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PubMed1986

Influence of ethosuximide and dipropylacetate on metrazol-induced electrocorticographic changes during ontogenesis in rats.

Influence of ethosuximide (ESI, 125 mg/kg i.p.) and dipropylacetate (DPA, 300 mg/kg i.p.) pretreatment on electrocorticographic changes induced by pentamethylenetetrazole (PTZ, 20 mg/kg dose every 5 min) was studied in rats aged 7, 12, 18 and 90 days. PTZ alone induced isolated spikes and/or sharp waves as the first sign of its action in all age groups except in adult animals where rhythmic theta activity was elicited. The antiepileptic effect of DPA was observed in 12- and 18-day-old rats, ESI specifically inhibited rhythmic activity in adult rats. ECoG seizures induced by high doses of PTZ were inhibited by DPA in all age groups, ESI tended to be effective in adult rats only. DPA did not change the pattern of ECoG seizures, whereas ESI led to replacement of the spike-and-wave rhythm by serrated waves in adult animals. The low ability of immature brain to generalize ictal activity was further diminished by ESI.

Animals↗

PubMed1986

Phase II trial of mitomycin, vindesine, and hexamethylmelamine in metastatic non-small cell bronchogenic carcinoma.

Mitomycin (10 mg/m2 iv on Day 1), vindesine (3 mg/m2 iv on Days 1 and 8), and hexamethylmelamine (100 mg/m2/day orally on Days 1-14) was administered to 32 patients with metastatic non-small cell bronchogenic carcinoma. No patient had been previously treated with chemotherapy and Eastern Cooperative Oncology Group (ECOG) performance status was 0-1 in 21 of 32 patients. Eleven partial responses (34%) were observed, with a median duration of 9 weeks. No complete responses were observed in this group of patients, whose median survival duration was 22 weeks. Moderate leukopenia (median leukocyte count nadir, 2500/mm3) was the major toxic effect. Although this regimen is active and relatively nontoxic, it will not be utilized in future ECOG trials because it has not produced an apparent improvement in survival duration.

Adult↗

PubMed1986

[Effect of cerebral hypoxia and hyperventilation hypocapnia on the epileptiform activity of the cerebral cortex of the cat].

Influence of cerebral hypoxia and hyperventilatory hypocapnia on the ECoG and focal epileptiform activity of the cerebral cortex induced with local application of strychnine was studied in cats with transection of spinal cord at C1. Although both hypoxia and hypocapnia produced synchronization of the cerebral cortex electrical activity, i.e. exerted the same effects on the ECoG, their influence on cortical excitability was quite different: hypoxia suppressed the epileptiform activity whereas hypocapnia facilitated it.

Animals↗

PubMedDate not supplied

[Role of the median forebrain bundle in organizing the electrical activity of the neocortex].

Bilateral coagulation of the forebrain medial bundle in the lateral hypothalamus enhances the formation of spontaneous spindles and facilitates the recruiting response in the neocortex. This combines with a defect of desynchronizing influences of the posterior hypothalamus and the concurrent dominance of synchronizing effects of the preoptic area (PA). PA stimulation enhances the slow wave and spindle activity in the ECoG of the intact brain. After disruption of PA connections with the bulbar synchronizing apparatus the stimulation effect is manifested only in enhanced spindle activity. It is assumed that in addition to hypnogenic influences which PA shares with the parasolitary apparatus, it maintains a definite level of cortical reactivity after the onset of sleep. Elimination of the orbito-frontal cortex, as well as PA coagulation, does not prevent the appearance of spindles in the ECoG of the preparation with an intersected medial bundle, only limiting them to some extent.

Animals↗

PubMed1986

The Torsion Swing Chair test: a ratio method for quantifying nystagmus.

In a Torsion Swing Chair (TSC) test for nystagmus, S is oscillated sinusoidally around the vertical axis with successive cycles diminishing in extent. Channel II of a standard recording ENG traces the chair's movement (differing among Ss according to their weight) while Channel I records S's ENG. A method was devised to quantify S's nystagmus by calculating, for each pair of succeeding cycles, the ratio of the decline in amplitude of the slow phase nystagmic velocity to the decline in amplitude of chair movement. This ratio, relatively constant across cycles, is greater with labyrinthine pathology. Ratios were established with 15 normal young adults as cut-offs for normalcy. The method was applied to 30 patients with peripheral hearing loss whose only complaint was slight vertigo following an acute stage of vertigo. The TSC test was validated by comparing it to the severity of vertigo and to the presence/absence of abnormal results on a standard clinical caloric test in ENG and on standard clinical ECoG. All but 1 of the 30 pts exhibited abnormal results on the TSC test, as compared with 18 for the caloric and 16 for the ECoG. Furthermore, abnormality on the TSC test was more likely to be associated with abnormal results on one or both of the other two tests than were either of the other two tests. It can be concluded that the TSC test is a valid and objective tool useful in ENG practice.

Caloric Tests↗

PubMed1986

[Changes in the functional activity of cortical brain structures and their blood supply during motion sickness in the alert rabbit].

In alert rabbits, sea sickness induced an increase in the cerebral blood supply, alteration of the ECoG frequency components, bradycardia, hypotension. Different responses of the bioelectrical activity were revealed in summer and winter. The enhancement of bioelectrical activity and blood flow in the motor cortex were shorter than in the auditory and visual areas. These changes become more obvious in repeated fits of sea sickness and gradually reduced later on. In winter, the responses of the rabbit electrophysiological parameters are more obvious and longer lasting than in summer. The blood supply parameters preserved in summer whereas the ECoG changes returned to initial values faster in summer.

Animals↗

PubMedDate not supplied

Effects of neonatal toluene exposure on the development of evoked and spontaneous cortical activity in the rat.

The effects of neonatal toluene exposure on the development of cortical evoked responses to sciatic nerve and light stimulation, as well as the spontaneous Electrocorticogram (ECoG) of frontal and occipital regions, were studied in rats at different developmental ages. The major findings following the solvent exposure were a significant prolongation in the mean peak latencies of both primary and secondary cortical evoked responses the effects being more severe in the sensorimotor area than in the visual cortical region. Additionally the experimental animals did not show significant differences in the average frequencies histograms of the ECoG in both neocortical areas when compared with control littermates. The data suggest that early toluene exposure was primarily affecting those brain structures underlying locomotor abilities than those related with the functionality of the CNS visual centers.

Aging↗

PubMedDate not supplied

[Theory of EEG potential in a model of the thin membranes of the brain].

The methods of estimating a momentary value of the epidural potential using several values of EEG, sampled at the same instant, are explored theoretically. The weights of the summation of these EEG-potentials for the case of simple disposition of electrodes, are single-valued by means of elementary consideration of the potential theory and symmetry. The space filters of EEG obtained in such a way, were analysed on the basis of the model of thin integuments of the brains. The systems of 4--8 electrodes on the scalp are proposed for the estimation of mono- and bipolar ECoG's, which are less sensitive to ECoG of the remote cortex than ordinary derivations of EEG.

Cerebral Cortex↗

PubMed1979

Impairment of cerebral blood flow autoregulation after hypertonic urea administration.

The effect of unilateral intracarotid administration of 3 M urea on resting cerebral blood flow, arterial blood pressure, perfusion pressure-cerebral blood flow relation, ECoG and Evans blue permeability was tested in dogs. The injection of urea was without effect on ECoG and enhanced the arterial blood pressure temporarily. Cerebral blood flow measured 10 min after the urea injection was not affected. Extravasation of Evans blue was observed in the urea-perfused hemisphere for about 40 min following the urea administration. Cerebral perfusion pressure-blood flow relation for the urea affected hemisphere studied at the time when blood-brain barrier to protein was restored revealed loss of the normal autoregulatory response, despite that it was preserved in the control hemisphere.

Animals↗

PubMed1983

Effect of isovolemic hemodilution on oxygen supply and electrocorticogram in cat brain during focal ischemia and in normal tissue.

The effect of isovolemic hemodilution on local tissue oxygen pressure (pO2) and on the power of the electrocorticogram (ECoG) was investigated in the brain of the cat under normal conditions and during focal ischemia. Ischemia, produced by clamping of the middle cerebral artery (MCA) by a transorbital approach, was performed in two series of cats for 2 h. In one group of animals, isovolemic hemodilution was achieved in the second hour of persisting clamping. Local pO2 was continuously recorded on the median ectosylvian gyrus by a multiwire surface electrode. After MCA clamping, local tissue pO2 markedly decreased and hypoxia occurred in the ischemic area. During isovolemic hemodilution until a hematocrit of 20%, local pO2 in the ischemic area did not decrease any further although arterial oxygen capacity was drastically reduced. The power of the ECoG did also not decrease any further in comparison to the situation of ischemia without hemodilution. In the normal brain isovolemic hemodilution until a hematocrit of 20% did not significantly change mean tissue pO2 and the power of the electrocorticogram. We conclude from these results that during isovolemic hemodilution the decreased arterial oxygen capacity is compensated by an increase in microflow in the normal and ischemic region of the brain.

Animals↗

PubMed1984

Chemotherapy for metastatic non-small cell bronchogenic carcinoma: cyclophosphamide, doxorubicin, and etoposide versus mitomycin and vinblastine (EST 2575, generation IV).

Between March and December 1979, the Eastern Cooperative Oncology Group (ECOG) compared the CAVP16 (cyclophosphamide, doxorubicin, and etoposide) and MV (mitomycin and vinblastine) regimens in 200 patients with metastatic non-small cell bronchogenic carcinoma. Most patients were ambulatory (ECOG performance status, 0, 1; 75%) and had not received prior radiation therapy (76%). The CAVP16 regimen resulted in one complete and 13 partial responses (14%) and the mitomycin and vinblastine regimen resulted in two complete and 11 partial responses (13%). These results did not differ significantly (P = 0.45) nor did the results for median survival, 18 weeks for each regimen. Good performance status and prior surgical resection were positive predictors of improved survival. Toxicity was significant with eight drug-related deaths, six due to leukopenia and infection and one each due to renal failure and interstitial pneumonitis. CAVP16 resulted in significantly more serious and life-threatening toxicity (P less than 0.0001). Neither regimen is recommended for further study.

Aged↗

PubMed1984

Piracetam and brain excitability. An electrophysiological study in cats.

The effect of piracetam on the excitability of the brain has been examined in cats by electrophysiological approaches: spontaneous electrocorticogram (ECoG), visual evoked potentials (VEPs) and their recovery cycles in some brain structures (visual and associative cortex, lateral geniculate body, centrum medianum thalami and mesencephalic reticular formation). Piracetam (100 mg/kg i.v.) increased the spectral power of ECoG and particularly in the associative cortex for the frequency bands of 10-12 and 19-22 Hz. Piracetam decreased the early components and facilitated the late components of VEPs predominantly in the associative cortex. Changes were found in the recovery cycles too, namely, facilitation and shortening of recovery in all structures studied except in lateral geniculate body. The data suggest that piracetam acts as a non-specific activator on the excitability thus optimizing the functional state of the brain.

Animals↗

PubMed1982

Synergic convulsant effects of dihydrofolic and kainic acid after intracaudate infusion in rats.

In rats the microinjection of kainic acid into the caudate nucleus produced dose-dependent motor and ECoG discharges. Similarly dihydrofolic acid microinfused into the same area produced an intense pattern of stereotyped movements, circling and high voltage electrocortical spikes, sharp waves and other abnormalities similar is those occurring in human epilepsy. The administration of dihydrofolic acid into the same site 10 min after kainic acid significantly increased the percentage of rats showing epileptic motor and ECoG seizures and potentiated the severity and duration of these effects. In conclusion, the present experiments provide evidence for the potentiation of the neurotoxic effects of folic and kainic acid when given in association into the brain.

Animals↗

PubMed1980

Shock-induced cytoplasmic NADH fluorescence changes in the living cat brain cortex: effect of dexamethasone.

The effect of dexamethasone administration on cerebrocortical NADH fluorescence, blood flow and blood volume, intracellular oxygen tension and electrocorticogram (ECoG) was studied in anaesthetized cats in two sets of experiments. Haemorrhagic shock was induced by stepwise decrease of mean arterial blood pressure from the control level a to 80, 60 and 40 mmHg. The bleeding was followed by reinfusion of the shed blood. The method of producing shock was identical in the untreated and dexamethasone treated groups. Dexamethasone was administered in the control period. The results are summarized as follows: (a) Dexamethasone, given in pharmacological doses failed to alter blood flow or blood volume, NADH fluorescence and the intracellular oxygen tension in the cerebral cortex of the cat; (b) Haemorrhagic shock resulted in a marked increase of cytoplasmic NADH fluorescence in the untreated group, while these changes were much smaller in the dexamethasone pretreated animals; (c) Dexamethasone pretreatment significantly reduced the extent of shock-induced cortical vasodilatation. In some experiments the brain cortex became ischaemic at 40 mmHg MABP; (d) Dexamethasone pretreatment failed to eliminate the shock-induced decrease in cortical intracellular oxygen tension and the irreversible deterioration of ECoG. It is suggested that the decrease in cortical cytoplasmic NAD reduction and the concomitant lactate acidosis might be involved in the ability of dexamethasone to control oedema during shock and other pathological conditions.

Animals↗

PubMed1981

Frequency analysis of EEG in rats during the preconvulsive period of O2 poisoning.

The EEG of rats exposed to hyperbaric oxygenation (HBO) displays electrical discharges prior to the onset of generalized clinical convulsions (GCC). The characteristics of preconvulsive electrocorticogram (ECoG) in awake, unrestrained rats exposed to 3, 4, and 5 ATA O2 were determined. The ECoG was continuously monitored and analyzed by a hybrid analog-digital system until GCC developed. The time integral of rectified voltage of the individual delta (0.5-4 c/s), theta (4-8 c/s), alpha (8-13 c/s) beta 1 (13-20 c/s), and beta 2 (20-30 c/s) bands were plotted vs. time. An elevation in delta and a temporary reduction in alpha activity before the onset of the first electrical discharge (FED) was observed. There was a continuous reduction in beta 1 and beta 2 frequency bands during the entire pre-electrical discharge period. The activity of theta, and alpha frequency bands was significantly elevated only about 1 min before the onset of the FED, and of beta 1 and beta 2 during appearance of the FED. The possible relationship between the occurrence of preconvulsive EEG changes and pathological effects of hyperbaric oxygenation is discussed.

Animals↗

PubMedDate not supplied

[Depth contours of the electrocorticogram].

Distribution of extracellular fields generated by partly synchronized activity of cells was studied. The cells were located in the basic generator layers of the cortex, i.e. the first, fifth and sixth ones. An increased intercellular correlation among the neighbouring neurons was taken into account. The neurons were located within vertical columns. The curves were obtained for depth distributions of standard deviation of ECoG and correlation coefficient between the depth and surface ECoG. The activity of the upper generator layer was shown to affect the potential recorded only within the limits of this layer and directly under it. The fields generated by subcortical structures essentially affect the potentials of the sixth layer and of the white substance. Conditions are studied which determine the initiation or absence of phase inversion of the depth integrated potential in relation to the surface one.

Biophysical Phenomena↗

PubMed1995

Prognostic factors in advanced prostatic carcinoma treated with total androgen blockade. Flutamide with orchiectomy or with LHRH analogues. A Belgian multicentric study of 546 patients.

Prognostic factors were evaluated in advanced loco-regional (M0) or distant metastatic (M1) prostatic carcinoma treated with total androgen blockade (flutamide with either orchiectomy of LHRH-analogues), in 546 patients from a Belgian multicentric study. After a mean follow-up of 16.5 months (maximum 37 months) 113 (21%) patients had progressed (90 were patients with M1 disease (31%)). The estimated median progression-free survival exceeded 37.5 months. The results of a univariate analysis show that the following parameters are important prognostic factors with respect to progression-free survival in these patients: M stage, G grade, ECOG performance status, weight loss, concomitant disease, pain, dysuria and haemoglobin (Lee-Desu test, p < or = 0.01). From a multivariate analysis (Cox regression) the following prognostic factors were indicative of a decrease in progression-free survival: M1 stage, high initial G grade, ECOG performance status > I, high serum PSA, presence of concomitant disease, presence of pain and absence of dysuria. Age did not appear to be a statistically significant prognostic factor.

Aged↗

PubMed1995

Phase III trial (E5592) comparing cisplatin plus etoposide with cisplatin plus paclitaxel at two dose levels for treatment of advanced non-small-cell lung cancer. Eastern Cooperative Oncology Group.

Non-small-cell lung cancer (NSCLC) is the most common cause of cancer-related death in the United States. Only about 30% of patients present with surgically resectable (and thus curable) disease. Because existing chemotherapeutic regimens are never curative in advanced NSCLC and because the median survival time is only modestly increased, the Eastern Cooperative Oncology Group (ECOG) has concentrated on a broad phase II testing program designed to identify new agents with activity against the disease. Of the more than one dozen drugs that have been thus evaluated during the past 10 years, only paclitaxel (Taxol) has been shown to result in an objective response rate of more than 20%. To determine if the paclitaxel-containing regimen can increase survival, ECOG has, therefore, embarked on a phase III trial (E5592) in which patients with stage IV NSCLC are randomly assigned to receive either cisplatin plus etoposide (the current standard chemotherapy) or cisplatin plus paclitaxel. The trial design should also help to determine the appropriate dose of paclitaxel in this clinical setting.

Antineoplastic Combined Chemotherapy Protocols↗