Loss of 1p in recurrent meningiomas. a comparative study in successive recurrences by cytogenetics and fluorescence in situ hybridization.

Deletion of 1p is associated with histological progression to meningiomas. Detection of this alteration may be a predicting factor for recurrences in this tumor. We present 8 meningiomas from four patients: the original tumor and the first recurrence in one patient, and the first and second recurrences in the other three were studied. We compared results of monosomy 22 and deletion of chromosome 1p with cytogenetic methods and fluorescence in situ hybridization (FISH) analysis obtained from slides of direct preparations, of cultured cells and slides of touch preparations. The cytogenetic study showed normal chromosome 22 and deletion on 1p32 in both samples of one patient; only monosomy 22 in both recurrences in another patient, and normal karyotypes with different non-clonal anomalies in the other tumors. However, with FISH analysis, monosomy 22 in both recurrences of three patients was demonstrated, as well as the loss of 1p in all tumors. These results were more evident in the analysis of direct and touch preparations than in those of cultured cells.

Histopathological and cytogenetic findings in benign, atypical and anaplastic human meningiomas: a study of 60 tumors.

Meningiomas may display benign (grade I), atypical (grade II) and anaplastic (grade III) histopathological findings. The cytogenetic studies strongly suggest that secondary changes (beyond loss of chromosome 22) appear to be associated with more atypical features and with greater clinical aggressivity. We studied 60 tumors from 52 patients. Histopathological features such as nuclear pleomorphism, nucleolar prominence, mitosis, necrosis, cellular density, PCNA labeling index, and karyotype have been evaluated. The distribution in histological grades was: 50% benign, 33% atypical and 17% anaplastic meningiomas. Nuclear pleomorphism and nucleolar prominence showed a progressive increase in grades I, II and III. Multifocal micronecrosis was considered a criterion of malignancy. A significant correlation was observed between PCNA-LI, mitotic index and grades. Complex karyotypes increased progressively: benign (34% of cases), atypical (45% of cases) and anaplastic (70% of cases). The most common numerical alterations were losses of chromosomes 10, 14, 18 and 22. The chromosomes most often involved in structural anomalies were: 1, 4, 7, 14 and 22. Telomeric associations were present in four cases and double minutes in two cases. Prognostic criteria for these tumors have been analyzed on the basis of these data.

Histopathological and cytogenetic findings in benign, atypical and anaplastic human meningiomas: a study of 60 tumors.

Meningiomas may display benign (Grade I), atypical (Grade II) and anaplastic (Grade III) histopathological findings. The cytogenetic studies strongly suggest that secondary changes (moreover loss of chromosome 22) appear to be associated with more atypical features and with greater clinical aggressivity. We studied 60 tumors from 52 patients. Histopathological features such as nuclear pleomorphism, nucleolar prominence, mitosis, necrosis, cellular density, PCNA labeling index, and karyotype have been evaluated. Nuclear pleomorphism and nucleolar prominence showed a progressive increase in Grades I-III. Multifocal micronecrosis was considered a criterion of malignancy. A significant correlation was observed between PCNA-LI, mitotic index and grades. Complex karyotypes increased progressively: benign (34% of cases), atypical (45% of cases) and anaplastic (70% of cases). The most common numerical alterations were losses of chromosomes 10, 14, 18 and 22. The chromosomes most often involved in structural anomalies were: 1, 4, 7, 14 and 22. Telomeric associations was present in four cases and double minutes in two cases. Prognostic criteria for these tumors have been analyzed on the basis of these data.

Interactive image-guided surgery system with high-performance computing capabilities on low-cost workstations: a prototype.

We present a new frameless stereotatic system prototype that has been initially validated in functional neurosurgery operations and that makes use of an optical position tracker for image-guided neurosurgery. Several devices for tracking different surgical instruments have been designed and manufactured. These devices include an array of infrared light-emitting diodes that are tracked by three charge-coupled device cameras. The system presents several new approaches for surgery planning. For high-quality 3D images of the patient's anatomy, we have developed a parallel version of a volume-rendering algorithm, thus enabling real-time 3D anatomy manipulation on low-cost PC workstations. In order to test the accuracy of the system, the localization of the target by means of a stereotatic frame has been compared with frameless techniques, obtaining a difference of about 1 +/- 1 mm.

Electrical inhibition of basal ganglia nuclei in Parkinson's disease: long-term results.

Since 1995 a group of 57 patients with familial tremor and Parkinson's disease have been operated in two main sets: the first, with 11 cases, with predominant tremor, where the ventro-oralis posterior (Vop) thalamic nucleus was stimulated, and the second, with 44 cases, with mainly rigidity and akinesia, where the globus pallidus internus (GPi) was unilaterally (10 cases) or bilaterally (34 cases) stimulated. In 2 cases, a combined thalamic-pallidal stimulation was achieved. In the last cases, an image fusion software with 3D correlation of MR and CT images and volumetric image matching has been used to correct MRI distortion. In all cases, an Itrell II stimulation system (Medtronic) was implanted. Result analysis shows that Vop stimulation is mostly effective for tremor, and GPi stimulation is better for rigidity and akinesia. Transcortical magnetic stimulation tests suggest that GPi pallidal electrical inhibition increases cortical excitability, as opposed to Vop thalamic stimulation, which implies a different mechanism of action.

Experimental arterial lesions after narrow-beam gamma irradiation used in stereotactic radiosurgery.

An experimental study on rats showing the arterial lesions caused by the beams of gamma irradiation used in stereotactic radiosurgery is presented. The common carotid artery of the rat was irradiated with a single narrow-beam of gamma radiation with a maximum dose of 30 and 60 Gy. The results were evaluated at 4, 12 and 24 weeks after irradiation. Several focal changes in the arterial walls were observed in all periods of study with a predominance of hyperplastic (proliferative) alterations at doses of 30 Gy, and hyaline degeneration at doses of 60 Gy. Total occlusion was not observed in any case. In conclusion, vascular hyperplasia is more prominent with the lower doses evaluated.

[Meningiomas with disomy of chromosome 22: study of 9 cases]. / Meningiomas con disomía del cromosoma 22: estudio de 9 casos.

BACKGROUND: Cytogenetic studies of meningiomas suggest that loss of (or parts of) chromosome 22 is a primary event in the development of these tumors; later on, other chromosomal changes would occur in the caryotypes. All these secondary changes are observed mainly in cases with high clinical aggressivity. However, in a few cases of meningiomas disomy 22 coexists, but with other chromosomic anomalies. We present clinical, histopathological and cytogenetic findings in a group of meningiomas with disomy of chromosome 22. PATIENTS AND METHODS: We collected 10 meningiomas from nine patients which ages ranged between 28-70 years. Fresh tumoral specimens were divided for histologic examination and cytogenetic study, performed after short-term culture. RESULTS: At microscopic examination 5 tumors were classified as benign meningiomas, four as atypical and one as malignant meningioma. Four cases were recurrent tumors. The cytogenetic studies showed that all tumors presented two chromosomes 22 and other chromosome abnormalities. Losses in chromosomes 4, 7, 10, 14, 16, 17 and 20 were frequent; cytogenetics rearrangements of chromosomes 1, 4, 5, 7, 14, 19 and 22 were frequently involved. CONCLUSIONS: In karyotypic evolution of meningiomas, secondary anomalies of chromosomes 1p, 10 and 14 are the most common and appear to be associated with a more aggressive clinical course. In this group of meningiomas with disomy 22, these anomalies were also frequently found, and were related in 50% of cases with atypical or malignant morphologies and of them with recurrent tumors in the 40%.

Involvement of the long arm of chromosome 9 in medulloblastoma in an adult.

Medulloblastoma is the most common primitive neuroectodermal tumor (PNET) in children, but is very rare in adults. An isochromosome for the long arms of 17, i(17q), is found in about 30% of pediatric cases. Cytogenetic studies in adults are very scarce; only six cases have been described cytogenetically: three cases had normal karyotype, two were studied partially, and another presented only two clonal structural anomalies: del(9)(q12) and del(11)(q22). We studied the chromosomes from medulloblastoma in a 27-year-old woman and found one hypotetraploid stemline with clonal alterations. In the structural anomalies, chromosomes 3, 9, 12, and i(17q) were involved. Chromosome 9 presented a deletion in the long arm, del(9)(q13), with consequent loss of the 9q13-->qter region. This anomaly was similar to one found in a previous case. We suggest that the partial loss of the long arm of chromosome 9 may be a characteristic change of adult medulloblastoma.

Cytogenetical findings of recurrent meningiomas. A study of 10 tumors.

Cytogenetic analyses of 10 cases of recurrent meningiomas growing in culture between 1-10 days are reported, of which seven showed benign morphology, one atypical, and two, malignant features. Normal karyotypes with nonclonal alterations were found in three cases, one case with only monosomy 22, and complex karyotypes in the remaining six. Four cases were hypodiploid, one pseudodiploid, and one hyperdiploid. The chromosomes most often involved in structural rearrangements were 1, 7, and 14 and the losses were chromosomes 7, 10, 14, 15, 18, and 22. Ring chromosome, dicentrics, double minutes, and association between satellites were found in one case. These complex karyotypes with hypodiploidy, structural rearrangements, and other markers in recurrent meningiomas may indicate aggressive tumor characteristics.

Stereotactic radiosurgery for the treatment of low-flow carotid-cavernous fistulae: results in a series of 25 cases.

25 patients with low-flow carotid-cavernous fistula (CCF) underwent radiosurgery between 1977 and 1992. 22 had spontaneous low flow fistulae and 3 traumatic high flow fistulae which had been previously treated with internal carotid trapping. The mean preoperative symptomatic period was 12.2 months (4-24 months). Fistulae were classified according to Barrow's classification. Type T was added for traumatic, high-flow fistulae with flow reduction after internal carotid trapping. 11 cases were of type B, 4 of type C, 7 of type D and 3 of type T. The target point for radiosurgery was calculated from selective internal or external carotid angiograms. Stereotactic radiosurgery was performed with a cobalt source, with 5- to 10-mm collimators. A total dose of 30-40 Gy was delivered in all cases, except 1 posttraumatic case in which the dose was 20 Gy. The follow-up period ranged between 14 years and 15 months (mean: 49.76 months). 20 of the 22 low flow fistulae (90.9%) completely closed in a mean period of 7.5 months (range: 2-20 months) after radiosurgery. Improvement of the symptoms began at a mean period of 2.37 months (range: 0.5-14 months). There were no recurrences, the follow-up period ranging between 14 years and 15 months. 100% of type B CCF closed after a mean period of 5.9 months, 75% of type C closed after a mean period of 12.66 months, and 85.7% of cases of type D closed after a mean period of 8.16 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Stereotactic radiosurgery may be effective in the treatment of idiopathic epilepsy: report on the methods and results in a series of eleven cases.

Between 1982 and 1991, 11 patients (4 male, 7 female) ranging in age from 16 to 42 years who had been diagnosed with idiopathic focal epilepsy resistant to medication, were treated with stereotactic radiosurgery. The preoperative symptomatic period was 3-24 years. The process of localizing epileptic focus was based on chronic electrocorticography with flexible electrodes introduced into the subarachnoid space through single burr holes, and left in place during a maximum of 7 days until a clinical seizure was recorded. In most cases the procedure had to be repeated until localization was clear. This process was aided by a computer-assisted automatic analysis procedure. Final confirmation of focus location was done with depth electrode recording in most cases. Stereotactic radiosurgery was performed with a 60Co gamma source using 10 mm collimators, except in two cases in which a betatron was used. The estimated dose was 10-20 Gy at the isocenter. Four of the 11 patients (36%) were medication- and seizure-free after a mean follow-up of 102.5 months. Five patients (45%) presented a reduction of seizures of 98, 89, 86, 75 and 75%, respectively. Two patients did not respond to treatment. Seizure reduction began after a delay period of 2-12 months except in 2 patients and in most cases seizure rate decreased progressively during several months (range: 3-48) postoperatively until stabilization. No complications related to irradiation were recorded. Doses effective for epilepsy are much lower than those for producing cerebral lesions, so the mechanism is not destruction of the focus of the pathways spreading the epileptic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiosurgery of carotid-cavernous fistulae.

25 cases of carotid-cavernous fistulae (CCF) who underwent radiosurgery with a conventional gamma source from 1977 to 1992 are reported. 22 were low-flow, spontaneous CCFs and 3 were high flow fistulae which had undergone a previous trapping. The total dose delivered was 30 to 40 Gy. 91% to patients with low-flow CCF cured after radiosurgery in a mean time of 7.5 months, presenting improvement in a mean time of 2.3 months. Only one of the high-flow fistulae was cured. Follow-up period ranged between 14 years and 15 months (mean: 50 months). No recurrence was recorded in any case. While intravascular embolotherapy is the treatment of choice for high-flow fistulae, stereotactic radiosurgery may be the elective treatment for low-flow CCF.

Radiosurgery of epilepsy. Long-term results.

Based on experimental research, since 1982 until 1991 a series of 11 patients diagnosed as suffering from idiopathic focal epilepsy have been treated with stereotactic radiosurgery. Focus location was determined with cortical electrodes and confirmed by stereotactically placed deep electrodes. Stereotactic radiosurgery was performed with photons from a cobalt source with a dose of 10 to 20 Gy, except in two cases in whom a betatron was used. The results were: complete cessation of seizures in four cases and a significant reduction in the number of seizures in five additional cases. Seizures began to decrease gradually after a period of three months of one year, except in two cases in whom there was an immediate response after treatment. In two cases there was no change. No complication related to the irradiation was recorded. The gradual and delayed effect, obtained with low doses, may favour the hypothesis that non-descructive permanent structural changes, possibly related to the neuronal plasticity phenomenon, constitute the mechanism underlying these facts. Although the number of cases so far is too small, the absence of side-effects may make this bloodless method the one of choice specially in those cases in whom eloquent areas are involved.

Stereotactic radiosurgery of deeply seated low grade gliomas.

The authors report the results of a series of 16 cases of low-grade gliomas in whom radiosurgery was performed. This series started in 1977. All the tumours received a single radiosurgical session (with a mean dose of 21.7 Gy, 5-10 mm. collimator; one patient received two sessions and in another patient two different targets were irradiated in the same session). Prior to radiosurgery, six patients received conventional external fractionated radiotherapy, with two lateral fields of up to 10 x 10 cm. and a mean dose of 55.1 Gy and another six patients with tumours less than 5 cm. in diameter, received stereotactic radiotherapy using four fields of up to 5 x 5 cm. and a mean dose of 53.1 Gy. In both cases, conventional fractionation was used, giving a dose of 1.8 to 2 Gy/day. The tumour disappeared in 8 cases (50%) and shunk or ceased its growth in 5 additional cases (31%). In 3 cases of brainstem gliomas in which the clinical condition was previously very poor there was no evolutional change and the patients eventually died. We conclude that radiosurgery is effective in the treatment of deeply seated low-grade gliomas, where it may become the treatment of choice in the absence of other more definitive choices.

High-cervical spinal cord electrical stimulation in brain low perfusion syndromes: experimental basis and preliminary clinical report.

Previous studies of our group showed that C1-C2 spinal cord stimulation increases carotid and brain blood flow in normal conditions in the goat and dog and it has a beneficial vasomotor effect in a model of vasospasm in the rat. For further clinical application it seemed rational to investigate the possible vascular changes mediated by this technique in experimental brain infarction. To this aim, 45 New Zealand rabbits were used. Brain infarction was produced by bilateral carotid ligation in 15, unilateral microcoagulation of the middle cerebral artery in 15 and by microcoagulation of the vertebral artery at the craniocervical junction in the other 15. One week later, following daily clinical scoring and cortical and posterior fossa blood flow readings by laser Doppler, a period of 120 min of right C1-C2 spinal cord electric stimulation was performed. A mean of 27% increase in previous blood flow recordings was obtained at the right hemisphere and a mean of 32% in the posterior fossa. This procedure was used in 10 patients presenting with various cerebral low perfusion syndromes. Though not constant, an increase in alertness, retention, speech, emotional lability and performance in skilled acts was achieved. No MR changes were observed, though SPECT readings showed an increase in blood flow in the penumbral perilesional area.

Radiosurgery of epilepsy.

Since 1982 a series of 11 epileptic patients have been treated with stereotactic radiosurgery. Patients were intracranially recorded with cortical and deep electrodes until the location of the epileptogenic focus was determined. A deep electrode was stereotactically placed at this point to confirm the accuracy of the location. All patients received radiosurgery with a gamma source and a dose of 10 to 20 Gy, except two of them in which a betatron was used. The results were: Total disappearance of the crises and withdrawal of medication: 4 cases (36%). More than 80% reduction of crises: 3 cases (27%). More than 50% reduction of crises: 2 cases (18%). Less than 50% reduction of crises: 2 cases (18%). No complications were observed, even in those cases in which the focus was located near critical areas of the brain. The efficacy of the low doses used accounts for non-destructive mechanisms, probably mediated by a neuronal plasticity phenomenon, as experimental studies suggest. The lack of complications can make this therapeutic approach an alternative to be considered when critical areas are involved.

Stereotactic radiotherapy plus radiosurgical boost in the treatment of large cerebral arteriovenous malformations.

Small sized AVMs respond well to stereotactic radiosurgery, while larger AVMs do poorly with stereotactic radiosurgery or stereotactic fractionated radiotherapy. A combination of both methods is proposed for the treatment of these larger lesions.

[Ag-NOR in meningiomas. Clinical and morphologic study of 14 cases]. / NORAg en los meningiomas. Estudio clínico y morfológico de 14 observaciones.

A total of 14 meningiomas were studied in this report, grouped in different subtypes. The number of NORAg of each was analyzed and quantified. This study analyzes the results obtained as opposed to different subtypes and with clinic and biologic characteristics of patients. Similarly, technical characteristics of silver impregnation method to determine nucleolar organizer regions (NORAg) and its application as a routine method were analyzed. We propose this as a fast and reliable method to analyze of neoplastic proliferative activity.

Radiosurgical treatment of low flow carotid-cavernous fistulae.

The good results obtained by stereotactic radiosurgery in arteriovenous malformations has led the authors to expect similar results in low flow carotid-cavernous fistulae. In this paper, 20 cases who underwent radiosurgery with a conventional gamma source are presented. The total dose delivered was 36 to 40 Gy. 90% of the patients were cured after radiosurgery after a mean time of 7 months. Those presenting a mild improvement after a mean time of 2 months and those with a marked improvement after 4 months.