[Ruptured proximal aorta after operation for type A dissection presenting as opacified left hemothorax; report of a case].

We report an unusual clinical presentation of ruptured proximal aorta as a left hemothorax after operation for type A dissection. A 74-year-old man who had undergone ascending aortic replacement for acute type A dissection 4 months previously developed a loss of consciousness followed by shock state. Both chest X-ray and computed tomography (CT) scan revealed opacified left hemothorax. The patient died during a diagnostic procedure. Post mortem examination showed rupture of proximal aortic dissection extended to the left pleural cavity path through the right atrial wall and the right ventricular wall.

Meningio-angiomatosis in a patient with focal epilepsy: value of PET in diagnoses and preoperative planning of surgery.

A 17-year-old boy with epileptic seizures due to meningio-angiomatosis without neurofibromatosis type 2 is presented. Low grade astrocytoma in the left temporal lobe was resected when he was 11 years old. A recurrence was suspected on following-up MRI and a positive PET scan with 11C-methionine PET 6 years later around the resected area. The language area was mapped using H2(15)O PET activation technique. The lesion was completely resected while preserving the verbal area assisted by three-dimensional imaging protocol of MR-registered PET. The patient was well and seizure-free for 8 years thereafter without antiepileptic drugs. Histologically, there was an increase of dilated arterioles and meningothelial cell-like spindle cells around them, which are characteristic pathological features of meningio-angiomatosis. It is most likely that angiomatous tissue developed perivascular meningiomatous components and formed the meningio-angiomatosis in our presented case. In addition, we presented our protocol of functional neuro-imaging which was useful in terms of the functional neurosurgery.

Concept and pathogenesis of "hypoxic-ischemic encephalopathy".

By experiments of acute carbon-monoxide intoxication, acute nitrogen hypoxia and histotoxic hypoxia using sodium cyanide in cats, and by hemodynamic studies using plastic branch models, the following was elucidated; (1) severe tissue hypoxia, regardless of the underlying cause, and subsequent slight ischemia of the brain due to mild hypotension induce selective involvement of the cerebral white matter and pallidum, these two conditions being necessary and sufficient and this encephalopathy should be separately categorized as "hypoxic-ischemic encephalopathy" in hypoxic brain injuries, (2) the background of the selective involvement of these structures is an enormous development of the cerebrum in the brain, which induces thick white matter resulting in proper and long medullary artery, and especially small diameter ratio of the pallidal perforators to the middle cerebral artery, (3) the long course of the medullary artery produces the blood pressure drop in the deep white matter according to Hagen-Poiseuille's low, and according to that the smaller the diameter ratio, the larger the branching-loss coefficient (energy-loss co-efficient), smaller diameter ratio of the pallidal perforator, as compared with that of the putaminal perforator, induces more severe loss of the local blood flow selectively to the pallidum. This state seems to be a failure of compromise between the cardiovascular system and the brain parenchyma.

A comparison of long-term neurological symptoms after two different focal ischemic models in Mongolian gerbils.

The aim of the present study was to elucidate the relationship between specific tasks and the responsible ischemic lesions after experimentally induced cerebral hemispheric ischemia in Mongolian gerbils. We used the elevated body swing test (EBST) to evaluate asymmetry motor behavior, the bilateral asymmetry test (BAT) to evaluate sensory dysfunction, and the T-maze test to assess cognitive deficit during 4 weeks after either 10-min single unilateral carotid artery occlusion (sCCAO) or 10-min repeated unilateral occlusion (rCCAO). rCCAO produced persistent sensorimotor and severe cognitive deficits. Infarction was confined to the ipsilateral cerebral cortex, hippocampus, dorsolateral nucleus of thalamus and caudate nucleus. sCCAO did not induce sensorimotor abnormalities, but did produce mild cognitive deficits; these animals also showed increased locomotor activity during the early post-ischemic period. In sCCAO, neuronal death was confined to the ipsilateral CA1 sector of the hippocampus. Thus, unilateral CA1 neuronal death was sufficient for evolution of cognitive deficits in this model of experimental focal ischemia. Ischemic lesions extending to the ipsilateral cerebral cortex, basal ganglia, and hippocampus produced persistent and severe sensorimotor impairment accompanying severe cognitive deficits. These findings regarding region-specific behavioral tasks in cerebral ischemia will facilitate improved assessment of stroke therapy.

Histopathological structure of the pial arteriovenous malformation in adults: observation by reconstruction of serial sections of four surgical specimens.

Surgical specimens of four adult cases of cerebral pial arteriovenous malformation (AVM) were examined by reconstruction of serial sections to disclose the actual anatomical structure and to analyze the mechanism of gradual growth and rupture. More than seven arteriovenous shunts (AV-shunts) per case were found in all four cases, and these were divided into two types; one or a few shunts larger than 700 microm, and those with several shunts smaller than 700 microm in diameter. The former were located exclusively in the subarachnoid space and showed severe mural fibrosis. The vessels just ahead of and just behind these segments were also markedly involved by so-called arterialization of the vein and segmental loss of the internal elastic membrane (IEM), and/or smooth muscle cells (SMCs) and aneurysm formation of the artery. However, the smaller shunts were mainly localized in the cerebral parenchyma, where dilated small arteries showed abrupt loss of IEM and gradual loss of SMCs and transformed into dilated and tortuous veins, and the mural fibrosis was mostly absent at the shunts and segments ahead of and behind these shunts. It is suggested, on the basis of these findings, that AV-shunt of pial AVM occurs first in the subarachnoid space, probably prenatally, and gradually dilates along with developement of the brain and body, and that the subsequent abnormal burden of the blood inflow to the peripheral or related territory secondarily induces formation of new small AV-shunts mainly in the parenchyma. This secondary shunt formation may also be a component of growth of pial AVM in adults. Moreover, our reconstruction study suggested that hemorrhage of AVM is caused by rupture of not only dilated veins, but also intranidal microaneurysms and that thrombosis is not always necessary.

Atypical form of dural graft associated Creutzfeldt-Jakob disease: report of a postmortem case with review of the literature.

A postmortem case of an atypical form of dural graft associated Creutzfeldt-Jakob disease (CJD) is described. A 42 year old man developed progressive spastic paresis 163 months after a cadaveric dura mater graft. He presented with no myoclonus and very late occurrence of periodic synchronous discharges on EEG. The prion protein (PrP) gene was homozygous for methionine at the polymorphic codon 129. Neuropathological examination disclosed plaque-like PrP deposits with atypical distribution of synaptic PrP accumulations in the brain. This patient represents an atypical form of dural graft associated CJD characterised by unusual clinicopathological features.

Pathology of radiation myelopathy.

Radiation myelopathy is principally a white matter injury of the spinal cord induced by ionizing radiation after a certain latent period. It involves myelinated fibers and blood vessels, and the lateral funiculi is most preferentially affected. Several factors, such as radiation dose, fractionation or linear energy transfer, modify its occurrence and severity. Although glial cells and vascular endothelium are proposed to be the main targets, and to play a role in the pathogenesis of radiation myelopathy, experimental researches support that radiation-induced vascular damage resulting in vascular hyperpermeability and venous exudation is a basic process. Effect of ionizing radiation on each cellular component of the central nervous system, their contribution to radiation myelopathy, mechanisms of selective permeability and remaining problems are discussed.

Binswanger's encephalopathy: serial sections and morphometry of the cerebral arteries.

To identify arterial changes that are characteristic of Binswanger's encephalopathy (BE), we analyzed cerebral subarachnoid and medullary arteries of seven BE autopsy specimens by reconstruction of stained serial sections. We also noted the frequency of intimal fibrosis with or without atheroma of the subarachnoid arteries, and determined the medial thickness of the subarachnoid and medullary arteries. The results for the BE specimens were compared with those of six hypertensive brain hemorrhage (HH) specimens and six normotensive (NT) specimens from patients without cerebral abnormalities. In medullary arteries of BE in comparison with HH, we observed nonspecific but significantly more widespread intimal fibrosis with or without atheroma, as well as segmental loss of the medial smooth muscle cells (SMCs), which was sometimes associated with intimal plasma exudation or microaneurysm. A few medullary arteries in BE were completely occluded by fibrous connective tissue. Intimal fibrosis of the subarachnoid arteries was significantly more widespread in BE than in HH and NT. The media of the subarachnoid and medullary arteries was significantly thicker in BE and HH than in NT, and tended to be thicker in BE than in HH. In NT specimens the medullary arteries tended to be thinner in medial thickness than the subarachnoid arteries. These findings suggest that dysfunction of blood flow regulation due to increased arterial stiffness caused by hypertension-induced intimal fibrosis and loss of medial SMCs is an essential mechanism resulting in diffuse myelin loss of the cerebral white matter in BE, whereas luminal stenosis or occlusion and adventitial fibrosis are secondary. Moreover, selective and severe involvement of the cerebral medullary arteries compared with the subarachnoid arteries may be explained by the following two factors, (1) that many medullary arteries have normally dilated segments, and (2) that their media is thinner compared with that of the subarachnoid arteries of the corresponding diameter.

Nitric oxide synthase expression in ischemic rat retinas.

PURPOSE: To investigate the expression of nitric oxide synthase (NOS) in the ischemic retina. METHODS: Retinal ischemia was induced in rats by bilateral common carotid artery occlusion (BCCAO) for various lengths of time. Using the retina after BCCAO, expression of neuronal NOS (nNOS) and inducible NOS (iNOS) and identification of their positive cells were studied by histological and immunohistochemical examinations. RESULTS: Histological examinations revealed significant reduction in the thickness of the inner plexiform layer and the outer plexiform layer of the retina. Expression of nNOS was detected in retinal ganglion cells, amacrine cells, and Müller cells after BCCAO. The expression of nNOS and iNOS detected in Müller cells became stronger and persisted long after BCCAO. CONCLUSIONS: In the ischemic retina, Müller cells and retinal ganglion cells expressed nNOS and iNOS. These phenomena may be involved in the ischemic damage to the retina.

N-[4-(3-ethoxy-2-hydropropoxy)phenyl] acrylamide selectively induces apoptosis of cerebellar granule cells in vivo and in vitro in rats.

Oral administration of N-[4-(3-ethoxy-2-hydropropoxy)phenyl] acrylamide (EHA) induced selective granule cell destruction in the granular layer of the cerebellar cortex together with neurological signs, such as delayed righting reflex, gait or truncal ataxia, and convulsion. Neuropathologically, it caused multifocal granule cell destruction with nuclear pyknosis and spongiosis of the neuropile in the granular layer. Other neurons, including Purkinje cells, were spared. Ultrastructurally, damaged granule cells showed aggregation of nuclear chromatin and cytoplasmic edema, but cytoplasmic organelles were preserved. The brain uptake index of 14C-labeled EHA was similar to that of H2O. When EHA was added to rat cerebellar tissue cultures, only the granule cells showed nuclear pyknosis, aggregation of nuclear chromatin, and karyorrhexis with cytoplasmic swelling. These granule cells were positive for DNA fragmentation by the TUNEL method. These results suggest that EHA permeates the blood vessel wall and directly affects the cerebellar granule cells, resulting in selective granule cell apoptosis.

Postmortem study of ataxia with retinitis pigmentosa by mutation of the alpha-tocopherol transfer protein gene.

A new syndrome of ataxia and retinitis pigmentosa with vitamin E deficiency caused by the missense mutation of alpha-tocopherol transfer protein (alpha-TTP) gene was recently proposed. After studying the first postmortem case with this mutation pathologically and biochemically, whether the symptoms can be treated by supplementation of vitamin E or not is discussed. The major pathological findings were retinal atrophy; severe dying back-type degeneration of the posterior column; and massive accumulation of lipofuscin in neurons including dorsal root ganglion (DRG) cells, which were almost identical to those in vitamin E deficient animals and patients with fat malabsorption. Also, mild loss of Purkinje cells was noted. Because robust expression of alpha-TTP was detected in the cerebellum as well as in the liver and the tissue concentration of vitamin E in the cerebellum was still low even after oral supplementation, the mild Purkinje cell loss might be related to the mutant alpha-TTP in the cerebellum. By contrast, in the DRG, thought to be mainly responsible for ataxia, no expression of alpha-TTP was detected, and the tissue concentration of vitamin E increased to normal after supplementation. It is therefore considered that oral supplementation of vitamin E should effectively counteract the progression of ataxia.

An inherited prion disease with a PrP P105L mutation: clinicopathologic and PrP heterogeneity.

OBJECTIVE: To clarify a clinical and neuropathologic phenotype of an inherited prion disease associated with a missense mutation at codon 105 in the prion protein (PrP) gene that was originally described as a variant of Gerstmann-Sträussler-Scheinker disease demonstrating spastic paraparesis. METHODS: Two siblings from a Japanese family are described. PrP gene analyses, neuropathologic studies with immunohistochemistry, and Western blot analysis of the PrP were performed. RESULTS: Both patients showed a missense (proline-->leucine) mutation at codon 105 and a methionine/valine polymorphism at codon 129 of the PrP gene. Clinically, Patient 1 presented with progressive spastic paraparesis, ataxia, and dementia. Patient 2, the sister of Patient 1, showed prominent action myoclonus and dementia. Neuropathologically, multiple PrP-positive amyloid plaques and diffuse PrP deposition in the deep cortical layers were found in the cerebral cortex with primarily frontal dominant atrophy in both patients. Tau-positive pathologic structures including neurofibrillary tangles, neuropil threads, and dystrophic neurites around the plaques were abundant in the brain of Patient 2. In contrast, the tau pathology was scarce in Patient 1. Western blot analysis of the brain showed different patterns of detergent-insoluble PrP fragments between the patients. CONCLUSIONS: Despite the identical codon 105 mutation and codon 129 polymorphism of the PrP gene, remarkable clinical and neuropathologic differences, and PrP heterogeneity were present between the affected siblings. The phenotypic variability might be related to PrP heterogeneity.

Correlations between the apparent diffusion coefficient, water content, and ultrastructure after induction of vasogenic brain edema in cats.

OBJECT: The authors examined the correlation between changes in the apparent diffusion coefficient, regional water content, and tissue ultrastructure after vasogenic brain edema. METHODS: Vasogenic edema was induced in the white matter of six cats by cortical cold lesioning. The trace of diffusion tensor (Trace[D]) obtained from magnetic resonance imaging to measure the orientationally averaged water diffusibility was compared with the corresponding tissue water content determined by gravimetric studies and with ultrastructural water localization. Edema fluid had spread to the subcortical and deep white matter by 4.5 hours postlesioning. The increase in Trace(D) showed a significant linear correlation with the increase in tissue water content, both in the subcortical and deep white matter as follows: y = 45.5x - 2367 (r = 0.94) and y = 37.0x - 1769 (r = 0.93), respectively, where x is the water content (gram water/gram tissue) and y the Trace(D) (x 10(-6) mm2/second). On histological examination, nerve fibers were found to be dissociated in the white matter and the extracellular space was markedly enlarged with protein-rich fluid. No noticeable hydropic swelling of the cellular components was observed. CONCLUSIONS: A linear correlation was observed between increases in Trace(D) and increases in extracellular water volume in in vivo vasogenic brain edema. A similar correlation between the subcortical and deep white matter showing different arrangements of nerve fibers (parallel compared with intermingled, respectively) indicated that measurement of Trace(D) is a suitable parameter for the evaluation of vasogenic brain edema.

Involvement of the spinal posterior horn in Gerstmann-Sträussler-Scheinker disease (PrP P102L).

OBJECTIVE: The authors studied the pathomechanisms of the characteristics associated with Gerstmann-Sträussler-Scheinker disease (GSS). BACKGROUND: GSS, associated with a missense mutation at codon 102 of the prion protein (PrP) gene (GSS102), is a hereditary disorder that presents with progressive ataxia and dementia, and is characterized by the loss of deep tendon reflexes and painful dysesthesias of the legs in its early stage. METHODS: The authors conducted immunohistochemical studies of the spinal cord and peripheral nervous system in one of two patients from a Japanese family with GSS102 in comparison with patients with GSS105. RESULTS: The authors found intense PrP immunoreactivities mainly in the posterior horn of the spinal cord, but not in the dorsal root ganglia or peripheral nerves. In addition to PrP amyloid plaques, synaptic-type, fine granular PrP deposits were distributed in the spinal posterior horns. In contrast to the GSS102 patient, the spinal cords of the GSS105 patients showed no granular PrP deposits. CONCLUSIONS: The PrP abnormalities in synaptic structures of the spinal posterior horn may cause synaptic dysfunction that leads to loss of deep tendon reflexes and painful dysesthesias in patients with GSS102.

A clinical, genetic, neuropathological study in a Japanese family with SCA 6 and a review of Japanese autopsy cases of autosomal dominant cortical cerebellar atrophy.

This report concerns a Japanese family with genetically confirmed SCA 6, including an autopsy case, and a review of Japanese autopsy cases of autosomal dominant cortical cerebellar atrophy (ADCCA). The proband (Case 1) was a Japanese woman. She developed gait disturbance at age 62. The father and younger sister (Case 2) had the same disorder. She died at age 67 due to subarachnoid hemorrhage. Neuropathological examination revealed severe loss of Purkinje cells in the cerebellum, prominently in the dorsal vermis, and absence of neuronal loss in the inferior olives. Molecular genetic study showed the CAG-repeat expansion of SCA 6 gene. The younger sister (Case 2) developed gait disturbance at age 62. Neurological examination at age 66 revealed cerebellar signs without sensory disturbance. Neuroimaging at this time showed cerebellar atrophy, prominently in the vermis. She died of multiple myeloma at age 66. A neuropathological review of Japanese autopsy cases of ADCCA showed that there are two patterns in the distribution of cerebellar cortical lesions of Japanese patients with ADCCA. The distribution of cerebellar cortical lesions in genetically confirmed Japanese patients with SCA 6 is more prominent in the vermis than in the hemisphere.

Delayed recovery of auditory cortical evoked potentials is correlated with cortical neuronal death after transient cerebral ischemia in awake gerbils.

Early detection of irreversible neuronal change after transient cerebral ischemia is important so that adequate treatment can be initiated within the therapeutic window. We have examined the correlation between changes in middle-latency auditory evoked potentials (MAEPs) and histological changes in the auditory cortex of awake Mongolian gerbils subjected to 4 min or 12 min of transient cerebral ischemia. Post-ischemic MAEPs were characterized by the appearance of a markedly large negative and positive component at approximately 17-22 ms latency in both groups. Delay in the appearance of the high amplitude (maximal amplitude at 45 min after recirculation in the 12-min ischemia group) precedes the slowly developing death of neurons in the auditory cortex that results from transient cerebral ischemia.