Temporary occlusion of the middle cerebral artery in the monkey: clinical and pathological observations.
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Animals↗
Biomedical subjects
Y Olsson
Publications and source records attributed to Y Olsson.
Endothelin peptides in brain diseases.
Recently, scientists interested in diseases of the human brain have paid much attention to the endothelin group of peptides. Under normal conditions they are found in some types of neurons and in endothelial cells of microvessels but not in glial cells. This review focuses on the endothelin peptides and their involvement in various brain diseases. Particular attention is paid to their expression in reactive astrocytes seen in many pathological conditions of the human brain. Endothelin-1 is a very potent vasoconstrictor which may be involved in the vasospasm occurring in subarachnoid haemorrhage. Intracerebral injection or application to cerebral arteries in animals will cause a focal necrosis, apparently due to severe vasoconstriction. Reactive astrocytes occurring in cases with infarcts, lacunae, Alzheimer's disease, progressive multifocal leukoencephalopathy (PML) and subacute sclerosing panencephalitis (SSPE) express endothelin-like immunoreactivity. Astrocytes in vitro may produce, store and release endothelins. To some extent astrocytes grown in vitro mimic reactive astrocytes in vivo since in cultures astrocytes are removed from their natural environment which may trigger reactive responses. Therefore, in vivo reactive astrocytes may produce, store and release endothelins just as in vitro. If endothelins are released from reactive astrocytes they may act as mitogens and may influence microcirculation by inducing vasoconstriction of intracerebral arterioles. In such ways endothelins may contribute to the final lesions seen in cases with infarcts, lacunae, traumatic conditions, Alzheimer's disease and inflammatory diseases of the brain.
Animals↗
Positron emission tomography and computed tomography in differential diagnosis between recurrent or residual glioma and treatment-induced brain lesions.
In previous studies of supratentorial gliomas with positron emission tomography (PET) and computed tomography (CT), high uptakes of L-methyl-11C-methionine (11C-L-methionine) were found even in astrocytomas without blood-brain barrier defects as judged by CT or 68Ga-EDTA PET. In a number of patients examined after radiation therapy, there were no consistent changes in the high uptake values. In the present investigation PET and CT were compared with regard to their abilities to visualize and delineate recurrent tumors and treatment-induced brain defects and to differentiate between them. The study was undertaken on four patients who were long-term survivors after treatment for high-grade gliomas. For PET, 11C-L-methionine and 68Ga-EDTA were used. In two patients recurrent/residual tumors appeared considerably larger with 11C-L-methionine PET than with CT or 68Ga-EDTA PET. In one patient, no signs of recurrence were seen with any of these three methods, and in a fourth patient, whose condition was clinically stable, the findings at PET with 11C-L-methionine were non-specific. In areas corresponding to the surgical parenchymal defects, the 11C-L-methionine uptake and, except in one case, the local blood volume was markedly reduced. PET with 11C-L-methionine thus has a potential for distinguishing between postoperative brain lesions and tumor recurrence with a higher accuracy than CT.
Adult↗
Beta-amyloid precursor protein accumulates in axons around hematogenous metastases of the human brain: immunohistochemical observations.
Axonal changes which develop around hematogenous metastases of the human brain were studied by immunohistochemistry using a monoclonal antibody to beta-amyloid precursor protein (beta APP) and the ABC method combined with glucose-glucose oxidase technique and nickel enhancement. The metastases were obtained from 18 autopsy cases with pulmonary carcinomas and 6 control cases without clinical history or gross pathology of brain diseases. beta APP immunoreactive material was present in distended axons around all the investigated metastases. Such immunoreactive axons were located close to the invading tumor cells. No immunoreactivity was seen in 5 of the 6 controls. Our investigation indicates that axonal transport is disturbed around metastases, made visible by the accumulation of beta APP immunoreactive material. The axonal dysfunction may well influence the clinical symptoms in cases with brain metastases.
Adult↗