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At least 865 records · Page 48Linked to original sources

PubMed1995

Interferon-alpha and survival in renal cell cancer.

OBJECTIVE: To establish whether the use of interferon-alpha might result in improved survival, using two large series of patients with advanced renal cell cancer treated during studies of chemotherapy and biological therapy, respectively. PATIENTS AND METHODS: Patients treated either in the Eastern Cooperative Oncology Group (ECOG) chemotherapy protocols (327 patients) or in protocols employing interferon as part of a European randomized study or phase II studies at the Norwegian Radium Hospital (231 patients) were retrospectively analysed. Groups for comparison were matched by exclusion of those with an ECOG performance status > 2, no prior nephrectomy, brain metastases or prior chemotherapy. Univariate analysis of prognostic factors for survival was performed by the log rank method and multivariate analysis by Cox regression. RESULTS: Univariate analysis of the whole population showed that performance status, time from diagnosis to treatment, sites of metastases and the use of interferon carried the greatest prognostic significance. In multivariate analysis, the use of interferon remained a significant predictor of survival (P < 0.001). Subgroup analysis suggested that the impact of interferon treatment was greatest in those patients with two of the following characteristics: good performance status, an interval of > 2 years from diagnosis to treatment and no more than one site of metastasis. CONCLUSION: Although a prospective randomized trial is needed to establish definite benefit from the use of interferon in advanced renal cell cancer, this analysis supports the rationale for performing such a trial, particularly in patients with relatively good prognostic features. Patients should be entered into the Medical Research Council study comparing interferon with medroxyprogesterone acetate.

Adult↗

PubMed1988

Slow channel inhibitor effects on brain function: tolerance to severe hypoxia in the rat.

1. The protective effects of ten slow channel inhibitor drugs against severe progressive hypoxia were investigated in rats breathing spontaneously during light anaesthesia. Respiration, heart rate, electrocorticogram (ECoG) and/or electroencephalogram (EEG) were recorded. 2. Tolerance times were monitored from hypoxia onset until cessation of respiration, ECoG, EEG synchronization, and 'background-EEG'. Drugs were administered i.v. 5 min before the onset of hypoxia. 3. Verapamil, gallopamil, and nimodipine resulted in a significant increase of tolerance times; fendiline and bepridil showed a small increase (not significant); bencyclan and prenylamine were ineffective; cinnarizine and diltiazem slightly reduced tolerance times as did flunarizine at low doses. 4. At protective doses, verapamil, gallopamil, and nimodipine significantly raised the respiration rate but had little or no cardiac depressor effects. Bencyclan showed ventilatory drive but cardiocirculatory depression. A clear-cut ventilatory drive did not occur with the other ineffective slow channel inhibitors. 5. It is suggested that the protective actions observed were not due to slow channel inhibition per se, nor to spasmolytic potency or increased cerebral blood flow. Ventilatory drive associated with other cardiopulmonary actions which secondarily raise the brain oxygen supply are likely to be responsible for this effect.

Animals↗

PubMed1993

Inhibition by N omega-nitro-L-arginine methyl ester of the electrocortical arousal response in rats.

In rats chronically implanted with cannulae into one lateral cerebral ventricle and recording electrodes onto the fronto-parietal cortex, the effects of systemic or intraventricular administration of the nitric oxide (NO) synthesis inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME), on electrocortical (ECoG) arousal response evoked by sound stimulation were studied. In control animals, a single acoustic stimulation (80 dB for 15 s) produced a significant decrease in ECoG total voltage power lasting approximately 25 s. No tolerance developed after repeating the same sound stimulation at 15, 30, 60 min and 24 h intervals. Under these experimental conditions, pretreatment with L-NAME, given systemically (10 mg kg-1, i.p.) or intracerebroventricularly (300 micrograms), significantly reduced the sound-evoked arousal response 1 h and 15 min later, respectively. In conclusion, the present data are in favour of a physiological role of NO in the control of arousal mechanisms.

Acoustic Stimulation↗

PubMed1977

Suppression of an eplieptiform type of electrocortical activity in the rat by stimulation in the vicinity of locus coeruleus.

Stimulation of the locus coeruleus, or in the vicinity of this nucleus or of its ascending tracts, could markedly suppress the appearance of epileptiform-like ECoG bursts. The latter were induced in rats by a subconvulsive dose of pentylenetetrazol. Electrode sites were identified histologically. A unilateral stimulus suppressed bursts bilaterally. An individual burst already in progress could be aborted, stopping within less than 0.5-1 sec after onset of a stimulus train. The antiepileptiform actions occurred with no evidence of any desynchronizing effect of the stimulus on the resting ECoG; they appear to be different in sites of origin and nature from those reported for stimulation of the reticular activating system. It is proposed that stimulation of the ascending noradrenergic system in the brain stem may limit the development and spread of hyperexcitatory, epileptiform states.

Animals↗

PubMedDate not supplied

Motor and electrocorticographic epileptic activity induced by bicuculline in developing rats.

Motor seizures were induced by intraperitoneally (i.p.) injected bicuculline in 270 rats aged 7, 12, 18, 25, or 90 days. Bicuculline was able to elicit both minimal (clonic) and major (tonic-clonic) seizures in all age groups, but in 7-day-old rats minimal seizures were only noted exceptionally. CD50s (for major seizures) ranged from 2.48 to 2.85 mg/kg in the three younger groups and increased to approximately 7 mg/kg in 25- and 90-day-old rats. An intravenous (i.v.) administration of bicuculline in 67 rats, 18 and 25 days old, caused identical CD50s in these groups, indicating that the difference that occurs with an i.p. administration is due to pharmacokinetic reasons. Electrocorticographic (ECoG) studies in acute experiments as well as in young rats with implanted electrodes demonstrated general principles of the development of EEG: an increase in frequency of individual elements, in generalization of the epileptic activity, in synchronization of activity among various cortical regions, and in the correlation between ECoG and motor phenomena. An exception occurred as an age-related phenomenon: rhythmic activity of the spike-and-wave type. This activity appeared in 18-day-old and older rats and was invariably accompanied by "freezing" of the animals.

Age Factors↗

PubMedDate not supplied

Seizures in a fetal lamb after cocaine exposure: a case report.

We report the chance observation of two generalized seizures in a fetal lamb that received cocaine. Cocaine was infused intravenously into a 138-day-old fetus while electrocortical (ECoG), electroocular (EOG), and neck electromyographic (EMG) activity were recorded. Fetal rapid eye movement (REM) and nonrapid eye movement (NREM) sleep were disrupted during the cocaine exposure and returned to a normal pattern after infusions were stopped. Seventy-two hours later, however, we recorded generalized seizures with ECoG spike and spike wave activity.

Animals↗

PubMedDate not supplied

Localization of the epileptic focus during methohexital-induced anesthesia.

A short anesthesia was provided by methohexital for painless percutaneous removal of subdural electrodes in 27 patients with medically intractable, complex partial seizures who had undergone invasive preoperative evaluation. Electrocorticographic(ECoG) recordings performed before and during the narcosis were submitted to visual (n = 27) and computerized (n = 3) analysis to obtain additional information about the location of the epileptic focus (or foci). The following observations were made: focal epileptiform potentials were induced in 24 of 27 patients (89%); (b) in 20 of these 24, the induced spikes appeared amid or were followed by isoelectric or subdelta activity. These spikes were characterized by high amplitude as well as rhythmic and synchronized appearance over a circumscribed focal area (or areas) known to be spontaneously epileptogenic. This phenomenon, termed spike-burst-suppression (SBS) pattern, allowed identification of the primary epileptic focus in many patients with temporal lobe epilepsy. Furthermore, it indicated a good outcome of epilepsy surgery. Computerized analysis of the induced synchronized spikes (n = 3) allowed further delineation of the primary site of epileptogenicity and quantitative comparison of multiple epileptic generators. ECoG recording during deep methohexital-induced narcosis is a valuable tool for lateralization and delineation of the primary epileptogenic focus.

Adolescent↗

PubMedDate not supplied

Significance of sharp waves in routine EEGs after epilepsy surgery.

We retrospectively analyzed the presence of sharp waves in 2-h EEGs performed 6 months after epilepsy surgery in 59 patients. To study the significance of the postoperative interictal epileptiform activity in the tissue remaining after resection, we included only patients with a single epileptic focus (as defined preoperatively by prolonged video/EEG recordings and subdural electrode arrays studies) and no progressive structural lesions. Temporal lobectomy was performed in 51 patients (86%); extratemporal resections were performed in the remainder. The epileptogenic focus was completely resected in 26 patients (44%). The immediate postoperative electrocorticograms (EcoG) showed spikes in 13 patients (22%). At 6-month follow-up, 43 patients (73%) were seizure-free or had auras only and 12 patients (20%) had epileptiform activity on EEG. A significant correlation was noted between presence of sharp waves in the 6-month postoperative EEG and recurrence of seizures (Fisher's exact test p = 0.011) and also with the extent of the resection (complete vs. incomplete p = 0.042). We noted no correlation between postoperative epileptiform activity and location of the resection (temporal vs. extratemporal), presence of spikes in immediate postoperative EcoG, or occurrence of auras only at 6-month follow-up.

Adolescent↗

PubMedDate not supplied

Effect of isoflurane (Forane) on intraoperative electrocorticogram.

Isoflurane, an inhalation agent often used for general anesthesia during craniotomy, has been reported to suppress spike activity in the intraoperative electrocorticogram (ECoG) during epilepsy surgery. We studied the effect of isoflurane concentrations of 0.25, 0.5, 0.75, 1, and 1.25% on the number of spike bursts per 5-min epochs in 15 patients undergoing ECoG during epilepsy surgery. N2O in O2 was maintained at 50% in 10 patients, at 60% in 2, and at 70% in 3. End tidal CO2 concentration was maintained in the hypocarbic range, and analgesia was maintained with the narcotic alfentanil in the range of 0.5-2 micrograms/min. The median number of spikes for each isoflurane concentration was 29 (range 3-107) at 0.25%, 27 (range 2-73) at 0.5%; 29 (range 5-90) at 0.75%, 33 (range 2-100) at 1%, and 40 (range 32-140) in 5 patients who tolerated 1.25% without occurrence of burst suppression pattern. No significant difference (Student's paired t test) was noted in the number of spikes for each isoflurane concentration. Therefore, if isoflurane concentrations are maintained between 0.25 and 1.25% or before burst suppression pattern occurs and N2O/O2 is maintained in the 50-70% range, isoflurane has no significant effect on spike activity.

Alfentanil↗

PubMedDate not supplied

Prognostic significance of ictal and interictal epileptiform activity in temporal lobe epilepsy.

Long-term electrocorticograms (ECoG), recorded by chronically implanted subdural electrodes during preoperative evaluation of 59 patients with temporal lobe epilepsy (TLE) were analyzed retrospectively to assess the prognostic relevance of distribution of interictal epileptiform potentials (IEP) and seizure origin (SO) and to investigate factors affecting their lateralization. Subsequent to preoperative evaluation, a standardized two thirds anterotemporal lobectomy including subtotal hippocampectomy had been performed in all patients. The following results were obtained: (a) Only patients with 100% lateralization of SO and IEP had excellent seizure outcome (= 89% seizure-free); (b) patients with bitemporal SO were unlikely to benefit from surgical treatment (= 12.5% seizure-free); (c) 40-56% patients with unilateral temporal SO and bitemporal IEP, became seizure-free irrespective of the degree of lateralization of IEP; and (d) multidimensional analysis of variance showed that lateralization of SO, presence of a magnetic resonance imaging (MRI)-detectable lesion, presence of hippocampal sclerosis, presence of febrile seizures and seizures at age < or = 6 years are the five most important variables indicating abolition of seizures. Combined analysis of ECoG-recorded SO and IEP allows prediction of postoperative seizure control within close boundaries.

Adolescent↗

PubMedDate not supplied

Postoperative EEG and electrocorticography: relation to clinical outcome in patients with temporal lobe surgery.

To evaluate the role of different EEG methods with respect to postoperative clinical follow-up, 32 non-lesionary epilepsy patients who had undergone temporal lobectomy were studied preoperatively and at 2-week, 3-month, and 1-year postoperative follow-up. Routine, sleep, and sphenoidal EEG recordings as well as intraoperative electrocorticography (ECoG) were made for all patients. At 1-year follow-up, the EEGs with sphenoidal electrodes and with sleep deprivation procedure provided important prognostic information; the appearance of seizures was associated with the presence of interictal epileptiform abnormalities in EEG. In the postresection ECoG, however, epileptiform abnormalities were not associated with clinical outcome or with postoperative epileptiform EEG at 1 year. Routine EEG reliably reflects clinical outcome after temporal lobectomy; with sphenoidal electrodes as well as with sleep deprivation procedure, the diagnostic yield can be further improved.

Adolescent↗

PubMedDate not supplied

Reevaluation of surgical failures and the role of reoperation in 39 patients with frontal lobe epilepsy.

Between 1929 and 1980, 284 patients with refractory nontumoral frontal lobe epilepsy (FLE) underwent operation at the Montreal Neurological Institute (MNI). We studied 39 patients (14%) who required reoperation. Mean age at the time of first operation was 18 years and at reoperation was 22 years. Clinical manifestations were similar to those of patients with "a pure culture of frontal lobe epilepsy" as reported by Rasmussen in 1983. At the time of first operation, large epileptogenic zones were noted in most patients. Resection was confined to the frontal lobe. Continuing seizure activity was due to residual areas of epileptogenesis, and reoperation with more extensive resection of cortex increased the number of seizure-free patients. Twenty-six patients underwent further frontal resection, and in 13 surgical removal was extended to the temporal lobe. Residual electrocorticographic (ECoG) spiking was documented in 15 of 23 (65%) of the reoperated patients. Thirty-five patients were followed for periods ranging from 4 to 46 years. One fifth became seizure-free, and 31% had significant seizure reduction. Thus, half of these patients had a good result. Patients with residual postexcision ECoG spiking had poor outcomes and evidence of large epileptogenic zones. None of the patients who underwent frontotemporal resections became seizure-free. Reoperation should be considered if initial resection does not lead to a satisfactory result and may convert an initial failure into a good surgical result.

Adolescent↗

PubMed1997

Convulsant action of D,L-homocysteic acid and its stereoisomers in immature rats.

PURPOSE: We wished to characterize the convulsant effect of homocysteic acid (HCA) in developing rats. METHODS: Seizures were induced in 7-, 12-, 18-, and 25-day-old rats by intraperitoneal (i.p.) administration of D,L-HCA and in 12-day-old rats by i.p. injection of L- and D-stereoisomers of HCA. The animals were observed for 30 min after injection. The incidence, latencies, pattern of motor seizures, and all behavioral phenomena were noted. Fifty percent convulsant dose (CD50) values were calculated by probit analysis. Electrocorticograms (ECoG) were recorded after injection. RESULTS: HCA did not elicit minimal clonic seizures whereas generalized tonic-clonic seizures (GTCS) occurred in all the age groups studied. Flexion (emprosthotonic) convulsions occurred to postnatal day 18. ECoG recordings exhibited delta activity in younger pups and sharp graphoelements in older pups, but electroclinical correlation was poor. Young animals were more sensitive to the convulsant effect of D,L-HCA. In addition, D-HCA was significantly more effective than L-HCA in inducing both flexion and generalized seizures. CONCLUSIONS: Our data clearly indicate that seizures induced by HCA differ from those evoked by homocysteine. There are no qualitative differences in the motor pattern of seizures induced by the two stereoisomers of HCA, but marked differences were apparent in the very first signs of their action. These differences might be due to interaction with different glutamate receptor subtypes.

Animals↗

PubMed1997

"Cavernous sinus EEG": a new method for the preoperative evaluation of temporal lobe epilepsy.

PURPOSE: In presurgical evaluation of temporal lobe epilepsy (TLE), invasive methods are necessary if results of various noninvasive methods are not sufficiently convergent enough to identify the epileptogenic area accurately. To detect the epileptiform discharges originating specifically from the mesial temporal lobe, we applied the cavernous sinus catheterization technique. METHODS: We placed Seeker Lite-10 guide wire electrodes into bilateral cavernous sinus through the internal jugular veins to record EEG (cavernous sinus EEG) in 6 patients with intractable TLE. Scalp EEG was simultaneously recorded in all 6 and electrocorticogram (ECoG) was also recorded in 4. RESULTS: The cavernous sinus EEG demonstrated clear epileptiform discharges, sometimes even when they were absent on the simultaneously recorded scalp EEG. The epileptiform discharges recorded from the cavernous sinus electrodes were specifically associated with those in the mesial temporal region on ECoG. Ictal EEG pattern originating from mesial temporal lobe was also clearly documented on the cavernous sinus EEG. CONCLUSIONS: This new, semi-invasive method of identifying epileptogenic areas can detect the epileptiform discharges specifically arising from the mesial temporal lobe; it is as useful as or complements the invasive techniques such as foramen ovale or depth recording.

Adolescent↗

PubMed1998

Clinical usefulness of the dipole tracing method for localizing interictal spikes in partial epilepsy.

PURPOSE: To clarify the clinical usefulness of the dipole tracing method in evaluation of interictal EEG spikes in patients with partial epilepsy. METHODS: Eight patients with partial epilepsy were studied. We compared the generator source of interictal spikes detected by the dipole tracing method with the results of magnetic resonance imaging (MRI), interictal/ictal measurement of cerebral blood flow (CBF) by single photon emission computed tomography (SPECT), interictal measurement of glucose metabolism by positron emission tomography (PET) and invasive electrocorticogram (ECoG). RESULTS: In 5 patients with mesial temporal lobe epilepsy (TLE), including 3 patients who underwent standard temporal lobectomy, the dipole tracing method showed results consistent with those of other examinations and better correlation with ECoG than with other noninvasive examinations. In a patient with mesial TLE who had defects in the skull due to previous surgery, the dipoles were located more laterally than expected. In a patient with frontal lobe epilepsy (FLE) who was finally proved to have an epileptogenic area in the lateral frontal area, the spike dipoles were identified in the medial side of the frontal lobe. CONCLUSIONS: The dipole tracing method used in the present study is useful for localizing epileptogenic areas in patients with mesial TLE. However, in patients with partial skull defects and in those with FLE, the reliability of this method is still in accuracy of the lobe level.

Adolescent↗

PubMed1999

Patients with epileptic seizures and cerebral lesions who underwent lesionectomy restricted to or associated with the adjacent irritative area.

PURPOSE: To analyze the best surgical procedure for patients with epileptic seizures and cerebral lesions-i.e., resection restricted to the lesion or resection associated with the adjacent irritative area-based on the clinical evolution of patients' seizure outcome and electroencephalographic (EEG) and electrocorticographic (ECoG) findings. METHODS: This study comprised 37 patients with epileptic seizures and cerebral lesions, ranging in age from 9 to 66 years. Patients were divided into two groups: Group 1 consisted of 21 patients with medically intractable epilepsy, Group 2 of 16 patients with medically controlled epilepsy. Eleven of the 21 patients in Group 1 (Subgroup A) underwent surgical resection of the cerebral lesion and adjacent irritative area as shown by ECoG. For the remaining 10 patients in Group 1 (Subgroup B), the resection was restricted to the lesion. The 16 patients in Group 2 all underwent lesionectomies. RESULTS: Of the 11 patients in group 1 who underwent resection of the cerebral lesion and adjacent irritative area, 91% became seizure free. Sixty percent of the remaining patients in group I whose resections were restricted to the lesion also became seizure free, as did all the patients in group 2. An overall analysis of the EEGs for all patients showed a statistically significant decrease in paroxysmal activity. CONCLUSIONS: In patients with uncontrolled seizures, resection of the cerebral lesion associated with the irritative area shows a tendency to obtain better seizure-outcome results than restricted lesionectomy.

Adolescent↗

PubMed2005

Origin and propagation of epileptic spasms delineated on electrocorticography.

PURPOSE: Ictal electrographic changes were analyzed on intracranial electrocorticography (ECoG) in children with medically refractory epileptic spasms to assess the dynamic changes of ictal discharges associated with spasms and their relation to interictal epileptiform activity and neuroimaging findings. METHODS: We studied a consecutive series of 15 children (age 0.4 to 13 years; nine girls) with clusters of epileptic spasms recorded on prolonged intracranial subdural ECoG recordings, which were being performed for subsequent cortical resection, and in total, 62 spasms were analyzed by using quantitative methods. RESULTS: Spasms were associated with either a "leading" spike followed by fast-wave bursts (type I: 42 events analyzed quantitatively) or fast-wave bursts without a "leading" spike (type II: 20 events analyzed quantitatively). Twenty-three of the 42 type I spasms but none of the 20 type II spasms were preceded by a focal seizure. A "leading" spike had a focal origin in all 42 type I spasms and involved the pre- or postcentral gyrus within 0.1 s in 37 of these spasms. A leading spike was associated with interictal spike activity >1/min in 40 of 42 type I spasms and originated within 2 cm from a positron emission tomography glucose hypometabolic region in all but two type I spasms. Failure to resect the cortex showing a leading spike was associated with poor surgical outcome (p = 0.01; Fisher's exact probability test). Fast-wave bursts associated with spasms involved neocortical regions extensively at least in two lobes within 1.28 s in all 62 spasms and involved the pre- or postcentral gyrus in 53 of 62 spasms. CONCLUSIONS: Epileptic spasms may be triggered by a focal neocortical impulse in a subset of patients, and a leading spike, if present, might be used as a marker of the trigger zone for epileptic spasms. Rapidly emerging widespread fast-wave bursts might explain the clinical semiology of epileptic spasms.

Brain Mapping↗

PubMed2005

Spontaneous epileptic rats show changes in sleep architecture and hypothalamic pathology.

PURPOSE: The goal of the present study was to investigate the relationship between sleep, hypothalamic pathology, and seizures in spontaneous epileptic rats. METHODS: Rats were implanted with radiotelemetry transmitters for measuring electrocorticogram (ECoG) and stimulation electrodes in the hippocampus. Epileptogenesis was triggered by 2 h of electical stimulation-induced self-sustained status epilepticus (SSSE). After SSSE, ECoGs were monitored over a 15-week period for the occurrence of interictal high-amplitude low-frequency (HALF) acitvity and spontaneous reoccurring seizures (SRSs). RESULTS: Spontaneous epileptic rats showed clinical features of temporal lobe epilepsy (TLE), such as spontaneous seizures, interictal activity and neuronal cell loss in the dorsomedial hypothalamus, a region important for normal sleep regulation. Interestingly, epileptic rats showed disturbances in sleep architecture, with a high percentage of the seizures occurring during sleep. CONCLUSIONS: Therefore we conclude that a close association exists between epileptiform activity and alterations in sleep architecture that may be related to hypothalamic pathology.

Animals↗