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At least 883 records · Page 49Linked to original sources

PubMed2006

Neocortical microenvironment in patients with intractable epilepsy: potassium and chloride concentrations.

PURPOSE: The regulation of extracellular ion concentrations plays an important role in neuronal function and epileptogenesis. Despite the many studies into the mechanisms of epileptogenesis in human experimental models, no data are available regarding the fluctuations of extracellular potassium ([K(+)](o)) and chloride ([Cl(-)](o)) concentrations, which could underlie seizure susceptibility in human chronically epileptic tissues in vivo. METHODS: By using cerebral microdialysis during surgical resection of epileptic foci, the basic [K(+)](o) and [Cl(-)](o) as well as their changes after epicortical electric stimulation were studied in samples of dialysates obtained from 11 patients by ion-selective microelectrodes. RESULTS: The mean basal values of [K(+)](o) and [Cl(-)](o) in all patients were 3.83 +/- 0.08 mM and 122.9 +/- 2.6 mM, respectively. However, significant differences were observed in the basal levels of both [K(+)](o) and [Cl(-)](o) between different patients. Statistically, no correlation was found between basal [K(+)](o) or [Cl(-)](o) and electrocorticogram (ECoG) spike activity, but in one patient, dramatically lowered baseline [Cl(-)](o) was accompanied by enhanced ECoG spike activity. Application of epicortical electrical stimulation increased [K(+)](o) but not [Cl(-)](o) in all cases. According to the velocity as well as spatial distribution of [K(+)](o) reduction to the prestimulation levels, three different types of responses were observed: slow decline, fast decline, and slow and fast declines at adjacent sites. CONCLUSIONS: These data may represent abnormalities in ion homeostasis of the epileptic brain.

Adolescent↗

PubMed2005

Percutaneous vertebroplasty in octogenarians: results and follow-up.

OBJECTIVES: To determine pain relief, performance status, morbidity, and mortality associated with percutaneous vertebroplasty for spinal pain in patients aged 80 years and older. DESIGN: Prospective, descriptive, third-party independent interview, clinical audit. SETTING: University Hospital, Geneva, Switzerland. PARTICIPANTS: Patients aged 80 years and older who underwent vertebroplasty between August 1997 and August 2004 because of vertebral fractures from osteoporotic or malignant etiologies. METHODS: Primary outcome measures were verbal rating scale (VRS) (0--no pain, 5--intolerable) and Eastern Cooperative Oncology Group (ECOG) performance status scale (0--normal activity, 4--unable to get out of bed) before and after procedure. Patients were interviewed 8 to 35 months post treatment (mean 25), independently assessed for pain relief, analgesic consumption, and overall satisfaction by using the American Society of Anesthesiologists (ASA) Outcome Measures questionnaire. RESULTS: Mean VRS scores significantly decreased from 4.86 +/- 0.64 to 2.39 +/- 1.14 (P < 0.05), and mean ECOG performance scores improved from 1.87 +/- 0.97 to 1.29 +/- 1.06 (P < 0.05) after treatment. When patients were analyzed by etiology (group 1--cancer; group 2--osteoporosis), both groups significantly reduced their VRS (P < 0.05); however, only group I significantly improved their performance (P < 0.05; P = 0.334, respectively). Nine patients answered the ASA questionnaire (18 deceased, 1 demented, 1 lost to follow-up) and reported an improvement in their ability to perform daily tasks. No early or late complications were observed; none of the deaths were procedure-related. CONCLUSIONS: Percutaneous vertebroplasty is a safe, minimally invasive, well-tolerated analgesic procedure among octogenarians suffering from spinal pain, permitting increased activities of daily living. Pain reduction is significant regardless of the etiology; performance scores are significantly improved in cancer pain.

Journal Article↗

PubMed1991

Electrocorticography in temporal lobe epilepsy surgery.

The results of intra-operative cortical EEG recordings (ECoG) were assessed in 30 patients with medically refractory complex partial seizures submitted to temporal lobectomy. Interictal spiking was most frequently recorded from mesial temporal lobe structures (amygdaloid-hippocampal region) and from the temporal neocortex synchronously, as observed in 21/30 patients. In 7 patients, the interictal spiking involved the temporal neocortex exclusively. Electrical stimulation of mesial temporal lobe structures reproduced the patient's habitual warning in 10 patients. The results of this study confirms that ECoG provides reliable intra-operative mapping of the epileptogenic brain tissue to be excised.

Adolescent↗

PubMed1991

Effects of dietary supplementation with vitamin E, riboflavin and selenium on central nervous system oxygen toxicity.

We attempted to modify the resistance of rats to hyperbaric oxygen (HBO)-induced central nervous system (CNS) toxicity, by increasing the tissue antioxidant potential through dietary factors. Groups of rats were fed excesses of vitamin E (VIT E) alone or in combinations with riboflavin (RIB), selenium (Se) or both, for 30 days. A control group was maintained on an unsupplemented diet. On the 23rd day animals to be exposed were implanted with chronic electrodes for electrocorticographic (ECoG) recording. Later, each group was divided into two subgroups, of which one was exposed to 4.5 atmospheres absolute (ATA) of 100% oxygen (O2) for 30 min., hereafter referred to as "exposed", noting the time of appearance of first electrical discharge (FED) in their ECoG. The remaining subgroups were left unexposed. Forty-eight hours later, all animals were sacrificed and some of their tissues were analyzed for glutathione (GSH). The GSH level in the liver, brain, lungs and blood of all experimental subgroups were significantly higher than in the control unexposed counterparts. Combinations of RIB and/or Se with VIT E failed to show a greater increase in GSH over VIT E alone. This increase was, however, not accompanied by a meaningful delay in the appearance of FED. Forty-eight hours post-exposure, the brain GSH levels of all exposed subgroups were still lower than the respective pre-exposure levels. Yet, in the treated exposed subgroups the GSH levels observed 48 hr after exposure were already higher than in the untreated unexposed controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2002

Adaptation to repeated cocaine administration in rats.

Quantitative electroencephalogram (EEG) studies in cocaine-dependent human patients show deficits in slow-wave brain activity, reflected in diminished EEG power in the delta and theta frequency bands. In the present study, electrophysiological measures were monitored in 10 nonanesthetized, adult male Sprague-Dawley rats via bipolar, epidural electrodes implanted over the somatosensory cortex. Control electrocorticograms (ECoG) were recorded twice within a two-week interval to establish a baseline. Rats were subsequently injected daily with cocaine HCl at 15 mg/kg, i.p., for two weeks. The ECoG was recorded during a 1-h session one day after the last injection. Total concentrations of dopamine (DA) and its metabolites were assayed in caudate nucleus (CN) and frontal cortex (FC) using HPLC/EC. Compared with controls, marked increases in DA concentrations were observed in both regions. The DA turnover decreased significantly. The power spectra, obtained by use of a fast Fourier transformation, revealed a significant decrease in slow-wave delta frequency bands following repeated exposure to cocaine. These data are consistent with reported findings in humans that repeated exposures to cocaine result in a decrease in slow-wave brain activity. Further studies are necessary to establish whether regional alterations in blood flow and metabolic activity may underlie such observations.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1977

The role of dopaminergic systems in gamma-hydroxybutyrate-induced electrocorticogram hypersynchronization in the rat.

The effects of dopaminergic agonists and antagonists on the duration of hypersynchronization induced in the electrocorticogram (ecog) by gamma-hydroxybutyrate (gamma-HB) were tested in rats. Apomorphine (0-2-8 mg kg-1), piribedil (2-5-10 mg kt-1) and haloperidol (0-5-1 mg kg-1) had no influence on the duration of the hypersynchrony. Amphetamine (1-5-6 mg kg-1) inhibited the hypersynchrony, while (3,4-dihydroxyphenylamino)-2-imidazoline (DPI; 5, but not 1, mg kg-1) prolonged its duration. The lack of effect of the dopamine receptor agonists apomorphine and piribedil, and the dopamine receptor blocker haloperidol, on the gamma-HB-induced hypersynchrony might indicate that the inhibition of the impulse flow in the nigrostriatal dopamine system by gamma-HB is not involved in the generation of the hypersynchrony. DPI is thought to be an agonist at a dopamine receptor not sensitive to apomorphine, and its facilitatory effect on gamam-HB-hypersynchrony can be interpreted in terms of a possible involvement of another dopamine system in the ecog hypersynchrony induced by gamma-HB. The antagonism of gamma-HB by amphetamine is possibly due to an indirect stimulatory effect on noradrenergic receptors.

Amphetamine↗

PubMed1993

Afferent and efferent components of the cardiovascular reflex responses to acute hypoxia in term fetal sheep.

1. We studied the effects of acute isocapnic hypoxia on arterial and central venous pressures, carotid and femoral blood flows and heart rate in intact and carotid denervated fetal sheep between 118 and 125 days gestation, after pre-treatment with either saline, atropine or phentolamine. Electrocortical activity (ECoG) and the incidence of fetal breathing movements (FBM) were also compared between intact and carotid denervated fetuses. 2. There were no significant differences between intact and denervated fetuses in any variable measured during normoxia. Soon after the onset of hypoxia a marked bradycardia occurred in intact, but not in denervated fetuses. Femoral blood flow and femoral vascular resistance (perfusion pressure/femoral blood flow) increased in intact, but not in denervated fetuses. Carotid blood flow increased in both groups of fetuses during hypoxia, but carotid vascular resistance did not change. During hypoxia, the incidence of FBM and low-voltage ECoG was similarly reduced in both groups of fetuses. 3. Atropine produced a rise in fetal heart rate during the control period in intact but not in denervated fetuses. At the onset of hypoxia atropine prevented the initial bradycardia seen in intact fetuses. In denervated fetuses a further increase in heart rate occurred throughout the hypoxia. 4. All denervated fetuses treated with phentolamine died during the hypoxic challenge, but nine out of fourteen intact fetuses treated with phentolamine survived. 5. In intact fetuses which survived hypoxia after treatment with phentolamine, the increase in arterial blood pressure was smaller and the increase in femoral resistance did not occur. In these fetuses a rise in heart rate occurred in hypoxia. Carotid vascular resistance decreased during hypoxia after administration of phentolamine. 6. Our results indicate that the initial cardiovascular responses of the late gestation sheep fetus to hypoxia are reflex, and that the carotid chemoreceptors provide the afferent limb of this reflex. The bradycardia is mediated through a muscarinic pathway, as it is blocked by atropine. The femoral vasoconstriction is mediated through an alpha-adrenergic mechanism, mediated both neurally by a carotid chemoreflex and via catecholamines released directly from the adrenal medulla. Both these components are blocked by phentolamine. 7. The differences in survival between intact and denervated fetuses during hypoxia after phentolamine suggest that the carotid chemoreflex response to hypoxia involves mechanisms in addition to vagal efferents to the heart and alpha-adrenergic actions at peripheral blood vessels.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗

PubMed2004

Directional analysis of coherent oscillatory field potentials in the cerebral cortex and basal ganglia of the rat.

Population activity in cortico-basal ganglia circuits is synchronized at different frequencies according to brain state. However, the structures that are likely to drive the synchronization of activity in these circuits remain unclear. Furthermore, it is not known whether the direction of transmission of activity is fixed or dependent on brain state. We have used the directed transfer function (DTF) to investigate the direction in which coherent activity is effectively driven in cortico-basal ganglia circuits. Local field potentials (LFPs) were simultaneously recorded in the subthalamic nucleus (STN), globus pallidus (GP) and substantia nigra pars reticulata (SNr), together with the ipsilateral frontal electrocorticogram (ECoG) of anaesthetized rats. Directional analysis was performed on recordings made during robust cortical slow-wave activity (SWA) and "global activation". During SWA, there was coherence at approximately 1 Hz between ECoG and basal ganglia LFPs, with much of the coherent activity directed from cortex to basal ganglia. There were similar coherent activities at approximately 1 Hz within the basal ganglia, with more activity directed from SNr to GP and STN, and from STN to GP rather than vice versa. During global activation, peaks in coherent activity were seen at higher frequencies (15-60 Hz), with most coherence also directed from cortex to basal ganglia. Within the basal ganglia, however, coherence was predominantly directed from GP to STN and SNr. Together, these results highlight a lead role for the cortex in activity relationships with the basal ganglia, and further suggest that the effective direction of coupling between basal ganglia nuclei is dynamically organized according to brain state, with activity relationships involving the GP displaying the greatest capacity to change.

Action Potentials↗

PubMed2006

Intracellular activity of cortical and thalamic neurones during high-voltage rhythmic spike discharge in Long-Evans rats in vivo.

Spontaneous high-voltage rhythmic spike (HVRS) discharges at 6-12 Hz have been widely described in the electrocorticogram (EcoG) of Long-Evans rats. These ECoG oscillations have been proposed to reflect a state of attentive immobility allowing the optimization of sensory integration within the corticothalamic pathway. This hypothesis has been challenged by recent studies emphasizing similarities between HVRS discharges and spike-and-wave discharges (SWDs) in well-established rat genetic models of absence epilepsy. Here, we made in vivo intracellular recordings to determine, for the first time, the cellular mechanisms responsible for the synchronized oscillations in the corticothalamic loop during HVRS discharges in the Long-Evans rats. We show that HVRS discharges are associated in corticothalamic neurones with rhythmic suprathreshold synaptic depolarizations superimposed on a tonic hyperpolarization, likely due to a process of synaptic disfacilitation. Simultaneously, thalamocortical neurones exhibit a large-amplitude 'croissant'-shaped membrane hyperpolarization with a voltage sensitivity suggesting a potassium-dependent mechanism. This thalamic hyperpolarizing envelope was associated with a membrane oscillation resulting from interactions between excitatory synaptic inputs, a chloride-dependent inhibitory conductance and voltage-gated intrinsic currents. These cortical and thalamic cellular mechanisms underlying HVRS activity in Long-Evans rats are remarkably similar to those previously described in the thalamocortical networks during SWDs. Thus, the present study provides an additional support to the hypothesis that HVRS activity in Long-Evans rats is an absence-like seizure activity.

Animals↗

PubMed1999

Intraoperative monitoring during surgery for acoustic neuroma: benefits of an extratympanic intrameatal electrode.

OBJECTIVES: To assess the utility of an extratympanic intrameatal electrode for intraoperative monitoring during acoustic neuroma and other cerebellopontine angle tumour surgery and to define the neurophysiological and surgical factors which influence hearing preservation. METHODS: Twenty two patients, 18 with acoustic neuromas and four with other cerebellopontine angle tumours, underwent intraoperative monitoring during tumour excision. The extratympanic intrameatal electrode (IME) was used to record the electrocochleogram (ECoG) and surface electrodes to record the brainstem auditory evoked response (ABR). RESULTS: The compound action potential (CAP) of the ECoG was two and a half times greater in amplitude than wave I of the ABR and was easily monitored. Virtually instant information was available as minimal averaging was required. Continuous monitoring was possible from the commencement of anaesthesia to skin closure. The IME was easy to place, non-invasive, and did not interfere with the operative field. Operative procedures which affected CAP or wave V latency or amplitude were drilling around the internal auditory meatus, tumour dissection, nerve section, and brainstem and cerebellar retraction. Hearing was achieved in 59% of patients. CONCLUSIONS: The IME had significant benefits in comparison with other methods of monitoring. The technique provided information beneficial to preservation of hearing.

Action Potentials↗

PubMed1982

Brain potassium ion homeostasis, anoxia, and metabolic inhibition in turtles and rats.

Microelectrode measurements of tissue oxygen tension (PtO2) and extracellular potassium ion concentration ([K+]o) and dual wavelength spectrophotometric measurements of the reduction/oxidation state of cytochrome aa3 were used to compare the resistance of turtle and rat brain to anoxia in vivo. In both species, respiration with 100% N2 resulted in a decrease of tissue oxygen tension to near 0 mmHg and reduction of cytochrome aa3. However, N2 respiration resulted in only moderate elevation of [K+]o in turtle bran while [K+]o in rat brain was elevated to levels greater than 50 mM. In addition, N2 respiration in turtles had no effect on the rate of recovery of [K+]o, which was elevated by direct electrical stimulation of the brain. Electrocorticographic activity (ECoG) of the turtle brain was only moderately depressed during N2 respiration for up to 4 h whereas the ECoG of rat brain became isoelectric within 1 min. Inhibition of glycolysis with iodoacetate (IAA) resulted in rapid elevation of [K+]o in turtle brain during anoxia, but IAA had little effect on [K+]o during normoxia. These results indicate that the remarkable resistance of the diving turtle to anoxia does not result from continued provision of oxygen to the brain either by redistribution of systemic blood flow or from blood O2 storage. In addition, the turtle brain does not rely on cellular stores of high-energy compounds for maintenance of ionic homeostasis. We conclude that potassium ion homeostasis in the anoxic turtle brain must result from increased glycolytic ATP production and from decreased energy utilization.

Animals↗

PubMed1985

Metabolic, ionic, and electrical responses of gerbil brain to ischemia.

The effects of short- or long-term complete cerebral ischemia were studied in the gerbil brain using a multi-parameter monitoring system. Metabolic (NADH redox state) and hemodynamic responses were monitored by surface fluorometry-reflectometry. Ionic activities (K+ and pH) were measured by surface macroelectrodes. Electrical activity was evaluated by monitoring the general electrocorticogram (ECoG) as well as local DC steady potential (two sites). Two groups of gerbils were studied to compare the effects of 4-5 min occlusions with those of 30 min complete ischemia. During bilateral carotid artery occlusion the cortex is exposed to complete ischemia resulting in the complete depletion of O2 with attendant maximal reduction of NADH. Extracellular K+ began to increase as soon as energy reserves were decreased with a time course suggesting two different kinetic areas. Surface pH decreased very shortly after the occlusion. During the recovery phase, NADH was reoxidized soon after recirculation, whereas the pH and K+ recovery showed a short delay. ECoG did not recover even when all other parameters reached base-line levels. The recovery of all the measured parameters was correlated to the duration of the ischemic insult; i.e., the recovery from 30 min of ischemia took significantly longer than after 5 min of ischemia. We conclude that pH recovery depends on recirculation and adequate O2 supply to the tissue, whereas K+ recovery required not only an adequate O2 supply but also the integrity of the adenosine triphosphatase system.

Animals↗

PubMed1977

Respiratory patterns during progressive asphyxia in newborn rabbits.

During acute progressive asphyxia an abrupt transition occurs from regular respiratory efforts to primary apnea and gasping. To study this transition we measured inspiratory duration (TI), expiratory duration (TE), maximal inspiratory tracheal pressure (Pmax), electromyographic activity (EMG) of different muscle groups, and the electrocorticogram (ECoG) of 3- to 5-day-old rabbits following airway occlusion at functional residual capacity (FRC). The onset of primary apnea was associated with other central nervous system events as indicated by decerebrate posture and maximal EMG activity which were followed by relaxation, loss of EMG activity, and an isoelectric ECoG. Indices of inspiratory drive (Pmax and Pmax/TI) were preserved or accentuated following primary apnea despite a reduction of overall respiratory activity (frequency X Pmax). The onset of primary apnea appears to be due to interruption of the respiratory cycling controls rather than failure of the respiratory center which regulates inspiratory force. Gasping appears to be linked with progressive changes in respiratory patterns which are observed prior to primary apnea. These findings do not support the concept of a "gasping" center.

Airway Obstruction↗

PubMed1986

Fetal breathing and behavior measured through a double-wall Plexiglas window in sheep.

The inability to see the fetus makes the assessment of fetal behavior difficult. To circumvent this problem we implanted a Plexiglas window in the left flank of the ewe. Fetuses were instrumented for measurements of sleep, breathing, and swallowing. Ten fetal sheep were studied on 32 occasions. Six fetuses were delivered through the window at term, and postnatal behavior was compared with intrauterine behavior. Fetuses observed during resting conditions alternated between periods of quiet sleep [high-voltage electrocortical activity (ECoG)] and active or rapid-eye-movement sleep (low-voltage ECoG). In quiet sleep, movements were absent except for periodic generalized electromyographic discharges. Eye and breathing movements were rare or absent. Swallowing was also absent. In active sleep, movements were increased with powerful breathing and swallowing activity. Fetal wakefulness defined by open eyes and purposeful movements of the head was never seen in utero but was clearly observed after delivery. We conclude that fetal wakefulness as defined postnatally was not able to be demonstrated in utero.

Animals↗

PubMed1994

Cortical blood flow and +Gz acceleration in conscious rabbits.

We examined whether superficial cortical blood flow (CBF) of nonanesthetized rabbits (n = 11) is affected by gravitational (G) stress. Blood flow was measured by laser-Doppler flowmetry through a chronic Plexiglas window implanted over the parietal cortex. Mean arterial blood pressure (MABP) was recorded via an aortic catheter with the pressure transducer situated at the level of the head. The electrocorticogram (ECoG) was also studied in seven rabbits. The animals were exposed to tail-to-head acceleration [6, 10, 15, and 20 G acceleration (Gz) for 1 min]. MABP fell with increasing acceleration (regression line equation: MABP = -7.0 Gz + 129.1; P < 0.001, r = 0.85), whereas CBF was statistically either not different from or greater than control. In one rabbit exposed to 20 Gz, high voltage and slow waves were observed on the ECoG and these changes were preceded by a decrease in CBF to 66% of control. We conclude that the stress and the siphon effect may account for the maintenance of elevated CBF despite low or negative MABP until the occurrence of vascular collapse that induces loss of consciousness.

Acceleration↗

PubMed2001

Adenosine A(1) and A(2A) receptors modulate sleep state and breathing in fetal sheep.

This study was designed to determine the adenosine (Ado) receptor subtype that mediates the depressant effects of Ado on fetal breathing and rapid eye movements (REM). In chronically catheterized fetal sheep (>0.8 term), intra-arterial infusion of N(6)-cyclopentyladenosine (CPA), an Ado A(1)-receptor agonist, increased the incidence of high-voltage electrocortical (ECoG) activity while virtually abolishing low-voltage activity, REM, and breathing. These effects were blocked by 9-cyclopentyl-1,3-dipropylxanthine (DPCPX), an Ado A(1)-receptor antagonist. Infusion of DPCPX alone increased breath amplitude but had no significant effect on inspiratory duration, breath interval, incidence of REM, or incidence of low-voltage activity. Ado A(2A)-receptor blockade with ZM-241385 increased the incidence of low-voltage ECoG activity, REM, and breathing but had no effect on breath amplitude or respiratory cycle. Both DPCPX and ZM-241385 eliminated the inhibitory effects of Ado on REM and breathing. We conclude that 1) Ado A(1) receptors tonically inhibit fetal respiratory drive, 2) Ado A(2A) receptors tonically inhibit REM-like behavioral state, and 3) both Ado A(1) and A(2A) receptors mediate the depressant effects of Ado on REM and breathing.

Adenosine↗

PubMed1999

Modulation of receptive field properties of thalamic somatosensory neurons by the depth of anesthesia.

Modulation of receptive field properties of thalamic somatosensory neurons by the depth of anesthesia. The dominant frequency of electrocorticographic (ECoG) recordings was used to determine the depth of halothane or urethan anesthesia while recording extracellular single-unit responses from thalamic ventral posterior medial (VPM) neurons. A piezoelectric stimulator was used to deflect individual whiskers to assess the peak onset latency, magnitude, probability of response, and receptive field (RF) size. There was a predictable increase in the dominant ECoG frequency from deep stage IV to light stage III-1 anesthetic levels. There was no detectable frequency at stage IV, a 1- to 2-Hz dominant frequency at stage III-4, 3-4 Hz at stage III-3, 5-7 Hz at stage III-2, and a dual 6- and 10- to 13-Hz pattern at stage III-1. Reflexes and other physical signs showed a correlation with depth of anesthesia but exhibited too much overlap between stages to be used as a criterion for any single stage. RF size and peak onset latency of VPM neurons to whisker stimulations increased between stage III-4 and III-1. A dramatic increase in RF size and response latency occurred at the transition from stage III-3 (RF size approximately 2 whiskers, latency approximately 7 ms) to stage III-2 (RF size approximately 6 whiskers, latency approximately 11 ms). Response probability and magnitude decreased from stage III-4 to stage III-3 and III-2. No responses were ever evoked in VPM cells by vibrissa movement at stage IV. These changes in VPM responses as a function of anesthetic depth were seen only when the nucleus principalis (PrV) and nucleus interpolaris (SpVi) trigeminothalamic pathways were both intact. Eliminating SpVi inputs to VPM, either by cutting the primary trigeminal afferent fibers to SpVi or cutting axons projecting from SpVi to VPM, immediately reduced the RF size to fewer than three whiskers. In addition, the predictable changes in VPM response probability, response magnitude, and peak onset latency at different anesthetic depths were all absent after SpVi pathway interruption. We conclude that 1) the PrV input mediates the near "one-to-one" correspondence between a neuronal response in VPM and a single mystacial whisker, 2) in contrast, the SpVi input to VPM is primarily responsible for the RF properties of VPM neurons at light levels of anesthesia and presumably in the awake animal, and 3) alterations in VPM responses produced by changing the depth of anesthesia are due to its selective influence on the properties mediated by SpVi inputs at the level of the thalamus.

Anesthesia↗

PubMed2000

A phase II study of gemcitabine and 5-fluorouracil in metastatic pancreatic cancer: an Eastern Cooperative Oncology Group Study (E3296).

Gemcitabine has recently been compared favorably to 5-fluorouracil (5-FU) as the standard chemotherapy for advanced pancreas cancer. Based on phase I data that combining gemcitabine with 5-FU is safe and has evidence for clinical activity, a phase II trial was conducted by the Eastern Cooperative Oncology Group (ECOG). Patients with metastatic disease, good performance status and organ function were eligible and enrolled after providing informed consent. Patients were given gemcitabine (1,000 mg/m(2)) followed by 5-FU (600 mg/m(2)) weekly for 3 weeks of every 4. Of 37 patients enrolled over a 3-month period, 36 were eligible. Partial responses were seen in 5 patients (14%). Median survival was 4.4 months with a 1-year survival rate of 8.6%. A randomized trial of the combination of 5-FU and gemcitabine versus gemcitabine alone is currently accruing patients in ECOG.

Adult↗