Purpose: In meningioma patients with postoperative residual masses, recurrent or primarily inoperable tumors, positron emission tomography (PET) with [(11)C]-L-methionine was used to evaluate treatment efficacy of IFN-alpha.Experimental Design: Twelve patients were treated with IFN-alpha at a dose of 1.5-5 million IU s.c. daily. PET, computed tomography, and/or magnetic resonance imaging were performed in all patients before and, at regular intervals, during IFN-alpha treatment. The ratio of tumor hot-spot uptake to cerebellar uptake or to cortex uptake was calculated. This ratio estimates the relative methionine accumulation in the tumor and presumably the proliferative activity in the tumor.Results: During IFN-alpha treatment, PET demonstrated a mean relative percentage of reduction in the uptake ratio (MRe1R) of 22.3% in the meningiomas. In nine patients who were considered responders, defined as patients with a positive MRe1R, the MRe1R was 30.4%. For the three nonresponders, defined as patients with a negative MRe1R, the MRe1R was -1.8%. Three patients were followed for a long time: two patients for 8 years and one patient for 4 years and 6 months; the two patients followed for 8 years are still on IFN. The volumes of these tumors were constant or showed a slight decrease. No correlation was found between histopathological diagnosis (PAD) WHO grading I-III of meningiomas and response to IFN-alpha treatment.Conclusions: PET was judged a useful method to predict which patients are suitable for long-term treatment with IFN-alpha and also for dose finding. In five patients treated from 9 months to 8 years, IFN-alpha seemed to be an effective oncostatic drug. The clinical usefulness of IFN-alpha, taking adverse reactions into account, must be evaluated in a larger series of patients.

Eighteen patients with intracranial skull base tumours diagnosed at CT or MR as neuromas or meningiomas were studied with positron emission tomography (PET) using L-(methyl-11C) methionine. Compared with normal cerebellar tissue, the uptake of methionine in the tumours increased more rapidly and reached a higher level, and showed a slow decline after a peak occurring about 5 min after the injection. All the meningiomas exhibited considerably higher accumulation of the tracer compared with the surrounding cerebellar tissue, which made the tumour easy to identify and to demarcate from the surrounding cerebellar tissue, which made the tumour easy to identify and to demarcate from the surrounding structures (tumour to cerebellum ratios 2.62-5.37, mean 3.63). The uptake was homogeneous in all meningiomas, which were all of the syncytial type. The neuromas showed lower contrast against the cerebellum (tumour to cerebellum ratios 1.1-1.87, mean 1.48). Some neuromas displayed an irregular pattern with regions of decreased tracer uptake corresponding to small cystic areas within the neuroma. There was no overlap in methionine uptake between the two tumour groups. The results indicate that PET-methionine may contribute to the evaluation, treatment planning and follow-up of patients with skull base meningiomas and neuromas.

Eleven cases of migraine with and without aura were investigated with positron emission tomography (PET). Regional cerebral blood flow (rCBF), oxygen metabolism (rCMRO2) and oxygen extraction (rOER) were measured during baseline (n = 11), aura (n = 6), headache (n = 10) and after treatment with sumatriptan (n = 4). Data were analysed using an ROI-based approach from 26 different anatomically defined regions, and also an exploratory approach whereby all subjects were normalized to a stereotactic brain atlas; t-maps were constructed by depicting significant changes between states. The exploratory approach revealed a region corresponding to the primary visual cortex with significant reductions in rCBF (23.1%) and rCMRO2 (22.5%), but no change in rOER during the headache phase compared to baseline. These data suggest that cerebral ischemia was not the primary cause of the attacks in these cases.

The growth of meningioma in vivo may be mediated by a growth factor. We evaluated inhibitory effect of IFN-alpha on DNA synthesis promoted by PDGF and EGF on meningioma cell cultures. Eight cases of meningioma were tested for the expression of PDGF receptor. The effects of PDGF AA, PDGF BB, EGF and TGF-beta1 on five meningioma cell cultures were investigated by measuring 3H-thymidine incorporation during 24 hours of incubation with the growth factors under serum-free culture conditions. The incorporation of 3H-thymidine was elevated in all of the five tested tumor cell cultures after the addition of PDGF BB and EGF. Maximal stimulation was observed on three cultures with EGF and two cultures with PDGF BB. Under the same culture conditions, simultaneous incubation with IFN-alpha inhibited the 3H-thymidine incorporation promoted by PDGF and EGF. Our results indicate the inhibitory effect of IFN-alpha both on DNA synthesis promoted by PDGF and EGF, and on the meningioma cell proliferation. The present study also demonstrates the inhibitory effect of TGF-beta 1 in meningioma cell culture.

We have investigated the effects of interferon-alpha (IFN-alpha) and 5-fluorouracil (5-FU) on meningioma cells in two different culture systems, evaluated by the uptake of radiolabelled methionine. With both IFN-alpha and 5-FU an inhibitory effect on the uptake of radiolabelled methionine by the meningioma cells was demonstrated, and we found a synergistic inhibitory effect with a combination of IFN-alpha and 5-FU. To obtain a maximal inhibition of cell metabolism without causing cell toxicity, we were able to decrease the dose of 5-FU by simultaneously adding IFN-alpha. Our results suggest that a combined treatment of IFN-alpha and 5-FU may be a successful alternative for patients with inoperable meningiomas. A novel in vitro positron emission tomography technique was used for the study of metabolic changes in tumour cells caused by drug treatment, which is complementary to conventional cell culture techniques.

Mutations in the TP53 tumor suppressor gene have been studied in different types of brain tumors. Little is known about this genetic event in human meningioma, a mostly benign tumor. To investigate the frequency of TP53 gene mutations in human tumors derived from meningeal tissues, paraffin‐embedded tissues from 30 cases (including 2 malignant and 4 atypical meningiomas, as well as 2 hemangioblastomas and 3 hemangiopericytomas) were screened by immunohistochemistry. Polymerase chain reaction/single strand conformational polymorphism (PCR/SSCP) and direct DNA sequencing were thereafter performed in selected cases. Nuclear p53 staining was not seen in any of the 19 benign meningiomas tested, while atypical meningiomas, hemangioblastomas, and hemangiopericytomas displayed nuclear staining in a subpopulation of tumor cells in 4 out of 5, 2 out of 2, and 3 out of 3 cases, respectively. One malignant meningioma showed an intense nuclear staining and a band shift in SSCP. In this case, we identified a mutation in the TP53 gene at codon 161 changing GCC to ACC and resulting in an alteration of alanine to threonine in this position. Our results indicate that TP53 gene mutation may be considered as a marker for malignant transformation in meningioma. p53 immunoreactivity, even in the absence of detectable gene mutation, is also associated with atypia and does not appear in regular benign meningiomas. © 1995 Wiley‐Liss, Inc.

Effects of exogenous leukotrienes and/or treatment with the 5-lipoxygenase inhibitor, AA-861, on the 3H-thymidine uptake were investigated in a human glioma cell line, U-343MGa, growing as monolayers or multicellular spheroids. The spheroids contained about four times more endogenous leukotrienes than the monolayers. Administration of 0.1 microM exogenous leukotriene D4 increased the 3H-thymidine uptake in the spheroids while it gave a decrease in the monolayers. Inhibition of 3H-thymidine uptake was induced in the spheroids by 10 microM AA-861 and this inhibition was only seen during the period at which central necrosis develops in the spheroids. This drug showed an inhibitory effect on monolayers one day after subculture but gave no measurable effect on the monolayers two days later. It seemed that AA-861 exerted an inhibitory action at culture conditions associated with "cellular stress" such as subculture (trypsinization) of monolayers and induction of necrosis in spheroids. Induction of "cellular stress" with heat or exposure to a Ca(2+)-ionophore also gave an inhibitory action of AA-861 and the inhibition could be counteracted by administration of exogenous B4 leukotrienes. The observed effects are probably related to the activation of the arachidonic acid cascade and indicate that leukotrienes in some way interact with "cellular stress" and induce acute changes in 3H-thymidine uptake. Further research is necessary to reveal the detailed molecular mechanisms.

Several reports have demonstrated effects of lipoxygenase products on DNA synthesis; in normal lymphocyte mitogenesis (1), psoriasis (2), neuroblastoma cells (3), erythropoietin stimulated erythroid progenitor cells (4), and prostate PC-3 cells (5). The inhibitior of eicosanoid biosynthesis, eicosatetraynoic acid (ETYA), decreased the DNA synthesis in the malignant human monocyte- macrophage U-937 line, and this effect was partially reversed by leukotriene C4 (6). The lipoxygenase inhibitor nordyhidroguaiaretic acid (NDGA) enhanced the glucocorticoid stimulated cell inhibition (7).

In 115 patients with pituitary macroadenomas, the findings on mid-field MRI were correlated with the hormonal activity of the tumours. Adenomas secreting growth hormone (GH), prolactin (PRL) and clinically nonsecretory adenomas were studied. Tumour size, invasiveness and signal intensity patterns were recorded. Relaxation times and ratios of signal intensity and proton density (relative to the corpus callosum) were analysed in areas of apparently solid tissue in a subgroup of 59 previously untreated patients. Invasiveness was more common in PRL- and GH-secreting adenomas than in the nonsecreting ones. Diffuse invasion of the base of the skull was most common in prolactinomas, and associated with a lower frequency of suprasellar tumour extension. In prolactinomas, a correlation was found between the maximum serum PRL level and tumour size. Haemorrhagic, cystic or necrotic areas were less common in GH-secreting tumours than in the other types. Haemorrhage was more common in prolactinomas than in nonsecreting tumours. MR parameters were similar in prolactinomas and nonsecreting adenomas, but indicated a smaller amount of water in GH-secreting tumours.

Seven patients with clinically nonsecreting pituitary adenoma and 5 patients with meningioma were examined with positron emission tomography using [11C]-LL-deprenyl and [11C]-LL-methionine. The dynamics of the uptake of [11C]-L-deprenyl in the pituitary adenomas demonstrated a rapid and high uptake immediately after the injection, and, later, an almost constant level was observed that was equal to or higher than that observed in normal brain tissue. In the meningiomas, however, the initially high uptake was followed by a marked decrease with time, reaching a level that was approximately half that observed in brain tissue. The study demonstrated high binding of [11C]-L-deprenyl to monoamine oxidase B in pituitary adenomas, whereas the binding in meningiomas was very low. This fact can be used in the differential diagnosis of pituitary adenoma and parasellar meningioma. Operative samples from 10 patients with meningioma and from 5 patients with pituitary adenoma were analyzed biochemically for activity of monoamine oxidase B, using [14C]-phenyl-ethylamine as substrate. The nonsecreting pituitary adenomas demonstrated high enzyme activity, the secreting adenomas about one-tenth of that of the nonsecreting, and the meningiomas one-thirtieth of that of nonsecreting adenomas.

PURPOSE To study the changes in macroprolactinomas during long-term bromocriptine therapy by means of serial MR imaging, and to correlate the findings to the serum prolactin (S-PRL) levels. PATIENTS AND METHODS Thirteen patients with macroprolactinomas were studied before and during bromocriptine therapy; six to 11 MR examinations were performed with a duration of follow-up of 22 to 74 months. Tumor size, extension, relationship to adjacent structures, and signal intensity patterns were evaluated. Signal intensity ratios and T2 values were calculated in areas of apparently solid tumor tissue. RESULTS Bromocriptine effectively reduced the size of all tumors; the size reduction was already significant at 1 week, but often continued for several years. Reenlargement during therapy was seen in three cases. The development of chiasmal herniation parallel to increasing cisternal invagination into the sella was a common finding, but was not correlated to visual symptoms. Signal intensity patterns corresponding to hemorrhage, cysts or necrosis were frequently observed, and transitions from one pattern to another were common. Hemorrhage occurred mainly in tumors corresponding to high initial serum prolactin levels. After 1 year of therapy, there was a significant increase in T2 values, indicating an increased water content in residual solid tumor tissue. CONCLUSIONS MR is valuable for follow-up in bromocriptine therapy of macroprolactinomas, and provides new information on the tumor size changes, the inner structure of the tumors, and the optic chiasm.

The findings on mid-field MR imaging and CT were compared retrospectively in 65 patients with pituitary macroadenomas. The evaluation comprised tumour extension and delineation, invasiveness, relationship to adjacent structures, and internal tumoral changes. MR was superior to CT except in the demonstration of bone changes and tumour calcification. The superiority of MR was most pronounced regarding cavernous sinus invasion, tumour relationship to the carotid arteries and optic chiasm, and tumour haemorrhage. Extensive bone changes were visualized with both methods; erosions were often seen only with CT. It is concluded that MR is the preferable method for evaluation of pituitary macroadenomas. CT is useful as a supplementary modality when detailed information on bone anatomy is required, particularly if a transsphenoidal surgical approach is contemplated.

Human glioma (U-343 MGa) and human colon carcinoma (HT-29) cell lines were cultured as multicellular spheroids, and the accumulations of the L- and D-enantiomers of 11C-methionine were investigated. The accumulation of radioactivity in the spheroids was expressed as relative counts, by dividing the radioactivity measured in the spheroid with the radioactivity of the same volume of the incubation medium. The experiments were verified using 14C-labeled L- and D-methionine. The influence of spheroid volume, specific activity, incubation time, washing time, and the environmental temperatures were investigated. The spheroid model was used to determine the effect of the lipoxygenase inhibitors BW A4C and AA-861, the ether-phospholipid type PAF-antagonist CV-6209 and the protein synthesis inhibitor cycloheximide on methionine uptake. The results showed that 11C-L-methionine can be applied in the study of drug effects on multicellular tumor cell aggregates.

Positron emission tomography (PET) was used in over 400 examinations in patients with pituitary adenoma. It was demonstrated that PET with carbon-11-methionine can give valuable complementary information in the diagnosis of this tumor due to PET's ability to adequately depict viable tumor tissue in contrast to fibrosis, cysts and necrosis. Furthermore, PET with dopamine D2 receptor ligands can characterize the degree of receptor binding and thus give information as to the prerequisites for dopamine agonist treatment. Most important is the very high sensitivity given by PET with carbon-11-methionine in the evaluation of treatment effects. It is concluded that when properly used PET can be fully justified in the clinical handling of patients with pituitary adenomas and other intracranial tumors.

In situ hybridization histochemistry was employed to detect mRNAs of pituitary hormones and chromogranins in normal pituitary gland and pituitary adenomas. Oligonucleotide probes specific to the mRNAs for prolactin, growth hormone, proopiomelanocortin, the alpha- and beta-subunits of the glycoprotein hormones and chromogranins A and B were used in the hybridization experiments. The oligonucleotides of 27 to 51 bases were labelled radioactively with dATP[alpha-S-35] at the 3'-end using terminal deoxynucleotidyl transferase. Positive hybridization reactions were visualized by autoradiography in the normal pituitary gland with all of the probes. The clinically diagnosed pituitary adenomas (prolactinoma, acromegaly, Cushing's disease, FSH-secreting tumour) showed positive hybridization with the corresponding oligonucleotide probes. In some cases positive hybridization was also obtained with other probes, suggesting multi-hormone-producing character of the tumour cells. A microprolactinoma was found in a pituitary gland obtained from a patient without any known pituitary disorders. Examination of mRNAs for chromogranin A and B revealed that the normal pituitary gland contains a larger number of cells expressing chromogranin B and a lower number expressing chromogranin A and, moreover, the microprolactinoma lacked the expression of mRNA for chromogranin A but expressed that of chromogranin B.

Cell lines of human glioma (U-343 MGa and U-251 MG) and human glia (U-533 CG) origin were cultured as monolayers and exposed to CV-6209, an alkyl-phospholipid analog and antagonist of platelet activating factor. This drug had very potent antiproliferative effects on the studied human glioma cell lines; IC50 was 0.9 μM after 48 h treatment and 0.2 μM after 2 weeks treatment. At these doses no growth inhibitory effect was noted on the normal glia cells. The effects on the glioma cells were reversible in the dose intervals, where cell proliferation, 3H-thymidine and 14C-methionine uptakes were greatly inhibited. The simultaneous administration of platelet activating factor [(R)PAF] did not influence the antiproliferative effects of CV-6209 on the cells cultured as monolayers. The structurally similar analog CV-3988 also had antiproliferative effects, although at 10 times higher concentration than CV-6209. Two other, structurally unrelated, PAF-antagonists (WEB-2086 and TCV-309) gave effects only at very high concentrations. The U-343 MGa cell line was also exposed to CV-6209 when growing as multicellular spheroids. The studies on the spheroid cultures also demonstrated good antitumoral effects with decreases of both the volume growth and the thymidine uptake. The simultaneous administration of (R)PAF reversed the inhibitory effect of CV-6209 on thymidine incorporation. This study demonstrates a strong antitumoral effect at low concentrations of CV-6209. The antiproliferative effects were probably primarily related to the ether-lipid structure and not to the PAF-antagonistic properties. The good antitumoral effect of CV-6209 on both monolayer and spheroid cultures and the possible PAF-antagonistic properties are discussed.