Biomedical subjects

M J Cook

Publications and source records attributed to M J Cook.

At least 19 recordsLinked to original sources

PubMed2006

Short-term effects of methylprednisolone on cerebral volume in multiple sclerosis relapses.

We prospectively investigated the short-term effects of intravenous methyl-prednisolone (IVMP) on cerebral volume in patients suffering a multiple sclerosis (MS) relapse. Ten patients underwent MRI brain studies immediately before and after IVMP treatment, and 4 and 8 weeks later. Whole brain volumes decreased significantly over the 8-week period. The greatest change occurred during IVMP administration. This has implications for MS treatment trials using cerebral atrophy as an endpoint.

Adult↗

PubMed2006

Volumetric analysis of a specific language region - the planum temporale.

Planum temporale volumes were determined for 42 control children (ages 4.2-15.7 years) using magnetic resonance imaging. The mean left planum temporale volume was 2729 mm3 (SD = 567) and the mean right planum temporale volume was 2758 mm3 (SD = 546). No significant hemispheric asymmetry was demonstrated. Analysis of co-variance (ANCOVA) showed that the absolute and proportional planum temporale volumes were not significantly associated with age or gender. We also demonstrated a reproducible method for planum temporale volume measurement by acquiring images in the coronal plane and then visualising the sagittal plane to improve accuracy for the posterior border.

Adolescent↗

PubMed2005

Seizures, not hippocampal neuronal death, provoke neurogenesis in a mouse rapid electrical amygdala kindling model of seizures.

PURPOSE: Proliferation of neural precursors adjacent to the granule cell layer of the dentate gyrus has been identified in previous epilepsy models. Convincingly demonstrating that seizure activity is the stimulant for neurogenesis, rather than neuronal death or other insults inherent to seizure models, is difficult. To address this we derived a rapid electrical amygdala kindling model in mice known to be resistant to seizure-induced neuronal death as an experimental model of focal seizures and to analyze subsequent neurogenesis. METHODS: Mice were implanted with bipolar electrodes in the left amygdala and given electrical stimulation (3 s, 100 Hz, 1 ms monophasic square wave pulses every 5 min, 40 in total) while being observed and graded for the development of seizures. Neurogenesis in the hippocampus was assessed by counting bromodeoxyuridine-immunoreactive cells co-labeled for astrocyte (glial fibrillary acidic protein) and neuronal nuclear markers. RESULTS: Bromodeoxyuridine-reactive cell numbers were three-fold higher in stimulated mice compared with controls at 1 week in the subgranular region and at three weeks extensive co-labeling with neuronal nuclear was noted in cells which had migrated into the body of the granule cell layer, while mice receiving stimulation but failing to kindle did not differ significantly from controls. No increase in neuronal death was detected by terminal deoxynucleotidyl transferase-mediated digoxigenin-11-dUTP nick end labeling, Fluorojade or fluorescent examination of hematoxylin and eosin-stained sections in any inter-group comparison. CONCLUSIONS: We propose that this kindling paradigm, not previously applied to mice, demonstrates more convincingly than previously the surge in neurogenesis in response to seizures, and the effects of seizures alone in regard to neuronal injury and regeneration.

Animals↗

PubMed2004

MRI-negative PET-positive temporal lobe epilepsy: a distinct surgically remediable syndrome.

Most patients with non-lesional temporal lobe epilepsy (NLTLE) will have the findings of hippocampal sclerosis (HS) on a high resolution MRI. However, a significant minority of patients with NLTLE and electroclinically well-lateralized temporal lobe seizures have no evidence of HS on MRI. Many of these patients have concordant hypometabolism on fluorodeoxyglucose-PET ([18F]FDG-PET). The pathophysiological basis of this latter group remains uncertain. We aimed to determine whether NLTLE without HS on MRI represents a variant of or a different clinicopathological syndrome from that of NLTLE with HS on MRI. The clinical, EEG, [18F]FDG-PET, histopathological and surgical outcomes of 30 consecutive NLTLE patients with well-lateralized EEG but without HS on MRI (HS-ve TLE) were compared with 30 consecutive age- and sex-matched NLTLE patients with well-lateralized EEG with HS on MRI (HS+ve TLE). Both the HS+ve TLE group and the HS-ve TLE patients had a high degree of [18F]FDG-PET concordant lateralization (26 out of 30 HS-ve TLE versus 27 out of 27 HS+ve TLE). HS-ve TLE patients had more widespread hypometabolism on [18F]FDG-PET by blinded visual analysis [odds ratio (OR = + infinity (2.51, -), P = 0.001]. The HS-ve TLE group less frequently had a history of febrile convulsions [OR = 0.077 (0.002-0.512), P = 0.002], more commonly had a delta rhythm at ictal onset [OR = 3.67 (0.97-20.47), P = 0.057], and less frequently had histopathological evidence of HS [OR = 0 (0-0.85), P = 0.031]. There was no significant difference in surgical outcome despite half of those without HS having a hippocampal-sparing procedure. Based on the findings outlined, HS-ve PET-positive TLE may be a surgically remediable syndrome distinct from HS+ve TLE, with a pathophysiological basis that primarily involves lateral temporal neocortical rather than mesial temporal structures.

Adult↗

PubMed2003

Amygdala volumetry in "imaging-negative" temporal lobe epilepsy.

OBJECTIVE: Although amygdala abnormalities are sometimes suspected in "imaging-negative" patients with video EEG confirmed unilateral focal epilepsy suggestive of temporal lobe epilepsy (TLE), amygdala asymmetry is difficult to assess visually. This study examined a group of "imaging-negative" TLE patients, estimating amygdala volumes, to determine whether cryptic amygdala lesions might be detected. METHODS: Review of video EEG monitoring data yielded 11 patients with EEG lateralised TLE and normal structural imaging. Amygdala volumes were estimated in this group, in 77 patients with pathologically verified hippocampal sclerosis (HS), and in 77 controls. RESULTS: Seven of 11 "imaging-negative" cases had both significant amygdala asymmetry and amygdala enlargement, concordant with seizure lateralisation. Although significant amygdala asymmetry occurred in 35 of 77 HS patients, it was never attributable to an abnormally large ipsilateral amygdala. Compared with patients with HS, patients with amygdala enlargement were less likely to have suffered secondarily generalised seizures (p<0.05), and had an older age of seizure onset (p<0.01). CONCLUSION: Abnormal amygdala enlargement is reported in seven cases of "imaging-negative" TLE. Such abnormalities are not observed in patients with HS. It is postulated that amygdala enlargement may be attributable to a developmental abnormality or low grade tumour. It is suggested that amygdala volumetry is indicated in the investigation and diagnosis of "imaging-negative" TLE.

Adult↗

PubMed2002

Clinical, EEG, and quantitative MRI differences in pediatric frontal and temporal lobe epilepsy.

OBJECTIVE: To examine the clinical, electrographic, and quantitative MRI differences between frontal lobe (FLE) and mesial temporal lobe epilepsy (MTLE) in children. METHODS: The population included children who underwent video-EEG monitoring between 1995 and 2000 who were classified as either FLE (n = 39) or MTLE (n = 17) according to the criteria of the International League Against Epilepsy. Clinical, EEG, and quantitative MRI data (including frontal cortical volumes) were compared between the two syndromes and a control group (n = 42). RESULTS: In FLE, seizures were significantly briefer, more frequent, and predominantly from sleep, and had differing motor characteristics. The rates of bilateral epileptiform interictal and ictal EEG abnormalities were significantly higher in FLE. A nonlesional MRI was significantly more common in FLE. Mean frontal cortical volume in FLE was significantly lower than MTLE and controls. Seizure freedom after surgery was lower in FLE. CONCLUSIONS: The clinical syndrome of FLE is clearly distinct from MTLE. The etiology of this disorder is unknown in the majority of cases despite extensive investigation. Because of a lack of a clearly defined etiology and frequent nonlateralizing EEG changes, few of these children are considered optimal surgical candidates. The demonstration of bilateral frontal cortical volume loss and bilateral EEG abnormalities suggests that FLE is a bilateral disease in a high proportion of patients. The outcome in those patients who were deemed surgical candidates was significantly worse than the MTLE cases.

Adolescent↗

PubMed2002

Insertion of depth electrodes with or without subdural grids using frameless stereotactic guidance systems--technique and outcome.

Over recent years frameless stereotactic systems have begun replacing framed systems for many neurosurgical procedures. However, little has been published regarding the use of these systems to guide intracranial electrode implantation for epilepsy surgery patients. Here we report our experience utilising such a system to insert depth electrodes and subdural grid electrodes. The SteathStation Image-Guided System (SSIGS) (Sofamor Danek, Memphis TN.) was used to insert bilateral depth electrodes in 13 patients, of whom 5 also underwent the insertion of subdural grids or strip electrodes. Initially, a surgical plan based on an entry and target point on axial and sagittal images was performed for the insertion of electrodes. Navigational views, using three-planar images, were then performed to determine which structures the electrodes would pass through to be correctly placed in the amygdala and hippocampus. The correct site of electrode implantation was confirmed post-operatively by spiral CT scans in 4 patients (which were then co-registered to the pre-implantation MRI using a surface matching technique) and the other 9 patients by post-implantation MRI. The SSIGS was found to have a mean registration error of 2.0 mm (range 1.8-2.5) in 10 cases; in the 3 cases where the error was greater than 2.5 mm a surfacemerge technique was used with a mean error 0.9 (0.8-1.00). The post-implantation MRI or CT-MRI co-registration confirmed an accurate electrode placement in the mesial temporal region in all cases. Seizure onset lateralisation was achieved in 11 patients, all of whom went onto formal resections based on these results. The only long-term complication was a case of osteomyelitis which required removal of the bone flap. 73% of patients had an excellent seizure outcome. Frameless stereotactic systems can be safely used to intracranial electrodes, avoid the disadvantages of the framed system and have the added advantage of the surgeon being able to visualise the trajectory and to adjust this to avoid vital structures. As well they eliminate surgical obstruction to the insertion of subdural grids at the same operation, which may be caused by a framed system.

Adult↗

PubMed2001

The renaissance of clinical leadership.

The purpose of this work was to explore clinical nursing leadership. The research was based on a critical examination of the leadership themes derived from the nursing literature of the United Kingdom, the United States of America and Australia, between 1992 and 1997. The work was also influenced by the findings from semistructured interviews undertaken with five clinical leaders in nursing from the United Kingdom, and study tours to both the United States of America and Australia. The findings support a proposed leadership model as a basis for further exploration and as a framework for contemplating clinical leadership and leadership preparation. A model is presented that identifies factors which influence leadership styles, such as external environment, internal environment, experience and understanding. Four leadership styles are outlined: transactional, transformational, connective and renaissance. These leadership styles are linked to nursing care approaches. A second model provides a basis for considering power and its impact in the workplace. Based on these findings, the contents of a leadership preparation course are outlined.

Attitude of Health Personnel↗

PubMed2001

Multimodality image-guided epilepsy surgery.

Co-registration of imaging modalities in the diagnosis of epilepsy is now commonly used in major epilepsy centres. However, the incorporation of these registrations into an image-guided system has only recently been developed. Using techniques of segmentation, surface matching and/or voxel-based matching, we have been able to co-register FLAIR MRI, SPECT, PET, and subdural grids into the 3-D space of the volumetric MRI and use these images on the StealthStation Image-Guided System to resect these foci. This greatly aids the surgeon in performing a more precise tailoring of the cortical resection so as to maximize the excision of the epileptogenic zone while minimizing the impact on eloquent cortex and epileptogenic foci.

Adult↗

PubMed2001

The utility of a 3-dimensional, large-field-of-view, sodium iodide crystal--based PET scanner in the presurgical evaluation of partial epilepsy.

UNLABELLED: (18)F-FDG PET is an accurate and reliable technique for localizing medically refractory temporal lobe epilepsy, but widespread use has been hindered by limited reimbursement in many countries because of the high cost of traditional PET equipment and radioisotopes. Additionally, the place of FDG PET as a cost-effective tool for presurgical evaluation of epilepsy has been questioned because of limited data showing that FDG PET provides localization information incremental to that provided by more established techniques, particularly MRI and ictal electroencephalography (EEG). Three-dimensional (3D), large-field-of-view, sodium iodide crystal-based scanners have lower equipment and running costs and better multiplanar resolution than traditional 2-dimensional bismuth germinate (BGO) systems but have not yet been validated for evaluation of epilepsy. Our purpose was to investigate the localization rate, accuracy, and prognostic value of FDG PET images acquired on a 3D, large-field-of-view, sodium iodide crystal-based PET scanner in the presurgical evaluation of intractable partial epilepsy. We also wanted to establish the incremental value of FDG PET over established MRI and ictal EEG techniques. METHODS: Fifty-five patients who were surgical candidates because of medically refractory partial epilepsy were examined. For most of these patients, the lesions had not been clearly localized on conventional assessment. The FDG PET scans were reviewed independently by 2 reviewers who were unaware of the patients' clinical details, ictal EEG findings, and volumetric MRI results, and the FDG PET results were correlated with those of MRI and EEG and with postsurgical outcome. RESULTS: Forty-two patients (76%) had localizing FDG PET images (37 temporal, 5 extratemporal). The ictal EEG recordings were localizing in 66%, and the MRI findings were localizing in 27% (which increased to 35% after the MRI findings were reviewed again after PET). Concordance between the site of the PET localizations and the site of the MRI or EEG localizations was 100%. The PET images were localizing in 63% and 69% of patients with nonlocalizing ictal EEG and MRI findings, respectively. Twenty-one of 24 patients who subsequently underwent epilepsy surgery had localizing FDG PET images; of these 21 patients, 18 (86%) had a class I outcome. Multiple regression analysis showed the FDG PET results to be predictive of postsurgical outcome independently of the MRI findings. CONCLUSION: For intractable partial epilepsy, FDG PET using a 3D, large-field-of-view, sodium iodide crystal-based scanner provided clinically useful localizing information that was at least as accurate as the results reported for traditional BGO-based scanners. The PET images provided prognostically significant localization information incremental to that provided by volumetric MRI and ictal EEG, particularly if 1 of these studies was nonlocalizing.

Adolescent↗

PubMed2000

Evaluation of SPECT in the assessment and treatment of intractable childhood epilepsy.

The authors retrospectively examined the role of SPECT in 65 children undergoing video-EEG telemetry. SPECT was concordant in most children whose lesions were already localized by MRI and epilepsy syndrome and provided localizing data in more than half not localized by these modalities. Ictal SPECT provided no additional prognostic benefit in patients undergoing epilepsy surgery (n = 23) who have a localized MRI lesion. In patients without lesions, however, ictal SPECT provides useful additional localization that may be used as a guide to intracranial implantation.

Brain↗

PubMed2000

Phthalocyaninodehydroannulenes.

4-Bromo- and 4,5-dibromo-3,6-dibutoxyphthalonitrile have been prepared and treated with 3,6-didecylphthalonitrile in cross tetramerisation reactions in the presence of nickel acetate to afford monobromo- and dibromo-dibutoxyhexadecylphthalocyaninato nickel(II) complexes. Sonogashira and Stille coupling reactions on these compounds displaced the bromine substituents by ethynyl groups. Oxidative coupling of the monoethynyl derivatised nickel phthalocyanine afforded a butadiynyl-linked dinuclear phthalocyanine. The corresponding coupling reaction of the diethynylated phthalocyanine gave a mixture of phthalocyaninodehydroannulenes. Separation of the mixture yielded the diphthalocyaninodehydro[12]annulene as the major product. Electrospray mass spectrometry provides evidence for its aggregation in solution. The corresponding cyclic trimer, the triphthalocyaninodehydro[18]annulene, has been identified as a minor product. Both compounds show a large splitting of the Q-band absorption in the visible region spectrum. Most of the mononuclear phthalocyanine precursors exhibit discotic liquid crystal behaviour. The diphthalocyaninodehydro[12]annulene also enters a mobile phase on heating, but undergoes an irreversible change at 220 degrees C. MALDI-TOF mass spectrometry of the product reveals that the compound undergoes oligomerisation at this temperature.

Journal Article↗

PubMed2000

Predictors of hippocampal, cerebral, and cerebellar volume reduction in childhood epilepsy.

PURPOSE: We examined the factors related to brain volume reduction in a pediatric sample of patients that included those with nonintractable epilepsy. METHODS: Entry criteria were children less than 18 years old with epilepsy referred for MRI, including a whole brain volumetric sequence. The sample size was 231. Risk factors were ascertained from interviews and reviews of medical records. Factors included age of onset, seizure years, family history, status epilepticus, intellectual disability, and febrile convulsions. MRI data were obtained for 44 normal childhood control subjects. RESULTS: Cerebral and cerebellar volumes were significantly associated with age, gender, moderate-to-severe intellectual disability (p < 0.001), seizure years, and status epilepticus (p < 0.03). Compared with controls, the brain volume of all patients was reduced by 10% (p < 0.001). Hippocampal volume was significantly associated with total brain volume, age (p < 0.001), focal cerebral ischemic injury, and complex febrile convulsions (p < 0.05). CONCLUSIONS: Significant brain volume reduction is present in children with epilepsy. A component of this reduction is due to acquired insults. The reduction is seen even in children with infrequent seizures over a brief time, suggesting an innate structural abnormality. When evaluating possible etiologic factors in the development of hippocampal volume reduction, one must control for total brain volume. We have confirmed the association of complex febrile convulsions with unilateral hippocampal volume reduction.

Adolescent↗

PubMed2000

Cerebral and cerebellar volume reduction in children with intractable epilepsy.

PURPOSE: Adult epilepsy studies have demonstrated cerebral and cerebellar volume reduction beyond the epileptogenic zone, correlating this with an inferior surgical outcome. We determined whether brain volumes were reduced in childhood epilepsy and the significance of this. METHODS: Cerebral, cerebellar, and hippocampal volumes were measured by quantitative magnetic resonance imaging on 112 children (ages 4-18) with epilepsy syndrome determined by video-EEG telemetry. Eighty-seven had partial epilepsy and 25 had generalized epilepsy or indeterminate syndrome. Normative volumes were obtained from 44 child controls from the community. RESULTS: A significant reduction in cerebral (12.6%) and cerebellar (7.9%) volume was present in the epilepsy group compared with controls. Analysis of subgroups revealed that cerebral volume was significantly decreased in frontal lobe and nonlocalized partial epilepsies. The mean hippocampal ratio of 0.73 for mesial temporal lobe epilepsy was significantly less than for all other syndromes and controls. There was no difference in the rate of hippocampal volume reduction between syndromes. There was a significant correlation between IQ and cerebral and cerebellar volume, but not duration or age of onset of epilepsy. CONCLUSIONS: Cerebral and cerebellar volume reduction is common in intractable epilepsy syndromes of childhood. These cross-sectional data suggest that brain volume reduction is present at epilepsy onset and is not a result of intractable seizures. Hippocampal asymmetry is more sensitive than volume reduction as a marker for mesial temporal lobe epilepsy, but neither measure is specific.

Adolescent↗

PubMed2000

Degree of hippocampal atrophy is not related to a history of febrile seizures in patients with proved hippocampal sclerosis.

OBJECTIVES: To examine the degree of hippocampal atrophy in patients with temporal lobe epilepsy and proved hippocampal sclerosis to determine whether or not patients with febrile seizures have more severe hippocampal atrophy. To determine whether or not there is a relation between age of seizure onset, duration of temporal lobe epilepsy, or seizure frequency, and severity of hippocampal atrophy. METHODS: Hippocampal volumes were measured from volumetrically acquired MR images in 77 consecutive surgical patients with temporal lobe epilepsy (37 febrile seizures (FS)+, 40 FS-) with proved hippocampal sclerosis, and compared with 98 controls. RESULTS: Ipsilateral and contralateral hippocampal volumes were not significantly different between the FS+ and FS- groups. There was no difference in the age of onset of habitual seizures, duration of epilepsy, or age at the time of surgery, between these groups. No clinically significant correlations were found between hippocampal volumes and age of onset of first non-febrile seizure, duration of temporal lobe epilepsy, or complex partial and secondarily generalised seizure frequency, in patients with and without febrile seizures. CONCLUSIONS: Although febrile seizures was associated with hippocampal sclerosis in 48% of patients in this surgical series, the degree of MRI determined hippocampal atrophy was not related to a history of such seizures. The results do not support the view that febrile seizures cause more severe hippocampal sclerosis and are consistent with the hypothesis that hippocampal sclerosis is a pre-existing abnormality.

Adult↗

PubMed1999

Improving care requires leadership in nursing.

The purpose of this paper is to provide a model of leadership in nursing. The model outlines factors that influence leadership styles, discusses approaches to leadership and the impact of the leadership style on nursing care. The model is based on a critical examination of the current leadership themes from nursing literature in the UK, USA and Australia, between 1992 and 1997, and the findings from semi-structured interviews with five leaders in nursing. These findings help support the proposed leadership model as a basis for further exploration and as a framework for thinking about leadership and leadership preparation.

Attitude of Health Personnel↗

PubMed1999

Surgical outcome in patients with epilepsy and dual pathology.

High-resolution MRI can detect dual pathology (an extrahippocampal lesion plus hippocampal atrophy) in about 5-20% of patients with refractory partial epilepsy referred for surgical evaluation. We report the results of 41 surgical interventions in 38 adults (mean age 31 years, range 14-63 years) with dual pathology. Three patients had two operations. The mean postoperative follow-up was 37 months (range 12-180 months). The extrahippocampal lesions were cortical dysgenesis in 15, tumour in 10, contusion/infarct in eight and vascular malformation in five patients. The surgical approach aimed to remove what was considered to be the most epileptogenic lesion, and the 41 operations were classified into lesionectomy (removal of an extrahippocampal lesion); mesial temporal resection (removal of an atrophic hippocampus); and lesionectomy plus mesial temporal resection (removal of both the lesion and the atrophic hippocampus). Lesionectomy plus mesial temporal resection resulted in complete freedom from seizures in 11/15 (73%) patients, while only 2/10 (20%) patients who had mesial temporal resection alone and 2/16 (12.5%) who had a lesionectomy alone were seizure-free (P < 0.001). When classes I and II were considered together results improved to 86, 30 and 31%, respectively. Our findings indicate that in patients with dual pathology removal of both the lesion and the atrophic hippocampus is the best surgical approach and should be considered whenever possible.

Adolescent↗

PubMed1998

ILAE-defined epilepsy syndromes in children: correlation with quantitative MRI.

PURPOSE: The role of quantitative magnetic resonance imaging (MRI) in evaluation of childhood epilepsy remains poorly defined, with minimal published data. Previous work from our center questioned the specificity of hippocampal asymmetry (HA) in an outpatient group whose epilepsy was defined by using clinical and interictal data only. By using childhood volunteer controls and defining epilepsy syndromes using video-EEG monitoring, we readdressed the utility of HA in differentiating mesial temporal lobe epilepsy (MTLE) from other partial and generalized epileptic syndromes in children. METHODS: Seventy children were enrolled; entry criteria were age younger than 18 years with predominant seizure type recorded on video-EEG telemetry with volumetric MRI in all cases. Thirty healthy child volunteers had volumetric MRI. Epilepsy syndrome classification was according to ILAE. RESULTS: Control data revealed symmetric hippocampi, mean smaller/larger ratio of 0.96 (0.95-0.97, 95% CI) with no gender or right/left predominance. Overall 23% of patients had significant HA. Mean hippocampal ratio for MTLE was 0.78 (95% CI, 0.70-0.86), significantly lower than controls and from all other epilepsy syndromes. HA was highly specific (85%) to the syndrome of MTLE. Other potential epileptogenic lesions were found in 27 (39%) patients, lowest yield in frontal and mesial temporal syndromes. Dual pathology was present in 10% of patients. There was no significant association between HA and risk factors. CONCLUSIONS: In this study, we found that HA in children with a well-defined epilepsy syndrome is highly sensitive and specific for MTLE. Whether this will correlate with surgical outcome, as in adults, is the subject of ongoing study.

Adult↗