This trial failed to demonstrate that the addition of surgery to radiation therapy improved outcome of patients with a single brain metastasis. Thus, the efficacy of surgery plus radiation compared with radiation alone needs to be addressed by further clinical trials and/or a meta-analysis.

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Astrocytes are involved in multiple brain functions in physiological conditions, participating in neuronal development, synaptic activity and homeostatic control of the extracellular environment. They also actively participate in the processes triggered by brain injuries, aimed at limiting and repairing brain damages. Purines may play a significant role in the pathophysiology of numerous acute and chronic disorders of the central nervous system (CNS). Astrocytes are the main source of cerebral purines. They release either adenine-based purines, e.g. adenosine and adenosine triphosphate, or guanine-based purines, e.g. guanosine and guanosine triphosphate, in physiological conditions and release even more of these purines in pathological conditions. Astrocytes express several receptor subtypes of P1 and P2 types for adenine-based purines. Receptors for guanine-based purines are being characterised. Specific ecto-enzymes such as nucleotidases, adenosine deaminase and, likely, purine nucleoside phosphorylase, metabolise both adenine- and guanine-based purines after release from astrocytes. This regulates the effects of nucleotides and nucleosides by reducing their interaction with specific membrane binding sites. Adenine-based nucleotides stimulate astrocyte proliferation by a P2-mediated increase in intracellular [Ca2+] and isoprenylated proteins. Adenosine also, via A2 receptors, may stimulate astrocyte proliferation, but mostly, via A1 and/or A3 receptors, inhibits astrocyte proliferation, thus controlling the excessive reactive astrogliosis triggered by P2 receptors. The activation of A1 receptors also stimulates astrocytes to produce trophic factors, such as nerve growth factor, S100beta protein and transforming growth factor beta, which contribute to protect neurons against injuries. Guanosine stimulates the output of adenine-based purines from astrocytes and in addition it directly triggers these cells to proliferate and to produce large amount of neuroprotective factors. These data indicate that adenine- and guanine-based purines released in large amounts from injured or dying cells of CNS may act as signals to initiate brain repair mechanisms widely involving astrocytes.

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Patients with primary and metastatic brain tumours achieved functional gains after rehabilitation. High functional improvement is a significant predictor of longer survival in brain metastases and GBM. This study has implications for rehabilitation in the post-acute management of patients who have disabilities due to brain tumours.

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Nitric oxide (NO), a diffusible and unstable gas, has been implicated in inter‐ and intra‐cellular communication in the nervous system. NO also plays a role in neural development, plasticity and alterations of synaptic function such as long‐term potentiation and long‐term depression (Gally et al.: Proc NY Acad Sci, 87:354–355, 1990; Zhuo et al.: Science 260:1946–1950, 1993; Schuman and Madison.: Science 254:1503–1506, 1991; Bruhwyler et al.: Neurosci Biobehav Rev 17:373–384, 1993) some of which likely involve growth and remodelling of neurites. Some actions of NO are mediated directly by protein modification (e.g., nitrosylation) and others by activation of soluble guanylyl cyclase (soluble GC), which increases intracellular levels of guanosine 3′,5′‐cyclic monophosphate (cGMP). NO is synthesized by the enzyme nitric oxide synthase (NOS), which is induced by treatment of CNS neurons (Holtzman et al.: Neurobiol Disease 1:51–60, 1994) or pheochromocytoma PC12 cells (Hirsch et al.: Curr Biol 3:749–754, 1993) with NGF. NO has been proposed to mediate some of the effects of NGF on PC12 cells by inhibiting cell division (Peunova and Enikolopov: Nature 374:68–73, 1995). In addition, NO can substitute for NGF by delaying the death of trophic factor‐deprived PC12 cells through a mechanism that does not involve a cytostatic action (Farinelli et al.: J Neurosci 16:2325–2334, 1996). We investigated whether NO stimulated neurite outgrowth from hippocampal neurons and PC12 cells. Primary cultures of E17 mouse hippocampal neurons co‐cultured with neopallial astrocytes were exposed to the NO donors sodium nitrite (100 μM) or sodium nitroprusside (100 nM). After 48 hr, NO donor‐treated cultures contained a greater proportion of cells bearing neurites and neurites that were much longer than those found in control cultures. In cultures of PC12 cells, NO donors also enhanced the neuritogenic effects of NGF. The proportion of PC12 cells with neurites 48 hr after exposure to NO donors sodium nitrite (100 μM–10 mM) or sodium nitroprusside (100 nM–1 μM) plus 2.5S nerve growth factor (NGF) was approximately twice the proportion of cells with neurites in sister cultures grown in NGF alone. Neither of the NO donors elicited neurites from the PC12 cells in the absence of NGF. The effects of the NO donors were likely mediated by release of NO since their effects were antagonized by addition of hemoglobin, which avidly binds NO, to the culture medium. The enhancement by NO of NGF‐mediated neurite outgrowth in PC12 cells appeared to occur through a cGMP‐dependent mechanism. The NO donors stimulated a prompt increase in intracellular cGMP in PC12 cells. Moreover their action was mimicked by addition of the membrane‐permeant cGMP analogs 8‐Bromo‐cGMP (8‐Br‐cGMP) and para (chlorophenylthio)‐cGMP (pCPT‐cGMP) to the culture medium and by atrial natriuretic factor which stimulates particulate guanylyl cyclase. The neuritogenic activity of the NO donors was inhibited by LY83583 and methylene blue, inhibitors of guanylyl cyclase. These data i...