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  • 1
    Electronic Resource
    Electronic Resource
    Linkage between O6-methylguanine-DNA methyltransferase (O6-MT) activity and cellular resistance to antitumour nitrosoureas in cultured rat brain tumour cell strains (1990)
    Springer
    Acta neurochirurgica 103 (1990), S. 62-66 
    Details
    ISSN: 0942-0940
    Keywords: O6-methyl-DNA methyltransferase (O6-MT) ; nitrosoureas ; nimustine (ACNU) ; ramustine (MCNU) ; glioma cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have examined O6-methylguanine-DNA methyltransferase (O6-MT) activity of rat brain tumour cell strains with reference to cellular resistance to antitumour nitrosoureas, 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (nimustine, ACNU) and methyl-6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-α-D-glucopyranoside (ramustine, MCNU). The values of O6-MT activity were 52 and 160 fmol/mg protein extract in 9 L and C 6 rat brain tumour cells, respectively; while HeLa S 3 cells, as a methyl excision repair positive (Mer+) cell strain, revealed a rather high value of 488 fmol/mg. 9 L cells indicative of a low O6-MT activity showed 13 μM for ACNU and 18 μM for MCNU at a 10% survival dose (SD10), determined by a clonogenic cell assay as an index of cellular resistance. In contrast to this, C 6 cells revealed a SD10 value of 67 μM and 36 μM for ACNU and MCNU, respectively, indicating higher resistance than 9 L cells. HeLa S 3 cells showed the highest SD10 value as follows: 84 μM for ACNU and 73 μM for MCNU. The relationship between the O6-MT activity and the cellular resistance was almost linear, with relatively resistant cell lines exhibiting the higher levels of the O6-MT activity. This correlation between the O6-MT activity and the cellular resistance to nitrosoureas as ACNU and MCNU was not observed among other antitumour drugs, which included bleomycin (BUM), neocarzinostatin (NCS),cis-diamminedichloroplatinum (II) (CDDP), and etoposide (VP-16) in clinical use for brain tumour chemotherapy. This indicates that O6-MT activity can be an indicator of cellular resistance to antitumour nitrosoureas in the chemotherapy of brain tumours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01420193
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  • 2
    Electronic Resource
    Electronic Resource
    Early and late stage positron emission tomography (PET) studies on the haemocirculation and metabolism of seemingly normal brain tissue in patients with gliomas following radiochemotherapy (1988)
    Springer
    Acta neurochirurgica 93 (1988), S. 110-115 
    Details
    ISSN: 0942-0940
    Keywords: Gliomas ; gray matter ; positron emission tomography (PET) ; radiochemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Haemocirculatory and metabolic changes in seemingly normal brain tissue following radiochemotherapy including nimustine hydrochloride (ACNU) and tegafur (FT) were analyzed using oxygen-15 and fluorine-18 positron emission tomography (PET) in seven patients with gliomas. At an early stage (within one month) after radiochemotherapy, marginal increases in regional cerebral blood flow (rCBF) and cerebral blood volume (rCBV) were found contralateral to the tumour in gray matter which was apparently normal brain structure, as seen on computerized tomography (CT). The oxygen extraction fraction (rOEF) decreased significantly (p 〈 0.05 by a paired-t test) from that of the pretreatment study, due to surgical decompression and radiochemotherapy. At the late stage (three to thirty-one months with a mean of thirteen months), rCBF decreased significantly from the early stage study (p〈0.05); oxygen consumption (rCMRO2) fell in all cases significantly from the pretreatment study (p〈0.01) and from the early stage study (p〈0.05); consequently, rOEF remained unchanged at a level similar to the early stage study. Glucose consumption (rCMRGl) increased slightly as compared with the early stage study but failed to be restored to the level of the pretreatment study. Noteworthy was a coupling reduction of rCBF and rCMRO2—presumably, a late delayed effect of radiochemotherapy. These preliminary results indicate that with PET studies it may be possible to predict damage to normal brain tissue after radiochemotherapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01402891
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  • 3
    Electronic Resource
    Electronic Resource
    Intracranial invasion of scalp carcinoma (1989)
    Springer
    Acta neurochirurgica 98 (1989), S. 66-69 
    Details
    ISSN: 0942-0940
    Keywords: Burn scar ; squamous cell carcinoma ; scalp tumour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Among 10 patients with squamous cell carcinoma admitted to our hospital, 5 showed intracranial invasion and 4 died with regrowth of intracranial tumour 9 to 24 months after incomplete extirpation of tumour. We reviewed our experience in the management of advaned scalp carcinoma, from neurosurgical and neuroradiological points of view. Durai invasion failed to be removed completely because of involvement of the middle part of the superior sagittal sinus. Therefore, total resection, facilitated by early detection prior to intracranial invasion, is mandatory for successful treatment of these scalp carcinomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01407179
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  • 4
    Electronic Resource
    Electronic Resource
    Potential of O6-methylguanine or O6-benzylguanine in the enhancement of chloroethylnitrosourea cytotoxicity on brain tumours (1994)
    Springer
    Acta neurochirurgica 128 (1994), S. 13-20 
    Details
    ISSN: 0942-0940
    Keywords: Brain tumours ; O6-methylguanine ; O6-benzylguanine ; ACNU
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purine analogues O6-methylguanine and O6-benzylguanine are well-known as a chemical modulator of the DNA repair enzyme O6-methylguanine-DNA methyltransferase. Inactivation of the enzyme by O6-methylguanine or O6-benzylguanine is expected to enhance sensitivity of tumours to chloroethylnitrosoureas. We studied the effect of O6-methylguanine or O6-benzylguanine pretreatment on cytotoxity of 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) in brain tumour cells and transplanted brain tumours. Two-hour exposure of O6-methylguanine at higher concentrations (500 μM, 1,000 μM) increased ACNU cytotoxicity by only 2 times in ACNU-resistant C6-1 brain tumour cells. O6-Benzylguanine at concentrations between 10 and 100 μM markedly enhanced the cytotoxic effecct. The ACNU sensitivity of the tumour cels pretreated with O6-benzylguanine was 5–40 times that of the cells without O6-benzylguanine. Neither O6-methylguanine nor O6-benzylguamne appreciably enhanced ACNU cytotoxicity of 9 L cells, which were origininally sensitive to ACNU. Intracarotid ACNU with O6-methylguanine or O6-benzylguanine decreased proliferating activity of transplanted C6-1 brain tumours significantly during 48 hours. O6-Benzylguanine pretreatment resulted in a greater degree of suppression for a long time. The C6-1 tumours treated only with intracarotid ACNU showed a transient inhibition and a rapid regrowth during 24 hours after the treatment. These results indicate that O6-methylguanine or O6-benzylguanine increases ACNU cytotoxicity and may be feasible for effective combination therapy with chloroethylnitrosourea in the chemotherapy of malignant brain tumours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01400647
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  • 5
    Electronic Resource
    Electronic Resource
    Detection of DNA sites damaged by 1-(4-amino-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) using a DNA sequencing procedure
    Amsterdam : Elsevier
    Cell Biology International Reports 11 (1987), S. 797-802 
    Details
    ISSN: 0309-1651
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0309-1651(87)90158-5
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  • 6
    Electronic Resource
    Electronic Resource
    Sequential PET studies in neuro-behcet's syndrome (1989)
    Springer
    Journal of neurology 236 (1989), S. 367-370 
    Details
    ISSN: 1432-1459
    Keywords: Neuro-Behcet's syndrome ; Positron emission tomography (PET) ; Cerebral blood flow ; Oxygen metabolism ; Steroids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of neuro-Behcet's syndrome is presented with sequential positron emission tomography (PET) studies. Regional cerebral blood flow (rCBF) and oxygen consumption (rCMRO2) were decreased in the brain lesion; however, on follow-up studies 3 months after steroid therapy rCBF and rCMRO2 had increased in the lesion, which demonstrated the reversibility of this disease. Such monitored improvement may accurately reflect the early stage of the disease and its response to steroid therapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314385
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  • 7
    Electronic Resource
    Electronic Resource
    Choroid plexus carcinoma (1986)
    Springer
    Neuroradiology 28 (1986), S. 374-374 
    Details
    ISSN: 1432-1920
    Keywords: Choroid plexus carcinoma ; Computerized tomography ; Positron emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333452
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of radiotherapy determined by11C-methyl-l-methionine positron emission tomography in patients with primary cerebral malignant lymphoma (1992)
    Springer
    Neuroradiology 34 (1992), S. 517-519 
    Details
    ISSN: 1432-1920
    Keywords: Cerebral malignant lymphoma ; 11C-methyl-l-methionine ; Positron emission tomography ; Radiotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two cases of histologically proven primary cerebral malignant lymphoma were examined serially with positron emission tomography (PET) using11C-methyl-l-methionine (11C Met). Lesions delineated by11C Met accumulation extended beyond enhancing areas on either X-ray computed tomography (CT) or magnetic resonance imaging. High uptake of11C Met accurately showed biologically active and residual tumours, at a time when disappearance of a contrast-enhancing lesion on CT seemed to indicate involution. PET provides valuable information on the extent of tumour and assessment of radiotherapy in malignant lymphoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00598964
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  • 9
    Electronic Resource
    Electronic Resource
    Spinal cord ependymoma: a positron emission tomographic study with (11C-methyl)-L-methionine (1995)
    Springer
    Neuroradiology 38 (1995), S. 53-55 
    Details
    ISSN: 1432-1920
    Keywords: Key words Spinal cord ependymoma ; Positron emission tomography ; (11C-methyl)-L-methionine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An intramedullary spinal cord ependymoma was studied by positron emission tomography (PET) using (11C-methyl)-L-methionine (11C-Met). MRI showed a homogeneously enhancing tumour at C6–T2 with cysts at its rostral and caudal ends. Sagittal PET images demonstrated high 11C-Met uptake in the solid portion of the tumour, particularly ventrally at C7-T2, where viable tumour cells proliferated in association with abundant perforating vessels. Met-PET would appear useful for delineating the viable portion of intramedullary ependymomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00593221
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  • 10
    Electronic Resource
    Electronic Resource
    Spinal cord ependymoma: a positron emission tomographic study with (11C-methyl)-L-methionine (1996)
    Springer
    Neuroradiology 38 (1996), S. 53-55 
    Details
    ISSN: 1432-1920
    Keywords: Spinal cord ependymoma ; Positron emission tomography ; (11C-methyl)-L-methionine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An intramedullary spinal cord ependymoma was studied by positron emission tomography (PET) using (11C-methyl)-L-methionine (11C-Met). MRI showed a homogeneously enhancing tumour at C6-T2 with cysts at its rostral and caudal ends. Sagittal PET images demonstrated high11C-Met uptake in the solid portion of the tumour, particularly ventrally at C7-T2, where viable tumour cells proliferated in association with abundant perforating vessels. Met-PET would appear useful for delineating the viable protion of intramedullary ependymomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00593221
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