blood volume (CBV) preoperatively in eight patients with aneurysmal SAH (one man and seven women, mean age 63.5 years) within 40 hours of onset by using positron emission tomography (PET). The patients' CBF, CMRO2, and CBF/CBV were significantly lower than those in normal control volunteers. However, OEF and CBV did not differ significantly from those in control volunteers. The significant decrease in CBF/CBV, which indicates reduced cerebral perfusion pressure, was believed to be caused by impaired cerebral circulation due to elevated intracranial pressure (ICP) after rupture of the aneurysm. In two of the eight patients, uncoupling between CBF and CMRO2 was shown, strongly suggesting the presence of cerebral ischemia. CONCLUSIONS: The initial reduction in CBF due to elevated ICP, followed by reduction in CMRO, at the time of aneurysm rupture may play a role in the disturbance of CBF and cerebral metabolism in the acute stage of aneurysmal SAH.

Acute Disease↗
PubMed2000

[Spinal dermoid cyst secondary to myelomeningocele repair: a case report].

Dermoid and epidermoid tumors arise from the invagination of epidermal elements into the neural tube during the embryonic period. However, many studies have reported that dermoid and epidermoid tumors occur 5 to 10 years after the first operation on myelomeningocele patients. A seven-year-old male with myelomeningocele which had been repaired in his neonatal period, presented leg pain and deterioration of gait disturbance and urinary incontinence. Neuroradiological examinations revealed a spinal dermoid cyst at the repaired myelomeningocele and tethered spinal cord. We removed the tumor and untethered the tethered spinal cord. Postoperatively, the patient's leg pain, gait disturbance and urinary incontinence improved immediately. Inappropriate surgical treatment of spina bifida may cause a second lesion, which leads to tethered-cord syndrome. We suggest that proper surgical treatment, early checkup and neuroradiological evaluations are very important for spina bifida patients who show signs of neurological deterioration. For the best treatment, neurological, urological and orthopedical follow-up study after the first repair operation is necessary.

Child↗
PubMed2000

Correlation between choline level measured by proton MR spectroscopy and Ki-67 labeling index in gliomas.

BACKGROUND AND PURPOSE: The clinical relevance of proton MR spectroscopy needs further clarification as to its usefulness and limitations. The purpose of this study was to investigate the correlation between the semiquantitative choline-containing compound level (Cho value) measured by MR spectroscopy and the Ki-67 labeling index in gliomas. METHODS: Localized proton spectra were obtained in 26 consecutive patients with glioma who subsequently underwent surgery for tumor removal. Metabolic values in the spectra were measured semiquantitatively using an external standard of reference. The Ki-67 labeling index was measured in the surgical specimen. Because the semiquantitative metabolic values may be affected by tissue components included in the spectroscopic voxel, the MR imaging appearance of the voxel within the tumor was classed as homogeneous or heterogeneous through visual evaluation of the presence of necrosis, cyst, hemorrhage, and calcification, and pattern of enhancement. RESULTS: We found a strong linear correlation between the Cho value and the Ki-67 labeling index in the 18 homogeneous gliomas, but no correlation was found in the eight heterogeneous gliomas, which turned out to be malignant. CONCLUSION: The semiquantitative Cho value is a reliable predictor of proliferative activity of gliomas when the tumor appears homogeneous on MR images.

Adult↗
PubMed1999

Cerebral blood-flow responses to induced hypotension and to CO2 inhalation in patients with major cerebral artery occlusive disease: a positron-emission tomography study.

Our aim was to study the relationship between cerebral blood flow (CBF) responses to induced hypotension and to CO2 inhalation in patients with occlusive disease of the carotid or middle cerebral arteries. In 13 patients (8 men, 5 women) aged 31-73 years (mean +/- 1 SD = 63.2 +/- 10.6), regional CBF values during the resting state (CBFrest), 7% CO2 inhalation (CBFhypercapnia), and hypotension induced by 10-20 microg/kg/min intravenous trimethaphan (CBFhypotension) were measured using positron-emission tomography (PET) with H2(15)O. The % CBF change during induced hypotension (% CBFhypotension) was defined as (CBFhypotension - CBFrest)/CBFrest multiplied by 100. The % CBF change during CO2 inhalation (% CBFhypercapnia) was defined as (CBFhypercapnia - CBFrest)/CBFrest/mm Hg arterial partial pressure of CO2 x 100. We defined symptomatic hemispheres as those with a stenotic or occlusive lesion with neurological symptoms or signs and asymptomatic hemispheres as those which had a similar lesion and/or were influenced by the collateral flow pattern without neurological symptoms. In the territory of the occlusive lesion, % CBFhypotension correlated significantly with % CBFhypercapnia (r = 0.793, P < 0.002) in the symptomatic hemispheres. In the brain regions in which trimethaphan did not induce a reduction in CBF. % CBFhypercapnia was 6.13 +/- 1.79. In those in which % CBFhypotension ranged from 0 to -5, from -5 to -10, and more than -10%, % CBFhypercapnia was 4.05 +/- 1.99, 3.21 +/- 1.17, and 1.73 +/- 1.61, respectively, with significant differences between each pair of groups. In the asymptomatic hemispheres, % CBFhypotension also correlated with % CBFhypercapnia (r = 0.979, P < 0.0001). Failure to maintain CBF during induced hypotension was associated with diminished cerebrovascular vasoreactivity to hypercapnia in patients with arterial disease. This may indicate that failure of autoregulation can be assessed by the CBF response to both induced hypotension and CO2 inhalation. From the technical point of view, estimation of the CO2 response may be useful for assessing failure of autoregulation.

Administration, Inhalation↗
PubMed1999

Anterior sacral meningocele completely occupied by an epidermoid tumor.

A 2-year-old girl presented with an anterior sacral meningocele completely occupied by an epidermoid tumor. Preoperative magnetic resonance imaging had shown the meningocele with contents of the same intensity as cerebrospinal fluid. Surgery via a posterior sacral approach disclosed the tumor beneath an unexpected membrane inside the meningocele. Additionally, the presence of pus inside epidermoid tumor suggested that possible episodes of asymptomatic meningitis or other infection might have occurred before treatment, these being the major complication in anterior sacral meningocele. Therefore, we recommend that surgical treatment should be performed at the earliest possible stage in childhood, once the diagnosis is established, and dural plasty carried out to prevent infectious complications.

Child, Preschool↗
PubMed1999

Surgical treatment of pineal region tumours through the occipital transtentorial approach: evaluation of the effectiveness of intra-operative micro-endoscopy combined with neuronavigation.

OBJECT: To determine the efficacy and accuracy of surgically-assisted systems including endoscopy combined with neuronavigation in the treatment of pineal region tumours through the occipital transtentorial approach, an evaluation of thirty-one patients undergoing surgery was performed over a 10-year period. METHOD: The study was performed in 2 parts. The surgical approach to the pineal region was the same in the two parts, but in part 2 a smaller craniotomy window was used. Part 1 (from March 1989 to March 1997) included 15 patients who underwent surgical removal of pineal region tumours without using assisted systems; four out of the fifteen patients had surgery-related complications, including seizure and hemianopsia. Part 2 (from April 1997 to February 1999) included 16 patients who underwent surgical treatment by the same surgical team and with assisted systems; all 16 patients had excellent outcomes, with no complications. CONCLUSIONS: Although this study was the first specifically to examine the efficacy of endoscopy combined with neuronavigation in the treatment of pineal region tumours, our findings suggest that these systems are very useful, safe, and accurate in evaluating the primary tumour and surrounding anatomy as well as in determining operative strategy, such as the location and size of the scalp incision, craniotomy, and the extent of surgical removal. Therefore, we conclude that the addition of endoscopy combined with neuronavigation to standard surgical procedures can improve the outcome of surgical treatment of pineal region tumours.

Adolescent↗
PubMed1999

Evaluation of neuronal loss in adult moyamoya disease by 123I-iomazenil SPECT.

BACKGROUND: Central benzodiazepine (BZD) receptor imaging is effective to evaluate neuron density in the pathological brain cortex. This study used BZD receptor imaging to evaluate neuronal damage in adult ischemic moyamoya disease. METHODS: Single photon emission computed tomography and a novel tracer, 123I-iomazenil, were used to measure BZD receptor density in the brain. Evaluation of early and late images was performed in three asymptomatic, unoperated patients, and six mildly symptomatic, operated patients. RESULTS: Uptakes in the frontal, parietal, and occipital lobes of symptomatic patients were significantly lower (p<0.05) than those of asymptomatic patients. The late image/ early image count ratios (L/E ratios) of asymptomatic patients were relatively constant (mean, 0.571; range, 0.550-0.581) in all regions of interest. In contrast, the L/E ratios of symptomatic patients were not uniform. CONCLUSIONS: The neuron density was preserved in adult asymptomatic patients despite harboring moyamoya disease. In contrast, the neuronal density was decreased in symptomatic patients even though their symptoms were mild and they had undergone revascularization.

Adolescent↗
PubMed1999

Non-anastomotic bypass surgery for childhood moyamoya disease using dural pedicle insertion over the brain surface combined with encephalogaleomyosynangiosis.

BACKGROUND: Anastomotic bypass surgery for childhood moyamoya disease provides more rapid improvement of blood circulation than indirect non-anastomotic bypass surgery, but there are several problems, such as the technical difficulty of the operation, the extended period of anesthesia, and temporary occlusion of blood flow in the vessels of the brain surface. METHODS: We describe a new non-anastomotic bypass procedure using dural pedicle insertion over the brain surface combined with encephalogaleomyosynangiosis and preservation of the superficial temporal artery (STA). We treated nine patients with childhood moyamoya disease admitted to our institution from 1989 through 1994. The operative field was determined based on the ischemic site identified by preoperative neuroimaging methods. Our procedure was performed in a total of 15 hemispheres, and the patients have been followed up for 5 months to 5 years after operation. RESULTS: Cerebral angiography, cerebral blood flow measurements, and clinical symptoms and signs were improved at the operation site in all patients. Because the STA and the superficial portion of the temporal muscle attached to the skin flap were preserved, the skin at the operation site was not depressed and no necrosis, infection, or alopecia developed. CONCLUSION: Childhood moyamoya disease is progressive, so repeated bypass surgery may be required. Therefore, non-anastomotic bypass surgery is better for the first operation because the STA is preserved. The present procedure using temporal muscle, galea, and dura can be extended over a wider brain surface than the operative field, and is suitable for establishing collateral circulation in the frontal lobe. Blood flow in the skin flap is maintained, so the cosmetic result is satisfactory.

Cerebral Angiography↗
PubMed1999

Coexistence of intracranial arteriovenous malformation with Turcot's syndrome: a case report.

Turcot's syndrome is a combination of multiple adenomatous gastrointestinal polyps and neuroepithelial tumors of the central nervous system (CNS). A 16-year-old man presented with Turcot's syndrome consisting of nonfamilial colorectal polyposis and multiple fibrillary astrocytomas accompanied by ruptured intracranial arteriovenous malformation (AVM) manifesting as generalized epileptic activity. Multiple CNS tumors are extremely unusual in Turcot's syndrome. This is the first description of Turcot's syndrome associated with an intracranial AVM. This case may correspond to a new phenotypic variant of colonic polyposis syndrome.

Adenomatous Polyposis Coli↗
PubMed1999

A case of adult moyamoya disease showing progressive angiopathy on cerebral angiography.

In moyamoya disease, progression of carotid occlusive lesion in an adult patient is very rare. We report a case of adult moyamoya disease with acute angiographical stage progression and hemodynamic deterioration. A 56-year-old female complaining of left motor weakness visited our department. On MRI, infarct lesion was found in the right white matter. On cerebral angiography, occlusive lesions in the bilateral internal carotid arterial siphons and moyamoya vessels were found. The right side was stage V and the left side was stage III. On IMP-SPECT, decreased cerebral hemodynamic reserve of the right cerebral hemisphere was found. In this patient, right STA-MCA anastomosis was performed. After operation, she became possible to walk and discharged to home. Five months after operation, good collateral formation and improvement of hemodynamic reserve in the right hemisphere were found. However, on left carotid arteriography, the anterior and middle cerebral arteries were only slightly imaged, and the disease state progressed to stage IV. In addition, decreased blood flow and hemodynamic reserve were appeared in the left hemisphere.

Brain↗
PubMed1999

Thallium-201 single-photon emission computed tomographic and proton magnetic resonance spectroscopic characteristics of intracranial ganglioglioma: three technical case reports.

OBJECTIVE: The correlation between thallium-201 (201TI) uptake, semiquantitative choline-containing compound values measured by proton magnetic resonance spectroscopy (1H-MRS), and Ki-67 labeling indexes (LIs) was investigated in three gangliogliomas. METHODS: The early and delayed 201TI indexes were calculated as the ratio of tumor to normal brain tissue uptake by 201TI single-photon emission computed tomography. Single-voxel 1H-MRS was performed to measure the levels of metabolites in the tumors. Ki-67 LI was measured in the surgical specimens. RESULTS: All three gangliogliomas showed very high 201TI uptake on both early and delayed images. 1H-MRS demonstrated malignancy based on the high choline peak relative to the creatine and N-acetylaspartate peaks. Ki-67 LI was less than 1% in two gangliogliomas and 3.5% in an anaplastic ganglioglioma. CONCLUSION: Both 201TI single-photon emission computed tomography and 1H-MRS indicated malignancy, whereas Ki-67 LI indicated low growth activity. 201TI single-photon emission computed tomography and 1H-MRS of ganglioglioma might be affected by metabolic characteristics other than growth activity.

Adolescent↗