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Publication
Journal: Journal of Neurophysiology
February/10/2011
Abstract
We recorded neuronal activity in the supplementary eye field (SEF) while monkeys made saccades to targets that yielded rewards of variable amount and uncertainty of delivery. Some SEF cells (29%) represented the anticipated value of the saccade target. These neurons encoded the value of the reward option but did not reflect the action necessary to obtain the reward. A plurality of cells (45%) represented both saccade direction and value. These neurons reflect action value, i.e., the value that is expected to follow from a specific saccade. Other cells (13%) represented only saccade direction. The SEF neurons matched the monkey's risk-seeking behavior by responding more strongly to the uncertain reward options than would be expected based on their response to the sure options and the cued outcome probability. Thus SEF neurons represented subjective, not expected, value. Across the SEF population, option-value signals developed early, ∼120 ms prior to saccade execution. Action-value and saccade direction signals developed ∼60 ms later. These results suggest that the SEF is involved in transforming option-value signals into action-value signals. However, in contrast to other oculomotor neurons, SEF neurons did not reach a constant level of activity before saccade onset. Instead the activity level of many (52%) SEF neurons still reflected value at the time just before saccade initiation. This suggests that SEF neurons guide the selection of a saccade based on value information but do not participate in the initiation of that saccade.
Publication
Journal: Infection and Immunity
July/14/1983
Abstract
A total of 136 isolates of Staphylococcus aureus were tested for production of staphylococcal enterotoxin F (SEF) and pyrogenic exotoxin C (PEC), both of which have been identified as reliable indicators of toxic shock syndrome (TSS)-associated strains. SEF and PEC production by isolates from TSS-associated and other sources was tested independently in two laboratories, after which the two sets of data were compared. A 100% concordance between SEF and PEC production was obtained. The TSS toxin candidates were produced by 30 of 136 isolates, and in all instances SEF and PEC were made concurrently by the same strains; in no case was one toxin made and not the other. In the five groups of S. aureus tested, toxins were detected as follows: 23 of 25 (92%) acute TSS isolates, 2 of 48 (4.2%) genital non-TSS isolates, 2 of 16 (12.5%) recovered TSS isolates, 1 of 23 (4.3%) clinical nongenital isolates, and 2 of 24 (8.3%) enterotoxigenic food outbreak isolates. Comparison of purified SEF and purified PEC by immunological and biochemical criteria by immunodiffusion, isoelectric focusing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western blot analysis show that the toxins are immunologically identical and strongly suggest that the two nominal TSS toxins are in fact a single protein.
Publication
Journal: Progress in Neurobiology
August/6/2000
Abstract
Averaged magnetoencephalography (MEG) following somatosensory stimulation, somatosensory evoked magnetic field(s) (SEF), in humans are reviewed. The equivalent current dipole(s) (ECD) of the primary and the following middle-latency components of SEF following electrical stimulation within 80-100 ms are estimated in area 3b of the primary somatosensory cortex (SI), the posterior bank of the central sulcus, in the hemisphere contralateral to the stimulated site. Their sites are generally compatible with the homunculus which was reported by Penfield using direct cortical stimulation during surgery. SEF to passive finger movement is generated in area 3a or 2 of SI, unlike with electrical stimulation. Long-latency components with peaks of approximately 80-120 ms are recorded in the bilateral hemispheres and their ECD are estimated in the secondary somatosensory cortex (SII) in the bilateral hemispheres. We also summarized (1) the gating effects on SEF by interference tactile stimulation or movement applied to the stimulus site, (2) clinical applications of SEF in the fields of neurosurgery and neurology and (3) cortical plasticity (reorganization) of the SI. SEF specific to painful stimulation is also recorded following painful stimulation by CO(2) laser beam. Pain-specific components are recorded over 150 ms after the stimulus and their ECD are estimated in the bilateral SII and the limbic system. We introduced a newly-developed multi (12)-channel gradiometer system with the smallest and highest quality superconducting quantum interference device (micro-SQUID) available to non-invasively detect the magnetic fields of a human peripheral nerve. Clear nerve action fields (NAFs) were consistently recorded from all subjects.
Publication
Journal: Journal of Biological Chemistry
October/1/2003
Abstract
We have previously utilized a combination of high throughput sequencing and genome-wide microarray profiling analyses to identify novel cell-surface proteins expressed in human umbilical vein endothelial cells. One gene identified by this approach encodes a type I transmembrane receptor that shares sequence homology with the intracellular domain of members of the interleukin-17 (IL-17) receptor family. Real-time quantitative PCR and Northern analyses revealed that this gene is highly expressed in human umbilical vein endothelial cells and in several highly vascularized tissues such as kidney, colon, skeletal muscle, heart, and small intestine. In addition, we also found that it is also highly expressed in the ductal epithelial cells of human salivary glands, seminal vesicles, and the collecting tubules of the kidney by in situ hybridization. This putative receptor, which we have termed human SEF (hSEF), is also expressed in a variety of breast cancer tissues. In co-immunoprecipitation assays, this receptor is capable of forming homomeric complexes and can interact with fibroblast growth factor (FGF) receptor 1. Overexpression of this receptor inhibits FGF induction of an FGF-responsive reporter gene in human 293T cells. This appears to occur as a result of specific inhibition of p42/p44 ERK in the absence of upstream MEK inhibition. This inhibitory effect is dependent upon a functional intracellular domain since deletion mutants missing the IL-17 receptor-like domain lack this inhibitory effect. These findings are consistent with the recent discovery of the zebrafish homologue, Sef (similar expression to fgf genes), which specifically antagonizes FGF signaling when ectopically expressed in zebrafish or Xenopus laevis embryos. Based on sequence and functional similarities, this novel IL-17 receptor homologue represents a potential human SEF and is likely to play critical roles in endothelial or epithelial functions such as proliferation, migration, and angiogenesis.
Publication
Journal: Journal of Neurophysiology
February/5/2002
Abstract
The role of the supplementary eye fields (SEF) during smooth pursuit was investigated with electrical microstimulation. We found that stimulation in the SEF increased the acceleration and velocity of the eyes in the direction of target motion during smooth pursuit initiation but not during sustained pursuit. The increase in eye velocity during initiation will be referred to as pursuit facilitation and was observed at sites where saccades could not be evoked with the same stimulation parameters. On average, electrical stimulation increased eye velocity by approximately 20%. At most sites, the threshold for a significant facilitation was 50 microA with a stimulation frequency of 300 Hz. Facilitation of pursuit initiation depended on the timing of stimulation trains. The effect was most pronounced if the stimulation was delivered before smooth pursuit initiation. On average, eye velocity in stimulation trials increased linearly as a function of eye velocity in control trials, and this function had a slope greater than one, suggesting a multiplicative influence of the stimulation. Stimulation during a fixation task did not evoke smooth eye movements. The latency of catch-up saccades was increased during facilitation, but their accuracy was not affected. Saccades toward stationary targets were not affected by the stimulation. The results are further evidence that the SEF plays a role in smooth pursuit in addition to its known role in saccade planning and suggest that this role may be to control the gain of smooth pursuit during initiation. The covariance between pursuit facilitation and the timing of the catch-up saccade as a result of stimulation suggests that these different eye movements systems are coordinated to achieve a common goal.
Publication
Journal: Electroencephalography and clinical neurophysiology
August/28/1997
Abstract
Cortical areas responsive to somatosensory inputs were assessed by recording somatosensory evoked magnetic fields (SEF) to electrical stimulation of the left median nerve at wrist, using a 122-SQUID neuromagnetometer in various conditions of stimulus rate, attentional demand and detection task. Source modelling combined with magnetic resonance imaging (MRI) allowed localisation of six SEF sources on the outer aspect of the hemispheres located respectively: (1) in the posterior bank of the rolandic fissure (area SI), the upper bank of the sylvian fissure (parietal opercular area SII) and the banks of the intraparietal fissure contralateral to stimulation, (2) in the SII area ipsilateral to stimulation and (3) in the mid-frontal or inferior frontal gyri on both sides. All source areas were found to be simultaneously active at 70-140 ms after the stimulus, the SI source was the only one active already at 20-60 ms. The observed activation timing suggests that somatosensory input from SI is processed to higher-order areas through serial feedforward projections. However the long-lasting activations of all sources and their overlap in time is also compatible with a top-down control mediated via backward projections.
Publication
Journal: Liver International
March/24/2004
Abstract
Vascular endothelial growth factor (VEGF) is an important regulator of vasculogenesis and vascular permeability. Hepatic sinusoidal endothelial cells (SECs) possess sieve-like pores that form an anastomosing labyrinth structure by the deeply invaginated plasma membrane. Caveolin is the principal structural protein in caveolae. In this study, we examined the role of VEGF on the fenestration and permeability of SECs and the relation with caveolin-1. SECs isolated from rat livers by collagenase infusion method were cultured for 24 h with (10 or 100 ng/ml) or without VEGF. The cells were then examined by transmission and scanning electron microscopy (EM). The expression of caveolin was investigated by confocal immunofluorescence, immunogold EM, and Western blot. Endocytosis and intracellular traffic was studied using horseradish peroxidase (HRP) reaction as a marker of fluid phase transport in SECs. Both transmission and scanning EM showed an increased number of sinusoidal endothelial fenestrae (SEF) in SECs cultured with VEGF. By confocal immunofluorescence, SECs cultured with VEGF displayed prominent caveolin-l-positive aggregates in the cytoplasm, especially surrounding the nucleus region. Immunogold EM depicted increased caveolin-1 reactivity on vesicles and vacuoles of VEGF-treated SECs compared with VEGF-nontreated cells. However, there was no change in the level of caveolin-1 protein expression on Western blot. After HRP injection, an increase of electron-dense tracer filled the SEF in cells treated with VEGF. Our results suggested that VEGF induced fenestration in SECs, accompanied by an increased number of caveolae-like vesicles. Increased caveolin-1 might be associated with vesicle formation but not with fenestration. Increased fenestration may augment hepatic sinusoidal permeability and transendothelial transport.
Publication
Journal: Progress in Brain Research
May/8/2003
Abstract
Our knowledge of the cortical control of saccadic eye movements (saccades) in humans has recently progressed mainly thanks to lesion and transcranial magnetic stimulation (TMS) studies, but also to functional imaging. It is now well-known that the frontal eye field is involved in the triggering of intentional saccades, the parietal eye field in that of reflexive saccades, the supplementary eye field (SEF) in the initiation of motor programs comprising saccades, the pre-SEF in learning of these programs, and the dorsolateral prefrontal cortex (DLPFC) in saccade inhibition, prediction and spatial working memory. Saccades may also be used as a convenient model of motricity to study general cognitive processes preparing movements, such as attention, spatial memory and motivation. Visuo-spatial attention appears to be controlled by a bilateral parieto-frontal network comprising different parts of the posterior parietal cortex and the frontal areas involved in saccade control, suggesting that visual attentional shifts and saccades are closely linked. Recently, our understanding of the cortical control of spatial memory has noticeably progressed by using the simple visuo-oculomotor model represented by the memory-guided saccade paradigm, in which a single saccade is made to the remembered position of a unique visual item presented a while before. TMS studies have determined that, after a brief stage of spatial integration in the posterior parietal cortex (inferior to 300 ms), short-term spatial memory (i.e. up to 15-20 s) is controlled by the DLPFC. Behavioral and lesion studies have shown that medium-term spatial memory (between 15-20 s and a few minutes) is specifically controlled by the parahippocampal cortex, before long-term memorization (i.e. after a few minutes) in the hippocampal formation. Lastly, it has been shown that the posterior part of the anterior cingulate cortex, called the cingulate eye field, is involved in motivation and the preparation of all intentional saccades, but not in reflexive saccades. These different but complementary study methods used in humans have thus contributed to a better understanding of both eye movement physiology and general cognitive processes preparing motricity as whole.
Publication
Journal: Investigative Ophthalmology and Visual Science
June/30/1996
Abstract
OBJECTIVE
To uncover abnormalities of extracellular matrix (ECM) distribution in human corneas with pseudophakic and aphakic bullous keratopathy (PBK/ABK).
METHODS
Indirect immunofluorescence with antibodies to 27 ECM components was used on frozen sections of 14 normal and 20 PBK/ABK corneas.
RESULTS
Fibrillar deposits of an antiadhesive glycoprotein tenascin in the anterior and posterior stroma, epithelial basement membrane (BM), bullae and subepithelial fibrosis (SEF) areas, and posterior collagenous layer (PCL) were revealed in disease corneas. Tenascin in midstroma, which was observed in some cases, correlated with decreased visual acuity. In normal central corneas, tenascin was never found. Other major ECM abnormalities in PBK/ABK corneas compared to normals included: discontinuous epithelial BM straining for laminin-1 (alpha 1 beta 1 gamma 1), entactin/nidogen and fibronectin; accumulation of fibronectin and alpha 1-alpha 2 type IV collagen on the endothelial face of the Descemet's membrane; and abnormal deposition of stromal ECM (tenascin, fibronectin, decorin, types I, III, V, VI, VIII, XII, XIV collagen) and BM components (type IV, collagen, perlecan, bamacan, laminin-1, entactin-nidogen, fibronectin) in SEF areas and in PCL.
CONCLUSIONS
The study provides a molecular description of an ongoing fibrosis on the epithelial, stomal, and endothelial levels in PBK/ABK corneas. These fibrotic changes may follow initial endothelial damage after cataract surgery, may be caused by the upregulation of fibrogenic cytokines, and may play a significant role in the progression of bullous keratopathy.
Publication
Journal: Journal of Neurophysiology
August/16/1995
Abstract
1. The companion paper reported that a substantial proportion of cells in the supplementary eye field (SEF) of macaque monkeys show significant evolution of neuronal activity as subjects learn new and arbitrary stimulus-saccade associations. The purpose of the present study was to compare and contrast the activity of the SEF and the frontal eye field (FEF) during such conditional oculomotor learning. 2. In both SEF and FEF, we observed learning-dependent and learning-selective activity, defined as significant evolution of task-related activity as monkeys learned which of four saccades was instructed by a novel stimulus. By definition, in addition to changes as the monkeys learned the instructional significance of a novel instruction stimulus, learning-dependent activity also showed task-related modulation for trials instructed by familiar stimuli, whereas learning-selective activity did not. Of the 186 SEF neurons adequately tested, 81 (44%) showed one of these two categories of learning-related change. By contrast, of the 90 FEF neurons adequately tested, only 14 (16%) showed similar properties. This difference was highly statistically significant (chi 2 = 21.1; P < 0.001). 3. We also observed persistent differences in activity for trials with familiar versus novel instruction stimuli, which we termed learning-static effects. In some cases, the learning-static effect coexisted with learning-dependent or learning-selective changes in activity, although in others it did not. In the former cases, activity changed systematically during learning, but reached a level that differed from that for familiar stimuli instructing the same saccade. In the latter cases, the activity did not change significantly as the monkey learned new conditional oculomotor associations, but did show a significant difference depending upon whether a novel or familiar stimulus instructed a given saccade. Overall, 66 of 186 (35%) cells in the SEF and 17 of 90 (19%) cells in the FEF showed learning-static effects in one or more task periods. This difference was statistically significant (chi 2 = 7.9; P < 0.005). 4. The significant difference in the properties of SEF and FEF cells suggests a functional dissociation of the two areas during conditional oculomotor learning. In this respect, the FEF resembles the primary motor cortex, whereas the SEF resembles the premotor cortex.
Publication
Journal: Chromosoma
November/7/2005
Abstract
MAP kinase (MAPK) signaling is among central signaling pathways that regulate cell proliferation, cell differentiation and apoptosis. As MAPK should transmit extracellular signals to proper regions or compartments in cells, controlling subcellular localization of MAPK is important for regulating fidelity and specificity of MAPK signaling. The ERK1/2-type of MAPK is the best characterized member of the MAPK family. In response to extracellular stimulus, ERK1/2 translocates from the cytoplasm to the nucleus by passing through the nuclear pore by several independent mechanisms. Sef (similar expression to fgf genes), a transmembrane protein, has been shown to be a regulator of subcellular distribution of ERK1/2. Sef binds to activated MEK1/2, the specific activator of ERK1/2, and tethers the activated MEK1/2/activated ERK1/2 complex to the Golgi apparatus and the plasma membrane. Thus, Sef blocks ERK1/2 signaling to the nucleus and allows signaling to the cytoplasm. Here we review recent findings on spatial regulation of MAPK, especially on nucleocytoplasmic trafficking of ERK1/2.
Publication
Journal: Journal of Neurophysiology
September/20/2004
Abstract
Anticipatory movements are motor responses occurring before likely sensory events in contrast to reflexive actions. Anticipatory movements are necessary to compensate for delays present in sensory and motor systems. Smooth pursuit eye movements are often used as a paradigmatic example for the study of anticipation. However, the neural control of anticipatory pursuit is unknown. A previous study suggested that the supplementary eye fields (SEFs) could play a role in the guidance of smooth pursuit to predictable target motion. In this study, we favored anticipatory responses in monkeys by making the parameters of target motion highly predictable and electrically stimulated the SEF before and during this behavior. Stimulation sites were restricted to regions of the SEF where saccades could not be evoked at the same low currents. We found that electrical microstimulation in the SEF increased the velocity of anticipatory pursuit movements and decreased their latency. These effects will be referred to as anticipatory pursuit facilitation. The degree of facilitation was the largest if the stimulation train was delivered near the end of the fixation period, before the moment when anticipatory pursuit usually begins. No anticipatory smooth eye movements could be evoked during fixation without an expectation of target motion. These results suggest that the SEF pursuit area might be involved in the process of guiding anticipatory pursuit.
Publication
Journal: Cell Research
March/29/2009
Abstract
Interleukin-17 (IL-17 or IL-17A) production is a hallmark of T(H)17 cells, a new unique lineage of CD4(+) T lymphocytes contributing to the pathogenesis of multiple autoimmune and inflammatory diseases. IL-17 receptor (IL-17R or IL-17RA) is essential for IL-17 biological activity. Emerging data suggest that the formation of a heteromeric and/or homomeric receptor complex is required for IL-17 signaling. Here we show that the orphan receptor IL-17RD (Sef, similar expression to FGF genes or IL-17RLM) is associated and colocalized with IL-17R. Importantly, IL-17RD mediates IL-17 signaling, as evaluated using a luciferase reporter driven by the native promoter of 24p3, an IL-17 target gene. In addition, an IL-17RD mutant lacking the intracellular domain dominant-negatively suppresses IL-17R-mediated IL-17 signaling. Moreover, IL-17RD as well as IL-17R is associated with TRAF6, an IL-17R downstream molecule. These results indicate that IL-17RD is a part of the IL-17 receptor signaling complex, therefore providing novel evidence for IL-17 signaling through a heteromeric and/or homomeric receptor complex.
Publication
Journal: Proceedings of the National Academy of Sciences of the United States of America
March/1/2000
Abstract
Enteric bacteria possess multiple fimbriae, many of which play critical roles in attachment to epithelial cell surfaces. SEF14 fimbriae are only found in Salmonella enterica serovar Enteritidis (S. enteritidis) and closely related serovars, suggesting that SEF14 fimbriae may affect serovar-specific virulence traits. Despite evidence that SEF14 fimbriae are expressed by S. enteritidis in vivo, previous studies showed that SEF14 fimbriae do not mediate adhesion to the intestinal epithelium. Therefore, we tested whether SEF14 fimbriae are required for virulence at a stage in infection after the bacteria have passed the intestinal barrier. Polar mutations that disrupt the entire sef operon decreased virulence in mice more than 1,000-fold. Nonpolar mutations that disrupted sefA (encoding the major structural subunit) did not affect virulence, but mutations that disrupted sefD (encoding the putative adhesion subunit) resulted in a severe virulence defect. The results indicate that the putative SEF14 adhesion subunit is specifically required for a stage of the infection subsequent to transit across the intestinal barrier. Therefore, we tested whether SefD is required for uptake or survival in macrophages. The majority of wild-type bacteria were detected inside macrophages soon after i.p. infection, but the sefD mutants were not readily internalized by peritoneal macrophages. These results indicate that the potential SEF14 adhesion subunit is essential for efficient uptake or survival of S. enteritidis in macrophages. This report describes a role of fimbriae in intracellular infection, and indicates that fimbriae may be required for systemic infections at stages beyond the initial colonization of host epithelial surfaces.
Publication
Journal: British Journal of Anaesthesia
March/27/1997
Abstract
We studied four electrophysiological variables (bispectral index (BIS), 95% spectral edge frequency (SEF), median frequency (MF) and auditory evoked potential index (AEP index) in 10 patients during emergence from anaesthesia. We compared correlation of the signals with gradually decreasing calculated blood propofol concentrations, and evaluated the signal differences between preinduction and emergence from anaesthesia. Values of BIS, MF and SEF correlated with calculated blood concentrations of propofol during emergence from anaesthesia. The correlation was best with BIS, but was poor with MF and SEF at low calculated blood propofol concentrations. Although AEP index values did not correlate with calculated blood concentrations of propofol during emergence from anaesthesia, values after eye opening and before anaesthesia were well distinguished from those during emergence from anaesthesia. BIS correlated best with calculated blood concentrations of propofol. AEP index appeared to distinguish the awake from asleep state.
Publication
Journal: Neuron
May/8/2002
Abstract
Complex learned motor sequences can be composed of a combination of a small number of elementary actions. To investigate how the brain represents such sequences, we devised an oculomotor sequence task in which the monkey had to choose the target solely by the sequential context, not by the current stimulus combination. We found that many neurons in the supplementary eye field (SEF) became active with a specific target direction (D neuron) or a specific target/distractor combination (C neuron). Furthermore, such activity was often selective for one among several sequences that included the combination (S neuron). These results suggest that the SEF contributes to the generation of saccades in many learned sequences.
Publication
Journal: Journal of Neurophysiology
June/28/2004
Abstract
The primate frontal cortex contains two areas related to smooth-pursuit: the frontal eye fields (FEFs) and supplementary eye fields (SEFs). To distinguish the specific role of the SEFs in pursuit, we examined discharge of a total of 89 pursuit-related neurons that showed consistent modulation when head-stabilized Japanese monkeys pursued a spot moving sinusoidally in fronto-parallel planes and/or in depth and with or without passive whole body rotation. During smooth-pursuit at different frequencies, 43% of the neurons tested (17/40) exhibited discharge amplitude of modulation linearly correlated with eye velocity. During cancellation of the vestibulo-ocular reflex and/or chair rotation in complete darkness, the majority of neurons tested (91% = 30/33) responded. However, only 17% of the responding neurons (4/30) were modulated in proportion to gaze (eye-in-space) velocity during pursuit-vestibular interactions. When the monkeys fixated a stationary spot, 20% of neurons tested (7/34) responded to motion of a second spot. Among the neurons tested for both smooth-pursuit and vergence tracking (n = 56), 27% (15/56) discharged during both, 62% (35/56) responded during smooth-pursuit only, and 11% (6/56) during vergence tracking only. Phase shifts (relative to stimulus velocity) of responding neurons during pursuit in frontal and depth planes and during chair rotation remained virtually constant (< or =1 Hz). These results, together with the robust vestibular-related discharge of most SEF neurons, show that the discharge of the majority of SEF pursuit-related neurons is quite distinct from that of caudal FEF neurons in identical task conditions, suggesting that the two areas are involved in different aspects of pursuit-vestibular interactions including predictive pursuit.
Publication
Journal: Journal of Neurophysiology
June/11/2002
Abstract
We analyzed neuronal activity in the supplementary eye field (SEF), supplementary motor area (SMA), and presupplementary motor area (pre-SMA) during the performance of three motor tasks: capturing a visual target with a saccade, reaching one arm to a target while gazing at a visual fixation point, or capturing a target with a saccade and arm-reach together. Our data demonstrated that each area was involved in controlling the arm and eye movements in a different manner. Saccade-related neurons were found mainly in the SEF. In contrast, arm-movement-related neurons were found primarily in the SMA and pre-SMA. In addition, we found that the activity of both arm-movement- and saccade-related neurons differed depending on the presence or absence of an accompanying saccade or arm movement. Such context dependency was found in all three areas. We also discovered that activity preceding eye or arm movement alone, and eye and arm movement combined, appeared more often in the pre-SMA and SEF, suggesting their involvement in effector-independent aspects of motor behavior. Subsequent analysis revealed that the laterality of arm representation differed in the three areas: it was predominantly contralateral in the SMA but largely bilateral in the pre-SMA and SEF.
Publication
Journal: Electroencephalography and clinical neurophysiology
January/26/1997
Abstract
Cerebral responses evoked by peripheral stimuli are known to depend critically on the interstimulus interval (ISI). Here we report on the effects of ISI on somatosensory evoked magnetic fields (SEFs) to right median nerve stimulation, obtained in 9 healthy adults with ISIs of 0.15 0.3, 1,3 and 5 s. At the contralateral (left) primary sensorimotor cortex (SMI), the first cortical response, N20m, was stable between the ISIs 0.3 and 5 s, but slightly attenuated at the shortest ISI of 0.15 s. In contrast, the P35m and P60m deflections were very sensitive to changes of the ISI, declining steadily with shortening of the ISI throughout the entire range. These deflections were frequently undetectable at the shortest ISI of 0.15 s. Concomitant with the reductions of P35m and P60m, an N45m deflection was enhanced toward the short ISIs. Responses from second somatosensory cortex (SII) and posterior parietal cortex (PPC) were seen only with ISIs of 1 s or greater, being strongest at the 5 s ISI. Based on known effects of the ISI on intracellular evoked potentials, we present the following tentative model for the generation mechanism of the SMI response: N20m represents early excitatory postsynaptic potentials (EPSPs), P35m early inhibitory postsynaptic potentials (IPSPs), N45m secondary EPSPs and P60m late IPSPs in pyramidal neurones of area 3b. For practical purposes, SEFs from SMI can be obtained with short ISIs, while responses from SII and PPC require an ISI of at least 1 s.
Publication
Journal: Anesthesiology
March/3/1996
Abstract
BACKGROUND
The electroencephalogram (EEG) has been used to study the effects of anesthetic and analgesic drugs on central nervous system function. A prospective study was designed to evaluate the accuracy of various EEG parameters for assessing midazolam-induced sedation during regional anesthesia.
METHODS
Twenty-six consenting adult patients were administered 4.5-20 mg intravenous midazolam (in increments of 0.5-1 mg bolus doses every 6-10 min) until they became unresponsive to tactile stimulation (i.e., mild prodding or shaking). The EEG was continuously recorded from a bifrontal montage (FP1-Cz and FP2-Cz) to obtain the bispectral index (BI), 95% spectral edge frequency (SEF), median frequency (MF), and delta, theta, alpha, and beta power bands. Sedation was assessed clinically at 6-10-min intervals using the Observers' Assessment of Alertness/Sedation (OAA/S) scale, with 1 = no response (unconsciousness) to tactile stimulation to 5 = wide awake. The EEG parameters were correlated with the OAA/S scores using nonparametric Spearman's rank-correlation analysis. Kruskal-Wallis analysis of variance was used to determine significant changes in EEG parameters during the onset of and recovery from midazolam-induced sedation.
RESULTS
Of the EEG parameters studied, the BI exhibited the best correlation with OAA/S scores during both the onset (Spearman's Rho = 0.815) and recovery (Spearman's Rho = 0.596) phases. With increasing sedation, there was a progressive decrease in the BI (OAA/S score of 5: BI = 95.4 +/- 2.3; 4: 90.3 +/- 4.5; 3:86.6 +/- 4.6; 2:75.6 +/- 9.7; 1:69.2 +/- 13.9). A similar pattern was found for the 95% SEF as the OAA/S score decreased from 4 to 1. Similarly, EEG-BI increased with recovery from the sedative effects of midazolam (OAA/S score = 2:BI = 75.2 +/- 10.2; 3:82.3 +/- 7.3; 4:90.8 +/- 6). However, no consistent changes were found with the other EEG parameters. The mean EEG values between OAA/S scores 3 and 2 and between OAA/S scores 2 and 1 during the onset and recovery phases from midazolam-induced sedation, defined as EEG50 values for response to verbal command (EEG50-VC) and to shaking of the head (EEG50-SH), were 79.3 +/- 8 and 70.8 +/- 14.3, respectively, for EEG-BI. The EEG-BI displayed the smallest coefficients of variation for the EEG50-VC and EEG50-SH values.
CONCLUSIONS
The EEG-BI appears to be a useful parameter for assessing midazolam-induced sedation and can predict the likelihood of a patient responding to verbal commands or to shaking of the head during midazolam-induced sedation.
Publication
Journal: Journal of Bacteriology
May/25/1993
Abstract
Salmonella enteritidis produces thin, filamentous fimbriae designated SEF14. A 3.9-kb region of a 5.3-kb fragment encoding genes responsible for SEF14 biosynthesis was sequenced and found to contain three genes, sefABC. sefA encoded a novel fimbrin, the structural subunit of SEF14 fimbriae. sefB and sefC encoded proteins homologous to Escherichia coli and Klebsiella pneumoniae fimbrial periplasmic chaperone proteins and fimbrial outer membrane proteins, respectively, and are the first such genes to be characterized from Salmonella spp. in vitro expression directed by the 5.3-kb DNA fragment identified SefA, SefB, and SefC as approximately 14,000-, 28,000-, and 90,000-M(r) proteins, respectively, which correlated with their predicted amino acid sequences. sefB and sefC were not expressed in the absence of sefA. Primer extension analysis of sefABC revealed two major transcription start sites located upstream of sefA. Transcription of sefBC also initiated from the sefA promoter region. Secondary-structure analysis of the mRNA transcript for sefABC predicted the formation of two stable stem-loop structures in the intercistronic region between sefA and sefB indicative of differential regulation of SefA, SefB, and SefC translation. E. coli cells carrying the 5.3-kb DNA fragment of S. enteritidis DNA were unable to assemble distinguishable SEF14 fimbriae; however, immunogold-labelled SEF14 fimbriae were displayed on E. coli clones containing a 44-kb DNA fragment which encompassed the 5.3-kb region. Therefore, sefABC genes make up part of a complex sef operon responsible for the expression and assembly of SEF14 fimbriae.
Publication
Journal: Journal of Neurophysiology
October/10/2005
Abstract
The latency and variability of latency of single-unit responses to identical visual stimulation were measured in the frontal eye field (FEF), supplementary eye field (SEF), and anterior cingulate cortex (ACC) of macaque monkeys performing visually guided saccades. The mean visual response latency was significantly shorter in FEF (64 ms) than in SEF (81 ms) or ACC (100 ms), and latency values determined by four methods agreed. The latency variability of the visual response was respectively less in FEF (21 ms) than in SEF (37 ms) or ACC (41 ms). Latency, variability of latency, and magnitude of the visual responses were correlated within FEF and SEF but not ACC. These characteristics of the visual response are consistent with the degree of convergence of visual afferents to these areas and constrain hypotheses about visual processing in the frontal lobe.
Publication
Journal: Journal of Neurophysiology
January/21/2004
Abstract
The organization of a series of actions into an appropriate temporal order is of particular importance in the voluntary control of motor behavior. Previous reports have emphasized the importance of medial motor areas for the temporal organization of movements. The aim of this study was to compare the neuronal activity in the supplementary and frontal eye fields (SEF and FEF) during sequential performance of multiple saccades to clarify the role of the two cortical oculomotor areas in the temporal organization of saccades based on memorized information. We analyzed neuronal activity while monkeys performed three saccades to peripheral targets in orders that were instructed and memorized. We found that activity that reflected saccade sequence or the numerical position of a saccade within a sequence (rank) was more prevalent in the SEF, whereas activity reflecting saccade direction was more dominant in the FEF. Furthermore, a sizeable number of SEF neurons exhibited an increase in activity when the animals were required to discard a current sequence and compose a novel sequence. We propose that the SEF is primarily involved in the process of planning, decoding, and updating saccade sequences, whereas the FEF plays a major role in determining the direction of forthcoming saccades.
Publication
Journal: American Journal of Surgical Pathology
July/11/2001
Abstract
Sclerosing epithelioid fibrosarcoma (SEF) is an uncommon tumor of deep soft tissues, originally described in 1995 by Meis-Kindblom et al. In the current study, the authors identified 16 cases of SEF in the pathology files of their institutions and studied their pathologic features and disease course. The group consisted of six male and 10 female patients (age range, 14-55 years; mean age, 40 years), and the tumors were located in a limb or limb girdle (n = 7), base of the penis (n = 1), back or chest wall (n = 3), and head and neck (n = 5). Tumor size ranged from 3.7 to 22 cm (mean, 8.9 cm). Histologically, the SEFs were composed predominantly of small to moderate-size round to ovoid, relatively uniform cells, often with clear cytoplasm, embedded in a hyalinized fibrous stroma. The only consistent immunohistochemical finding was a strong, diffuse reactivity of tumor cells for vimentin. Ultrastructural analysis performed in eight cases confirmed their fibroblastic nature. Bone invasion and tumor necrosis, features not reported before, were found in six cases each. Treatment consisted of intralesional excision (n = 2), attempted wide local excision (n = 11), and amputation (n = 3), with either adjuvant radiation therapy (n = 9) or chemotherapy (n = 3). Follow-up of at least 1 year in 14 cases revealed persistent disease or local recurrence in seven patients (50%), and distant metastasis in 12 patients (86%). Eight patients (57%) died of disease 16 to 86 months after diagnosis. Five patients were alive with disease as of last follow-up. SEF shares some pathologic features with two other fibrosing fibrosarcomas, low-grade fibromyxoid sarcoma and hyalinizing spindle cell tumor with giant rosettes, but in the authors' experience behaves clinically as a fully malignant sarcoma.
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