Kunio Nakai

Dopaminergic neuroprotection and regeneration by neurturin assessed by using behavioral, biochemical and histochemical measurements in a model of progressive Parkinson’s disease

Trophic effects of neurturin, a member of the glial cell line-derived neurotrophic factor-family, have been demonstrated on mesencephalic dopaminergic neurons, suggesting its therapeutic potential for Parkinsons disease. This study was designed to test the neuroprotective and regenerative effects of an intrastriatal injection of neurturin based on behavioral, neurochemical and histochemical changes in a rat model of progressive Parkinsons disease. An extensive and progressive dopaminergic lesion was unilaterally made by intrastriatal convection-enhanced delivery of 6-hydroxydopamine (6-OHDA), in which 20 microg of 6-OHDA dissolved in 20 microl of vehicle was infused at a rate of 0.2 microl/min. For neuroprotection study, recombinant human neurturin (5 microg in 5 microl of vehicle) was stereotaxically injected into the unilateral striatum. The 6-OHDA lesion was made on the ipsilateral side 3 days after the neurturin treatment. Tyrosine hydroxylase (TH)-immunoreactive neurons of the substantia nigra were protected from progressive degeneration in the neurturin-treated animals compared with the vehicle-treated animals 2 and 8 weeks after the 6-OHDA lesion. Eight weeks after the 6-OHDA lesion, dopamine concentration significantly increased in the striatum of neurturin-treated animals with improvement of methamphetamine-induced rotation behavior. For neuroregeneration study, 5 microg of neurturin was injected into the striatum 12 weeks after the 6-OHDA lesion. Four weeks after neurturin or vehicle injection, there were no significant differences in the survival of nigral TH-immunoreactive neurons between the groups. However, TH-immunoreactive fibers were thicker and more abundant in the striatum of the neurturin-treated rats compared to those of the control group, suggesting neurturin-induced growth of the dopaminergic axons. Striatal dopamine levels also significantly increased in the neurturin-treated rats compared with those in the control group of rats, accompanied by the recovery of methamphetamine-induced rotation in the neurturin-treated rats. In conclusion, an intrastriatal injection of neurturin is a useful method to protect nigral dopaminergic neurons from extensive cell death in a model of progressive Parkinsons disease, as well as to promote the axonal regeneration and dopaminergic function.

Microangioarchitecture of rat parietal cortex with special reference to vascular "sphincters". Scanning electron microscopic and dark field microscopic study.

Microangioarchitecture of the rat parietal cortex was studied by means of scanning electron microscopy and dark field microscopy. The richest supply of blood vessels in the parietal cortex was found in layer HI + IV and layer V, where 2 isolated plexuses of microressels were prominent. Tbe appearance of the plexuses was quite different between motor and sensory areas. In the motor area the capillary plexuses were narrow and compact, while in sensory area the plexuses were wide and diffuse. Characteristic ring formations, called ring-shaped-compressions in the present study, were frequently observed at branching sites of arterioles. The ring-shaped-compression probably corresponds to the precapillary sphincter. A similar structure was also seen in capillaries and venules and, therefore, it is likely that not only arterioles, but also capillaries and eren venules, can actively change diameter to control cerebral blood flow.

Cerebral blood flow in mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes.

Background and Purpose The precise mechanism of neurological symptoms with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) is still controversial. We investigated the correlation between strokelike episodes and cerebral blood flow in two patients with MELAS and discuss the pathogenesis of strokelike episodes with MELAS. Summary of Report Cerebral dynamic computed tomography and cerebral angiography, were used to measure cerebral circulation in the first case, that of a 20-year-old woman with MELAS. The second subject was a 13-year-old female who was studied with xenon-enhanced computed tomography. The cerebral blood flow studies were performed 3–72 hours after the onset of strokelike episodes. Serial cerebral angiography, dynamic computed tomography, and xenon-enhanced computed tomography showed vasodilation localized in the affected cerebral cortexes during strokelike episodes, without any reduction in regional cerebral blood flow. Conclusions Our study suggests that the strokelike episodes associated with MELAS are different in origin from ischemic stroke.

Spontaneous subperiosteal hematoma of the orbit

Spontaneous subperiosteal hematoma of the orbit is extremely rare. This is a case of an 81-year-old woman. The presenting symptom was protrusion of the right eye with severe intraorbital pain. Computed tomography scanning showed a high-density area in the upper part of the right orbit, which, at operation, was found to be a subperiosteal hematoma of the orbit.

Percutaneous transluminal angioplasty for the M2 portion vasospasm following SAH : development of the new microballoon and report of cases

A new silicone microballoon was developed for the percutaneous transluminal angioplasty of smaller intracranial vessels, such as A1, A2 and M2. This balloon was 0.5 x 2.0 mm in the deflated condition and became 2.2 x 6.5 mm inflated with 0.02 mL of fluid, and its bursting pressure was 2 atm. Two illustrative cases are presented. The first case was not treated in the M2 distribution. The second case of vasospasm of the left M2 portion was successfully treated with this new balloon, with prompt improvement of the neurological condition and cerebral circulation. The usefulness of our microballoon in treating a patient with vasospasm of small intracranial arteries is discussed.

Is unilateral spatial neglect a single phenomenon

Abstract The aim of this study is to report the preliminary findings of a traditional battery of tests and our original battery capable of assessing the presence of components and extent of lesions in patients with unilateral spatial neglect. Thirty patients who had unilateral spatial neglect with a stroke in the right hemisphere were assessed for unilateral spatial neglect on exploratory-motor (E-M) tasks, visual-counting (V-C) tasks, and traditional neglect batteries at least 4 weeks after the onset. Other neuropsychological tests and computed tomography were also performed to investigate the relationship with neglect. A factor analysis showed that our tasks loaded significantly on three factors. E-M neglect was found in 16 patients, and V-C neglect in 22 patients with unilateral spatial neglect. There were high correlations between E-M neglect and motor paralysis, word fluency, backward digit span and motor impersistence. There were high correlations between V-C neglect and visual-field defect, line bisection, line cancellation and figure copying. Lesions in the frontal lobe, caudate, insula, and anterior portion of the paraventricular white matter were commonly associated with E-M neglect. Lesions in the occipital lobe were also associated with V-C neglect. We suggest that unilateral neglect is not a single phenomenon, but rather involves several different components. We propose that E-M and V-C tasks are useful methods for evaluating the extent of lesions in patients with unilateral spatial neglect.

Intraoperative hemorrhage in medulloblastoma: a case report and review of the literature

HeadingAbstract Object. We present the first case of intraoperative hemorrhage in a medulloblastoma. Case report. A 10-year-old girl presented with a 4-week history of headache, nausea, and vomiting. Radiological examination showed a space-occupying mass in the cerebellar vermis. Surgical removal was performed via a midline suboccipital approach. When the dura was incised and the occipital sinus was ligated after suboccipital craniectomy, bleeding occurred in the tumor. Macroscopically, hematoma was found only in the left part of the tumor and not in the right part. Microscopically, different architectures of tumor vessels, thin-walled and thick-walled, were found between the left part and the right part, respectively. The tumoral contents and hematoma were totally removed. Histological examination revealed a medulloblastoma. Conclusion. We experienced a very rare case of medulloblastoma in which intratumoral hemorrhage occurred during operation. We speculate that ligation of the occipital sinus and thin-walled vessels within the tumor might have caused the hemorrhage in our case.

Jargonagraphia with severe aphasia due to a right hemisphere lesion: case report.

The authors report a case of a patient who developed jargonagraphia, severe aphasia, unilateral spatial neglect and apraxia due to a right hemisphere lesion. Jargonagraphia with severe aphasia, unilateral spatial neglect and apraxia is quite rare. The mechanisms of jargonagraphia remain unknown. A possible mechanism underlying this case of jargonagraphia is discussed.

Transcortical mixed aphasia from ischaemic infarcts in a non-right handed patient

Sirs: Transcortical mixed aphasia (TMA), which is characterized by a severely reduced verbal output and impaired language comprehension in the presence of echolalic repetition and automatic completion of openend sentences [9, 10], has only rarely been reported. The localization of lesions producing TMA is variable [16, 20]. Albert et al. [1] reported that the syndrome is seen most often with diffuse or multifocal pathological changes that involve both anterior and posterior left hemisphere cortical association areas but spare the perisylvian language core. Similarly, Geschwind et al. [9] maintain that this condition is caused by anterior and posterior lesions of the left hemisphere when the perisylvian speech area is intact, and refer to it as ‘the syndrome of isolation of speech areas’. Recently some investigators [3, 5] have suggested that the mechanism which preserves repetition in transcortical aphasia is linked to an exceptional ability for repetition of the right hemisphere. We describe a patient with TMA who underwent an amytal test to determine hemispheric language dominance. The patient was a 53-year-old Japanese man with 9years of school education and employed as an office worker. His hand dominance can best be described as “mixed”; as a child he was taught to write, draw and use chopsticks with his right hand, and as an adult these activities are thus performed with the right hand, while throwing, brushing and cutting are performed with the left hand. His daughter is left-handed. He had a 10-year history of diabetes mellitus and hypertension, but no prior history of neurological problems. He suddenly began to exhibit speech disturbance and was referred for diagnosis to our Neurological Surgery Unit. Initially he was completely conscious and fully oriented but manifested a right homonymous hemianopsia. There was no apparent motor paralysis or sensory disturbance. The patient spoke little of his own volition, and often demonstrated echolalia when he was questioned. His phonological structure was clear. Formal language assessment was undertaken 2 weeks after the onset of symptoms, using the Standard Language Test of aphasia [18]. The results are presented in Fig. 1. When presented with picture-description tasks, the patient exhibited perseveration and literal paraphasic errors. This was in contrast to the full ability to repeat phonemes and short sentences (some five or six words). Reading aloud of kanji (Chinese characterbased) words was preserved and reading aloud of kana (syllable-based) letters was partially spared; however, the patient was unable to read aloud kana words or short sentences. Agraphia was almost total for both kanji and kana; however, writing to dictation of kana letters and single words (kanji and kana) was partially preserved. Testing also revealed some constructional apraxia but no evidence of oral, ideomotor or ideational apraxia. On the Wechsler Adult Intelligence Scale-Revised his performance intelligence quotient (IQ) was 55. Verbal IQ was unmeasurable in the presence of aphasia. Magnetic resonance imaging revealed cerebral infarcts in the left LETTER TO THE EDITORS J Neurol (1999) 246 :504–506