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Biomedical subjects

R Shirane

Publications and source records attributed to R Shirane.

89 records · Page 5Linked to original sources
PubMed1990

Cerebral metabolite dynamics during temporary complete ischemia in rats monitored by time-shared 1H and 31P NMR spectroscopy.

The changes in cerebral phosphorus metabolites, intracellular pH, and lactate during 30 min of complete global ischemia and 2 h of reperfusion were monitored by time-shared 1H and 31P in vivo NMR spectroscopy in rats. After the induction of ischemia, intracellular pH decreased from 7.14 +/- 0.01 to 6.32 +/- 0.10, and lactate concentration increased from 1.6 +/- 0.4 to 15.8 +/- 2.5 mumol/g; ATP and phosphocreatine were totally depleted, while inorganic phosphate increased 715 +/- 47%. Within 1 h after blood flow was restored, high-energy phosphates and lactate levels had recovered close to baseline levels. The changes in intracellular pH and lactate levels during ischemia and reperfusion correlated well.

Adenosine Triphosphate↗
PubMed1990

The accumulation of 11C-methionine in cerebral glioma patients studied with PET.

Fourteen patients with cerebral gliomas were studied with positron emission tomography (PET) using L-[methyl-11C]methionine (11C-MET). Positive images of tumour were obtained in all cases regardless of histological grades. The analysis of differential absorption ratio (DAR) showed the higher accumulation of 11C-MET in high grade gliomas than in low grade gliomas. PET study with 11C-MET will be of great value not only in delineating the location of gliomas, but also in making a qualitative diagnosis from the view point of the biological properties of gliomas.

Adult↗
PubMed1990

Opiate-receptor antagonist improves metabolic recovery and limits neurochemical alterations associated with reperfusion after global brain ischemia in rats.

Opiate-receptor antagonists improve behavioral, electrophysiologic and/or histologic outcome in various experimental models of central nervous system ischemia. To address the potential mechanism(s) by which opiate-receptor antagonists may exert their protective actions in cerebral ischemia, metabolic and biochemical changes were measured in brain of rats pretreated with the opiate-receptor antagonist nalmefene or vehicle and subjected to 60 min of global ischemia followed by 2 hr of reperfusion. 31P and 1H magnetic resonance spectroscopy were used to follow the metabolic changes during ischemia and reperfusion, after which brain tissue was frozen in situ. Biochemical assays included free fatty acids, thromboxane B2, ascorbate, vitamin E and amino acids. Nalmefene-treated animals showed more rapid and complete recovery of cellular bioenergetic state (as indicated by the phosphocreatine to inorganic phosphate ratio), tissue acidosis and lactate levels during reperfusion than placebotreated controls. Ischemia/reperfusion caused significant increases of fatty free acids and thromboxane, associated with significant decreases of ascorbate and glutamate; nalmefene pretreatment limited each of these changes. The degree of metabolic improvement as reflected by recovery of high energy phosphates and reduction of lactic acidosis were highly correlated with changes in tissue levels of arachidonate and glutamate. Thus, the beneficial effects of opiate-receptor antagonists in cerebral ischemia may be due, in part, to an ability to enhance metabolic recovery with associated, reduction in phospholipid hydrolysis and excitotoxin release.

Adenosine Triphosphate↗
PubMed1986

Evaluation of cerebral blood flow and metabolism in childhood moyamoya disease: an investigation into "re-build-up" on EEG by positron CT.

The cerebral blood flow and cerebral metabolic rate of oxygen (CBF and CMRO2) of three cases of childhood moyamoya disease were examined by positron-emission-computed tomography for the purpose of investigating the mechanism of the "re-build-up" phenomenon on EEG. Decrease in both CBF and CMRO2 were observed following hyperventilation. However, dissociation between the decrease in CBF and CMRO2 was also observed. Arterial blood-gas analysis disclosed hypocapnea during hyperventilation and hypoxia following hyperventilation. These results clearly indicate that the re-build-up seen on EEG is the manifestation not only of ischemic hypoxia but also of hypoxic hypoxia characteristically seen in moyamoya disease.

Adolescent↗
PubMed1986

Bilateral symmetrical middle cranial fossa arachnoid cysts in a neonate.

A newborn girl was admitted suffering from convulsive seizures in both legs. A computed tomography (CT) scan revealed bilateral symmetrical middle cranial fossa arachnoid cysts and intraventricular hemorrhage. In the course of a year, only the cyst on the right side became gradually larger; the cyst on the left side was reduced in size. At the age of 1 year and 2 months, her intellectual development was normal, but she could not stand by herself. On metrizamide-enhanced CT cisternography, the cyst on the right side was of a noncommunicating type. Membranectomy of the right-sided cyst was performed and the cyst proved to be of the intraarachnoid type. The postoperative course was uneventful and a CT scan, taken 10 months after the operation, revealed no abnormality on either side. The intellectual and motor development was normal, and no abnormality was observed by electroencephalography. This may be the first report of arachnoid cysts found in a neonate. It gives us clues for understanding the etiology of this disease, which has not been fully clarified.

Arachnoid↗
PubMed1985

[A study of the optimum dose of a glucocorticoid, methylprednisolone sodium succinate, before and after neurosurgical major operations--relationship between beta-glucuronidase level and post operative brain edema].

The effects of pre- and postoperative administration of methylprednisolone (5, 10, 15 mg/kg/day) was studied on 50 cases of major neurosurgical operation. The serum level of beta-glucuronidase was also analyzed in 20 cases so as to determine whether it could be useful as an indicator of post operative brain edema. Methylprednisolone seemed to be effective in the cases administrated in the dosage of 10, 15 mg/kg/day. However, several kinds of postoperative infections were seen in the cases administrated 15 mg/kg/day. The results may suggest that the dosage tested, 10 mg/kg/day, causes little side effects while it is clinically effective. The serum level of beta-glucuronidase tended to increase from the second postoperative day to the seventh day. Those increase were remarkably in the cases with brain edema. Recovery of beta-glucuronidase level was earlier in the cases with 10 mg/kg/day administrated rather than in the cases with 5 mg/kg/day administrated. These results suggest that the measurement of serum beta-glucuronidase level may be useful for evaluating the degree of brain edema.

Adolescent↗
PubMed1985

[A case of giant intracranial teratoma in early infancy. A 13 years' follow-up study after operation].

A long-term result after total removal of a giant intracranial teratoma in early infancy is reported. The patient was a 5-month-old boy with vomiting, convulsion and right hemiparesis occurring acutely and shortly before admission. Plain skull films, In-113m brain scintiscanning and carotid angiography revealed a giant tumor located widely over both frontal lobes. At operation, the tumor, originated from the base of the anterior half of the cranial cavity. A mature teratoma weighing 320 grams was totally removed without sacrificing the adjacent brain and vessels. Both cerebral hemispheres were found severely compressed by the tumor. Postoperative respiratory and convulsive disorders were well controlled. The boy was discharged in the third month after operation. At present, 13 years after operation, he is developing normally for his age. In the junior high school, he studies and plays sports with no handicap. Computed tomography reveals no recurrence of the tumor. EEG shows reactive pattern of activity and small, but rare spikes in the frontal area. And his pituitary function is revealed to be normal.

Brain Neoplasms↗
PubMed1984

[Proteus mirabilis brain abscess in a neonate].

A case of neonatal brain abscess was reported. This female infant was born by spontaneous vertex delivery at 38 weeks gestation, weighing 3.1 kg. There were no antenatal and perinatal complications. The Apgar's score was 8 points and her head was 32.8 cm in circumference. Fifty-six hours after birth, she had a clonic general convulsion for about 3 minutes. On the next morning, convulsion recurred, and she was transferred to our hospital. When admitted to the Pediatrics, she was exhausted and irritable. But after hospitalization, she improved without convulsions. CT scan, performed 7 days after birth, revealed large low density areas in both frontal lobes. Electroencephalography showed spike discharge at all leads. The head circumference gradually increased and subsequent CT scans revealed enlargement of the bifrontal low density areas. The first operation was done 28 days after birth. A large amount of yellowish grey pus was aspirated from both sides and the cavity was irrigated. Tobramycin was administered into the abscess cavity. Culture of the pus grew proteus mirabilis. The postoperative conditions were good. But two weeks later her head started to enlarge with the bulging fontanelle. CT scan revealed marked dilation of the ventricles and enlargement of the left frontal abscess. At 2 months of age, second operation was done. Left frontal abscess was punctured and serous pus was aspirated. Proteus mirabilis was cultured again from the pus. Tobramycin was administered into the cavity via the drainage tube every day for a week. As the content of the abscess cavity became clear, V-P shunt and cyst-peritoneal shunt were performed. After shunting procedure, the increase of head circumference stopped and the fontanelle became flat and soft.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Abscess↗
PubMed1983

[Case of multiple calcifications of the cerebellar hemisphere].

A 38-year-old woman with three intracerebellar calcifications visible in roentgenogram was reported. She had not suffered from any disease that should induce intracranial calcification. Plain x-ray films of the skull showed three small calcifications in the posterior fossa. The laboratory study and neurological examination revealed no abnormality. Computerized tomography showed no abnormal findings either. Histological examination was carried out. The tissue surrounding the calcification seemed to be gliosis.

Adult↗
PubMed1982

Computer tomography of ruptured intracranial arteriovenous malformations in the acute stage.

We studied the CT findings of 23 AVM cases confirmed by cerebral angiography and their clinical findings, and discussed mainly the lesions of ruptured AVM in the acute stage. The 10 cases, in which CT was performed within 7 days after the onset of a ruptured AVM, presented with blood stained CSF except for two cases. All of the 10 cases showed intracerebral haemorrhages in the CT findings, and four of these cases were associated with ventricular rupture. In the plain CT of these 10 cases, high density in the cerebral cistern, such as seen in the acute stage of ruptured intracranial aneurysms, was not found except for 1 case. In the enhanced CT within 7 days after the onset of ruptured AVM, no enhanced findings were found in eight cases. On the contrary, in 12 cases in which CT was performed later than the 8th day after the onset, enhanced findings were found in 11 cases. It has been previously reported that SAH is seen in the lesion of ruptured AVM in the acute stage. From our CT findings of ruptured AVM in the acute stage, however, it was concluded that the lesion of a ruptured AVM in the acute stage does not cause SAH but an intracerebral haematoma or ventricular rupture and that blood may enter the CSF only secondarily.

Acute Disease↗
PubMed1982

[Chronic subdural hematoma developing after EMS for moyamoya disease].

A case of chronic subdural hematoma following EMS (Encephalo-Myo-Synangiosis) for moyamoya disease was presented. Two and a half year-old girl was admitted to our division because of right hemiparesis. Left carotid angiography revealed a very narrow left carotid bifurcation and small moyamoya vessels. EMS was performed on the left side and a right hemiparesis was improved. But she developed a headache and vomiting one month after the operation. CT scan and angiogram showed a chronic subdural hematoma on the left side. A hematoma weighing approximately 30 g was evacuated. We reviewed a similar case of 5-year-old boy in the literature and discussed the mechanism accounting for formation of the chronic subdural hematoma following EMS.

Arterial Occlusive Diseases↗
PubMedDate not supplied

Infantile myofibromatosis located in the temporal bone.

Infantile myofibromatosis (IM) is a proliferative disorder of infancy and early childhood characterized by the nodular or diffuse growth of lesions that are comprised of a mixture of mesenchymal elements. Intracranial involvement is reportedly rare, only eight such patients having been reported to our knowledge. We report on a 4-year-old boy with intracranial IM with a mass in his left temporal bone. A previous report on intracranial IM proposed that the underlying dura mater should be resected because of the possibility of early recurrence. At surgery in this case, the tumor was noted to be located in the bone itself and did not arise from the underlying dura. Therefore, the underlying dura mater and venous sinus were preserved. The follow-up MRI showed no sign of recurrences. It may not to be necessary to resect the dura mater in patients with intracranial IM.

Child, Preschool↗
PubMedDate not supplied

Prenatal diagnosis of lissencephaly by magnetic resonance image.

Two cases of lissencephaly were prenatally diagnosed by a magnetic resonance image (MRI). Smooth surface of brain and remarkable sylvian fissure, which were barely detectable by ultrasound, were easily observed in MRI. MRI is the most appropriate tool in diagnosing lissencephaly.

Adult↗
PubMedDate not supplied

A new model of bilateral hemispheric ischemia in the rat--three vessel occlusion model.

A new model of bilateral hemispheric ischemia was created in the rat by occluding the common carotid arteries and the basilar artery; this resulted in consistent and severe impairment of the cerebral blood flow. The procedure for producing this model is described, and the results of EEG and autoradiography obtained by this model are compared to those obtained by the four-vessel occlusion model.

Animals↗
PubMedDate not supplied

CT and MR findings in diastematomyelia, with embryogenetic consideration.

Diastemstomyelia is an extremely rare disorder that is seldom found among the Japanese. This paper presents two Japanese patients, a newborn male and a newborn female, with diastematomyelia. CT demonstrated bony spurs more clearly than plain film, and magnetic resonance images indicated split cords and associated anomalies. Although the embryogenesis of diastematomyelia has not been clearly elucidated, the coincidence of levels of associated anomalies and diastematomyelia in our cases and in the literature supports Bremer's embryogenetic explanation of persistent accessory neurenteric canal.

Female↗
PubMedDate not supplied

Cortical laminar necrosis in a patient with moyamoya disease associated with Down syndrome: MR imaging findings.

We report a case of moyamoya disease associated with Down syndrome and congenital heart malformations. Findings of cranial MR imaging indicated cortical laminar necrosis along with cerebral infarction. To explain the development of these findings, we hypothesized that hypoxic brain damage manifesting cortical laminar necrosis was caused by hypoperfusion of the brain due to occlusive changes to the cerebral vessels in moyamoya disease, in addition to a state of general hypoxemia secondary to congenital heart malformations.

Brain↗