Striatal cells containing the Ca2+-binding protein calretinin (protein 10) in ischemia-induced neuronal injury

The present study concerns the vulnerability of striatal interneurons immunopositive for the Ca²⁺-binding protein calretinin to ischemic neuronal injury. An immunohistochemical study was carried out on the striata of rats which had undergone transient middle cerebral artery occlusion. Two weeks after the ischemia, there was a marked reduction in the number of calretinin-positive neurons in the ipsilateral ischemic lesion, although the striatal interneurons positive for parvalbumin, which are a neuronal population distinct from the calretinin-immunoreactive cells in the striatum, were spared in the insulted areas. The present data indicate that the striatal calretinin-positive neurons are less resistant to transient ischemia, suggesting that there may exist vulnerability differences among the striatal interneurons in ischemia-induced neuronal injury.     

Paroxysmal choreoathetosis precipitated by movement, sound and photic stimulation in a case of arterio-venous malformation in the parietal lobe.

A patient is presented with paroxysmal choreoathetosis precipitated by movement, sound and photic stimulation associated with an arterio-venous malformation (AVM) who responded to carbamazepine treatment. Hemodynamic circulatory disorder of the sensory-motor cortices having AVM may alter striatal function and produce paroxysmal choreoathetosis. This finding supports the concept that paroxysmal choreoathetosis results from an abnormality at the connections between basal ganglia and cerebral cortices.     

Germinoma with granulomatous reaction arising from the corona radiata; case report and review of articles]

We report a rare case of germinoma with granulomatous reaction arising from the corona radiata. This 20-year-old man was admitted to our hospital complaining of progressive motor weakness on the right side. CT demonstrated a poorly demarcated high density area in the left corona radiata, which was heterogeneously enhanced after administration of contrast medium. Moreover, the continuity of the mass to the ventricular wall was confirmed on MRI. At the first operation, subtotal removal of the tumor was performed through a fronto-parietal craniotomy. The diagnosis for the specific neoplasm was not established histologically, but granuloma caused by fungal infection was the most likely cause of the lesion. We tried amphotericin B (AmB), and remission of the tumor was obtained. However, during the following 3 months, the size of the tumor gradually enlarged again. AmB was repeatedly administered, but this time the treatment was ineffective. Six months later, on May 21, 1990, the second operation was performed and histological examination revealed typical germinoma consisting of two-cell pattern. Subsequently, the patient underwent focal irradiation of 33 Gy to the tumor site, and the tumor completely disappeared. As intracranial germinomas are observed to be successfully cured by radiotherapy and/or chemotherapy, choice of the therapeutic management must be carefully determined according to the histological diagnosis, especially in young people. A variety of locations of germinomas and the accompanying granulomatous reactions could create some diagnostic confusion, so great care must be taken in the treatment of much intracranial germinomas.     

Deep vein thrombosis in the psychiatric patients under physical restraint]

Pulmonary thromboembolism induced by deep vein thrombosis (DVT), which is known as economy-class syndrome, is one of sudden death in psychiatric patients under physical restraint. (1) A decrease in venous blood flow, (2) damage to vessel walls, and (3) the enhancement of blood clotting are the major risk factors for DVT (Virchow triad). It has been speculated that physical restraint inhibits venous blood flow, and that antipsychotic drugs facilitate blood clotting. In order to prevent sudden death due to DVT, prophylactic measures and early diagnosis are crucial. Whereas Doppler ultrasonography and contrast venography are the gold standards for the diagnosis of DVT, more simplified methods are now under development. Of those, D-dimer measurement, which can be conducted with a small blood sample, is the most potent candidate for the biochemical diagnosis of DVT. Although there are many prophylactic measures, including anticoagulant medications and physical therapies, it is not clear which is the most effective and suitable in psychiatric practice. Psychiatric professionals should pay closer attention to DVT in psychiatric patients under physical restraint.     

Preoperative identification of subthalamic nucleus for deep brain stimulation using three-dimensional phase sensitive inversion recovery technique.

PURPOSE: We assessed the feasibility of utilizing three-dimensional (3D) phase sensitive inversion recovery (IR) images for preoperatively determining deep brain stimulator position. METHODS: We measured geometric distortion with a grid phantom and evaluated images of 3 volunteers to determine optimum imaging parameters for 3D phase sensitive IR. RESULTS: Geometric distortion measured less than 1.0%. Respective inversion and recovery times, which provided high T(1) contrast between the subthalamic nucleus and adjacent tissue, were 200 and 4000 ms. In studies of 3 volunteers and 2 patients, the subthalamic nucleus was clearly depicted in 3D phase sensitive IR images. The measured coordinates of the subthalamic nucleus agreed well with those calculated by conventional estimation from midpoint of the anterior and posterior commissure. CONCLUSION: Three-dimensional phase sensitive inversion recovery was useful in visualizing the subthalamic nucleus for effective deep brain stimulation.     

Molecular design of hybrid tumour necrosis factor alpha with polyethylene glycol increases its anti-tumour potency.

This study was conducted to increase the anti-tumour potency and reduce the toxic side-effects of tumour necrosis factor alpha (TNF-alpha). Natural human TNF-alpha was chemically conjugated with monomethoxy polyethylene glycol (PEG) using succinimidyl coupling of lysine amino groups of TNF-alpha. The number-average molecular weight of PEG-modified TNF-alpha (PEG-TNF-alpha) increased with an increase in the reaction time and the initial molar ratio of PEG relative to TNF-alpha. The resulting modified TNF-alpha was separated into fractions of various molecular weights. The specific activity of separated PEG-TNF-alpha s relative to that of native TNF-alpha gradually decreased with an increase in the degree of PEG modification, but the plasma half-life was drastically increased with the increase in molecular weight of modified TNF-alpha. PEG-TNF-alpha s, in which 29% and 56% of lysine residues were coupled to PEG, had anti-tumour activity approximately 4 and 100 times greater than unmodified TNF-alpha in the murine Meth-A fibrosarcoma model. Extensive PEG modification did not increase its in vivo activity. A high dose of unmodified TNF-alpha induced toxic side-effects, but these were not observed with the modified TNF-alpha s. Optimal PEG modification of TNF-alpha markedly increased its bioavailability and may facilitate its potential anti-tumour therapeutic use.     

Muscle spasm induced sympathetic reflex bursts on microneurography in a case with pontine demyelination

Microneurography was performed in a 39-year-old woman with demyelination of the pontine white matter associated with muscle spasms in the lower extremities. Single bursts on the microneurogram were observed immediately after cessation of the spasm with no systemic changes in the blood pressure or heart rate. Voluntary tonic flexion of the lower extremities induced similar bursts with small amplitudes. These reflex bursts possessed a characteristic of muscle sympathetic nerve activity, because the latency between the peak of each burst and the prior R-wave on the electrocardiograph was constant. The occurrence of these bursts suggests that a segmental compensatory mechanism in the spinal cord may stabilize the muscle blood flow influenced by muscle contraction.     

Prediction of spinal cord ischemia with a retrievable stent graft on endovascular treatment for a case of thoracic aortic aneurysm

Multiple aortic aneurysms in Behçet’s disease were repaired with transluminaly placed endovascular stent grafts. Before deploying the stent graft device for permanent implantation for the saccular aneurysm located in the descending thoracic arota, from which feeding arteries for the spinal cord possibly branched, a retrievable stent graft was inserted and evoked spinal cord potential (ESP) were monitored in order to predict spinal cord ischemia. The original retrievable stent graft, constructed of a self-expandable Z-shaped stainless steel stent covered with e-PTFE, can be easily withdrawn into a 18 Fr. sheath after deployment. Blood flow into intercostal arteries branching from that part of the descending aorta where the permanent stent graft is planned to be implanted, is intercepted by the retrievable stent graft. A change of ESP during the temporary implantation of the device indicates that spinal cord ischemia would be caused by permanent implantation of the stent graft. In this case, no change of ESP was observed and the patient showed no postoperative paraplegia.The retrievable stent graft was useful for prediction of spinal cord ischemia before endoluminal stent graft repair of the descending aortic aneurysm. However, the device is not flexible enough to fit a severely tortuous aorta, therefore we are obliged to select patients to some extent. Further improvement of the device is required to make prediction of spinal cord ischemia with the retrievable stent graft possible in all cases.