Makoto Miyaoka

Intraorbital meningiomas. Surgical management and role of radiation therapy.

The authors discuss their experience with 11 cases of intraorbital meningioma, revealing how computed tomography scanning has aided in early diagnosis of primary optic nerve meningiomas. Despite the difficulty of removing apical, primary optic nerve meningioma without sacrificing the central retinal artery, the authors prefer a surgical approach backed up by radiation therapy. It appears that general improvement, although generally elusive, is worth the risk incurred in trying to overcome the deficits stemming from these tumors.

Cervical radiculomyelopathy due to calcification of the ligamenta flava

Three cases of cervical radiculomyelopathy caused by calcification of the ligamenta flava of the cervical spine are reported. A review of the literature yielded 13 cases of calcification of the cervical ligamenta flava with findings similar to those in our cases. Specifically, we observed that 1) all patients were more than 50 years of age; 2) most were female; and 3) the calcifications appeared consistently as oval nodules, located symmetrically and paramedially in and around the region of the fifth cervical vertebra. Such characteristic similarities in both clinical and radiologic features are important in considering the etiology of calcification of the cervical ligamenta flawa.

Measurement of local cerebral glucose utilization before and after V-P shunt in congenital hydrocephalus in rats

Local cerebral glucose utilization (LCGU) was measured by the [14C]deoxyglucose autoradiographic method in rats with congenital hydrocephalus before and after a V-P shunt. LCGU was decreased throughout the brain in hydrocephalus. The most severely affected regions were found in the cortex, with which a marked degree of subcortical cerebrospinal fluid (CSF) edema was associated; regions in the brain-stem structures were less affected. These metabolic disturbances were improved in many regions after a V-P shunt. However, no improvement was found in the cortex; therefore, damage was considered irreversible. CSF edema was also found in the periaqueductal gray matter in which impaired LCGU was observed; however, this metabolic disturbance was normalized after a V-P shunt. This study suggests that regional differences in the brain seen in hydrocephalus and CSF edema may have varying ill effects on cerebral metabolism. Without prompt treatment, metabolic damage progresses and becomes irreversible. It is suggested that metabolic impairment in the brain stem which is reversible is due mainly to increased intracranial pressure (ICP).

Early Vs Delayed Ventriculoperitoneal Shunt-Effects on the Impairment of the Developing Brain in Congenitally Hydrocephalic HTX-Rats

In the present investigation, we report on the effects of the early placement of a ventriculoperitoneal shunt (V-P shunt) on the development of cerebral synapses by counting spine density of the cortical pyramidal neurons (stained by rapid Golgi method) and measuring one of the synaptic vesicle proteins, SVP-38. The techniques used were quantitative histochemical and immunoblot analysis. The learning ability of congenitally hydrocephalic HTX-rats whose hydrocephalus had been arrested by insertion of a V-P shunt 7–9 days after birth (Early Shunt) was assessed by the light-darkness discrimination test. When a V-P shunt was inserted into the hydrocephalic animals approximately 4 weeks after birth (Delayed Shunt), not only was there no reduction in the size of the abnormally enlarged ventricles, but also there was no increase in cortical mantle thickness. Furthermore, spine density in the cerebral cortex in such animals was found to be decreased. Learning disability could not be corrected by the delayed shunt procedure. Contrary to these observations, early shunt placement was found to result in normalization of the abnormally enlarged ventricles, concomitant with simultaneous cortical mantle thickening and prevention of both decreased spine density and decay of SVP-38 in the affected cerebral cortex. The learning disability of such animals was not found to be disturbed, compared with that of the sham-operation group. From these observations, it is concluded that early shunt placement may have a beneficial role not only in repairing, but also in preventing the impairment of synaptogenesis caused by the progression of congenital hydrocephalus.

The Effect of V-P Shunt on Local Cerebral Glucose Utilization in HTX Congenital Hydrocephalic Rats

Local cerebral glucose utilization (LCGU) was measured by the [14C]-deoxyglucose autoradiographic method in rats with congenital hydrocephalus before and after V-P shunts. As the hydrocephalus continuously progressed, body weight and motor activity were rapidly decreased at the age of 4 weeks. When hydrocephalus was treated with V-P shunt at this age, the animals increased their food intakes from the following day and motor activity increased rapidly together with body weight.