Liposomal transfection efficiency and toxicity on glioma cell lines: in vitro and in vivo studies

To evaluate the influence of cell type and cationic liposomal formulation on gene transfection efficiency three liposomes (lipofectin, lipofectamine and DOTAP) were used to transfect the human (A172 and MOG-G-CCM) and rodent (C6 and A15A5) glioma cell lines with the Lac Z gene. Parallel studies evaluated in vitro cytotoxicity and the neuropathological changes following intracerebral injection. The transfection efficiency and cytotoxicity of the liposomes varied both quantitatively and qualitatively between the cell lines. There were no behavioural disturbances following intrastriatal or hippocampal injection and the neuropathological changes at the injection sites were focal and similar for all liposomes. The influence of glial cell lineage on both liposomal transfection facility and cytotoxicity may have important implications for in vivo gene transfection in the central nervous system.

Apoptosis in human primary brain tumours: actions of arachidonic acid

It has been postulated that loss of proliferative control in tumour cells is a consequence of depletion of cellular arachidonic acid (AA) and that exogenous AA and n-6 fatty acids may restore control of proliferation. To test this hypothesis and to investigate the activity of AA, apoptosis in human primary brain tumour cells was analysed using flow terminal deoxynucleotide transferase uridine nick end-labelling (TUNEL). The effect of exogenous AA (30 microM) was analysed in collagenase-dispersed tissue from seven human primary brain tumours and in the normal brain tissue surrounding one of the tumours. Exogenous AA stimulated apoptosis in tumour tissue. A rapid three-fold increase in endonuclease activity was detected in tumour cells incubated with AA. The increase in apoptosis was significantly greater than the contemporary (< 15%) increase in necrosis detected using propidium iodide permeability and was greater than AA effects on normal brain tissue. These results are consistent with activation of the pathways of apoptosis by AA.

The utility of the Right Hemisphere Language Battery in patients with brain tumours

The Right Hemisphere Language Battery (RHLB) (Bryan, 1989) was devised to assess the presence of language disorders in patients with damage to the right cerebral hemisphere and to permit an evaluation of the efficacy of therapeutic techniques. To evaluate the utility and sensitivity of the RHLB in patients with solitary right hemispheric brain tumours 20 patients were assessed before and after neurosurgery. Twenty control subjects with no signs or symptoms of brain disease who were undergoing lumbar spinal surgery were also assessed. On six of the seven RHLB subtests there was no significant difference between the scores obtained preoperatively by patients with right hemispheric brain tumours and the control subjects. There was also no significant change in the scores of the patients with tumours before and after resection of the lesion. The RHLB is therefore not recommended for either evaluating communication deficits or for measuring the efficacy of therapeutic techniques in patients with right hemisphere brain tumours. This study does, however, show that there are statistically significant differences between the control and brain tumour groups on the discourse analysis subtest preoperatively. The implications of the study are discussed together with possible reasons for the findings.

Treatment by a specialist surgical neuro-oncologist does not provide any survival advantage for patients with a malignant glioma

To determine whether patients with malignant glioma (glioblastoma and anaplastic astrocytoma) had longer survival times, and lower morbidity and mortality if operated on by a surgical neuro-oncologist rather than a general neurosurgeon the outcomes of 236 patients managed within a university surgical neurology department were analysed. Although both surgical morbidity (8.9 versus 11.8%) and mortality (3.6 versus 8.8%) were lower following surgery by the specialist neuro-oncologist neither difference was statistically significant. Crude outcome data suggested patients operated upon by a specialist surgical neuro-oncologist survived longer (p = 0.067). However, after adjustment for case mix (type of tumour, year of treatment, MRC prognostic index) using multiple logistic regression and a hazards model, there was no difference in outcome (p = 0.46, HR 0.884, 95% CI 0.639-1.22). This retrospective study (i) suggests that other outcome measures are required to validate specialist surgical neuro-oncologist treatment of patients with malignant glioma; and (ii) confirms the importance of adjustment for case mix when comparing non-randomized treatment outcomes.

Can experimental models of rodent implantation glioma be improved? A study of pure and mixed glioma cell line tumours

To evaluate the hypothesis that co-implantation of different rodent glioma cell lines might result in experimental brain tumours that more closely resemble human gliomas the neuropathology and immunocytochemical features of implantation gliomas derived from single cell lines (C6, A15A5, F98), two cell lines admixed 50:50 prior to implantation (C6 + F98 and C6 + A15A5) and three cell lines equally admixed (C6 + A15A5 + F98) was studied in the adult Wistar rat. Tumours grew consistently following implantation of the single and the two admixed cell lines, however tumour growth following triple mix implantation was considerably and consistently impaired. The tumours derived from admixed cell lines showed regional heterogeneity with areas characteristic of both the primary cell lines. Foci of lymphocytic infiltrates, tumoural necrosis, often with pseudopallisading, and peritumoural edema were consistent features of all tumours. Limited parenchymal and more extensive perivascular tumoural invasion was seen predominantly in tumours containing the C6 cell line. There were no significant differences in GFAP, vimentin and HSP70 staining between the mixed tumours, although the pure F98 and A15A5 tumours were, unlike the pure C6 gliomas, S-100 negative. Using PCNA expression as a measure of the tumour proliferation all except the tumours derived from the three cell lines mix, which had a staining index of 7-10%, had focal staining indices in viable tumour of between 40-80%. There was focal positive staining in both perilesional brain and in regions of all tumours for the macrophage markers ED-1 and ED-2. None of the three cell lines stained in vitro for either ED1 and ED2 but all were constitutively positive in vitro for OX-6, a proposed marker for antigen presenting cells. The macrophage and lymphocytic response suggest a vigorous but largely ineffective immunological response had been mounted against all tumours. The consistent failure of the triple mix tumours to grow is unexplained. This work has shown the feasibility of producing 'mixed' cell line experimental gliomas by combining two cell lines at the time of innoculation. However, the relative failure to produce (i) mixed tumours that have properties not inherent to either parent cell line and (ii) implantation glioma with three cell lines suggest there are limits to this approach. Admixture of cell lines at the time of implantation therefore does not make experimental glioma models that more closely resemble natural gliomas, and also has some particular disadvantages. This experimental approach is therefore not recommended for use in the study of tumour biology and in evaluating the effectiveness of novel therapies.

Effects of nitric oxide manipulation on the disposition of platinum in an experimental glioma model

Rodents with striatal C6 glioma were given carboplatin (65 mg kg(-1) in a 10 mg ml(-1) solution, i.v.) after pretreatment with the NO modulating agents 3-morpholinosydnonimine (SIN-1), NG-nitro-L-arginine methyl ester (L-NAME), bradykinin or dexamethasone, to determine whether platinum disposition in the glioma and normal brain was altered. There was no significant change in mean glioma platinum disposition after 3 days of dexamethasone (32+/-9.7 microg/g). Treatment with SIN-1 (45.1+/-14.2 microg/g), L-NAME (42.9+/-4.9 microg/g) and bradykinin (45.7+/-11.3 microg/g) all resulted in increased tumour platinum concentration compared with controls (29+/-5.5 microg/g) but these results were not statistically significant. Dexamethasone significantly (p < 0.05) reduced the platinum concentration in normal brain but the other agents had no effect. Although glioma platinum concentration could be increased by some agents that alter tissue NO levels, the patterns of response were unpredictable and the magnitude (approximately 50%) of the increased platinum disposition is unlikely to be biologically significant.

Nitric oxide synthase activity in human glioblastoma : a histochemical study

Nitric oxide (NO), which is synthesised by the enzyme Nitric Oxide Synthase (NOS), mediates many physiological and pathological mechanisms in the brain. Experimental studies of rodent C6 glioma show that NO has a major role in regulation of tumour blood flow. To determine the relevance of these findings to human malignant glioma, NADPH diaphorase (NADPHd) histochemistry, which is a marker for NOS expression, was performed in 20 glioblastomas. Except for one tumour which was totally necrotic, all the 19 tumour specimens showed evidence of NADPHd expression. The neoplastic vascular endothelium, areas of endothelial proliferation and neoplastic astrocytes all consistently showed high levels of NADPHd positivity. Areas of necrotic tumour were always NADPHd negative. Both the extent and the intensity of cellular staining within the glioblastoma was considerably greater than NADPHd positivity in normal brain tissue. These results together with findings in experimental glioma strongly suggest that NOS has a definite role in the pathophysiology of glioblastoma and that it may be possible to pharmacologically manipulate them for therapeutic benefit.

Exophytic pontine glioblastoma mimicking acoustic neuroma

A 22-year-old male with unilateral facial, cochlear and glossopharyngeal cranial nerve dysfunction and ataxia that was slowly progressive over one year is described. Although clinically it was considered he probably had an acoustic neuroma, surgery revealed a pontine glioblastoma exophytic into the cerebellopontine angle and internal acoustic meatus. Clinicoradiological features that distinguish this extremely rare lesion of the hindbrain from acoustic neuroma are discussed.

Stereotactic biopsy of nonpolar tumors in the dominant hemisphere: a prospective study of effects on language functions

A prospective study of patients undergoing computerized tomography (CT)-guided stereotactic biopsy of nonpolar tumors in the dominant hemisphere was undertaken to determine if stereotactic biopsy caused a deterioration of language functions. Language was assessed using the Western Aphasia Battery (WAB) and the Boston Naming Test (BNT) before and after a biopsy sample was obtained. Of 16 patients studied, five (31%) were dysphasic preoperatively. After the biopsy the Aphasia Quotient (AQ), derived from the WAB, had significantly deteriorated in four (80%) of these patients, whereas in the fifth it remained relatively unchanged. One of these patients with an extensive infiltrating hemispheric oligoastrocytoma subsequently recovered normal language function after radiotherapy. In 10 of the 11 patients who had normal language function preoperatively there were no deleterious changes after biopsy in either the WAB subtest or BNT scores. In the other patient whose WAB score was normal preoperatively, there was a significant deterioration in postoperative AQ. This patient, who declined steroid therapy before and after biopsy, had a glioblastoma multiforme in Wernicke's area. A postoperative CT scan revealed no changes from what was shown on preoperative scan. This clinical study shows that CT-guided stereotactic biopsy of nonpolar tumors in the dominant hemisphere using the Brown-Roberts-Wells system and the Sedan-Nashold biopsy cannula carries a 9% risk (95% confidence intervals 0-26%) of impairing language functions if the patient is not dysphasic preoperatively. If the patient is dysphasic preoperatively, there is a very high risk of aggravating the dysphasia with stereotactic biopsy.

Cerebrovascular effects of nitric oxide manipulation in spontaneously hypertensive rats

1. Evidence that nitric oxide (NO) bioactivity is altered in chronic hypertension is conflicting, possibly as a result of heterogeneity in both the nature of the dysfunction and in the disease process itself. The brain is particularly vulnerable to the vascular complications of chronic hypertension, and the aim of this study was to assess whether differences in the cerebrovascular responsiveness to the NO synthase (NOS) inhibitors, NG-nitro-L-arginine methyl ester (L-NAME) and 7-nitroindazole (7-NI), and to the NO donor 3-morpholinosydnonimine (SIN-1) might indicate one possible source of these complications. 2. Conscious spontaneously hypertensive (SHR) and WKY rats, were treated with L-NAME (30 mg kg-1, i.v.), 7-NI (25 mg kg-1, i.p.), (0.54 or 1.8 mg kg-1 h-1, continuous i.v. infusion) or saline (i.v.), 20 min before the measurement of local cerebral blood flow (LCBF) by the fully quantitative [14C]-iodoantipyrine autoradiographic technique. 3. With the exception of mean arterial blood pressure (MABP), there were no significant differences in physiological parameters between SHR and WKY rats within any of the treatment groups, or between treatment groups. L-NAME treatment increased MABP by 27% in WKY and 18% in SHR groups, whilst 7-NI had no significant effect in either group. Following the lower dose of SIN-1 infusion, MABP was decreased to a similar extent in both groups (around -20%). There was no significant difference in MABP between groups following the higher dose of SIN-1, but this represented a decrease of -41% in SHR and -21% in WKY rats. 4. With the exception of one brain region (nucleus accumbens), there were no significant differences in basal LCBF between WKY and SHR. L-NAME produced similar decreases in LCBF in both groups, ranging between -10 and -40%. The effect of 7-NI upon LCBF was more pronounced in the SHR (ranging from -34 to -57%) compared with the WKY (ranging from -14 to -43%), and in seven out of the thirteen brain areas examined there were significant differences in LCBF. 5. Following the lower dose of SIN-1, in the WKY 8 out of the 13 brain areas examined showed significant increases in blood flow compared to the saline treated animals. In contrast, only 2 brain areas showed significant increases in flow in the SHR. In the rest of the brain areas examined the effects of SIN-1 upon LCBF were less marked than in the WKY. 6. Infusion of the higher dose of SIN-1 resulted in further significant increases in LCBF in the WKY group (ranging between +30% and +74% compared to saline-treated animals), but no significant effects upon LCBF were found in the SHR. As a result, there were significant differences in LCBF between SIN-1-treated WKY and SHR in six brain areas. In most brain areas examined, cerebral blood flow in SHR following the higher dose of SIN-1 was less than that measured with the lower dose of SIN-1. 7. Despite comparable reductions in MABP (approximately 20%) in both groups, calculated cerebrovascular resistance (CVR) confirmed that the vasodilator effects of the lower dose of SIN-1 were significantly more pronounced throughout the brain in the WKY (ranging between -3% and -50%; median = -38%) when compared to the SHR (ranging between -10% and -36%; median = -26%). In the animals treated with the higher dose of SIN-1, CVR changes were broadly similar in both groups (median = -45% in WKY and -42% in SHR), but with the reduction in MABP in SHR being twice that found in WKY, this is in keeping with an attenuated blood flow response to SIN-1 in the SHR. 8. The results of this study indicate that NO-dependent vasodilator capacity is reduced in the cerebrovasculature of SHR. In addition, the equal responsiveness to a non-specific NOS inhibitor but an enhanced effectiveness of a specific neuronal NO inhibitor upon LCBF in the SHR could be consistent with an upregulation of the neuronal NO system.

Progressive focal neurological dysfunction following experimental implantation glioma

One of the difficulties in understanding peritumoural brain dysfunction is the lack of defined clinical deficits in experimental glioma models. In this study progressive focal neurological dysfunction was measured using the staircase test in rodents subjected to striatal implantation of C6 glioma cells. After 22 days none of the animals, all of which had cortico-striatal tumours ranging in size from 93 to 140 mm3, showed any obvious gross behavioural abnormality. However, contralateral forelimb function was significantly worse than that before surgery by day 7 (p < 0.01) and worse than sham-implanted animals by day 12 (p < 0.01). Using this experimental paradigm the staircase test can be used to measure progressive focal neurological deterioration and evaluate both the mechanisms of, and therapies for peritumoural brain dysfunction.

Glioma cells transduced with selection transgenes may not form gliomas in vivo and can also inhibit glioma formation by admixed wild glioma cell lines

Following in vitro lipofection transfection of the rat glioma cell line A15A5 with the plasmid transgene CMV/HyTK, which confirms hygromycin resistance and ganciclovir sensitivity, a series of experiments was planned in which the "bystander" phenomenon would be evaluated using the rodent implantation glioma model. However examination of the brain of rodents in which the A15A5HyTK cells were implanted showed no evidence of glioma growth. Furthermore, rodents having intracerebral implantation of (i) wild A15A5 and A15A5HyTK cells in a 50/50 mix, (ii) wild A15A5 and A15A5HyTK cells in a 90/10 mixture and (iii) wild C6 and A15A5HyTK cells in a 50/50 mix all failed to grow macroscopic tumours by 15-17 days irrespective of whether the animals had been administered ganciclovir (GCV) in the week before sacrifice. Neuropathological and immunocytochemical analysis of the implantation sites showed no difference between the GCV and saline treated groups of animals for any implantation cell mix. These observations confirm previous results that suggest transduction of malignant rodent glioma cell lines with a variety of selection, oncogenic and marker genes significantly impairs their in vivo tumorigenic potential compared to the wild type cell lines. This study also demonstrates that even without GCV treatment the transduced cells inhibit, by an unknown mechanism(s), the tumorigenicity of other non transfected malignant cells. The implications of this study for gene therapy of human malignant glioma are discussed.

Acute intraoperative brain herniation during elective neurosurgery: pathophysiology and management considerations

OBJECTIVES

To describe operative procedures, pathophysiological events, management strategies, and clinical outcomes after acute intraoperative brain herniation during elective neurosurgery.

METHODS

Review of clinical diagnoses, operative events, postoperative CT findings, intracranial pressure, and arterial blood pressure changes and outcomes in a series of patients in whom elective neurosurgery had to be abandoned because of severe brain herniation.

RESULTS

Acute intraoperative brain herniation occurred in seven patients. In each patient subarachnoid or intraventricular haemorrhage preceded the brain herniation. The haemorrhage occurred after intraoperative aneurysm rupture either before arachnoidal dissection (three) or during clip placement (one); after resection of 70% of a recurrent hemispheric astroblastoma; after resection of a pineal tumour; and after a stereotactic biopsy of an AIDS lesion. In all patients the procedure was abandoned because of loss of access to the intracranial operating site, medical measures to control intracranial pressure undertaken (intravenous thiopentone), an intraventricular catheter or Camino intracranial pressure monitor inserted, and CT performed immediately after scalp closure. The patients were transferred to an intensive care unit for elective ventilation and multimodality physiological monitoring. Using this strategy all patients recovered from the acute ictus and no patient had intracranial pressure > 35 mm Hg. Although one patient with an aneurysm rebled and died three days later the other six patients did well considering the dramatic and apparently catastrophic nature of the open brain herniation.

CONCLUSIONS

There are fundamental differences in the pathophysiological mechanisms, neuroradiological findings, and outcomes between open brain herniation occurring in post-traumatic and elective neurosurgical patients. The surprisingly good outcomes in this series may have occurred because the intraoperative brain herniation was secondary to extra-axial subarachnoid or intraventricular haemorrhage rather than intraparenchymal haemorrhage or acute brain oedema. Expeditious abandonment of the procedure and closure of the cranium may also have contributed to the often very satisfactory clinical outcome.

Management of poor grade patients after subarachnoid haemorrhage: the importance of neuroradiological findings on clinical outcome

The prognosis for patients in poor neurological grade (WFNS grades IV and V) after subarachnoid haemorrhage (SAH) is grave. Previous reports of such patients have analysed outcome without defining either the cause or the course of the depressed level of consciousness. We report a retrospective study of the outcome of 62 consecutive patients in poor grade after SAH analysed with respect to their clinical course and the predominant computed tomographic feature. Neuroradiological findings were (1) intracranial haematoma, (2) hydrocephalus with or without intraventricular haemorrhage (IVH) and (3) SAH alone. Sixteen patients (25.8%) had a Glasgow Coma Score (GCS) < or = 12 on admission to hospital and subsequently deteriorated. The predominant computed tomographic feature of these patients was hydrocephalus/IVH. Twelve patients (19.4%) had a GCS < or = 12 on admission and subsequently improved without intervention; all had SAH on computed tomography (CT) on admission. Thirty-four patients (54.8%) had a GCS < or = 12 on admission and did not improve or improved only after emergency surgical intervention. Haematoma (44%) and hydrocephalus/IVH (47%) were the predominant CT features in this group. The overall mortality in the 62 patients was 44%. Fifty-two per cent of patients achieved a good outcome or were moderately disabled. Patients harbouring an intracerebral haematoma had a significantly poorer prognosis when compared with the other groups. Patients in poor neurological grade after SAH are a heterogenous group both clinically and neuroradiologically. Management approaches must consider the cause of clinical deterioration and the related CT findings.

Nitric oxide synthase is expressed in experimental malignant glioma and influences tumour blood flow

The distribution and function of nitric oxide synthase (NOS) was studied in the rodent C6 implantation glioma model. Using a histochemical stain for NADPH diaphorase, which colocalises with NOS, morphological studies revealed non homogenous staining of the constituent tumour cells and the neoplastic endothelium. Immunocytochemical staining for macrophages (ED1, ED2) showed dense positivity at the tumour brain interface with more patchy positivity within the tumour mass. This finding suggests that both macrophages, which are known to produce large amounts of NO, and the C6 cells contribute to the NADPH diaphorase positivity. Administration of the NOS inhibitor Ng-nitro-L-argine methyl ester (L-NAME) significantly reduced both tumour (40%) and contralateral local cerebral blood flow (20%) compared to control animals. These findings demonstrate that (i) NOS is present in experimental malignant glioma; (ii) NO mediated mechanisms contribute to tumour blood vessel dilatation and blood flow regulation; and (iii) using this model there is a significant differential sensitivity of the tumour and brain parenchymal vascular beds to a NOS inhibitor. Further investigations are required to determine the potential therapeutic and biological relevance of these findings and the relative contributions of tumour cells, neoplastic endothelium and reactive macrophages to NO mechanism in gliomas.

Public perceptions of brain tumours in Scotland: the need for access to appropriate information

The aim of the study was to evaluate knowledge and perceptions of brain tumours in a heterogeneous, highly educated group of adults living in Edinburgh. Two hundred and forty four respondents answered a questionnaire about the causes, effects and treatments of brain tumours. There were misconceptions about several clinical and biological aspects of intracranial tumours although most respondents were aware of the bleak prognosis associated with many neoplasms. These results, from the intellectual elite of Scotland's capital, suggest that access to information about brain tumours should be readily available. Five leaflets, covering various aspects of brain tumours, that are available through the recently established Scottish charity Brain Tumour Action seem well formulated to address areas of concern and misconception.

Referral pattern and management of patients with malignant brain tumours in south east Scotland

We reviewed hospital case notes of all incident cases of intracerebral tumours in SE Scotland to analyse referral pattern and time intervals between presentation, diagnosis and treatment. We identified 439 new patients with intracerebral tumours in a two year period: 64% single (primary brain tumours 43%: metastasis 21%) and 36% multiple (metastases). Ninety-two per cent of patients were referred by GP's and 88% were self referrals to hospital or were initially identified at hospital follow-up clinics. Only 27% of patients were initially referred to the specialist centre (Western General Hospital) but 57% were CT scanned at the specialist centre and 83% were referred to there at some time. Time from GP referral to CT scan was related to availability of local CT scanning. Only 10% of cases with probable single metastases and 39% with HGG were treated with surgery plus radiation. Cranial irradiation was started within four weeks of CT diagnosis in 79% of those with metastases but in less than 5% of patients with HGG. The patterns of care for patients with brain tumours show great variation. Hospital referral guidelines, better inter-hospital and inter-department communications and more available access to CT scanning and radiotherapy should improve the quality of care and possibly treatment outcome in this group of patients.

Cerebrovascular responsiveness to NG-nitro-L-arginine methyl ester in spontaneously diabetic rats

1. There is evidence that endothelial dysfunction is associated with diabetes mellitus. The purpose of the present study was to assess local cerebral blood flow (LCBF) and cerebrovascular responsiveness to the NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME) in spontaneously diabetic insulin-dependent BioBred (BB) rats. 2. Diabetic rats, and non-diabetic controls, were treated with L-NAME (30 mg kg-1, i.v.) or saline, 20 min prior to the measurement of LCBF by the fully quantitative [14C]-iodoantipyrine autoradiographic technique. 3. There were no significant differences in physiological parameters (blood pH, PCO2, and PO2, rectal temperature, arterial blood pressure, or plasma glucose) between any of the groups of rats, and no difference in either the extent or the temporal characteristics of the hypertensive response to L-NAME between diabetic and non-diabetic rats. 4. In diabetic rats, a global reduction in basal LCBF was observed, although significant reductions (between -20 and -30%) were found in only 5 (mainly subcortical) out of the 13 brain regions measured. Following L-NAME injection, significant reductions in LCBF (between -20 and -40%) were found in the non-diabetic animals. In diabetic animals treated with L-NAME, a significant reduction in LCBF was measured only in the hypothalamus (-33%). 5. The cerebrovascular response to acute L-NAME is attenuated in spontaneously diabetic insulin-dependent BB rats. This would be consistent with the endothelial dysfunction in cerebral vessels, known to be associated with diabetes mellitus and it is possible that a loss of NO-induced dilator tone, amongst other factors, may underlie the observed reductions of basal LCBF in these animals.

The effects of malignant glioma on the EEG and seizure thresholds: an experimental study

Generalised or partial seizures are a common problem with many supratentorial gliomas. Their underlying pathophysiological mechanisms are poorly understood. To investigate this problem clinical and EEG seizure thresholds were investigated in experimental rodent gliomas using the epileptogenic drug pentylenetetrazole (PTZ). Mixed C6/A15A5 malignant gliomas were grown in adult Wistar rats after unilateral stereotactic implantation of a 50:50 cell mix into the caudoputaminal region. Eleven to 14 days later EEG (raw and spectrally analysed) was recorded bilaterally from the frontal and parietal regions under mixed alpha-chloralose and urethane anaesthesia. Baseline EEG (15 minutes), EEG during and after (30 minutes) PTZ infusion (100 microliters/min) and the time to appearance of seizure manifestations after starting PTZ were recorded. Fourteen animals were studied (5 normal, 5 with tumours, 4 sham implants) and mean BP, PaCO2, PaO2 and temperature were similar in the three groups. Baseline raw EEG showed predominate slow wave activity with lower amplitude and less spontaneous activity overlying tumours. Following PTZ infusion a sequence of vibrissal twitching (following a mean of 14.5 mg/kg PTZ in control and sham animals); jaw/nasal twitches (17.5 mg/kg); fore and hind limb jerking (46 mg/kg); myoclonic jerking (47 mg/kg); and status (77.5 mg/kg) was observed. The seizure thresholds for all PTZ induced seizure phenomena were, except for status epilepticus, highest in the tumour bearing animals. The time to 70% seizure activity on the EEG was also significantly longer in the tumour bearing animals. Spectral analysis of the EEG, although showing increased alpha and theta activity after PTZ infusion, did not discriminate between the three experimental groups either before or after PTZ activation. These studies have confirmed that experimental gliomas alter baseline EEG and both the EEG and behavioural response to PTZ. The reasons for the raised seizure threshold in the glioma bearing animals and the relevance of this experimental paradigm to human tumour associated epilepsy are discussed.

Microsurgical excision of a pontomedullary epidermoid cyst with prepontine extension: case report

We report the case of a patient with a pontomedullary epidermoid cyst extending into the prepontine cistern. The patient presented with a progressive VIth nerve palsy, ataxia, and headache. Magnetic resonance imaging demonstrated a well-defined pontomedullary tumor with a high fat content. We excised the lesion using a microsurgical approach through the floor of the fourth ventricle. Postoperative magnetic resonance imaging confirmed the removal of both intra- and extra-axial components. We discuss the anatomic configuration, radiological appearances, and management of this unusual pathological finding.

Management of primary malignant brain tumours

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Repair of the facial nerve in the cerebellopontine angle using freeze-thawed skeletal muscle autografts. An experimental surgical study in the sheep

Six adult blackface sheep underwent repair of the transected facial nerve in the cerebellopontine angle using short freeze-thawed muscle autografts. A typical facial palsy was observed on the side of the intervention immediately after operation. The sheep were allowed to recover for one year by which time clinical observation showed a complete recovery of the facial palsy in 5 sheep and a partial recovery in the remaining sheep. Under general anaesthesia function of the repaired VIIth nerve and the normal contralateral facial nerve were assessed using electrophysiological stimulating and recording techniques. These studies showed restoration of facial nerve continuity to have taken place with functional reinnervation of target facial muscles. Electrophysiological indices of nerve function were consistent with those expected after repair of any peripheral nerve. Morphometric study of the nerves after their removal showed structural changes which though quantitatively different from those of normal nerve were consistent with those seen in other sites and studies where nerves have been repaired. This technique is discussed as a possible treatment for facial nerves whose continuity is disrupted during the removal of cerebellopontine angle tumours.

Successful excision of a giant acoustic neuroma in the third trimester of pregnancy

Intracranial neoplasms presenting during pregnancy are uncommon. We report the case of a woman with a giant acoustic neuroma, presenting with hyperemesis gravidarum, and detail the surgical excision of the tumour during the third trimester. The case illustrates the unusual presentation and that such surgery can be performed safely without detriment to mother or fetus.

CT-guided stereotactic antero-medial pulvinotomy and centromedian-parafascicular thalamotomy for intractable malignant pain

A quick and safe CT image-guided stereotactic thalamotomy technique that has proved ideal for alleviating medically refractory intractable pain due to malignant disease is described. A simple method of deriving cartesian coordinates for target points that facilitates functional neurosurgery using CT images and the Brown-Roberts-Wells stereotactic system is also described.

Seizures in patients with supratentorial oligodendroglial tumours. Clinicopathological features and management considerations

In this study of 34 consecutive histologically confirmed oligodendroglial brain tumours (15 oligoastrocytoma, 12 oligodendroglioma, 7 anaplastic oligodendroglioma) twenty five patients (75%) presented with symptoms related to seizures. Although the seizure incidence was lowest in anaplastic oligodendroglioma (57%) it was not statistically different from either pure (75%) or mixed (80%) oligodendroglial tumours. Patients with seizures had a significantly lower age (p < 0.001) at diagnosis (median 36 years) than those without seizures (57 years). The types of seizure disorder, that were present for a median of 15 months prior to surgery, were variable with 32% having generalised, 36% partial and 32% mixed patterns. There were no significant differences between either the type or incidence of seizures and the particular cerebral location of the oligodendroglial tumour. Twenty four of the patients presenting with seizures underwent surgery (5 stereotactic biopsy, 5 stereotactic guided resection and 14 conventional craniotomy and resection) without intraoperative electrocorticography (ECoG). Eighteen (75%) of these patients also had postoperative radiotherapy (40 to 54 Gy in 30 fractions. Following these treatments the percentage of patients fit free at 6, 12, and 24 months were 67%, 56%, and 53%, respectively. Median time to first post operative seizure was 32 weeks (range 5 weeks to 5.3 years). After a median follow up time of 30 months 20 of the 25 patients who presented with seizures were still alive. Eight (40%) were seizure free and three other patients (15%) had experienced less than three postoperative seizures in follow-up periods ranging from 42 to 62 months. Although the numbers of patients on preoperative (87%) and postoperative (83%) anticonvulsant medications were similar, some had their medications either withdrawn (17%) or reduced (4%) whilst others had it introduced (12%) after interventional management. Only five (20%) patients who presented with seizures, compared to 6 (67%) who had not presented with seizures had died during median follow-up of 28 months. Three of nine patients (33%), who were initially seizure free, developed seizures between 25 and 36 months after initial surgery and radiotherapy. This study (i) confirms the high incidence of epilepsy in supratentorial oligodendroglial tumours; (ii) has shown that seizures associated with these tumours are significantly more common in younger patients; (iii) suggests that younger age, but not the presence of seizures, is a significant independent prognostic variable; (iv) that seizure control following a second operation is generally disappointing and (v) suggests that tumour resection and radiotherapy often facilitate control of the seizures by anticonvulsants. Because of the multiple clinicopathological and management variables involved a prospective study would be required to assess the optimal management of patients with seizure disorders associated with oligodendroglial brain tumours.

CT guided thalamotomy for movement disorders in multiple sclerosis: problems and paradoxes

Unilateral ventrolateral (VL) thalamotomy for medically refractory tremorigenic movement disorders (MD) was performed in 9 patients with established multiple sclerosis. All patients had abolition of their coarse action/kinetic tremor with improvement in arm and hand function. In two patients some intention tremor either remained or was unmasked. Target coordinates ranged from 2 to -5 mm relative to the intercommissural line and from 8 to 16 mm lateral to the midline. There were no permanent surgical complications and the one stage procedure under local anesthetic was well tolerated. Although there were also improvements in posture and speech in some patients the overall and longer term functional impact of surgery was, except in two patients, disappointing. Since multiple sclerosis is a spectrum of disease entities, and tremor may be only one manifestation of the disease, clinical studies that use comprehensive patient assessments and objective criteria may allow prediction of longer term functional outcome in specific patient subgroups. The specific aims of the stereotactic procedure in severely disabled patients with MS and MD must also be clear.

Focal necrotising herpes simplex encephalitis: a report of two cases with good clinical and neuropsychological outcomes

Two patients with atypical focal necrotising herpes simplex encephalitis are described. They presented with relatively mild clinical disease but despite treatment with acyclovir (10 mg/kg/day for three days in case 1 and 10 days in case 2) they developed dramatic, progressive changes (shown on brain CT) that mimicked space occupying lesions of the temporal lobes. Both patients therefore had a diagnostic and therapeutic temporal lesionectomy followed by further 10 day courses of acyclovir. They subsequently went on to make good clinical and neuropsychological recoveries.

Nail gun injury to the brain: an unusual case of suicide

An unusual case of fatal suicidal craniocerebral penetrating injury due to a nail gun is described. The victim, a 52 year old joiner experienced in the use of nail drivers, shot himself just above the forehead in the midline, driving the nail through his hypothalamus and midbrain. Death was delayed by nearly 24 hours.

Recording neurological impairment in clinical trials of glioma

The criteria for clinical response to treatment in cerebral glioma remain poorly defined, but could be made more objective if simple measures of neurological impairments were included in the definitions. We assessed the utility of simple fast previously validated tests of limb impairment (Timed nine hole peg test and 10 meter walk), memory (Williams delayed recall test) and language (Boston Aphasia Severity Rating Scale) in fifty patients with primary brain tumours to see if they could act as a surrogate for neurological impairment. The tests were compared with established measures of physical disability (Barthel Disability Index [BDI]) and handicap. Timed tests of hand function and gait were sensitive to minor impairments and were abnormal in patients with physical disability on BDI. Timed tests correlated well with handicap (rank correlation 0.734). Short term memory was impaired more commonly with tumours involving the left hemisphere (p < 0.01). Dysphasia limited testing of memory in 8%. Depression was associated with problems in limb function (p < 0.01), memory (p < 0.001), language (p < 0.001), BDI (p < 0.001) and handicap (p < 0.001). The number of abnormal fast tests also correlated with the severity of handicap (rank correlation 0.786) indicating that memory impairment and aphasia contribute to handicap and should be assessed. Median time to complete all assessments was 7 minutes 20 seconds. Utilization of these simple tests will add sensitivity and objectivity to evaluation of neurological response in clinical trials and can be performed quickly by non medical staff.

Stereotaxic brain biopsy in AIDS patients: does it contribute to patient management?

The authors analysed all cases of brain biopsy done in AIDS or HIV+patients at the Department of Clinical Neurosciences, Western General Hospital, Edinburgh, during the period 1989-92 to determine the clinical utility of the procedure. Thirteen lesions were biopsied revealing toxoplasmosis in five, lymphoma in four, progressive multifocal leucoencephalopathy in three, HIV encephalitis in two and encephalitis of unknown aetiology in one. One biopsy specimen contained abnormal tissue but was non-diagnostic. The median survival after biopsy was only 7 weeks, but preoperative immunological (median CD4 count 45) and clinical status of the patients were poor. Although the impact of tissue diagnosis on patient survival was minimal it did enable modification of drug therapy. The authors preliminary experience with biopsy in AIDS patients suggests that the diagnostic information obtained is of limited value in prolonging the lives of patients in poor immunological status, but may be useful in refining medical therapies for toxoplasmosis and progressive multifocal leucoencephalopathy. Whether biopsy should be performed earlier in the course of cerebral disease in an effort to prolong survival time remains unclear.

An experimental study to evaluate the accuracy of diencephalic and pallidal target localization using the Brown-Roberts-Wells stereotactic system and unreformatted axial GE8800 CT scanning

An experimental study was undertaken to evaluate the accuracy with which the intercommissural line (IL) length and anterior-posterior commissural (AC-PC) plane could be selected using unreformatted axial CT8800 imaging. Using these reference points, the Schaltenbrandt and Bailey stereotactic atlas and the Brown-Roberts-Wells (BRW) stereotactic system 1.82 mm ball bearings were deposited at selected diencephalic and pallidal targets in cadaver brains. There were errors in both IL length (median 1.5 mm) and AC-PC plane (median forward angulation of 9 degrees) estimation. Ball bearing deposition into large nuclei such as the pulvinar and globus pallidus and those in proximity to the mid IL such as the nuclei ventro oralis anterior (Voa), ventro oralis posterior (Vop) and ventro intermedius (Vim) was generally good; however, localization of the relatively small intralaminar nucleus was poor. This study suggests that when the AC and PC are not well imaged on sagittal reformations of axial diencephalic CT scans estimation of the AC-PC plane and IL from axial CT scans may be accurate enough for anatomical localization of certain functional stereotactic targets. The implications of this experimental study to operative functional stereotaxy are discussed.

Rapid resolution following chemotherapy of Broca's dysphasia due to recurrent anaplastic astrocytoma

A middle-aged man re-presented with a Broca's aphasia due to a recurrent fronto-cingulate anaplastic astrocytoma. Although the language disturbance did not improve with dexamethasone therapy, within 4 weeks of treatment with procarbazine, CCNU and vincristine, the dysphasia had almost completely resolved. The anatomico-functional aspects and possible mechanisms of production and resolution of the aphasia are discussed. Assessment of dysphasias in patients undergoing intensive therapy for brain neoplasms is often neglected, but it can provide good objective information about the efficacy of therapy.

Acute subdural haematoma secondary to ruptured intracranial aneurysm: diagnosis and management

Acute subdural haematoma secondary to a ruptured intracranial aneurysm may lead to coma or sudden death. We describe five cases encountered in our department over the last 3 years emphasizing the differential diagnosis and approaches to management.

Management and long-term outcome following subarachnoid haemorrhage and intracranial aneurysm surgery in elderly patients: an audit of 199 consecutive cases

To address the question of managing subarachnoid haemorrhage (SAH) in the older patient, the management and outcome of 199 consecutive patients aged > or = 60 years with a confirmed diagnosis of subarachnoid haemorrhage (n = 186) or an unruptured intracranial aneurysm (n = 13) were reviewed. In seven patients, the cause of the SAH was an arterio-venous malformation and these were excluded from further analysis. Angiography was performed in 141 patients with a complication rate of 2.1%. Angiography was not performed in 51 patients and, in this cohort, the in-patient mortality rate was 68.6% and only 27.5% had a favourable outcome at discharge. Operation was not performed in 21 patients with demonstrated aneurysms for a variety of reasons. In this group, the in-patient mortality rate was 47.6% and 38.1% had a favourable outcome at discharge. Eighty-one patients in good neurological grade underwent surgery for a ruptured aneurysm and six patients underwent surgery for a symptomatic unruptured aneurysm. The surgical mortality was 1.1% and a favourable outcome at discharge was achieved in 83.9% of patients. Thirty-three patients were angiographic negative and there was a favourable outcome in 97% of this group. The management mortality in these selected patients admitted to the Department of Clinical Neurosciences was 24.4% and a favourable outcome was recorded in 66.2% of patients. Long-term follow-up (median 40 months, range 3-120 months) was obtained in 97% of discharged patients. The probability of survival at 60 months for patients in good condition at discharge was 0.826 (95% confidence interval 0.722-0.894).(ABSTRACT TRUNCATED AT 250 WORDS)

Teaching image-guided stereotactic methodology and functional neuroanatomy of the thalamus and pallidum: a simple ex vivo technique

A simple and cheap model that enables on site, ex vivo, but very practical, learning of frame-based image-guided stereotactic technique and methodology, and the functional anatomy of the pallidum and thalamus is described. Using a cadaver skull, a specially prepared, formalin-fixed cadaver brain, and a modified stereotactic probe application of a stereotactic frame to the cranium, fiducial point acquisition, target point acquisition, computation of both arc and probe depth settings, and verification of target point accuracy can all be practiced. If diencephalic targets are selected for targeting with ball bearings then section of the cadaver brains, and study of a human thalamic stereotactic atlas provides an excellent and clinically relevant method of learning functionally important thalamic and pallidal anatomy. The method and techniques are described for CT imaging using the Brown-Roberts-Wells frame, but they are equally applicable to other frame types.

Neuropathological and neurophysiological effects of interstitial white matter autologous and non-autologous protein containing solutions: further evidence for a glioma derived permeability factor

The feline infusion model of brain edema was used to evaluate the pathophysiological effects of 0.6 ml infusions of autologous serum protein (66%), human serum protein (66%), human glioma cyst fluid and a tissue culture medium (TCM) on the structure and function of the forebrain white matter. These infusions increased local white matter water content by between 10.8 and 12.5 ml/100 g brain and were associated with moderate increases in ICP and CSF outflow resistance and a significant decrease in lumped craniospinal compliance. Cortical somatosensory potentials, motor evoked potentials, EEG and local cerebral blood flow (rCBF) at normocapnia were generally unchanged by the various infusions. All infusates except the 66% autologous serum protein infusion impaired rCBF CO2 reactivity. Histologically all infusates caused marked extracellular edema. The autologous serum protein infusion caused no additional histological changes whereas the glioma cyst infusates caused profound endothelial and astrocytic swelling, focal endothelial necrosis, basement membrane disruption, perivascular microglial reaction and pavementation and perivascular migration of polymorphonuclear leukocytes. Similar but less marked changes were seen after infusion of human serum protein whilst the TCM produced only minimal changes. The intensity and extent of Evans Blue extravasation into the forebrain white matter was greatest with glioma cyst infusates and with all infusions reflected the extent to microvascular changes. These studies show that products derived from gliomas cause additional damage to the blood-brain-barrier than that caused by non-autologous serum proteins. These results add further support for the existence of glioma derived permeability factors (GDPF), but suggest neither serum proteins nor glioma derived compounds in the white matter interstitium significantly influence local electrophysiological function. Some limitations of the infusion edema model when using non-autologous infusions and difficulties quantitating brain dysfunction are emphasised.

An experimental study of cerebrovascular resistance, pressure transmission, and craniospinal compliance

To successfully match the treatment to the cause for raised intracranial pressure (ICP) after a severe head injury, it is important to know the underlying mechanism at a given moment for the raised pressure. In particular, it is important to distinguish between active cerebral vasodilation, indicating functional autoregulation, and a passive vascular dilation as the cause for raised ICP. An experimental study was performed in feline models of diffusely raised ICP (n = 6), of active arterial vasodilation caused by arterial hypercarbia (n = 6), and of passive arterial dilation caused by pharmacologically induced arterial hypertension (n = 6) to determine if wave form analysis of ICP can distinguish active from passive arteriolar vasodilation. Pulsatile pressure transmission from the blood pressure pulse to the ICP pulse (cerebrovascular pressure transmission [CVPT]), cerebrovascular resistance, and craniospinal compliance were measured simultaneously at each level of raised ICP, arterial hypercarbia, and arterial hypertension. Arterial hypercarbia, caused by both 5 and 10% inspired CO2 increased low-frequency CVPT, which was followed by an increasingly negative phase shift between the blood pressure and ICP wave form (P < 0.05). Diffusely raised ICP caused by intraventricular infusion of mock cerebrospinal fluid caused increased low-frequency CVPT (P < 0.01) but resulted in no overall change in phase shift, although the sign of the phase shift remained negative. After arterial hypertension, caused by the infusion of angiotensin II, where there was loss of myogenic tone, an increased low-frequency CVPT was accompanied by a positive phase shift (P < 0.01). These data demonstrate it may be possible to distinguish active arteriolar vasodilation from a passive loss of autoregulatory vascular tone through simultaneous measurement of the low-frequency CVPT and phase shift. Analysis of the ICP wave form provides information relevant to the management of raised ICP.

Epidermal growth factor receptor activity and clinical outcome in glioblastoma and meningioma

Epidermal growth factor receptor (EGF-r) activity in patients with glioblastoma multiforme (GBM: n = 27) and meningioma (n = 18) was compared with clinical outcome. All patients with GBM were followed up to time of death. In patients with GBM there was no significant relationship between EGF-r activity and either patient survival time or age. EGF-r activity in patients with meningioma was neither related to age nor, at a median of 40 months after surgery, to clinical outcome. These results suggest that routine estimation of EGF-r activity in these intracranial tumours is not indicated.

Accuracy of ventrolateral thalamic nucleus localization using unreformatted CT scans and the B-R-W system. Experimental studies and clinical findings during functional neurosurgery

The accuracy with which the ventrolateral thalamic nucleus could be targetted using the BRW stereotactic system and unreformatted axial CT imaging was evaluated in cadaver brains mounted in a skull. Ball bearings (1.82 mm diameter) were placed in the nuclei ventro intermedius (Vim), ventro oralis anterior (Voa) and posterior (Vop) and the brains then sectioned, the locations of the ball bearings relative to the anterior (AC) and posterior commissures (PC) measured and evaluated with reference to a Schaltenbrandt and Bailey stereotactic atlas. Targetting of the ventrolateral thalamic region was frequently accurate (77%) but because of errors in estimation of the AC-PC plane (mean forward angulation of 9 degrees) some ball bearings were placed too deeply in the Fields of and Forel, zona incerta and rostral subthalamic nucleus. Ventrolateral thalamotomy using the BRW stereotactic system and unreformatted axial CT imaging was undertaken in six patients with tremor due to a range of pathologies. The tremor was abolished or altered in four patients whilst no lesion was made in the other two patients since no site that reduced the tremor, could be located. The surgical and clinical implications of this study are discussed.