Incidental lesions should be considered a cause of false-positive findings (6.1%) when an imaging diagnosis is made of a functioning pituitary microadenoma.

The ability of MET-PET to reflect the biological nature of gliomas makes it an excellent method for monitoring active tumor tissue, and treatments based on its findings should provide a powerful clinical protocol in the course of glioma therapy.

Plasma and cerebrospinal fluid (CSF) endothelin (ET)-1-like immunoactivity in 27 patients with aneurysmal subarachnoid hemorrhage (SAH) was measured serially by radioimmunoassay for 2 weeks after SAH onset. Mean ET-1-like immunoactivity levels in plasma of patients with SAH were highly elevated during the whole study period, while the levels in CSF of the same patients were not. Plasma ET-1-like immunoactivity levels in patients with SAH classified as Fisher computerized tomography (CT) Group 3 were higher than those in patients with SAH classified as Fisher CT Groups 1 and 2. There were no significant differences in plasma ET-1-like immunoactivity levels between the patient groups stratified by Hunt and Kosnik grade. In this series, plasma ET-1-like immunoactivity levels in the 12 patients with vasospasm were higher than those in the 15 patients without vasospasm during the 1st week; CSF ET-1-like immunoactivity levels in patients with vasospasm were in the normal range on Days 0 to 3 after SAH onset, then became elevated on Days 5 to 7 and remained high until the end of the 2nd week. In contrast, CSF ET-1-like immunoactivity levels in patients without vasospasm were within the normal range during the entire period of study. The time course of the occurrence of vasospasm and that of the increase in CSF ET-1-like immunoactivity coincided precisely. The possible role of endogenous ET-1 in the pathogenesis of vasospasm due to SAH is discussed.

No abstract

We present morphological data of the early stage of tumor invasion in the central nervous system. C6 rat glioma cells were injected into the caudate-putamen of rat brain using glass micropipettes to minimize traumatic reactions. Four days after the inoculation, we examined the tumor-brain interface using light and electron microscopy. Ultrastructurally the tumor processes were attached to the perivascular basement membrane instead of the astroglial end-feet. At the tumor periphery, the vessel walls were in contact with both tumor processes and astroglial end-feet. Astrocytes withdrew their processes from the vascular walls and changed into a reactive phenotype, while the neuronal cells remained virtually intact, even when surrounded by tumor cells. Immunohistochemical study using C6 cells labeled with bromodeoxyuridine showed migration of the cells toward the perivascular space that was distant from the site of injection. These observations represent the earliest morphologically detectable changes of the tumor-brain interface, and suggest that the C6 cells possess the characteristics of high affinity to the endothelial basement membrane and invade along the preexisting blood vessels with brain parenchymal infiltration.