An autopsy case of a 52-year-old man suffering from chronic manganese poisoning (CMP) is reported with determination of the manganese distribution in the brain. The patient had been working in a manganese ore crushing plant since 1965. In 1967 he began to complain of difficulties in walking and diminished libido. Later, he developed various neuropsychiatric symptoms including euphoria, emotional incontinence, masked face, monotonous speech, "cock-walk", increased muscle tone, weakness of upper and lower extremities, tremor of the eye lids, and exaggeration of knee jerks. The major neuropathological change was degeneration of the basal ganglia, in which the pallidum was severely affected. The pallidum disclosed a loss and degeneration of nerve cells, which was especially marked in the medial segment, a prominent decrease of myelinated fibers, and moderate astrocytic proliferation. The substantia nigra was intact. Distribution of manganese in the brain of the present case of CMP was determined using flameless atomic absorption spectrometry and compared with control cases and also a case of Parkinson's disease (PD). There was no significant difference between the control cases and the case of PD in average concentration of manganese and its distribution in the brain. The present case of CMP showed no elevation in average concentration of manganese in the brain. However, there were some changes in its distribution. Thus, the continuance of neurological disorders in CMP is not linked to an elevated manganese concentration itself in the brain. CMP appears to be different from PD in neuropathology and manganese behavior in brain.

Background and Purpose-There is little information regarding the pathogenesis underlying diffuse myelin loss in the cerebral white matter and sparing of the U fibers in cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), in which the medial smooth muscle cells of systemic arteries are characteristically involved. We sought to examine the precise extent and severity of changes in the cerebral arteries in an autopsy case of CADASIL in relation to pathogenesis of the diffuse myelin loss. Methods-We reconstructed 1000 serial sections of the frontal cerebral medullary arteries of an autopsy subject, which was the first identified Japanese case of CADASIL, as confirmed by the presence of ultrastructural deposits of granular osmiophilic material in the media of some visceral arteries and by genetic analysis. Results-We reconstructed 11 medullary arteries of the frontal lobe showing diffuse myelin loss and atrophy of the white matter with sparing of the U fibers. All of these showed complete loss of medial smooth muscle cells over their entire length and severe adventitial fibrosis. Although intimal fibrosis or hyalinosis was present, luminal occlusion was scarce. These changes were also observed in the small and large arachnoidal arteries but were relatively mild in the latter and in the cortical and subcortical medullary arteries. Conclusions-These arterial changes resulted in transformation of the cerebral arteries, in particular almost all the medullary arteries, to a so-called earthen pipe state. This supports the reported findings of a reduction in vascular reactivity to fluctuations in CO 2 levels and systemic blood pressure in CADASIL.

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.

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.