A scanning electron microscopy study of vascular casts from senile human brains.

A scanning electron microscope study was performed of vascular casts from 26 senile human brains. In 15 of these, three types of arterial deformities (glomerular loop formations, vascular wickerworks and bundles) were frequently encountered. They were compared with the appearance in microangiograms and histological sections.

Cerebral aneurysm in an infant with fibromuscular hyperplasia of the renal arteries. Case report.

The authors report a case of subarachnoid hemorrhage in an 11-month-old infant with tragic outcome. Radiological investigation showed an anterior communicating aneurysm, and postmortem examination confirmed the aneurysm to be a so-called "berry" aneurysm. There were also typical signs of fibromuscular hyperplasia of the renal arteries. The microscopic findings are discussed. In view of the rarity of both aneurysms and fibromuscular hyperplasia in such a small child, a possible association of these entities suggested by several earlier investigators is reviewed.

Fibrinolytic activity in the walls of cerebral saccular aneurysms.

The fibrinolytic activity of 28 cerebral saccular aneurysms from 24 patients and of controls consisting of 10 cerebral arteries has been studied by Todd's autography technique. An increased activity was seen in the minute adventitial vessels and in the endothelium in ruptured cerebral saccular aneurysms, but the aneurysms showed somewhat less activity than the surrounding arteries. Seven patients with subarachnoid haemorrhage had the same increase in fibrinolytic activity in the aneurysmal wall despite antifibrinolytic therapy ante mortem. This finding has been discussed.

Late effects on rabbit brain morphology and monoamine metabolites produced by 60C0-irradiation.

Twenty-three rabbits were exposed with 60Co irradiation over the skull. Nineteen of the animals received 29.6 Gy over the right hemisphere and 4 animals received 20 Gy over both hemispheres. Six months after the exposure the cncentrations of 5-hydroxyindolacetic acid (5-HIAA) and homovanillic acid (HVA) in seven different brain regions were assayed. No significant differences in the levels of these monoamine metabolites as compared to nonirradiated control animals were found. In contrast to discrete biochemical changes, a relatively marked parenchymal destruction was demonstrated by means of light microscopy, microangiography and scanning electron microscopy of the vessels, which exhibited telangiectases, fibrinoid necroses and thrombosis due to the late effects of irradiation.

Effect of sympathetic denervation on chronic cold injuries in rabbit brain. A microangiographical and histological study.

Sympathetic denervation of the brain vessels was performed uni- or bilaterally in 13 adult rabbits, and cortical cold lesions were induced bilaterally 10-18 days afterwards. After a further 4-35 days the vascular and morphological changes in the lesion areas were studied histologically and with angiography. No difference was observed between the denervated and the non-denervated lesion areas. The results are discussed with regard to a proposed functional plasticity of the chronically denervated brain vessels and/or to possible changes in metabolic demands of the brain tissue.

Enzymatic destruction of the elastic lamella at the mouth of cerebral berry aneurysm? An ultrastructural study with special regard to the elastic tissue.

Destruction of the elastic tissue is probably an acquired lesion and is decisive for the appearance of cerebral arterial aneurysms at the sites of congenital media defects. The elastic component in the mouths of aneurysms has therefore been studied by electron microscopy, using two new staining methods, i.e. ruthenium-red staining and prolonged osmium-tetroxide treatment. The hypertrophic, duplicated, elastic lamellae showed a disintegration of their luminal portions not earlier described. In close connection with the disintegrated portions, extracellular lysosome-like granules were observed. It is hypothesized that discharged leucocyte grannules containing elastase help to destroy the elastic lamellae.

Arterial cell renewal after experimentally induced thrombosis.

Thrombosis was experimentally induced in one common carotid artery in 40 rats. One hour to 180 days afterward, the cell renewal in the arterial wall was studied by tritiated thymidine autoradiography. An increased number of labeled cells were observed, especially in the early developmental phase of the thrombosis and mainly in the tunica media. These findings seem to accord best with the hypothesis that the thrombi are mainly organized by smooth muscle cells from the tunica media, which are partly dedifferentiated toward fibroblast-like cells.

The angio-architecture of normal, hypertrophic and denervated muscle. A study in the rat, using micro-angiography and the scanning electron microscope.

The angio-architecture of normal, hypertrophic and denervated rat muscles was studied by micro-angiography and by scanning electron microscopy of vascular casts made of methylmethacrylate. In hypertrophy, there was a slightly coarse-meshed irregular capillary network with some loss of normal parallelism, an increased calibre and a slight spiralization of all vessels. Probably all these changes, except the slight spiralization, increase the circulation. In denervation atrophy, the vascular pattern was much more irregular, with much more marked spiralization and loss of parallelism and narrowed capillaries. The changes probably contribute to the impairment of the circulation.

Vascular and morphological changes in the urinary bladder wall after irradiation.

Twelve adult rabbits were used to study radiation-induced changes in the urinary bladder by angiographic, microangiographic, light microscopic and scanning electron microscopic methods. Angiographic, microangiographic and light microscopy examinations were performed on 2 animals in which the urinary bladders were not irradiated and on 4 animals in which parts of the bladders received high radiation doses of 60Co. The bladders irradiated in this manner exhibited advanced changes within a shorter time after irradiation than those in an earlier study. In this study a lower dose of irradiation was given over the entire bladder. Otherwise, the radiation changes were similar. Light and scanning electron microscopic studies were carried out on 2 normal and 4 irradiated bladders. In the latter, atrophy of the mucosa, epithelial desquamation, cellular atypisms and ulcerations were observed.

Scanning electron microscopy of saccular intracranial aneurysms.

Eight intracranial saccular aneurysms from 6 autopsies were studied with the scanning electron microscope and the cerebral arteries from control autopsies and rabbits were compared. The intima of the aneurysms had a more uneven and rugged surface than the surroundings. Only slight atherosclerotic changes were discovered in the immediate vicinity of the aneurysms. The windows of the internal elastic lamella were enlarged at the mouth of the aneurysms; the edge of the muscle layer was rounded and showed fibrosis. The structure of the walls of the aneurysms differed from that of the control arteries because they were composed of collagenous connective tissue. The adventitia of the aneurysms resembled that of control arteries. The findings are in accord with the assumption that saccular aneurysms develop at sites of developmental media defects. The internal elastic lamella over the area of the media defect shows primarily compensatory hypertrophy and later degeneration, extension and decay.